You should never feel sorry for speaking truth to power. Calling a spade a spade is what is missing in this world. Thank you for measuring this Decware amp and posting the results. If this is what folks enjoy listening to, there is nothing wrong with that. If they are looking for an amp with lower distortion, you have provided the information for them to be an informed buyer. Thank you.
I bought this amp in 2016. My path is - Amazon HD Music > Audiolab 6000N > Schitt Bitfrost MB > Decware SE84UFO > Omega high sensitivity speakers. Honestly, anyone can put up all the graphs they want - to me, it's about the sound. This setup sounds AMAZING. I don't know how to describe it like a pro, but I couldn't be happier. Just my opinion as an everyday average "ear".
This is one reason why I love your channel. Honest and straight forward. Very interesting to see these measurements since I have been curious about the hype around Decware. I am not an experienced tube guy, but I do know that some tube folks talk about good distorsion that are distorsion but pleasing to the ears. Perhaps this is one of those amps?
People clearly hear all sorts of thing. I try to be more analytical in my reviews, which also tends to upset some folks. There are other channels that give glowing reviews of every piece of gear they test, which is probably why they are more popular.
Thanks for your excellent work. My LTspice simulation shows similar THD results as your measured. I have long been puzzled with the results. Now your measurement proves the model is reasonable. One of the possible explanations is that the extra distortion, mainly second order in nature, sounds good to human years. If you play a note on acoustic instruments like violin, cello, or guitar and watch the spectrum on an phone app, you will see many peaks with different frequencies. These are harmonics of the note you played. The more expensive instruments normally generates the harmonics that people like. It looks like the EL84UFO amp adds its own harmonic spectrum when playing music and people like the sound of the spectrum. When people roll tubes, just like musicians switching to a different make of the same instrument, they hear different sound spectrum. If they like them, the tube must be highly sought after. Imagine how boring the music will be if you play a Stradivarius violin that no longer generates rich harmonics except the base notes. On the other hand, life acoustic performances have rich and subtle harmonics and ambience. An amplifier may remove them without being able to be measured. I have not heard EL84UFO so I don't know whether it manages to retain some of the details because it has no feedback and "fast speed" as described by the designer. If so, I am sure many people will like it regardless of the higher second harmonic. As you stated, we all have different music preferences. Stick to what you like. Enjoy the music!
Like I said several times, I'm not a fan of the thick syrupy triode strapped pentode sound, especially when ladled on in large quantities. Clearly some people are.
Good Job young lady !! It is what it is. $1,200 is about the right price for a amp like this after all is said an done. That’s the reason I got into DIY in the first place. I thought I could build as good or better product than I could buy off the shelf for a lot less money. Let’s face it, you can spend $1,200 on two output transformers, not me but there out there lol. Thanks Skunkie for being here. Don’t let the company Trolls get to ya. It is what it is
In Decware's defense, primarily 2nd order distortion around 5% can give audio some really nice flavor. I would like to see 2nd order in addition to THD, as that is an important thing to consider when analyzing single-ended performance. I'm willing to bet it's nearly all 2nd order and that's the reason listeners are really vibing with it.
It's shown in the spectrum analysis on the left lower window of the THD vs frequency. I said some people might love this high distortion triode strap sound. I'm not one of them and failed to hear all this "Air" I heard other reviewers talk about.
I was real fond of these EL84 SE pentode amps in my ol tape machine Triode strapping 'em sounded a bit Meh - ( UL might be worth a try ) Sadly that one got lost in the mega eviction :(
If its almost 10 percent dist at a couple of watts its not going to be that much lower for 3rd harmonics as well, as you can see for the most part the 2nd h is only about 20 db higher than 3rd. I built a solid state amp with 1 percent thd at 4 watts and the 2nd h is 40 db higher than the 3rd.
And. I have been looking at Decware products for a while. Very interesting indeed. Lots of love out there. But I am super happy with my Reisong A10 amp with Skunkworks mods. It is beautiful. Thank you.
Nice Video thanks for showing it as it is, that is what makes your channel unique. It'd be intriguing to experiment with different tubes to discern whether it's a design or tube-related issue. It's a shame that companies often don't thoroughly test their products before shipping, often they are not fully tested or tested with factory tubes but not with the tubes they later add in the shipping box.
You are a National Treasure, anyone who speaks their truth and does not pander to manufacturers should be commended. Thank you. I had the same reservations regarding the power output. I am in the UK and really thought it was too risky to wait 2 years for an amp that would probably be a disappointment.
@@SkunkieDesignsElectronics Agreed. Unfortunately, in the UK there isn't much of a selection of Single driver high sensitivity speakers. Which is what I would go for with this type of amplifier. Thank you for your reply.
Hello I built a Decaware amplifier based on a Decaware printed circuit board. It is as you describe. I think the problem is in the speaker transformers. I agree with you opinion. Thank you for the real information.
I built the DIY version of the Decware amp (the ZKIT1 board Decware sells) and used it for years with a pair of Sachiko single driver horns with 98db efficient single drivers (Fostex FE206ES-R) for several years. When you start at 98db efficiency it works but that would be the MINIMUM efficiency IMHO. Seeing so much purple prose about a 2W amplifier says more about the surprise many people experience when they actually hear real music with such a low powered amplifier rather than it being absolutely amazing. I'd say if you wanted to build a DIY project I'd say look at the RH84 SE amplifier, it's really popular and to my knowledge no one has actually built it and tested it with the level of rigor that you've done with your projects. It's supposed to put out a solid 3.5W of EL84 pentode power.
@@johnstuchlik5828 Do a Google search for RH84 and Alex Kitic, there will be lots of results. Alex has a blog where he goes into great detail on the many amplifiers he's designed. There are also videos people have posted of the RH84 here on RUclips.
So I am very curious about the audio analyzer suite. I have been using it for a while now on more than 10 amplifiers that I rebuilt and it worked great. My last amp was a mono integrated 1955 6L6 GC push pull. The audio analyzer suite measured its distortion at 2% to begin and went immediately off the charts. Using my HP 8903 it reads under .8% All away to its rated 24 watts. And the amp sounds fantastic. It's sine wave and square wave signatures are phenomenal. I think there may be something with the audio analyzer suite that's causing some erroneous measurements. I also don't use the bnc breakout board. I have it wired the way the documentation included with the analyzer suite indicates to measure.
Please share more details and I'll try to assist. Make sure to always use a load, especially for tube amps with output transformers, also if you use the BNC board, keep it mind it shorts the negative inputs to ground, so you no longer have differential inputs. This will be a problem for all amplifiers with bridged outputs, but can also cause issues with tube amps having a floating secondary together with global feedback. Alternatively if you don't use the BNC board and the secondary of the amps output transformers are floating, then it can help to connect the negative to ground. Cheers, Jake
Thank you so much for the reply. Also, thank you more for the wonderful software. You have personally gifted so many of us something very useful. I'm using the inputs as differential. A load of 8 or 4 ohms is always present. This particular unit is 8 ohm. Like I said previously I've never had an issue before. Even the spectrum section has helped me fine-tune the power supply harmonics as well as see the side spurs of 120 hz of a 1khz test tone. I do have one question for you: a while back I had found a PDF I believe from you that showed construction of several boards that plugged into the AD2 that could be constructed for the different types of testing. Does this sound familiar to you? I have the boards and the right angle connectors ready to go and then I could no longer find the PDF! Anyhow I just want to say your program is amazing and I greatly appreciate as well as others what you have done for this community.
Also, Stephe, this is in no way a rebuttal to your results. I think the pure percentage of distortion does not always show what we are actually hearing. I know you have mentioned stuff along this line many times and I am in complete agreement. I've heard amps with incredibly low distortion that just don't sound good to me. I've had amps with 4% and they sound great. For me personally the testing is a lot of fun because you get to see your tweaks and alterations in real time. But at the end of the day it's all about enjoyment of the music. Thanks to you both for all that you do
@@MrMersh-ts7jl Thanks, much appreciated, it just sounded you encountered some issue and I'm of course interested in providing assistance and if you found a bug I want to correct it. I do have a number of plug-in boards for the Audio Analyzer Suite, I'll try see if I can make them available on ebay or something, but my issue is a lack of spare time so I'll probably need to find someone who can handle this for me. Cheers, Jake
@@TheStuffMade is there anyway I can contact you off of RUclips and I can send you photos of my setup and see if perhaps I am doing something incorrect? The output transformer is a straight ahead 8 and 16 ohm with a common tap and that's how it's hooked to the HP. Yeah I remember The PDF being a bunch of schematics. I'm definitely not the guy to get boards made as I haven't learned that part yet. But I'm sure they'd be more than a few people to purchase a bundle for the IMD testing etc
Nothing wrong with the russian 6p14 tubes. As long as they test ok all variants will sound sweet in a good amp. Can't comment on the input tubes though as not used them.
Having built this with their schematic point to point wiring-the Russian tubes they suggest- I tested and seen the same results but Iam happy with the sound as long as you don't push this little guy to the max- you'll need some very very efficient speakers for it to really shine-also Iam using the "heafty" power transformer and with the Edcors outputs that Iam using Iam seeing the same low freq roll off starting at around 100Hz it's slow dropoff as your spud amp so your guess with a bigger power trans won't change anything - Decware does have a better output trans even if it is smaller. The company that you had with your kt120's thermoinic labs might be the best way to go as far as output transformers.
@@steven3557 so if you were about to go check them out how did you know there stuff can get expensive lol. In the words of Sargent Shultz You Fool Know One
Yeah. Nothing more disappointing than buying something that your favourite reviewer recommended and then not liking it. I've found Thomas and Stereo has ears closest to mine. Thomas will say something sounds bright end edgy . And Jay Yagi will say the high end is spot on. So need to find a reviewer that matches your tastes. I bought the CSS kit speakers. And I can hear why they have good reviews. But to me, the midrange, while super clean and 3D, it does not sound natural. I'm after natural sound and can tolerate some mudyness to get it. Which describes the speakers I have now
H2 is largely dominant, though. The HF roll-off is not my preference, but a lot of people equate tubes with warm sound. So, this amp is what people call “warm euphonic”.
16:55 If you bridge the outputs, you get double the output voltage. For a constant load resistance, the current doubles, so, all other things being equal, the power quadruples. P = (V^2)/R or (I^2)*R. The ACTUAL power, will, however, also depend on the internal resistance of the voltage source, which is why you're only getting 6W instead of 8W.
No, it's not. And what I said was that if you connect a PERFECT voltage source (internal R = 0) to a resistance, and double the voltage, you get four times the power. But real-world equipment, and certainly, amplifiers, aren't nearly that simple.
Great vid per usual. No need to tip toe around your findings..is what it is. People can make up their own minds on what to make of it. I certainly wouldnt give someone a down payment for a low watt tube amp I'll get 1 and a half to 2 years later..but i came to this conclusion way before watching this video. American made with a nice transformer though👍
I bought a Decware z box over a decade ago that was designed as a buffer stage for improving the sound of CD. After doing measurements, The trick behind it was running the tube at low voltage and biasing it to soft clip on one side of the wave. A couple of CD's did sound smoother but overall it removed the air and ambience in music which I love to hear so a big no to use it. The capacitor inside was nothing special either. After this I realised Steve is as much a marketing genius as an amp designer. I also bought car speaker wiring mod plans for $20 from decware. All it was, was wiring the front and rear speaker in series. This was supposed to change the phase and timing of sound to the ears. I didn't hear it. There's nothing in a Decware that a skunkie designs or experimental home builder couldn't do as good or better. I'm saying this now more to encourage home builders than put down Decware. The Amps look nice, have development and research behind them and are american made. So can't argue against that. 💚 Thanks for the review
I guess I was just expecting a more straight forward tube amp and not a "bag of tricks" amplifier, hence my disappointment. We will see if tube rolling changes anything but I think it's doing what it was designed to do, insert 5 to 6% distortion into the sound, roll off the top end to have an obvious "tube sound".
I've been super skeptical of the hype around these amps, especially their claims about the OPTs, which are small enough to fit inside the chassis. I thought, "But maybe he's found a way to cheat the laws of physics." After seeing that waveform at 20 Hz, I guess not! Thanks for stepping up with this video!
I own mono-block version of this amp. Which equates to maybe 5-6wpc. Couple things that I would add. You already mentioned possibility of tube rolling and that’s true. Decware doesn’t really give you anything other than standard, economy tubes at this price point. It’s just what it is. NOS exotic tubes would add another 25%-%30 percent of the cost. 2nd, anything with sensitivity of less than 92-95dB should probably be fed with more capable amp. I own Cornwalls IV which are extremely sensitive speakers so that 5-6wpc that mono version provides is just enough to get some level of dynamic range and almost non existent headroom. At least at levels I listen to. As to build quality, these are build like a tank. Not in the context of robustness or anything like that. Just that in almost 20 years of use I had absolutely zero issues whatsoever. So quality is there and if any issues occurred I’m sure Decware would fix/address it without question asked. Even if you bought the unit second hand. As to sound quality….well, that’s a bit more difficult answer to give. Due to speaker type, sensitivity and characteristics it will simply come down to proper matching and component synergy. I bought my monos for $900 used and I’m extremely happy with them. Are they my reference amps? No. But for heavy everyday use and quite a bit of beating, they perform great. Good stuff (review). I will just add that its distortion is actually a little surprising. I don’t care for spects much but 3% is a little high. Even for spects-don’t giver -a-fucker like me. Cheers. Again, good stuff.
I can see why some people would love these. I guess I was expecting a more mainstream amp and not something designed to so heavily change the sound it is used in. I'm sure with the right synergy of stuff, room ect. it would sound good for folks looking for that "tube sound" this has.
Hi. There ia a switch in the front of the amp, you should be aware of. It suposed to change amplifiers "working point" as it chcanges the value of tube bias resistance. I think You should have other measurements after using the swich. It suposed to intentionally add some "drive" to the sound. On the measure side it is distorted output, but some consider it sound as nice and more "tuby". Hope it helps :)
I get some folks like this "sound" and it does likely have a unique sound signature. This "warm triode strap sound" just isn't something I really enjoy listening to.
Steph I have some nice SE OT's rated at 5k - 8ohms but only rated at 60ma. I was going to use them for a decware clone, I am thinking that 60ma they are just too small for a Skunkie circuit 300b instead. Am I correct?
I am beginning to think that a lot of the magical tube "air" sound audiophiles go on about is actually excessive distortion. I know that as I progressively replaced the tubes in my R8, as well as losing the weird noises the cheap stock tubes created, it also lost some of that tube sound and now sounds closer to a solid state amp when playing music.
I'd argue that it sounds closer to the actual music. If a well designed tube circuit gets closer then great. If an op amp circuit does better then hopefully I'll call it like I hear it.
Thank you for telling it like it is. I appreciate your honesty. I have built your 6LU8 amp and truly enjoy it. You mentioned using a larger power transformer. If I try a larger power transformer what other parts will I need to replace and what is the formula to calculate the new values of the replacement parts.
Very interesting video Stephe. While I do not care so much about the specific amp, I am interested in what you find out about the use of larger power transformer. My 6LU8 power tranny gets REAL hot, probably no out of spec, but man, I am a little bit worried. Now, that 6LU8 is driving my Polk Monitor 50s at 89dB/W really well, and has lots of bass, erm, well, enough bass for me, sort of. Anyway, I am interested in anything you find out about increasing the siuze of the power transformer has on perfromance. My 6BM8 is currently driving my desktop speakers, which a really small, but the sound detail at near field is pretty good. I swapped out my 15W edcors on the 6BM8 to use in the 6LU8, and bought less expensive SXE-15-8-5K. Both amps are great. I originally thought I would continue with another higher power DIY tube amp, either a SEUL using a 6l6GC or KT88, or perhaps an EL84PP, but really, this 6LU8 sounds great, and has enough power to fill my 16x19 room with plenty of sound. Thanks again, Roger
I compared a decware to my heavily modded ACA using my forte's. I liked the modded ACA much better in every regard. In all fairness to the UFO it is built beautifully and it is built to produce a warm sound and I think for its intended purpose it does it really well.
Is there a way to learn more about the mods that you did to the ACA? I own two of them, and have been thinking about ways to improve them. I like them a lot.
When I used to follow Decware years ago Steve always said that little amp had the fastest tightest response because of the small tubes. So it shouldn't sound warm. That's if I remember correctly what he said
If this is triode mode, 2.3 watts is probably about right. Found a schematic for another Decware EL84 amp which shows that setup, couldn't find one for the UFO model. It was also a zero feedback design, which would explain the response and distortion performance. A schematic of this specific version would confirm that.
@@SkunkieDesignsElectronics Same design then, so yeah those measurements make sense. The LF distortion on the 6BM8 amp looks more like crossover distortion than transformer limits to me, maybe a smidge under-biased. Usually saturation makes the peaks look really horrible, not the zero crossing. Didnt watch the videos on it but depending on the idle current and dissipation limits, maybe you can squeak a little more out of it by fooling with the cathode resistor value to run it hotter.
Newer versions of this amp use the “Hazen grid mod” it is a cap across g3 and cathode(that is not internally connected in the tubes you tested with). An easy way to negate it, and see if it is the source of your top end distortion, would be to test again with standard el84 tubes that have an internal connection. This will short out the cap across those pins.
I built the ss rect version of this amp, with Decware OPTs and all anniversary mods, tried all sorts of mods and gave up on the amp. The RH-84 (with the same edcor/decware opt’s)walks all over it. This review, along with others (inc his aca review) has led me to question all of Steve Gutt’s reviews, for my ears, at least.
I find this so fascinating. I prefer the sound signature of 2A3 tubes over 300b. I like the EL34 over kt77s. So I’m not sure how distortion of the high frequencies really impacts the sound I like. So I go back to not what measures the best or what those “reviewers” say but to what I actually hear. I own a higher output Decware that sounds much warmer than an Acoustic Research model. But one isn’t better than the other-just different
Very interesting! I think you are right about using a bigger power transformer. it will get you better inherent regulation as well. I like Antek toroids. I'm surprised the distortion was as high as it was. As you said maybe there is one or more bum tubes. If the frequency responses in each amp are primarily the result of the OTs I would say the Edcor is the better transformer. Id give up bass extension over high end distortion, especially at 2 watts (lets get real ; ) ) any day of the week. Lastly if you really want to make peoples heads explode add a touch of feedback to the decware. I bet it sounds and measures much better but god knows how much power you would end up with.
Looks like i made a good purchase getting the a10 and modding it. Remember all the people that rave about this amp have never measured the amp with test equipment . They also raved about the 10 without the mods, lots of clowns out there.its not your fault just look up the average IQ in america.
Hi, thanks for the efforts you put in those videos. Since you use the Analog discovery single ended board, can you verify that the amp negative output are actually grounded. You may have to use the Analog discovery in differential mode to get good results.
I got hum from the power transformer itself (not to speakers... Yes, a bit but it's not that) since day one (my UFO is 10 months old). what about yours? Same thing? Trying to solve the problem with the help of Decware but no success yet. It's annoying because I keep the amp close to listening spot.
Bought a Decaware phono pre, that has unacceptable hum. Despite waiting for months for it, couldn't even get the wood chassis I wanted. Built an Ear834p clone with separate psu that sounds far better.
Like to see the output transformers ;) I'd have hoped for a BIT more power but if you go for EL84-triode, you prob cant get much more (Not staying within tube specs?) So maybe ok for what it is - the price is a lil Ouch, but I'm like that abt most ALL trendy SE's - if we had a Pentode or UL mode for more watts THEN itd be a lil more value But all I'm thinking is what kinda iron and tubes i can get for that much ;) for someone with genteel taste in music, and VERY efficient trendy speakers, it could be nice - esp with lifetime warranty! Not really me tho ;) Oh yeah I was hoping for a direct comparison w your 6BM8 number (a smaller tube but maybe you go Pentode?) Re power/distortion - I'll watch again in case I missed it PS I guess still no source of any substitute tubes for the KT120 number? That was a brave project, and tho I like to go PP for that much iron, it was a brave project, and deserves to live!!
I wonder how the RH84 circuit would stand up to it. I have not got the gear to test mine. Hope its better cos it sure sounds good to my ears. Sweeter than my tubelab.
You should never feel sorry for speaking truth to power. Calling a spade a spade is what is missing in this world. Thank you for measuring this Decware amp and posting the results. If this is what folks enjoy listening to, there is nothing wrong with that. If they are looking for an amp with lower distortion, you have provided the information for them to be an informed buyer. Thank you.
I bought this amp in 2016. My path is - Amazon HD Music > Audiolab 6000N > Schitt Bitfrost MB > Decware SE84UFO > Omega high sensitivity speakers. Honestly, anyone can put up all the graphs they want - to me, it's about the sound. This setup sounds AMAZING. I don't know how to describe it like a pro, but I couldn't be happier. Just my opinion as an everyday average "ear".
That's all that matters, just not my cup of tea.
Well done Stephe. Telling it 'like it is' has my respect
This is one reason why I love your channel. Honest and straight forward. Very interesting to see these measurements since I have been curious about the hype around Decware.
I am not an experienced tube guy, but I do know that some tube folks talk about good distorsion that are distorsion but pleasing to the ears. Perhaps this is one of those amps?
People clearly hear all sorts of thing. I try to be more analytical in my reviews, which also tends to upset some folks. There are other channels that give glowing reviews of every piece of gear they test, which is probably why they are more popular.
Thanks for your excellent work. My LTspice simulation shows similar THD results as your measured. I have long been puzzled with the results. Now your measurement proves the model is reasonable.
One of the possible explanations is that the extra distortion, mainly second order in nature, sounds good to human years. If you play a note on acoustic instruments like violin, cello, or guitar and watch the spectrum on an phone app, you will see many peaks with different frequencies. These are harmonics of the note you played. The more expensive instruments normally generates the harmonics that people like.
It looks like the EL84UFO amp adds its own harmonic spectrum when playing music and people like the sound of the spectrum. When people roll tubes, just like musicians switching to a different make of the same instrument, they hear different sound spectrum. If they like them, the tube must be highly sought after. Imagine how boring the music will be if you play a Stradivarius violin that no longer generates rich harmonics except the base notes.
On the other hand, life acoustic performances have rich and subtle harmonics and ambience. An amplifier may remove them without being able to be measured. I have not heard EL84UFO so I don't know whether it manages to retain some of the details because it has no feedback and "fast speed" as described by the designer. If so, I am sure many people will like it regardless of the higher second harmonic.
As you stated, we all have different music preferences. Stick to what you like. Enjoy the music!
great analogy.
Like I said several times, I'm not a fan of the thick syrupy triode strapped pentode sound, especially when ladled on in large quantities. Clearly some people are.
Good Job young lady !! It is what it is. $1,200 is about the right price for a amp like this after all is said an done. That’s the reason I got into DIY in the first place. I thought I could build as good or better product than I could buy off the shelf for a lot less money. Let’s face it, you can spend $1,200 on two output transformers, not me but there out there lol. Thanks Skunkie for being here. Don’t let the company Trolls get to ya. It is what it is
10K & a review of Decware, Great!
In Decware's defense, primarily 2nd order distortion around 5% can give audio some really nice flavor. I would like to see 2nd order in addition to THD, as that is an important thing to consider when analyzing single-ended performance. I'm willing to bet it's nearly all 2nd order and that's the reason listeners are really vibing with it.
Spot on!!
It's shown in the spectrum analysis on the left lower window of the THD vs frequency. I said some people might love this high distortion triode strap sound. I'm not one of them and failed to hear all this "Air" I heard other reviewers talk about.
I was real fond of these EL84 SE pentode amps in my ol tape machine
Triode strapping 'em sounded a bit Meh - ( UL might be worth a try )
Sadly that one got lost in the mega eviction :(
If its almost 10 percent dist at a couple of watts its not going to be that much lower for 3rd harmonics as well, as you can see for the most part the 2nd h is only about 20 db higher than 3rd. I built a solid state amp with 1 percent thd at 4 watts and the 2nd h is 40 db higher than the 3rd.
And. I have been looking at Decware products for a while. Very interesting indeed. Lots of love out there. But I am super happy with my Reisong A10 amp with Skunkworks mods. It is beautiful. Thank you.
Nice Video thanks for showing it as it is, that is what makes your channel unique. It'd be intriguing to experiment with different tubes to discern whether it's a design or tube-related issue. It's a shame that companies often don't thoroughly test their products before shipping, often they are not fully tested or tested with factory tubes but not with the tubes they later add in the shipping box.
No shit! I’m watching your test results with huge anticipation! Thank you, dear!!
You are a National Treasure, anyone who speaks their truth and does not pander to manufacturers should be commended. Thank you. I had the same reservations regarding the power output. I am in the UK and really thought it was too risky to wait 2 years for an amp that would probably be a disappointment.
In the right use case, it's an excellent product, but that use case is 1/2-3/4 of a watt.
@@SkunkieDesignsElectronics Agreed. Unfortunately, in the UK there isn't much of a selection of Single driver high sensitivity speakers. Which is what I would go for with this type of amplifier. Thank you for your reply.
Hello
I built a Decaware amplifier based on a Decaware printed circuit board.
It is as you describe. I think the problem is in the speaker transformers. I agree with you opinion. Thank you for the real information.
Thanks for the info!
I built the DIY version of the Decware amp (the ZKIT1 board Decware sells) and used it for years with a pair of Sachiko single driver horns with 98db efficient single drivers (Fostex FE206ES-R) for several years. When you start at 98db efficiency it works but that would be the MINIMUM efficiency IMHO. Seeing so much purple prose about a 2W amplifier says more about the surprise many people experience when they actually hear real music with such a low powered amplifier rather than it being absolutely amazing. I'd say if you wanted to build a DIY project I'd say look at the RH84 SE amplifier, it's really popular and to my knowledge no one has actually built it and tested it with the level of rigor that you've done with your projects. It's supposed to put out a solid 3.5W of EL84 pentode power.
That sounds like a good plan on something to clone and probably is more my cup of tea sonically as well.
RH 84? Any details that help me look for that amp circuit? Thanks
@@johnstuchlik5828 Do a Google search for RH84 and Alex Kitic, there will be lots of results. Alex has a blog where he goes into great detail on the many amplifiers he's designed. There are also videos people have posted of the RH84 here on RUclips.
So I am very curious about the audio analyzer suite. I have been using it for a while now on more than 10 amplifiers that I rebuilt and it worked great. My last amp was a mono integrated 1955 6L6 GC push pull. The audio analyzer suite measured its distortion at 2% to begin and went immediately off the charts. Using my HP 8903 it reads under .8% All away to its rated 24 watts. And the amp sounds fantastic. It's sine wave and square wave signatures are phenomenal. I think there may be something with the audio analyzer suite that's causing some erroneous measurements. I also don't use the bnc breakout board. I have it wired the way the documentation included with the analyzer suite indicates to measure.
Please share more details and I'll try to assist. Make sure to always use a load, especially for tube amps with output transformers, also if you use the BNC board, keep it mind it shorts the negative inputs to ground, so you no longer have differential inputs. This will be a problem for all amplifiers with bridged outputs, but can also cause issues with tube amps having a floating secondary together with global feedback. Alternatively if you don't use the BNC board and the secondary of the amps output transformers are floating, then it can help to connect the negative to ground.
Cheers,
Jake
Thank you so much for the reply. Also, thank you more for the wonderful software. You have personally gifted so many of us something very useful. I'm using the inputs as differential. A load of 8 or 4 ohms is always present. This particular unit is 8 ohm. Like I said previously I've never had an issue before. Even the spectrum section has helped me fine-tune the power supply harmonics as well as see the side spurs of 120 hz of a 1khz test tone.
I do have one question for you: a while back I had found a PDF I believe from you that showed construction of several boards that plugged into the AD2 that could be constructed for the different types of testing. Does this sound familiar to you? I have the boards and the right angle connectors ready to go and then I could no longer find the PDF!
Anyhow I just want to say your program is amazing and I greatly appreciate as well as others what you have done for this community.
Also, Stephe, this is in no way a rebuttal to your results. I think the pure percentage of distortion does not always show what we are actually hearing. I know you have mentioned stuff along this line many times and I am in complete agreement. I've heard amps with incredibly low distortion that just don't sound good to me. I've had amps with 4% and they sound great. For me personally the testing is a lot of fun because you get to see your tweaks and alterations in real time. But at the end of the day it's all about enjoyment of the music. Thanks to you both for all that you do
@@MrMersh-ts7jl Thanks, much appreciated, it just sounded you encountered some issue and I'm of course interested in providing assistance and if you found a bug I want to correct it.
I do have a number of plug-in boards for the Audio Analyzer Suite, I'll try see if I can make them available on ebay or something, but my issue is a lack of spare time so I'll probably need to find someone who can handle this for me.
Cheers,
Jake
@@TheStuffMade is there anyway I can contact you off of RUclips and I can send you photos of my setup and see if perhaps I am doing something incorrect? The output transformer is a straight ahead 8 and 16 ohm with a common tap and that's how it's hooked to the HP. Yeah I remember The PDF being a bunch of schematics. I'm definitely not the guy to get boards made as I haven't learned that part yet. But I'm sure they'd be more than a few people to purchase a bundle for the IMD testing etc
Very good content, and fair. Definitely you should go for a second video with Tube-Rolling. Cheers Stefan
Coming soon!
Tube rolling changes the sound. Good NOS tubes would do marvells! That amp seems to be build like a tank! Thanks for your revue! As always: 5* :)
Nothing wrong with the russian 6p14 tubes. As long as they test ok all variants will sound sweet in a good amp. Can't comment on the input tubes though as not used them.
Having built this with their schematic point to point wiring-the Russian tubes they suggest- I tested and seen the same results but Iam happy with the sound as long as you don't push this little guy to the max- you'll need some very very efficient speakers for it to really shine-also Iam using the "heafty" power transformer and with the Edcors outputs that Iam using Iam seeing the same low freq roll off starting at around 100Hz it's slow dropoff as your spud amp so your guess with a bigger power trans won't change anything - Decware does have a better output trans even if it is smaller. The company that you had with your kt120's thermoinic labs might be the best way to go as far as output transformers.
Hmm I might get them to make some OT for my 6BM8 and see how they perform. Thanks for the info on the power transformer!
Does give pause when all the golden ears are praising such amps so highly....thanks for the reveal...
@@steven3557 so if you were about to go check them out how did you know there stuff can get expensive lol. In the words of Sargent Shultz You Fool Know One
Yeah. Nothing more disappointing than buying something that your favourite reviewer recommended and then not liking it. I've found Thomas and Stereo has ears closest to mine.
Thomas will say something sounds bright end edgy . And Jay Yagi will say the high end is spot on. So need to find a reviewer that matches your tastes. I bought the CSS kit speakers. And I can hear why they have good reviews. But to me, the midrange, while super clean and 3D, it does not sound natural. I'm after natural sound and can tolerate some mudyness to get it. Which describes the speakers I have now
The "Golden Ears" 😂 I love it!
I praise it and I'm anything but "Golden Ears".
H2 is largely dominant, though. The HF roll-off is not my preference, but a lot of people equate tubes with warm sound. So, this amp is what people call “warm euphonic”.
Human hearing system is all but nasty distortion and high levels of HD....BUT...that is percieved as REAL sound by the brain decoder !
16:55 If you bridge the outputs, you get double the output voltage. For a constant load resistance, the current doubles, so, all other things being equal, the power quadruples. P = (V^2)/R or (I^2)*R. The ACTUAL power, will, however, also depend on the internal resistance of the voltage source, which is why you're only getting 6W instead of 8W.
But clearly the distortion isn't improved.
No, it's not. And what I said was that if you connect a PERFECT voltage source (internal R = 0) to a resistance, and double the voltage, you get four times the power. But real-world equipment, and certainly, amplifiers, aren't nearly that simple.
Your disapointment is quite palpable, you obviously wanted to say how great this amp is, but your honesty and integrity shone through this video.
Thank you
Great vid per usual. No need to tip toe around your findings..is what it is. People can make up their own minds on what to make of it. I certainly wouldnt give someone a down payment for a low watt tube amp I'll get 1 and a half to 2 years later..but i came to this conclusion way before watching this video. American made with a nice transformer though👍
I bought a Decware z box over a decade ago that was designed as a buffer stage for improving the sound of CD. After doing measurements, The trick behind it was running the tube at low voltage and biasing it to soft clip on one side of the wave. A couple of CD's did sound smoother but overall it removed the air and ambience in music which I love to hear so a big no to use it. The capacitor inside was nothing special either. After this I realised Steve is as much a marketing genius as an amp designer. I also bought car speaker wiring mod plans for $20 from decware. All it was, was wiring the front and rear speaker in series. This was supposed to change the phase and timing of sound to the ears. I didn't hear it.
There's nothing in a Decware that a skunkie designs or experimental home builder couldn't do as good or better. I'm saying this now more to encourage home builders than put down Decware. The Amps look nice, have development and research behind them and are american made. So can't argue against that. 💚 Thanks for the review
I guess I was just expecting a more straight forward tube amp and not a "bag of tricks" amplifier, hence my disappointment. We will see if tube rolling changes anything but I think it's doing what it was designed to do, insert 5 to 6% distortion into the sound, roll off the top end to have an obvious "tube sound".
I've been super skeptical of the hype around these amps, especially their claims about the OPTs, which are small enough to fit inside the chassis. I thought, "But maybe he's found a way to cheat the laws of physics." After seeing that waveform at 20 Hz, I guess not! Thanks for stepping up with this video!
I own mono-block version of this amp. Which equates to maybe 5-6wpc. Couple things that I would add. You already mentioned possibility of tube rolling and that’s true. Decware doesn’t really give you anything other than standard, economy tubes at this price point. It’s just what it is. NOS exotic tubes would add another 25%-%30 percent of the cost. 2nd, anything with sensitivity of less than 92-95dB should probably be fed with more capable amp. I own Cornwalls IV which are extremely sensitive speakers so that 5-6wpc that mono version provides is just enough to get some level of dynamic range and almost non existent headroom. At least at levels I listen to. As to build quality, these are build like a tank. Not in the context of robustness or anything like that. Just that in almost 20 years of use I had absolutely zero issues whatsoever. So quality is there and if any issues occurred I’m sure Decware would fix/address it without question asked. Even if you bought the unit second hand.
As to sound quality….well, that’s a bit more difficult answer to give. Due to speaker type, sensitivity and characteristics it will simply come down to proper matching and component synergy.
I bought my monos for $900 used and I’m extremely happy with them. Are they my reference amps? No. But for heavy everyday use and quite a bit of beating, they perform great.
Good stuff (review).
I will just add that its distortion is actually a little surprising. I don’t care for spects much but 3% is a little high. Even for spects-don’t giver -a-fucker like me.
Cheers.
Again, good stuff.
I can see why some people would love these. I guess I was expecting a more mainstream amp and not something designed to so heavily change the sound it is used in. I'm sure with the right synergy of stuff, room ect. it would sound good for folks looking for that "tube sound" this has.
Hi. There ia a switch in the front of the amp, you should be aware of. It suposed to change amplifiers "working point" as it chcanges the value of tube bias resistance. I think You should have other measurements after using the swich. It suposed to intentionally add some "drive" to the sound. On the measure side it is distorted output, but some consider it sound as nice and more "tuby". Hope it helps :)
I did post with that front switch both ways, very aware of it. In was the one that increases the input tube sensitivity. Distortion stays the same.
You are just showing the readings you get with is A-OK with me!
I get some folks like this "sound" and it does likely have a unique sound signature. This "warm triode strap sound" just isn't something I really enjoy listening to.
Steph I have some nice SE OT's rated at 5k - 8ohms but only rated at 60ma. I was going to use them for a decware clone, I am thinking that 60ma they are just too small for a Skunkie circuit 300b instead. Am I correct?
Yeah, probably are.
I am beginning to think that a lot of the magical tube "air" sound audiophiles go on about is actually excessive distortion. I know that as I progressively replaced the tubes in my R8, as well as losing the weird noises the cheap stock tubes created, it also lost some of that tube sound and now sounds closer to a solid state amp when playing music.
I'd argue that it sounds closer to the actual music. If a well designed tube circuit gets closer then great. If an op amp circuit does better then hopefully I'll call it like I hear it.
Thank you for telling it like it is. I appreciate your honesty. I have built your 6LU8 amp and truly enjoy it. You mentioned using a larger power transformer. If I try a larger power transformer what other parts will I need to replace and what is the formula to calculate the new values of the replacement parts.
You really shouldn't have to change anything, just buy the next larger ma rated transformer at the same voltage level.
Very interesting video Stephe. While I do not care so much about the specific amp, I am interested in what you find out about the use of larger power transformer. My 6LU8 power tranny gets REAL hot, probably no out of spec, but man, I am a little bit worried.
Now, that 6LU8 is driving my Polk Monitor 50s at 89dB/W really well, and has lots of bass, erm, well, enough bass for me, sort of. Anyway, I am interested in anything you find out about increasing the siuze of the power transformer has on perfromance. My 6BM8 is currently driving my desktop speakers, which a really small, but the sound detail at near field is pretty good. I swapped out my 15W edcors on the 6BM8 to use in the 6LU8, and bought less expensive SXE-15-8-5K. Both amps are great.
I originally thought I would continue with another higher power DIY tube amp, either a SEUL using a 6l6GC or KT88, or perhaps an EL84PP, but really, this 6LU8 sounds great, and has enough power to fill my 16x19 room with plenty of sound.
Thanks again,
Roger
It's not going to hurt anything to use a larger power transformer on your 6LU8!
I have wondered when someone would test DEC's low-power amps. Thank you.
I compared a decware to my heavily modded ACA using my forte's. I liked the modded ACA much better in every regard. In all fairness to the UFO it is built beautifully and it is built to produce a warm sound and I think for its intended purpose it does it really well.
Is there a way to learn more about the mods that you did to the ACA? I own two of them, and have been thinking about ways to improve them. I like them a lot.
When I used to follow Decware years ago Steve always said that little amp had the fastest tightest response because of the small tubes. So it shouldn't sound warm. That's if I remember correctly what he said
If this is triode mode, 2.3 watts is probably about right. Found a schematic for another Decware EL84 amp which shows that setup, couldn't find one for the UFO model. It was also a zero feedback design, which would explain the response and distortion performance. A schematic of this specific version would confirm that.
It's on their website
@@SkunkieDesignsElectronics Same design then, so yeah those measurements make sense. The LF distortion on the 6BM8 amp looks more like crossover distortion than transformer limits to me, maybe a smidge under-biased. Usually saturation makes the peaks look really horrible, not the zero crossing. Didnt watch the videos on it but depending on the idle current and dissipation limits, maybe you can squeak a little more out of it by fooling with the cathode resistor value to run it hotter.
Newer versions of this amp use the “Hazen grid mod” it is a cap across g3 and cathode(that is not internally connected in the tubes you tested with). An easy way to negate it, and see if it is the source of your top end distortion, would be to test again with standard el84 tubes that have an internal connection. This will short out the cap across those pins.
This amp was bought a year ago, there is a newer than that version?
That one would have that mod. Worth testing again with el84’s
I plan too but I think this thing is working as designed. It's sure gonna give some "tube sound".
I built the ss rect version of this amp, with Decware OPTs and all anniversary mods, tried all sorts of mods and gave up on the amp. The RH-84 (with the same edcor/decware opt’s)walks all over it. This review, along with others (inc his aca review) has led me to question all of Steve Gutt’s reviews, for my ears, at least.
We all have different tastes, Steve clearly has a different one from which I think sounds good.
I find this so fascinating. I prefer the sound signature of 2A3 tubes over 300b. I like the EL34 over kt77s. So I’m not sure how distortion of the high frequencies really impacts the sound I like. So I go back to not what measures the best or what those “reviewers” say but to what I actually hear. I own a higher output Decware that sounds much warmer than an Acoustic Research model. But one isn’t better than the other-just different
Very interesting! I think you are right about using a bigger power transformer. it will get you better inherent regulation as well. I like Antek toroids. I'm surprised the distortion was as high as it was. As you said maybe there is one or more bum tubes. If the frequency responses in each amp are primarily the result of the OTs I would say the Edcor is the better transformer. Id give up bass extension over high end distortion, especially at 2 watts (lets get real ; ) ) any day of the week. Lastly if you really want to make peoples heads explode add a touch of feedback to the decware. I bet it sounds and measures much better but god knows how much power you would end up with.
Hi, what kind of card do you use in front of the analog discovery when using the suite?
Looks like i made a good purchase getting the a10 and modding it. Remember all the people that rave about this amp have never measured the amp with test equipment . They also raved about the 10 without the mods, lots of clowns out there.its not your fault just look up the average IQ in america.
😂
As George Carlin noted, that means that 49.999% are even more stupid😢
Hi, thanks for the efforts you put in those videos. Since you use the Analog discovery single ended board, can you verify that the amp negative output are actually grounded. You may have to use the Analog discovery in differential mode to get good results.
Pretty sure this testing is correct, spice sims show the same expected results.
I got hum from the power transformer itself (not to speakers... Yes, a bit but it's not that) since day one (my UFO is 10 months old). what about yours? Same thing? Trying to solve the problem with the help of Decware but no success yet. It's annoying because I keep the amp close to listening spot.
I'll look for this in my next video on this unit.
Bought a Decaware phono pre, that has unacceptable hum. Despite waiting for months for it, couldn't even get the wood chassis I wanted. Built an Ear834p clone with separate psu that sounds far better.
Return it, I have few pieces of deckware and absolutely no hum in my system
Like to see the output transformers ;) I'd have hoped for a BIT more power but if you go for EL84-triode, you prob cant get much more (Not staying within tube specs?)
So maybe ok for what it is - the price is a lil Ouch, but I'm like that abt most ALL trendy SE's - if we had a Pentode or UL mode for more watts THEN itd be a lil more value
But all I'm thinking is what kinda iron and tubes i can get for that much ;) for someone with genteel taste in music, and VERY efficient trendy speakers, it could be nice - esp with lifetime warranty!
Not really me tho ;)
Oh yeah I was hoping for a direct comparison w your 6BM8 number (a smaller tube but maybe you go Pentode?) Re power/distortion - I'll watch again in case I missed it
PS I guess still no source of any substitute tubes for the KT120 number? That was a brave project, and tho I like to go PP for that much iron, it was a brave project, and deserves to live!!
I did direct compare it to my 6BM8 :)
My bad - sorry not paying attention with all this awful World War 3 stuff on the other screen y'know?
Lets look again...
Be great if you could do the kit version with the edcor transformers
Honestly, this sound is not really something I enjoy listening to.
Willing to bet my Dennis Hadd amps were the better choice.
Did you put your ear near the cone ?
Not yet, I didn't hear any loud humming.
I was so excited, I was gonna build one. Thanks for saving me the wasted time. Will stick to RH84's. Don't believe the hype!
You and me both!
I wonder how the RH84 circuit would stand up to it. I have not got the gear to test mine. Hope its better cos it sure sounds good to my ears. Sweeter than my tubelab.
Hello puppy.
Dolly says Hi!
Like an audiophile magazine said many years ago: " Female voices sound like warm palpable liquid syrup " 😂
@@Peter-yt7xmwhat does that mean? Thank you
After searching, there are two Decware: SE84UFO and SE84UFO2. And SE84UFO2.1. None is EL84UFO.
OK you are right, this is officially called the SE84UFO.
Ah, I get to make the FIRST comment!
And I made the second one...lol
@pedrocols and two is bigger than one so you win 🏆 😁
The inside of these amps look like a rats nest.
Decware is overhyped by youtube audiophile reviewers.
ALL I WANT TO SAY IS.....AWESOME! 🐍 🛢 😮