Let me know your experiences with Op Amp rolling! Please consider liking and subscribing, means a lot to me and really helps me to grow this channel, take care!
Worked for Bell Laboratories for decades and was into HIFI deep from the 70's through the 90's, Had a Rotel integrated in the 90's that used average sounding op amps, I had some old non functioning CD players and I pulled the buffer chips out of those. JRC has some decent sounding op amps, but I really liked the Ti TL082 J-FET package. But only the Hecho in Mexico - for some odd reason the Fabriqué En CHINE units had poor sound (silicon die possibly wirebonded with Al wire instead of Au, then possibly poor metallurgy on the DIP leads). I will say, Don't like gain limiting feedback chip operational amplifiers in any audio circuit Period. p.s.: Scientists and engineers at Bell labs invented the LASER, the MASER the 300B triode, the Transistor and Westrex Motion Picture Sound. And ... the Stereo LP. Cheers! - Sandy the Ancient Boston Audiophile
I enjoy these type of videos. I have tried tube rolling in my little Fosi tube buffer amp and I just couldn't tell a difference. Knowing that I had better tubes made me happy, so it was worth it. I repaired office machines for 40 years and I replaced a lot of Rom and EProm chips. It's amazing how much smoke a little tiny chip can generate if you put it in wrong. LOL
I tried the Burson V5i in an old Topping A30 a few years ago. That little headphone amp went from being a decent little budget headphone amp to being a truly great performer. The difference was incredibly noticeable. The stock OPA2134 opamps just sounded veiled by comparison. That said, I then tried putting a V5i into a different unit (FX Audio DAC X6) and there was no noticeable improvement. When I posted about this, someone more knowledgeable than myself point out that in the Topping the opamp is both the main opamp as well as the buffer but in the FX Audio unit the opamp is just the buffer. So where the opamp is in the circuit and what it is doing apparently plays a big role in whether you'll be able to hear an improvement. I don't know much about amp topology but I thought it was interesting and worth keeping in mind. With all of the different gear people may be putting these into it really is a "your mileage may vary" scenario and there may be some really valid reasons for why people didn't hear a difference in x gear vs y.
I rolled the op amps in my Ayima a07 with the Sparkos chips. I have to say that that little amp sounds deeper, richer and more detailed than it did with the stock chips. I’m very happy with the sonic improvements. Cheers!
Just opened up an already nice sounding stock Fosi BT20A PRO. Mostly for the sake of tinkering and curiosity, I installed the Sparkos Dual Op Amp SS3602s. Wowsa! Thank you Matt for the easy and detailed instructions for the install. Especially the tips about the notch for correct flow and using hose pliers for manipulating the tiny bits. The audio is stunningly better, driving a pair of top notch bookshelf speakers. Better and far beyond any subjective placebo effect. As an OG stereo guy, I know this upgrade matches the performance of a four figure A/B amp.
For the Fosi BT20A Pro, I recommend upgrading to the LME49720 in the preamp stage and the Sparkos SS3602 in the amp driver stage. Here’s why this combination makes sense based on the specs: The LME49720 has a slew rate of 20 V/µs, output current of ±26 mA, and noise density of 2.7 nV/√Hz. These characteristics make it well-suited for the preamp stage, where lower current demand and low noise are priorities. This op-amp offers a significant improvement in noise performance compared to the stock NE5532, which has a slew rate of 9 V/µs, output current of ±38 mA, and noise density of 5 nV/√Hz. While the NE5532 has higher current output, its slower slew rate and higher noise density limit its performance in the preamp role. In the amp driver stage, the Sparkos SS3602 provides a slew rate of 23 V/µs and output current of ±50 mA, making it ideal for driving the demanding input requirements of the power amplifier section. This op-amp offers more than double the current drive of the NE5532 and a faster slew rate, ensuring better handling of the TPA3255’s input. This makes the SS3602 a more suitable choice for maintaining performance, especially during dynamic signal peaks. This hybrid approach optimizes the strengths of each op-amp: the LME49720 for its low noise and adequate preamp drive, and the SS3602 for its high current output and rapid response in the amp driver stage. This combination ensures improved performance in both stages of the BT20A Pro while reducing cost since the LME49720 is about $4.
Howdy Matt I have a quick question. Did you do any of your testing with just using the Bluetooth? No dac just Bluetooth? I just bought two of them sparko op-amps haven't received them but am SUPER excited. Im currently connecting through bluetooth with my phone and was hoping it would still make a big difference aswell. Thanks for your time, love watching your reviews keep it up.
Hey Kevin, I did test this with Bluetooth, the Bluetooth actually varies a lot between these little amps. This one has pretty good performance as far as the implementation goes, range and quality. You should notice a difference with the Sparko’s. I still have mine installed in that same amp, sounds great.
Interesting video. Just wanted to note that Geshelli Labs has a J2S DAC, "S" meaning socketed, that can use various op-amps in both its RCA and XLR output stages. I believe the SS3602 is one you can buy from them among three choices. However, I saw someone post they had tried the even better SS2590, and thought it was simply amazing, rivaling his Denafrips Ares II 12th anniversary edition DAC. So wow, rolling these op-amps can make a difference. Yeah, the costs go up as you move up the ladder, but man, might still be worth it. Thanks! Looking forward to the other reviews you have coming up, especially the Eversolo.
@@MattCoykendall1 yes you should. I have a standard J2 AKM with linear PSU, and more recently, added the J2 S using Sparkos SS2590 Pro's + linear PSU and upgraded dc cable. This setup has now replaced an older >$3k DAC/PSU combo in my main system. I think that a real testimonial to Geshelli &Sparkos Labs as well as a nod to the maturing of digital technology over the last few years.
@@MattCoykendall1 definitely! I bought the Fosi BT20A Pro and love it "as is" but might try rolling the op-amps one day for fun. Thanks for the video showing exactly how to do that without damaging the amp.
I upgraded to a Sparkos opamp in my Aune X8 dac and it made all the difference. It goes from an average dac at its price to one that rivals 3X its cost. Recently received the Aune linear PS but haven't hooked it up yet and any improvement even if small would be welcome to its current performance with the Sparkos. Other options include Staccato and Burson op amps as well which I have not tried.
I put one of these in my FX-Audio DAC-X6 and it’s probably the only thing I’ll ever need for headphones since I’m currently running AKG K240s with Beyerdynamic pads. And with all that together, it’s fantastic to my ears.
I replaced some op amps in a fairly high end DAC, a $2600 Gustard, I used Staccato op amps. Made a pretty big difference. Especially with regards to things like: imaging, soundstage, and other spatial cues. The soundstage width increased, and there was more layering within it.
Hi Matt, You sure tip-toed thru the minefields nicely on this one. 😉 Nonetheless your observations, advice, judgements and conclusions are spot-on and closely match & agree with my own experience with the BT20A Pro/Sparkos 3602 combo - subtle (and not so subtle) but noteable & welcome improvements across the board ,esp in richness of tonality . Worth the added expense? I sure think so! Well done! k
I bought a Burson DAC back in late 2020 that came with stock discrete op amps (can't remember the model) and I paid a little more for the upgraded package (remote and Burson V6 Vivid op amps (2 dual and 2 single). The Burson Vivid op amps added much more detail, depth, wider soundstage, and took the presentation from 2D to 3D. The only downside was that the mid range was a bit thin for my taste. I then purchased a pair of V6 classic, which made the midrange fuller at the cost of speed, detail and three dimensionality. Finally I bought a pair of Sparkos singles and duals and experimented with those. The sound was more neutral and the bass stronger than with any of the others. I ended up mixing and matching and found the Sparkos singles in the LP stage and the V6 Classic Duals in the I/V stage to give me about 85 to 90 percent of the sound I wanted. The next best pairing was the V6 Vivid duals in the IV stage and the Sparkos singles in the LP stage. This mix had a slightly thinner(but bearable) midrange, but better soundstage depth and three dimensionality. Soundstage was slightly narrower. I will probably go back and forth between these two pairings.
Nice work. I own three of these BT20A digital chip amps. Not sure it is worth the money without some type of dyno test, THD, RMS, etc to compare. I also own several Douk Audio, Nobsound, etc digital chip amps. This Fosi Audio BT20A sounds better (out of the box) then those ones. 36v/10 amp AC/DC power adapter or booster works best from my bench...not 48v.
I upgraded my BT20 Pro with Burson Vivid op amps. They are too tall for the case, so a little bit of modification with a drill was necessary. It does look cool, however, with the red op amps sticking out the top. The sound undoubtedly improved, but had I not had a spare op amp lying around and sourced another one cheaply, I don't think it would have been worth the expense.
It does !. Also, due to a drill disaster, I scratched up the casework, so I ended up painting it in the style of Mondrian. It now looks either cool or ridiculous depending on your point of view.
due to the fact that the Burson op amps are taller they also offer a " soft " riser that is made from small wires so you can lay the opamp down on its side and pretty much fit the opamp anywhere to where the wires reach by bending them over slightly...
Take these reviews with a big spoon of salt. I have this little ChiFi amp, it’s wonderful for what it is for desktop listening, casual game room setup etc. but let me be clear, it’s no match for even a entry level, but well built, well priced offerings from Cambridge or Emotiva etc. The Emotiva Mini X-A100 that I also own beats the snot out of this little bugger in terms of superb midrange weight, bass depth and tightness and well resolved treble and separation. But for $80, this BT20a Pro does hold a surprise or two on how well it still can drive medium to large speakers. Anything upto 11 O’clock position sounds good. Beyond that it loses its composure, but it’s already pretty loud 90db by then. Try this for fun and you may find a use case. I haven’t done any OPAMP rolling, but replacing with a pair of Sparkos chip costing more than the amp itself makes no sense. Just buy some well established Integrated.
Because of variables beyond the amp itself such as speakers, room acoustics, inputs, personal tastes and so forth, everyone's miles are going to vary as to the perceived improvement. However adding the Muse02 to the Fosi V3 mono yielded in my case a worthwhile improvement. It makes no sense in my mind to put expensive op amps into budget equipment (I could be wrong) but there are plenty of inexpensive options for those looking to eke out a little more performance shall we say from their equipment. In this case the Fosi amps replaced nCore amplification and for not much money provided a noticeably better listening experience. With the Muse op amps it was better again. But YMMV.
I was hoping they would allow the option to turn the amp into a mono with a simple switch on the circuit board... then you could stack two amps together in mono mode and create a fantastic balanced headphone amp for hard to drive headphones...
you needed 2 bt20a pro amps and switch them at the flip of a switch without relying on audio memory. the real question is bt20a pro+sparkos is the same price as a midfi amp such as cambridge audio axa25 but which sound better ?
Ever since discovering the Sparkos Labs Op Amps, which began when I purchased the inexpensive Aiyima A07, I became hooked. Yes, the Sparkos Labs Op Amps are much more expensive (but you get what you pay for here). In each case now (using them on a half-dozen other Chinese-made Op-Amp upgradeable amplifiers), the sound improved, making the overall sound signature sound closer to the warmth of a class AB amp. It was enough of a difference for me to make the adjustment to be sure. As an aside, I've not found a class AB amp that accepts interchangeable Op Amps, and it seems the entire genre (correct me here if I'm wrong) can only be found in class D amps, that typically have a colder, 2D type of sound. The Sparkos Labs Op Amps change all this for the better (in my subjective opinion of course). I've also put them in various other components such as FX-Audio and Douk Audio DAC's - and it made a huge difference there also. A very close runner up (if you don't want to dish out the money for the Sparkos) are the IC design Muses02 - that IC chip also has a much warmer, tube-like sound. In the end, if you love the colder, 2D type of sound of Class D amps, don't change a thing.
@@jericlee1509 Keep in mind that no one OpAmp will give you a total transformation. I've been experimenting with OpAmps now for over two years, and here are my observations/recommendations: 1. For the most part, I've found that the Discrete (remember that word - Discrete) OpAmps wind up giving you the greatest improvements in sound quality. This includes improvements in instrumental timbre, overall sound tonality, and warmth. Of course, Discrete Op Amps are also more expensive. 2. Of all the IC (small) Op Amps that you notice inside of class D amplifiers, I have found that the MUSES02 (in my opinion) is the best of that variety. Now the MUSES02 will still set you back in the $40+ USD price range. 3. Of the Discrete Op Amps, there are 3 that I can strongly recommend, those being: a. Burson V5i - this one may run you from the $40 - $50 range (depending on where you get it from) and is roughly 1 - 2 times larger in size than the regular IC based Op Amps. It adds (again, in my opinion) more overall warmth, better instrumental timbre, more dynamics, and better bass response. But do remember that there are some class D amplifiers that already a built-in tonal curve to accentuate the bass and there's not much you can do about that. What discrete Op Amps might do is to try and make that bass tighter and more dynamic. The website address to that OpAmp is here: www.bursonaudio.com/product/supreme-sound-opamp-v5i/ b. The 2nd recommendation that I can make, and this one is most expensive of the bunch (but not necessarily the best overall) is the Burson V6 classic - but I'll tell you right now that it may NOT fit most of the budget class D amps because it is very tall and that may interfere with the amplifier casing. That runs from $89 to $100 USD, depending on where you buy it from. The website address to that OpAmp is here: www.bursonaudio.com/product/supreme-sound-opamp-v6/ c. The final recommendation, and in my opinion, the best (again, remember, I'm offering personal opinions here based on experimentation), is the Sparkos Labs SS3602. Now this OpAmp is much larger width-wise (around 3-4 times larger an an IC), is priced between the Burson V5i and the Burson V6 classic. Overall, it has a warmer tonality - spread through the entire frequency range, not just one particular area. It demonstrates great dynamics, superb highs, and a very nice midrange. It cost (before discount) - $79.80 USD, however new customers usually get a discount which ranges 15-20% off). If you are a repeat customer (you have to be a repeat customer though), the 20% repeat discount can be had with the code: RETURN20. The website for this OpAmp is: sparkoslabs.com/product/dual-discrete-op-amp-ss3602/ In the end, there is no one OpAmp that makes an amplifier sound "just" like a Tube Amp. What these OpAmps do is to change the personality and tonality of the amp and no two users will have the same musical tastes on how they prefer their music to sound. With budget amps, I've long since found out that the Sparkos Labs OpAmps give you a huge bang for the buck and inches your amp closer to that Class AB or Hybrid Tube sound. Good luck:
@@jericlee1509 I've tried a variety of the small IC based ones. They have limitations and the right now, the only Discrete versions I can recommend are those I recommended in my previous reply.
I claim to have Golden Ears 🙂 The Sparkos op-amps are very good, some of the best out there, but it does not pay of to put them in this amp. Much better do it in the newer Fosi V3 amp. And why is that you may ask? Because you are only able to change 2 of the 4 sound killer op-amps 5532 in this amp, the 2 others are surface mount op-amps, which are very hard to change. The 2 problems in this amp are: They have implemented a tone control that introduces fase shift (bader sound), and it can not be dialed out even in the mid position, and the other one is that it has 2 SMD mounted 5532 op-amps that can´t be changed, if you are not very skilled at SMD soldering. The Fosi V3 does not have those 2 SMD mounted 5532, and sounds much better.
I actually moved the Sparkos op-amps over to the new V3, they will likely live in that one until something new comes along to experiment with. It was a tight fit on the v3 and does require a riser but its doable.
not to mention that as the 5532 was the standard in the audio professional equipment for decades, it means that amost all the music existing on the planet has passed trough tens of 5532 before reaching the final customer. So the claim is that the change of the last final opamp in the chain will magically recovers all the sound quality lost during all the production process? I claim that a change in sound is necessarily measurable. If a change is measured, so it mean that the original signal has been distorted in some way. the so called "subjective" changes that can't be objectively measured are a bullshit. it's a reaction to a belief and bias. if you like the "smoothness" and other magic words introduced by distortion in a signal up to you, but don't pretend it's a more pure sound.
Hello Matt, Could you tell me the exact size of the socket wrench you’re using to remove the screw from the volume pot to take the chassis off?, as I’ve a Fosi Audio V3 just arrive moments ago, as well as several different brands of Op-Amps come in I’d like to roll. TIA!.
Thanks for this revue and your honest impressions. Just got my Fosi V3 and and so far it pretty good considering I am using the Wiim Pro with its average or below par integrated DAC. So I am waiting for my Geshelli J2S upgraded with a single SS3602 for the RCA output. So if I were to get the Sparkos 3602 for my Fosi V3, would I need the raisers due to the Fosi V3 small space for Opamp? And also will this set up work well, having single J2S SS3602 and also on the V3 or is it overkill? I hope my post makes sense. Best regards
Hey sounds like a great little system your putting together. I can’t speak on the synergy of the J2S 3602 along with 3602’s in the V3, I haven’t had that combo yet, yes you will need risers for the V3, it’s a tight fit.
He told me i needed more power supply to do the opamp swaps and i have no idea how to do any technical stuff or what more power supply even means. I thought the point of opamp rolling was anyone could do it, but now sounds like i have to learn how to solder and use something to read how much power supply i have by increasing capacitor size? but to what size and what end?
You can flip chips in any of these amplifiers with only the right screwdriver to open the case and a pair of tweezers. No soldering involved. The Op-Amps will be in sockets so it's a pull out, push in deal just like Matt showed in the video. No... you do not need a different power supply. In fact flipping on the stock 32volt supply that comes with the amp seems (can't swear to "is") more pronounced. But even if you did need a different power supply, the new one would simply plug into the back of the amp, like the stock one does... unplug the old, plug in the new.
I'm not sure what you're talking about on the back of the amp. My dac has 32 multibit dacs, 16 per board. The dude from sparkos just said i would need more power supply per board running 32 total i/v converter single opamps and a pair of duals for outputs. I basically need to change my capacitors to higher capacitance and/or higher voltage. I just don't know how much more and if all the caps around each dac and i/v discrete or just around the i/v discrete or just the main larger power supply caps before the voltage regulators or ALL of the above. I'm not tech savvy with this kind of stuff, but neither is my local tech and i would need exact directions to give him to do the work which requires soldering. I've also read some say that you can't just increase voltage or capacitance to designs without doing calculations or something so i cant just say, hey tech put in the biggest capacitors you can fit physically on the board@@Douglas_Blake_579
@@HailKingCeezer Okay ... so now I discover you're not even talking about the BT20A amplifier. Sorry, can't help you without a lot more specifics about your equipment...
Without a resolving system already nothing maybe detected,OP-Amps are the heart of Audio you can make one with Vacuum Tubes there is not one piece of HIFI without it in mordern equipment. There is no controversy because when done properly it can be the difference of a V4 engine or a V12
Hook this amp up to a pair of Heresys or L-100s and you're in for a real treat. The TPA3255 chip will drive almost any speaker you can find to room filling volume.
1, bose 901 eq. No, Bose isn't hi-fi. But installing new opamps drastically improved the sound. 2. Rotel cdp -1990's model: Woke up the player, far more vivid and impactful like a modern cdp 3. carver M1.5T and C-1 preamp. More modern and cleaner sound. Opamps are like having a 180hp 4 cylinder in your car and swapping in a 335hp V-6 engine, Just like that.
plz help I bought a Fosi BT20A pro amp and I’m trying to figure out the best way to connect my source wich is my iPhone 15 and my MacBook Air as well. I have a rca to aux cable that I use to connect the fosi amp to my iPhone 15 with the usb c to aux dongle. Would the shcitt dac be any better than the dac in the apple usb c to aux dongle??? I noticed that the Bluetooth volume on the fosi amp is louder than the rca to aux cable method. Would the external dac be louder than the usb c to aux dac??? I also use Apple Music lossless.
I just got my Fosi BT20A Pro and AirPlay from my iPhone through a very old Apple Airport Express WiFi wireless router extender A1264 with 3.5mm audio jack. You can get one under $20. The sound quality is more dynamic than the Bluetooth route.
Haven't bought the Sparkos opamps yet, but consider that you cannot find them on the used market, none used on Ebay. People who buy them, don't sell them.
I tried sparkos only to find the most fake sound, i returned to a super fast 80s gold and ceramic video opamp from burr brown works wonders as audio opamp
The only valid test to me would be a blind test. When you spend 80$ on a chip, I think it's more what you want to hear, than what you are really hearing.......the proof is that there are only 2-3 videos with direct side to side sound comparisons and even there there's hardly any difference.
@@MichaelBeeny Not necessarily. It's about the requiremenrs of the circuit, supply voltage, slew rate, needs compensation or not, type of input (JFET, FET, bipolar, etc). The opamp is only a part of the equation, opamp rolling is funny (I have done it), but to date I haven't done any test where one opamp magically sounds better than the rest, just because it's more expensive. If that be true, you'd see plenty of evidence and countless YT videos.....
A better option would be don't buy a class D in the first place. To say buying discreet allows better matching of components. Not true, you cannot beat laser trimmed ICs for matching and near 100% consistency. All at a fraction of the price, just avoid the many fakes from China. Avoid snake oil at all costs and, it's gotta be better, if it cost more than the amplifier. Sure, they often have a higher current rating, but will this help? No, it's a preamp, it's a voltage amplifier, not a current amplifier. Sometimes, these can overload the current available from the power supply. A typical IC will draw about 10mA, the many discrete versions can draw 60-100mA. Overheating the 15 volt supply.
Data. Record the audio. Use data. It doesn't mean a God damn thing when people say "it's warmer, sharper, fuller" when there's no data. This video was nearly useless aside from showing us how to roll the opamps.
You listen with your ears, not an HP spectrum analyser. Instruments are used in design to confirm proper functioning and stable circuit. DATA, specs. Are you measuring the correct attributes? Forget % THD- it's virtually useless. This is for product brochure one upmanship. Ask Sparkos for data. Cheers! Sandy - Bell Labs Engineer (ret.) and long time Boston Audiophile
Let me know your experiences with Op Amp rolling! Please consider liking and subscribing, means a lot to me and really helps me to grow this channel, take care!
Worked for Bell Laboratories for decades and was into HIFI deep from the 70's through the 90's, Had a Rotel integrated in the 90's that used average sounding op amps, I had some old non functioning CD players and I pulled the buffer chips out of those. JRC has some decent sounding op amps, but I really liked the Ti TL082 J-FET package. But only the Hecho in Mexico - for some odd reason the Fabriqué En CHINE units had poor sound (silicon die possibly wirebonded with Al wire instead of Au, then possibly poor metallurgy on the DIP leads). I will say, Don't like gain limiting feedback chip operational amplifiers in any audio circuit Period. p.s.: Scientists and engineers at Bell labs invented the LASER, the MASER the 300B triode, the Transistor and Westrex Motion Picture Sound. And ... the Stereo LP. Cheers! - Sandy the Ancient Boston Audiophile
I enjoy these type of videos. I have tried tube rolling in my little Fosi tube buffer amp and I just couldn't tell a difference. Knowing that I had better tubes made me happy, so it was worth it. I repaired office machines for 40 years and I replaced a lot of Rom and EProm chips. It's amazing how much smoke a little tiny chip can generate if you put it in wrong. LOL
Ha I have no doubts there, glad I didn’t let any of the magic smoke out of these two!
I tried the Burson V5i in an old Topping A30 a few years ago. That little headphone amp went from being a decent little budget headphone amp to being a truly great performer. The difference was incredibly noticeable. The stock OPA2134 opamps just sounded veiled by comparison. That said, I then tried putting a V5i into a different unit (FX Audio DAC X6) and there was no noticeable improvement. When I posted about this, someone more knowledgeable than myself point out that in the Topping the opamp is both the main opamp as well as the buffer but in the FX Audio unit the opamp is just the buffer. So where the opamp is in the circuit and what it is doing apparently plays a big role in whether you'll be able to hear an improvement. I don't know much about amp topology but I thought it was interesting and worth keeping in mind. With all of the different gear people may be putting these into it really is a "your mileage may vary" scenario and there may be some really valid reasons for why people didn't hear a difference in x gear vs y.
I rolled the op amps in my Ayima a07 with the Sparkos chips. I have to say that that little amp sounds deeper, richer and more detailed than it did with the stock chips. I’m very happy with the sonic improvements. Cheers!
Hey Frank, yep spot on, such a simple upgrade as well.
Sparko here - glad to hear that you are liking the devices :)
I had the same results. Actually needed to turn my sub level down, because of the added low- end extension.
@@andrewsparks3157 so... "Sparkos Inside" decal??? If I ever sell my A07, those Op Amps are staying with me!
@@ADREISTER 🤡🤡
Just opened up an already nice sounding stock Fosi BT20A PRO. Mostly for the sake of tinkering and curiosity, I installed the Sparkos Dual Op Amp SS3602s. Wowsa! Thank you Matt for the easy and detailed instructions for the install. Especially the tips about the notch for correct flow and using hose pliers for manipulating the tiny bits. The audio is stunningly better, driving a pair of top notch bookshelf speakers. Better and far beyond any subjective placebo effect. As an OG stereo guy, I know this upgrade matches the performance of a four figure A/B amp.
For the Fosi BT20A Pro, I recommend upgrading to the LME49720 in the preamp stage and the Sparkos SS3602 in the amp driver stage. Here’s why this combination makes sense based on the specs:
The LME49720 has a slew rate of 20 V/µs, output current of ±26 mA, and noise density of 2.7 nV/√Hz. These characteristics make it well-suited for the preamp stage, where lower current demand and low noise are priorities. This op-amp offers a significant improvement in noise performance compared to the stock NE5532, which has a slew rate of 9 V/µs, output current of ±38 mA, and noise density of 5 nV/√Hz. While the NE5532 has higher current output, its slower slew rate and higher noise density limit its performance in the preamp role.
In the amp driver stage, the Sparkos SS3602 provides a slew rate of 23 V/µs and output current of ±50 mA, making it ideal for driving the demanding input requirements of the power amplifier section. This op-amp offers more than double the current drive of the NE5532 and a faster slew rate, ensuring better handling of the TPA3255’s input. This makes the SS3602 a more suitable choice for maintaining performance, especially during dynamic signal peaks.
This hybrid approach optimizes the strengths of each op-amp: the LME49720 for its low noise and adequate preamp drive, and the SS3602 for its high current output and rapid response in the amp driver stage. This combination ensures improved performance in both stages of the BT20A Pro while reducing cost since the LME49720 is about $4.
Howdy Matt I have a quick question. Did you do any of your testing with just using the Bluetooth? No dac just Bluetooth? I just bought two of them sparko op-amps haven't received them but am SUPER excited. Im currently connecting through bluetooth with my phone and was hoping it would still make a big difference aswell. Thanks for your time, love watching your reviews keep it up.
Hey Kevin, I did test this with Bluetooth, the Bluetooth actually varies a lot between these little amps. This one has pretty good performance as far as the implementation goes, range and quality. You should notice a difference with the Sparko’s. I still have mine installed in that same amp, sounds great.
Interesting video. Just wanted to note that Geshelli Labs has a J2S DAC, "S" meaning socketed, that can use various op-amps in both its RCA and XLR output stages. I believe the SS3602 is one you can buy from them among three choices. However, I saw someone post they had tried the even better SS2590, and thought it was simply amazing, rivaling his Denafrips Ares II 12th anniversary edition DAC. So wow, rolling these op-amps can make a difference. Yeah, the costs go up as you move up the ladder, but man, might still be worth it. Thanks! Looking forward to the other reviews you have coming up, especially the Eversolo.
I have heard positive notes about that Geshelli as well, I should try to get my hands on one sooner than later.
@@MattCoykendall1 yes you should.
I have a standard J2 AKM with linear PSU, and more recently, added the J2 S using Sparkos SS2590 Pro's + linear PSU and upgraded dc cable. This setup has now replaced an older >$3k DAC/PSU combo in my main system. I think that a real testimonial to Geshelli &Sparkos Labs as well as a nod to the maturing of digital technology over the last few years.
@@kenlyon8285 I am actually on their site doing a bit of reading right now.
@@MattCoykendall1 just give Sherri @ Geshelli a buzz. Very helpful folks.
@@MattCoykendall1 definitely! I bought the Fosi BT20A Pro and love it "as is" but might try rolling the op-amps one day for fun. Thanks for the video showing exactly how to do that without damaging the amp.
I upgraded to a Sparkos opamp in my Aune X8 dac and it made all the difference. It goes from an average dac at its price to one that rivals 3X its cost. Recently received the Aune linear PS but haven't hooked it up yet and any improvement even if small would be welcome to its current performance with the Sparkos. Other options include Staccato and Burson op amps as well which I have not tried.
I put one of these in my FX-Audio DAC-X6 and it’s probably the only thing I’ll ever need for headphones since I’m currently running AKG K240s with Beyerdynamic pads. And with all that together, it’s fantastic to my ears.
Cool Thank You for this !
Sure thing! Thanks for the support
My mrs got me two of the dual op amps for Christmas 2022. They are nice, I prefer my ayima a07 now. I wouldn’t have spent my own money on it though.
I replaced some op amps in a fairly high end DAC, a $2600 Gustard, I used Staccato op amps.
Made a pretty big difference. Especially with regards to things like: imaging, soundstage, and other spatial cues.
The soundstage width increased, and there was more layering within it.
Hi Matt,
You sure tip-toed thru the minefields nicely on this one. 😉
Nonetheless your observations, advice, judgements and conclusions are spot-on and closely match & agree with my own experience with the BT20A Pro/Sparkos 3602 combo - subtle (and not so subtle) but noteable & welcome improvements across the board ,esp in richness of tonality .
Worth the added expense? I sure think so!
Well done!
k
Hey Ken, glad you enjoyed the combo with the Fosi as well. As for the tip-toeing... yes, some topics require a delicate touch.
@@MattCoykendall1 yes. I imagine the life of a RUclips megastar requires a delicate balance and superior restraint.😃
@@kenlyon8285 LOL megastar is a bit of a stretch, more like gain of sand on the beach, but I'm trying, we are growing!
Glad to hear that you are liking the devices :)
Looks super fun! Cool upgrade. Only problem is now I want to buy a cheap amp and pay even more for discrete opamps 😅
I know this feeling!
I bought a Burson DAC back in late 2020 that came with stock discrete op amps (can't remember the model) and I paid a little more for the upgraded package (remote and Burson V6 Vivid op amps (2 dual and 2 single).
The Burson Vivid op amps added much more detail, depth, wider soundstage, and took the presentation from 2D to 3D. The only downside was that the mid range was a bit thin for my taste.
I then purchased a pair of V6 classic, which made the midrange fuller at the cost of speed, detail and three dimensionality.
Finally I bought a pair of Sparkos singles and duals and experimented with those. The sound was more neutral and the bass stronger than with any of the others.
I ended up mixing and matching and found the Sparkos singles in the LP stage and the V6 Classic Duals in the I/V stage to give me about 85 to 90 percent of the sound I wanted. The next best pairing was the V6 Vivid duals in the IV stage and the Sparkos singles in the LP stage. This mix had a slightly thinner(but bearable) midrange, but better soundstage depth and three dimensionality. Soundstage was slightly narrower. I will probably go back and forth between these two pairings.
Devin you certainly have went down the rabbit hole! Have fun with it!
Nice work. I own three of these BT20A digital chip amps. Not sure it is worth the money without some type of dyno test, THD, RMS, etc to compare. I also own several Douk Audio, Nobsound, etc digital chip amps. This Fosi Audio BT20A sounds better (out of the box) then those ones. 36v/10 amp AC/DC power adapter or booster works best from my bench...not 48v.
Really nice instructive video!
Thank you!
Interesting. Thanks for sharing 👍
No problem 👍
I upgraded my BT20 Pro with Burson Vivid op amps. They are too tall for the case, so a little bit of modification with a
drill was necessary. It does look cool, however, with the red op amps sticking out the top. The sound undoubtedly improved, but had I not had a spare op amp lying around and sourced another one cheaply, I don't think it would have been worth the expense.
Sounds almost like the thumbnail for the video with the added hole in the case ha!
It does !. Also, due to a drill disaster, I scratched up the casework, so I ended up painting it in the style of Mondrian.
It now looks either cool or ridiculous depending on your point of view.
due to the fact that the Burson op amps are taller they also offer a " soft " riser that is made from small wires so you can lay the opamp down on its side and pretty much fit the opamp anywhere to where the wires reach by bending them over slightly...
Take these reviews with a big spoon of salt. I have this little ChiFi amp, it’s wonderful for what it is for desktop listening, casual game room setup etc. but let me be clear, it’s no match for even a entry level, but well built, well priced offerings from Cambridge or Emotiva etc. The Emotiva Mini X-A100 that I also own beats the snot out of this little bugger in terms of superb midrange weight, bass depth and tightness and well resolved treble and separation. But for $80, this BT20a Pro does hold a surprise or two on how well it still can drive medium to large speakers. Anything upto 11 O’clock position sounds good. Beyond that it loses its composure, but it’s already pretty loud 90db by then. Try this for fun and you may find a use case. I haven’t done any OPAMP rolling, but replacing with a pair of Sparkos chip costing more than the amp itself makes no sense. Just buy some well established Integrated.
Very well said & you're totally right about going with something better & definitely the part about if the chip cost more then the amp part 👍🏿🤦🏿🤷🏿
Because of variables beyond the amp itself such as speakers, room acoustics, inputs, personal tastes and so forth, everyone's miles are going to vary as to the perceived improvement. However adding the Muse02 to the Fosi V3 mono yielded in my case a worthwhile improvement. It makes no sense in my mind to put expensive op amps into budget equipment (I could be wrong) but there are plenty of inexpensive options for those looking to eke out a little more performance shall we say from their equipment. In this case the Fosi amps replaced nCore amplification and for not much money provided a noticeably better listening experience. With the Muse op amps it was better again. But YMMV.
I'd be interested in hearing your thoughts on the Fosi Audio V3 with a modified case, cut for clearance for Orange Amps' Dual Discrete Op-Amps.
I was hoping they would allow the option to turn the amp into a mono with a simple switch on the circuit board... then you could stack two amps together in mono mode and create a fantastic balanced headphone amp for hard to drive headphones...
Full set of Sparkos op amps in my SoundBlaster x7 makes for some epic gaming!
Nice! Plus the modding in general is fun.
you needed 2 bt20a pro amps and switch them at the flip of a switch without relying on audio memory. the real question is bt20a pro+sparkos is the same price as a midfi amp such as cambridge audio axa25 but which sound better ?
Agreed, 2 BT20A's would have been optimal. I wouldn't doubt the Fosi sounds better but the Cambridge will open you up to a lot more inputs.
Ever since discovering the Sparkos Labs Op Amps, which began when I purchased the inexpensive Aiyima A07, I became hooked. Yes, the Sparkos Labs Op Amps are much more expensive (but you get what you pay for here). In each case now (using them on a half-dozen other Chinese-made Op-Amp upgradeable amplifiers), the sound improved, making the overall sound signature sound closer to the warmth of a class AB amp. It was enough of a difference for me to make the adjustment to be sure.
As an aside, I've not found a class AB amp that accepts interchangeable Op Amps, and it seems the entire genre (correct me here if I'm wrong) can only be found in class D amps, that typically have a colder, 2D type of sound. The Sparkos Labs Op Amps change all this for the better (in my subjective opinion of course). I've also put them in various other components such as FX-Audio and Douk Audio DAC's - and it made a huge difference there also.
A very close runner up (if you don't want to dish out the money for the Sparkos) are the IC design Muses02 - that IC chip also has a much warmer, tube-like sound. In the end, if you love the colder, 2D type of sound of Class D amps, don't change a thing.
sir what other op amp have test? what op amp is close to sound of tube? ( sweet, mild, bass)
@@jericlee1509 Keep in mind that no one OpAmp will give you a total transformation. I've been experimenting with OpAmps now for over two years, and here are my observations/recommendations:
1. For the most part, I've found that the Discrete (remember that word - Discrete) OpAmps wind up giving you the greatest improvements in sound quality. This includes improvements in instrumental timbre, overall sound tonality, and warmth. Of course, Discrete Op Amps are also more expensive.
2. Of all the IC (small) Op Amps that you notice inside of class D amplifiers, I have found that the MUSES02 (in my opinion) is the best of that variety. Now the MUSES02 will still set you back in the $40+ USD price range.
3. Of the Discrete Op Amps, there are 3 that I can strongly recommend, those being:
a. Burson V5i - this one may run you from the $40 - $50 range (depending on where you get it from) and is roughly 1 - 2 times larger in size than the regular IC based Op Amps. It adds (again, in my opinion) more overall warmth, better instrumental timbre, more dynamics, and better bass response. But do remember that there are some class D amplifiers that already a built-in tonal curve to accentuate the bass and there's not much you can do about that. What discrete Op Amps might do is to try and make that bass tighter and more dynamic. The website address to that OpAmp is here:
www.bursonaudio.com/product/supreme-sound-opamp-v5i/
b. The 2nd recommendation that I can make, and this one is most expensive of the bunch (but not necessarily the best overall) is the Burson V6 classic - but I'll tell you right now that it may NOT fit most of the budget class D amps because it is very tall and that may interfere with the amplifier casing. That runs from $89 to $100 USD, depending on where you buy it from.
The website address to that OpAmp is here:
www.bursonaudio.com/product/supreme-sound-opamp-v6/
c. The final recommendation, and in my opinion, the best (again, remember, I'm offering personal opinions here based on experimentation), is the Sparkos Labs SS3602. Now this OpAmp is much larger width-wise (around 3-4 times larger an an IC), is priced between the Burson V5i and the Burson V6 classic. Overall, it has a warmer tonality - spread through the entire frequency range, not just one particular area. It demonstrates great dynamics, superb highs, and a very nice midrange.
It cost (before discount) - $79.80 USD, however new customers usually get a discount which ranges 15-20% off). If you are a repeat customer (you have to be a repeat customer though), the 20% repeat discount can be had with the code: RETURN20. The website for this OpAmp is:
sparkoslabs.com/product/dual-discrete-op-amp-ss3602/
In the end, there is no one OpAmp that makes an amplifier sound "just" like a Tube Amp. What these OpAmps do is to change the personality and tonality of the amp and no two users will have the same musical tastes on how they prefer their music to sound.
With budget amps, I've long since found out that the Sparkos Labs OpAmps give you a huge bang for the buck and inches your amp closer to that Class AB or Hybrid Tube sound.
Good luck:
@@MrBenherrmann thanks so much, really help, have heard or try of staccato op amp?
@@jericlee1509 Not off hand - I haven't heard of that one.
@@jericlee1509 I've tried a variety of the small IC based ones. They have limitations and the right now, the only Discrete versions I can recommend are those I recommended in my previous reply.
I claim to have Golden Ears 🙂 The Sparkos op-amps are very good, some of the best out there, but it does not pay of to put them in this amp. Much better do it in the newer Fosi V3 amp.
And why is that you may ask? Because you are only able to change 2 of the 4 sound killer op-amps 5532 in this amp, the 2 others are surface mount op-amps, which are very hard to change.
The 2 problems in this amp are: They have implemented a tone control that introduces fase shift (bader sound), and it can not be dialed out even in the mid position, and the other one is
that it has 2 SMD mounted 5532 op-amps that can´t be changed, if you are not very skilled at SMD soldering. The Fosi V3 does not have those 2 SMD mounted 5532, and sounds much better.
I actually moved the Sparkos op-amps over to the new V3, they will likely live in that one until something new comes along to experiment with. It was a tight fit on the v3 and does require a riser but its doable.
@@MattCoykendall1 Maybe you will give your opinion on the sound of the 2 amps? I find the V3 much better.
not to mention that as the 5532 was the standard in the audio professional equipment for decades, it means that amost all the music existing on the planet has passed trough tens of 5532 before reaching the final customer.
So the claim is that the change of the last final opamp in the chain will magically recovers all the sound quality lost during all the production process?
I claim that a change in sound is necessarily measurable. If a change is measured, so it mean that the original signal has been distorted in some way. the so called "subjective" changes that can't be objectively measured are a bullshit. it's a reaction to a belief and bias.
if you like the "smoothness" and other magic words introduced by distortion in a signal up to you, but don't pretend it's a more pure sound.
These should be great on the v3!
Hello Matt,
Could you tell me the exact size of the socket wrench you’re using to remove the screw from the volume pot to take the chassis off?, as I’ve a Fosi Audio V3 just arrive moments ago, as well as several different brands of Op-Amps come in I’d like to roll.
TIA!.
5:40 is very true.
Yep, I need to be fair being this is my subjective take.
@@MattCoykendall1 and that’s why I sub’d. I appreciate you.
Thanks for this revue and your honest impressions. Just got my Fosi V3 and and so far it pretty good considering I am using the Wiim Pro with its average or below par integrated DAC. So I am waiting for my Geshelli J2S upgraded with a single SS3602 for the RCA output. So if I were to get the Sparkos 3602 for my Fosi V3, would I need the raisers due to the Fosi V3 small space for Opamp? And also will this set up work well, having single J2S SS3602 and also on the V3 or is it overkill? I hope my post makes sense. Best regards
Hey sounds like a great little system your putting together. I can’t speak on the synergy of the J2S 3602 along with 3602’s in the V3, I haven’t had that combo yet, yes you will need risers for the V3, it’s a tight fit.
Can we connect Equalizer?
same experience except with an ayima a07. the sparkos smoothed out the high mids.
If it smooths things out, you are removing detail, it's as simple as that. Just like a valve amplifier.
@@MichaelBeeny it wasnt detail. it was harsh..exaggerated.. ears are different
He told me i needed more power supply to do the opamp swaps and i have no idea how to do any technical stuff or what more power supply even means. I thought the point of opamp rolling was anyone could do it, but now sounds like i have to learn how to solder and use something to read how much power supply i have by increasing capacitor size? but to what size and what end?
You can flip chips in any of these amplifiers with only the right screwdriver to open the case and a pair of tweezers. No soldering involved. The Op-Amps will be in sockets so it's a pull out, push in deal just like Matt showed in the video.
No... you do not need a different power supply. In fact flipping on the stock 32volt supply that comes with the amp seems (can't swear to "is") more pronounced. But even if you did need a different power supply, the new one would simply plug into the back of the amp, like the stock one does... unplug the old, plug in the new.
I'm not sure what you're talking about on the back of the amp. My dac has 32 multibit dacs, 16 per board. The dude from sparkos just said i would need more power supply per board running 32 total i/v converter single opamps and a pair of duals for outputs. I basically need to change my capacitors to higher capacitance and/or higher voltage. I just don't know how much more and if all the caps around each dac and i/v discrete or just around the i/v discrete or just the main larger power supply caps before the voltage regulators or ALL of the above. I'm not tech savvy with this kind of stuff, but neither is my local tech and i would need exact directions to give him to do the work which requires soldering. I've also read some say that you can't just increase voltage or capacitance to designs without doing calculations or something so i cant just say, hey tech put in the biggest capacitors you can fit physically on the board@@Douglas_Blake_579
@@HailKingCeezer
Okay ... so now I discover you're not even talking about the BT20A amplifier.
Sorry, can't help you without a lot more specifics about your equipment...
Without a resolving system already nothing maybe detected,OP-Amps are the heart of Audio you can make one with Vacuum Tubes there is not one piece of HIFI without it in mordern equipment.
There is no controversy because when done properly it can be the difference of a V4 engine or a V12
What should be the maximum watts of speakers attached? Can we attach medium to large size speakers?
Yes, as long as the speaker is sensitive enough, anything with a mid to high sensitivity should be fine at reasonable volumes.
Hook this amp up to a pair of Heresys or L-100s and you're in for a real treat. The TPA3255 chip will drive almost any speaker you can find to room filling volume.
@@MattCoykendall1 Thanks for reply. Can we attach equalizer?
Hi great video thank you! Would the op amps you used on the fosi also work with the aiyima a07 pro?
Yes but I believe you do require the risers for a A07 that I show in this video.
@@MattCoykendall1 that falls in line with other things I’ve heard , thank you!
1, bose 901 eq. No, Bose isn't hi-fi. But installing new opamps drastically improved the sound.
2. Rotel cdp -1990's model: Woke up the player, far more vivid and impactful like a modern cdp
3. carver M1.5T and C-1 preamp. More modern and cleaner sound.
Opamps are like having a 180hp 4 cylinder in your car and swapping in a 335hp V-6 engine, Just like that.
you have upgraded op amp everywhere
plz help I bought a Fosi BT20A pro amp and I’m trying to figure out the best way to connect my source wich is my iPhone 15 and my MacBook Air as well. I have a rca to aux cable that I use to connect the fosi amp to my iPhone 15 with the usb c to aux dongle. Would the shcitt dac be any better than the dac in the apple usb c to aux dongle??? I noticed that the Bluetooth volume on the fosi amp is louder than the rca to aux cable method. Would the external dac be louder than the usb c to aux dac??? I also use Apple Music lossless.
I just got my Fosi BT20A Pro and AirPlay from my iPhone through a very old Apple Airport Express WiFi wireless router extender A1264 with 3.5mm audio jack. You can get one under $20. The sound quality is more dynamic than the Bluetooth route.
Do the SS3602's work in the new Fosi v3? I bought them for the Aiyima A07
They do, it’s a tight fit.
Haven't bought the Sparkos opamps yet, but consider that you cannot find them on the used market, none used on Ebay. People who buy them, don't sell them.
Aren't discreet opamps class D?
No, most are class AB or class A
I tried sparkos only to find the most fake sound, i returned to a super fast 80s gold and ceramic video opamp from burr brown works wonders as audio opamp
I adore mine
Just because you can measure it, doesnt mean you can hear it or not.
Way more important is room acoustic treatment.
The only valid test to me would be a blind test. When you spend 80$ on a chip, I think it's more what you want to hear, than what you are really hearing.......the proof is that there are only 2-3 videos with direct side to side sound comparisons and even there there's hardly any difference.
If I just spent $80 on a preamp chip. I KNOW it will sound better! lol. Wont it?
@@MichaelBeeny Not necessarily. It's about the requiremenrs of the circuit, supply voltage, slew rate, needs compensation or not, type of input (JFET, FET, bipolar, etc). The opamp is only a part of the equation, opamp rolling is funny (I have done it), but to date I haven't done any test where one opamp magically sounds better than the rest, just because it's more expensive. If that be true, you'd see plenty of evidence and countless YT videos.....
A better option would be don't buy a class D in the first place. To say buying discreet allows better matching of components. Not true, you cannot beat laser trimmed ICs for matching and near 100% consistency. All at a fraction of the price, just avoid the many fakes from China. Avoid snake oil at all costs and, it's gotta be better, if it cost more than the amplifier. Sure, they often have a higher current rating, but will this help? No, it's a preamp, it's a voltage amplifier, not a current amplifier. Sometimes, these can overload the current available from the power supply. A typical IC will draw about 10mA, the many discrete versions can draw 60-100mA. Overheating the 15 volt supply.
Liked and suscribed
Appreciate it
Demo sound
Fosi ZA3 + Sparkos Op-amp - The Real Deal - Don't miss out !!!
ruclips.net/video/AmG4vL2yvwQ/видео.html
Sparko is too expensive, i rather get muse or opa
Always good options as well.
Data. Record the audio. Use data. It doesn't mean a God damn thing when people say "it's warmer, sharper, fuller" when there's no data. This video was nearly useless aside from showing us how to roll the opamps.
Warmer usually means, loss of detail. Fuller means added harmonics. Valves basically.
DaTa! MuSt hAvE dAtA! I dOn'T bElIeVe PeOpLe WhEn tHeY uSe ThEiR wOrDs! /s
@@kraig7777 I have no idea what you are talking about. Try English.
@@MichaelBeeny woosh
You listen with your ears, not an HP spectrum analyser. Instruments are used in design to confirm proper functioning and stable circuit. DATA, specs. Are you measuring the correct attributes? Forget % THD- it's virtually useless. This is for product brochure one upmanship. Ask Sparkos for data. Cheers! Sandy - Bell Labs Engineer (ret.) and long time Boston Audiophile
Without measurement data this video is useless. Get some audio measurement gear and repost.
Magic beans only lead you up the beanstalk to a mean old giant.
I don't care to meet him.
Lower the treble a bit or toe away the speaker a bit, same result. Cheers
Questo amplificatore e fantastico le mie casse autocostruite tre vie con woofer da 25 suonano meravigliosamente molto analitico e dettagliato.