I wanted to thank you very much. I have a Reisong 10, it is an amplifier at a good price for beginners like me, but it has its drawbacks. The distortion was terrible, it was impossible to listen at higher volumes. We made modifications in accordance with your design. Now the amplifier sounds great, thank you very much once again and greetings from Poland

Great summary thanks Stephe. A lot of work, testing, and listening to get to this point and many viewers will benefit from your efforts. Looking forward to a Skunkie Designs high end 300b 😉

Excellent video, and the community really does appreciate your efforts.

Being new to Valve amps I thank for the info and mods you are doing on all these Chinese amplifiers, will be doing some of your mods myself and reporting my findings on my channel

Wow your reviews are awesome. Even though I don't fully understand everything your talking about, I feel like im learning more about electronics with each video i watch.

Thanks for your review, it’s a honest, an well thought out review.

Thanks again Skunkie. An honest appraisal that didn't blow my mind.

Thanks for the video.

👍great work!

I did all the A50 mods on the A50 300B to great effect. I'm in the UK and as you say my B+ wasn't as bad as yours but I just adjusted the resistor to suit and added the 5U4G and ended up with the desired voltage, went full cascode with led too. RCA Sylvania too. Sounded great. Ive just been gifted an A10 (same as A12) so I'm modding that next. Thanks for your work, most appreciated.

Awesome channel.

Hi Stephe, I have now been enjoying my updated Reisong A10 a'la Skunkie Designs, for more than a month, and many, many listening hours, and I am very happy with how it sounds now. I did leave out the feedback loop after some testing A-B-A as we discussed previously , but that is more of nuances, and a matter of personal preferences and characteristics of rest of system. Last thing I did was to swap the stock coupling caps to 0.22uF Mundorf Supreme Aluminium, since you had found it gave a nice improvement. I would immediately agree to that there is a significant difference, and to me it is about considerably more fine detail and refinement, and a clearer richer sound stage. Thanks for that tip also. One thing I have invested quite some time in, is to install a remote control system. Because of the rather large motorized Japanese stereo volume potentiometer, and the rather crowded area behind stock potentiometer, it took quite some engineering and trial and error. Now it works like a charm, and was worth every droplet of sweat, and every word of curse...! I got a 3D printer as birthday gift a week ago, and will perhaps make solution to the remote volume control system, that I could 3D print and share. Just as you, I find the mirror like finsh of the A10/A12 not that elegant, and will as next step put rosewood panels to front and sides. BR and thanks for much appreciated work of yours. P.S. Forgot to say that EL84:s sound phenomenal in my A10 D.S. Magnus

Really starting to enjoy the Skunkie mods A12. Miflex 600V coupling caps, 1M feedback resistors, Sylvania 12AX7’s, reissue Mullard EL34’s and Sovtek 5AR4. Still tracking down a slight 120hz buzz in one channel. Tried grounding all unused pins but that didn’t do it. Thank you for the videos and great service you’ve done for budget audiophiles. Enjoy those Chorus’!!

Love your dog sneaking up the stairs.. C41 chemistry, nice.

keen

My A50 has plenty of clean bass for me, I use .47uf Audio Note copper foil mylar in oil coupling capacitor and they are quite large caps. I have used magnepan 1.7i and Klipsch RP-280FA floorstander. It produces enough bass in the magnepan but synergy happens with the Klipsch floorstander. Selection of 300B tubes are also important, I am using linlai WE300B and I am very happy with the outcome.

Thank you Skunkie. I did the mods you did on the A12 on the A10 and since they are quite similar in build up I created a modified A12. Changed the tubes to TAD and Tungsol rectifier and 12ax7's and did the rewiring to accommodate the 12ax7's. Had a couple of russian coupling caps. I use a sub because my open baffles like a bit of bottom help but the whole setup sounds amazing, even compared to a 300B amp a friend of mine has. I would recommend to buy the A10 and do the mods. You then start with € 350 delivered to your doorstep. I spent € 200 in parts... Just have to get rid of the Reisong logo....😀

Great review Skunkie!!! I think I will opt to get the A12 and try the modifications. I'll try it out on my Klipsch RP-8000s. I'm with you, the bass response has much to do with the output transformers. More iron and higher quality iron. The same applies with most of the AM ham radio guys I know that build their own transmitters. They might use 6L6 or 6146 or 811 in the modulator but big iron too. What sound!!!! Keep up the good work and i think I'll get a second t-shirt!!!

I can only agree with that..... It is often the case, that the designers of these circuits grew up with transistor technology. This can be seen from the wrong operating points on the tubes....incorrectly dimensioned power supplies...bad coupling components, etc..Anyone who reads old specialist books, can see for themselves, that this is the most critical designpoints of these devices.Bytheway..the A12 had always the better chance to be modified!.....thx for the Video

Hi Skunkie and thanks for all of your information you generously supply. I was wondering what 300b tube replacement you suggest for the A50 and which ones you used in your 300b diy build. Keep up the great work!

The only person on utub telling the truth about these amps. Being that I have no facility to make these mods, I'm just going to save up and buy a Decware. Thank you Skunkie Designs.

I appreciate all the work you've done on this amp. However, my biggest takeaway is that there must be a great deal of variability in the A50's build. I only replaced all the tubes with good NOS valves and I don't hear any distortion whatsoever. The sound out of the A50 is downright glorious. Perhaps it's the synergy with the rest of my gear. Tonality, instrument separation, soundstage, power up to 85db - they are all there. That possible variability might keep someone from acquiring an A50. However, based on my 50 years of listening experience, I can only give it my highest recommendation, with the caveat that the tubes must be replaced. That is true, however, for most valve amps, even ones that are much more expensive.

Using Reisong 50 with a LOC as a preamp to an amplifier. Any thoughts on this for more lush or warm sound

I agree w/ your assessment of the JJ/Tesla tubes. Not too long ago I had a Jolida 502a and went all JJ/Tesla w/ an excellent outcome and excellent sound. IMO the JJ kt88 sounded easily as good as the GL kt88's they replaced. You can't beat them for the price. I'm thinking of starting a discussion on one of the forums as to why some tubes sound better than others: is it; the construction, the design, the dellacy and attention to detail during manufacturing, the materials used all of the above ? I can read people's opinions of of various tubes and what basic type of sound they might provide but, IMO that's only worth a basic starting point. I'd like to know the "grit" of why some tubes are created more equal than others.

Really enjoy your vids. In your opinion would an a12 drive 89 db 3 way towers (fairly high end)? I already have a freya noval tube preamp and vidar 2 but am looking for a part time change. China hi fi has an open box a10 on sale. Can this be easily converted to an a12 by rewiring the driver tube. Thanks in advance for your advice

My Casta B speakers can run loud on 3 watts .my Audio Space 3i is my amp now

Darling I love KT 77 to replace EL34 tube

Great review and recommend. Since a lot people talk about AC and DC filament on 300B, can you one day test and compare if they are sound different? I have AC on my 300B without any hum so I am not sure if I want to convert to DC.

Nice comparison! Could the better bass of the A12 be because you are using Schade feedback? Feedback normally lowers output impedance. P.S... I have an A10 and can confirm your measurements on the factory version. Very poor. At some point I look forward to incorporating your mods.

Very intresting🤔 What do you thinking obout the A20. Same tube changing as the A12 and fine!?

Hi Skunkie / readers, would you recommend changing the a12 output transformers to for example Edcors or Hammonds?

Was thinking about the A12 was wondering if I could replace the el 34 with kt150. Thanks.

I've already done your mods to my A10 to A12 and I'm very happy with the results. Now considering the coupling cap upgrade. Do you recommend the Mundorf Supreme over the regular EVO? Is there much difference in the results. Thanks again.

Do you have parts list for A12 ?, im ordering one im in usa so im guessing i should choose 120v ? thank you.

I wil need work on tube amps

I know that this is an old video but would an A12 with the mods be able to withstand using KT88s instead of the EL84s?

I gonna modify it with 6BG6 nos tubes ditch the 6CA7

So would you recommend the modded A12 over the modded 6P1 you’ve worked on before?

In this world theirs plenty of NOS tubes that are not so pricey

another great tube is a 807 why use the common tube

look up EL34D tube 1/2 price from Chicago dealer but not for Canada I tried.These are 300b clone type remakes

Yeah, but you can change tubes as you get a bit of dish in. Start off in the Chinese, then some Russian, and some Martians to blow it away. It's really about the journey of flavour and no flour