Boyuurange Reisong A12: Doing the Mods Video #1
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- Опубликовано: 29 сен 2024
- First of a 2 part step by step video on how to do these mods to your A12. The only major part replaced was the rectifier tube, everything else was just some resistors and 1 capacitor was added. This transformed the test results, huge distortion reduction and at the same time extended the frequency response.
I initially thought I would be keeping the output tube cathode bypass capacitor, but I then realized changing the cathode resistor would require the bypass cap also be changed, and I have spec'd a 470uf 35V replacement.
This A12 amp is sold on Amazon for just under $500 and for many folks this is their first taste of a tube amplifier. I plan to do a complete video series, critically testing this and exploring ways to improve the sound just like I did on the A50 amp. I know a lot of people own these and like them, I'm curious how they actually perform!
I will upload a schematic and updates after I finish working on this amp.
Ich glaube das es wieder richtig gut wird was Sie macht.
Ich habe den A50 in der Finale Version umgebaut.
Das Ergebnis ist sehr sehr gut geworden.
Ich danke hier an der stelle für das tolle Video.
Grüße aus Deutschland.
Dankeschön!
@@SkunkieDesignsElectronics Gerne, ich finde es großartig was du hier leistest. Ich weiß wieviel Arbeit das mit dem Schneiden der Videos ist.
Du hast meinen Respekt.
VG Markus
Skunkie Why are you not cursing an talking about other people’s mother. That always makes things go better for me. lol. Ha I forgot, we’re not turning wrenches. Nice Work I Love You’re Channel 🌹
Hahaha, how do you I'm not off camera :P
Wonderful, clear, concise presentation - fun to watch. Looking fwd to mod'ing one of these as you're doing - thanks!
Your videos get better and better. Keep up the great work!!!
Greetings from Hanover Germany. I have trouble getting the 250Ohm 10 watt resistance. 220Ohm or 270Ohm are no problem. Does that have any consequences?
270 is fine.
You’re the best Skunkie! You made a lot of people happy this holiday season by vastly improving a bad design and turning it to an excellent amp. I plan on repeating what you’re doing on my A10 but I will have to take into account that I have converters for 12ax7 tubes when the A10 uses 6n2p triodes. But that should be easy to overcome.
I would ditch the adapters and rewire it to natively use 12AX7 tubes.
Part 1 doesn't seem to difficult. Great job explaining and showing the modifications.
It's not, I should be posting #2 tomorrow and it's about the same.
This is the answer
Thank you for all your hard work. This is my first tube amp and I’ve been dying to make it better. Would be very interested to hear your deep dive into changes to the circuit and why. Very happy to have found you.
Yeah, I do plan to do that soon.
Absolutely brilliant video Steph.Really great clear image of the process.Has given me the confidence to try these mods myself.I own the A10 amp and the output stage looks exactly the same as your A12.In the driver stage the A10 uses 6N2J tubes would you recommend making any alterations to this stage.
The 6N2J looks electrically similar but if I had a point to point wired A10, I would just wire it up to use a 12AX7, much easier to source tube with more options on rolling.
@@vespass225 Thanks for the reply Magnus
What temperature do you solder with?
I run a hot iron so I can keep the iron on the joint as short as possible. For point to point wiring I use 750F
Been looking into the difference in wiring for the 6N2P on the A10 and the 12AX7 on the A12 I’m guessing that I could modify the wiring to the socket, and not need the adapter with my A12 quite easily. The only difference is the heater wiring for the tube. Everything else is identical.
I did the same on my A10 ; without adapter
@@edverbeek6292 cool, and it was simple enough?
12ax7 is not a great for driver stage, if i where you ill use a 12at7.
Можно использовать лампу psvane 5AR4 для изменения А10? Какая лучше TAD,Gold lion,sovtek? Китайская лампа в комплекте плохая? Она на звук влияет? Спасибо.
Just changing the rectifier tube does absolutely nothing.
@@SkunkieDesignsElectronics я купил резисторы из ваших рекомендаций, конденсаторы nichicon FG, лампы 6p2p sovtek.
Hi, where is the list of the type of parts you need? I would of thought you would of mentioned them as well as the tools you need. regards Rob
Posted ages ago, you should be able to determine which tools you don't have from watching the videos.
www.skunkiedesigns.com/a12-mods
Thanks. @@SkunkieDesignsElectronics
EL34 pin 8 cathode, pin 1 suppressor.
Dear you are the best, so polite honest and caring about video watchers
Awesome As Ever Stephi Sweetie 💖🙏🎵🎶🎧
Hi Skunkie and thanks a lot for your videoes. I've just bought a Boyuurange Reisong A10 and wonder if I can use your mods for the A12 on this? Kind regards Bjørn
Yes you can!
Подойдёт это изменение для boyuu A10?
yes, just be aware if you switch to 12AX7 tubes, the heater wiring must be changed.
@@SkunkieDesignsElectronics схема А10 и А12 одинаковые? Можно сделать полное изменение А10 как вы делали на А12?
Nooooo! I gotta wait until tomorrow! :)
I definitely want to see schematics: before and after. I’ve ordered a Reising A12. Without the modifications are we talking about the same amplifier?
www.skunkiedesigns.com/a12-mods This is a Reisong, at least what is what they are sold as on Amazon. I have no clue what a Reising is lol.
Awesome stuff. Thank you again!
replace the 12ax7 variant with 12at7 is one great modification
If you want to lower to input sensitivity and the power... The main problems this amp has is with the way the output tube is biased, the input tube is fine. Tube rolling isn't going to fix this amp.
I have the A10 and don't want to rewire for 12ax7's?
Then don't. :)
I meant, Can I still do the mods per the videos..@@SkunkieDesignsElectronics
yes
Really nice work. It is all so neat. Can’t wait till the camara is cooled down 😉.
Greatings from the Netherlands.
Thank you very much!
thanks for these great videos!
Hi Steph.Just a quick about the 250R 10W resistor your using.Does it have to be chassis mount style or doesn't it matter.Thanks Steve.
Doesn't have to be. I would try to mount it over near those lent holes so the heat can escape.
@@SkunkieDesignsElectronics Thanks for the reply Steph
Intetesting too that in the uk the a12 is not easily available now but a10 is. Same at china Hi-fi too, no a12 now. I wonder if the a10 ones on sale for uk are PCB or wired models. Should be possible to convert a10 to 12ax7 easily while doing the Skunkie mods as long as the ironwork is the same. Skunkie I appreciate you are trying to keep as much original hardware as possible but those couplng caps look cheap and nasty to me.Hope you change them at some point.
Yeah, I have a pair of Mundorf Alum/oil caps ready to drop in and try :)
Skunkie I am going to wait and see how yours comes out but if its decent. I may buy an A10 just to mod for fun. The valves alone are worth a fair chunk of the asking price, and I have spare 5ar4's and few pairs of nos winged c el34's kicking around. Given the small amount of components I think I would change the whole lot, electrolytics and all. :)
SRPP would be a great driver stage for this amp
Why would that be needed? One side of a 12AX7 easily drives the output tube to full power.
Is it worth replacing or by-passing the coupling capacitor with a better quality item.What gauge wire would you recommend for the signal path.Mant thanks
You would need to replace it and it probably will help, I need to play around with that. And the gauge wire in the "signal path": if it's pure signal, 22ga is fine, if there is signal + current like on the cathode, a bit larger but remember, everything except the heaters is running at less than 100ma. I just use 18ga solid core for everything because it stays where I put it.
@@SkunkieDesignsElectronics Thanks for the reply Steph.
Wow - amazing - great job. Super smart 😎
Thank you 🤗
wonderfully detailed "how to" !
Re-design the driver stage with 12at7
No need or reason to do that.
Hi! I may have missed something, but I don't have a green resistor on the power board on the left side, it's missing from the circuit and it's not installed in the stock version of the amplifier. Can you tell me what kind of resistor it is? Thanks!
That is covered in part 2. The stock amp doesn't have this "bleeder" resistor to drain the power caps down. It's something I added for safety. ruclips.net/video/WQaatvcy6fM/видео.html
@@SkunkieDesignsElectronics Спасибо! Мне стоит внимательнее смотреть твои видео!
@@SkunkieDesignsElectronics I should watch your videos more carefully! Thank you!
What is the preparation steps to make sure amp is safe to work on? Thanks!
If you are new to this, I would leave it unplugged for a hour or so, and then make sure there is no DC voltage from the power supply large cap to ground, and then ground that cap just to be sure there is no stored voltage. I made a video about tube safety as well as others on youtube. Blueglow electronics also has one.
@@SkunkieDesignsElectronics Ok thanks for sharing that. I will check out those videos! 😊
Does anybody have a mod video for the A10?
It's the same amp, just different driver tubes.
@@SkunkieDesignsElectronics Had a feeling. Just wasn't sure if there were any other differences. This is all new to me. Just enjoy your work! Thanks so much for responding!
Maybe I missed it, but I did not see you adding the 820k Schade or Shunt feedback resistor in this or video 2.
It's a bit out of order, I install it near the end of one of the videos.
@@SkunkieDesignsElectronics OK thanks, I will give it another try.
@@vespass225 ruclips.net/video/WQaatvcy6fM/видео.html
@@SkunkieDesignsElectronics Yeah, thanks , I actually got it at 16:30 roughly. My components arrive by Fedex today, so it will be mighty interesting to hear what such a leap in available power sounds like tonight. Thx.
Hi! Thanks for the video and the detailed explanation. I was wondering, if I just change the EL34 section and leave the preamp tube part alone, is that OK? I am afraid to implement the changes as described in the website since my unit is an A10 instead of the A12 and the tubes (an wiring) are different for the front section. Thanks!
It will help but I the expansion of the frequency response came from the driver changes. The tubes AFAIK are different only in the pinout and it shouldn't be rocket science to apply these simple mods to those tubes.
@@SkunkieDesignsElectronics Thanks a lot for your answer. One other question: why the original design uses both triodes and you decided to not use one of them? I remember you mentioning in the video you are going to explain but I never saw the explanation (maybe I missed it). Thanks again!
@@bernardosilva7306 Because an EL34 doesn't need two triodes to drive it. While you halve the plate resistance (which isn't a problem), you double the Miller Capacitance which then becomes a problem, which can be seen in the frequency response. I honestly think they used two driver tubes for aesthetic reasons and then decided to use both just because it was there.
@@SkunkieDesignsElectronics Interesting, so, the fact that they use both triodes is responsible for the terrible distortion? I am curious if I do all your mods but keep using the two triodes just out of curiosity if that will still have the terrible distortion. Thanks!
@@SkunkieDesignsElectronics It just feels so weird not using those two extra triodes :)…
If you complete these mods on the a-10 will you get the same benefits?
Yes. My understanding is there were two versions of the A10, you need the "point to point" wired version to be able to do these mods and that version has the nicer output transformers as well. The difference between an A10 and an A12 is the input tubes, the A10 will require the heater wiring to be changed to the scheme using on an A12 to accommodate the 12AX7 tube.
@@SkunkieDesignsElectronics thank you for the quick reply. I have an opportunity to get in a-10 used for about $170. I feel like this is a pretty good value even though it's not the best tube amp out there. Would you recommend it at that price?
@@kylecoffey4943 Yes, especially if it's a point to point wired version and you are able to do these mods to it.
@@SkunkieDesignsElectronics yes it is point to point. I want to get into tubes and with the price being so cheap I won't feel bad experimenting with these mods. Thanks for the advice.