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

@danila.1985

18 күн бұрын

Что вы изменили в данном усилителе? Можете электронный адрес отправить?

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.

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.

@SkunkieDesignsElectronics

8 ай бұрын

Amazing the difference isn't it!

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!!!

Thanks for the video.

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

@SkunkieDesignsElectronics

2 жыл бұрын

Love to see your mods on my forum! www.skunkiedesigns.com/forum

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’!!

@SkunkieDesignsElectronics

2 жыл бұрын

90% it's the lead dress to the input tube heaters. Several people have responded they needed to twist the heater wires better and route them away from any signal wiring. Glad you are enjoying it.

@jaspers49

Жыл бұрын

Miflex caps sound great and are very reasonable in price compared to other high end caps. Used them both in speakers and a phono. Would recommend.

👍great work!

Awesome channel.

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

@SkunkieDesignsElectronics

10 ай бұрын

Dolly is the best! :)

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!

@SkunkieDesignsElectronics

Жыл бұрын

I used the Shuguang Treasure 300B-Z, they sound amazing! youdaelectronics.com/products/shuguang300b-z

@jakep8484

Жыл бұрын

@@SkunkieDesignsElectronics my a50 came with psvane tubes and they sounded ok, I have both and stock the a50 sounded better at lower volumes in the midrange but I knew the 300b def wasnt reaching close to the performance that it could.

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.

@SkunkieDesignsElectronics

2 жыл бұрын

I am A-B listening to this amp compared to multiple other amps. It literally electrically can't make over 2W of power the way the front end is wired, there isn't enough voltage swing generated and with the size of the grid leak resistor, anything larger than a 0.33uf is just introducing subsonic, under 20hz amplification which is never a good thing. Putting $700 tubes into a $850 amp with substandard output transformers isn't what I would recommend anyone doing. Not attacking you here, but I have a lot of viewers and I want to be very clear. And while I'm sure after investing what you have into this, you think it sounds good, the fact is, between the poorly designed input stage, that is measurably not up to the task of driving any 300B tube, and the measurably and audibly sub par output transformers, there is no way I would recommend anyone sinking close to $2K into this like you have.

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....😀

@SkunkieDesignsElectronics

2 жыл бұрын

Yeah, the one I am returning had the Reisong logo replaced with a Skunkie Designs logo :)

@greganderson1681

Жыл бұрын

I did essentially the same thing with my A10 with equally amazing results. Thanks Skunkie!

@cyrilsalillas4383

Жыл бұрын

Hi need help on my A10 to rewire 12ax7 I’m using adapter

@theonoo

Жыл бұрын

@@cyrilsalillas4383 kzread.info/dash/bejne/c41lxbuNmbTbc6g.html

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

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.

@SkunkieDesignsElectronics

2 жыл бұрын

No hum? Then absolutely is no reason to convert.

@Warclock07

2 жыл бұрын

@@SkunkieDesignsElectronics Thanks, I have seen a lot using DC so I am not sure if it's effect the sound or something else.

@SkunkieDesignsElectronics

2 жыл бұрын

@@Warclock07 I'm sure it does affect the sound, and some folks say AC sounds better if you can do it without hum, so enjoy!

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.

@SkunkieDesignsElectronics

2 жыл бұрын

The feedback could be part of it BUT: My DIY 300B has a better bass response that either of these amps and is wired like the mod'd A50. The only diff is the output transformers. This budget Edcor iron destroys what the A50 uses. I think it's more that the A12 iron is better and/or matches the output tubes better.

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.

@SkunkieDesignsElectronics

2 жыл бұрын

The only bad JJ tubes I have found so far are their 5AR4 tubes. They are junk and unless you are using them in low voltage, low current applications, they arc out and die almost instantly.

keen

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.

@SkunkieDesignsElectronics

Жыл бұрын

The problem with simply listening is: our ears don't hear tube distortion well. And in isolation it does sound nice. But 100% of the people who have done all my mods were blow away at how much better it sounds after, it's a night and day improvement. I also built my own DIY 300B using this same "Sun audio" schematic the A50 uses and had the same results, it sounded good but it also didn't sound any better than my EL34 amp. Changing it from a cascade to a cascode front end transforms this amplifier design. You just don't know what you are missing until you hear a modified one.

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

@SkunkieDesignsElectronics

Жыл бұрын

Never seen one, if someone wants to send me one I'm happy to check one out :)

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

@SkunkieDesignsElectronics

9 ай бұрын

The 15W edcors would be a reasonable cost upgrade

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.

@SkunkieDesignsElectronics

7 ай бұрын

I like the alum/oil EVO but you might want to do some research on their various caps and see which one might fit your tastes. This alum/oil cap is what I would call "spunky" and detailed.

@Tweedman

7 ай бұрын

Got that but they have a "white" EVO and a "black" Supreme EVO. Both are alum/oil caps with the Supreme being supposedly better and more expensive. Do you use the white ones? Thanks again

@SkunkieDesignsElectronics

7 ай бұрын

Yeah, the white ones mainly for the cost. I personally haven't tried the $$$ versions.

@Tweedman

7 ай бұрын

Thank you so much

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

@SkunkieDesignsElectronics

2 жыл бұрын

No, the power transformer doesn't have the headroom for the current even a KT88 needs to sound good.

@willwill5595

2 жыл бұрын

@@SkunkieDesignsElectronics Thanks

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

@SkunkieDesignsElectronics

Жыл бұрын

Yes and Yes www.skunkiedesigns.com/a12-mods

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.

@SkunkieDesignsElectronics

2 жыл бұрын

Thanks!

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?

@SkunkieDesignsElectronics

11 ай бұрын

No, neither the power transformer nor the output transformers can handle the current load.

@blurry_eyes

11 ай бұрын

@@SkunkieDesignsElectronics thanks for taking the time to reply. Will stick to good EL34s

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

I wil need work on tube amps

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

@SkunkieDesignsElectronics

Жыл бұрын

Absolutely, it's no contest. The modded A12 is much better.

@ofiroman123

Жыл бұрын

@@SkunkieDesignsElectronics thank you! How about the modded A12 VS the modded A10? Worth the extra $$ ? I’m trying to find the right balance between price and decent tube amp

@SkunkieDesignsElectronics

Жыл бұрын

@@ofiroman123 The point to point wired versions of the A10 vs A12 are almost the same, other than the driver tubes and their wiring. If you are sharp with wiring, modding the A10 to use 12AX7 tubes isn't complex and you save a few bucks, but then you still have to buy some 12AX7 tubes, so not a lot saved in the end.

@ofiroman123

Жыл бұрын

@@SkunkieDesignsElectronics thanks!

Darling I love KT 77 to replace EL34 tube

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

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

@SkunkieDesignsElectronics

2 жыл бұрын

$300 pair of tubes in place of the $30 pair of JJ EL34L?

@wpg_dude1400

2 жыл бұрын

ICON AUDIO - EL34D Vacuum Tube a British tube only amp builder custom made tubes to perform as a 300B

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

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