Upgrade capacitors in tube amplifier?


I have upgraded crossovers with very good results.  I now have a "very good" IMO chinese tube amplifier that can probably be improved with a couple of capacitor upgrades.  

I don't have a schematic, but I have a picture and I expect some of you knowledgeable folks can point me to/confirm the ones to change.  My thought is to change the two large silver ones first and then maybe the four smaller silver ones (on the circuit boards). 

Would probably replace with something like Jantzen Superior Z-Cap or comparable and go with a higher voltage if space permits.  

https://imgbox.com/rtBfoyg0

Thoughts?


chinook9
I agree - don't mess with the circuit if it sounds good.  Their branded tubes are decent and I did not hear any significant difference with other tubes but the tube construction is a little better with Tung Sol or some others. 

The biggest upgrade you can do is buy the R-300B model. It is amazing! I also have the R8 with KT88 tubes and the R-300B is significantly more organic sounding. I have not owned the model you have but likely is similar in tone to the R8. I am running the R-300B thru Klipsch Forte III....simply amazing match.
The biggest upgrade you can do is buy the R-300B model. It is amazing! I also have the R8 with KT88 tubes and the R-300B is significantly more organic sounding.

calieng3, thank you for this information. Yong Lee recommended the R300B as an upgrade and I have been looking for anything on the comparison of the other Willsenton amplifiers and the R-300B.

I am playing with the R-35i now, but I know, with Covid19 limiting my other hobbies, I will be trying to improve upon it before too long.

My hobby, at this time, is to work at getting the best possible sound (IMO) for the least possible cost. 
Hi chinook9. Think about Mundorf capacitors for the audio caps. Get the best ones you can afford. I've used them in at least 8 stereo amps and they have made a positively remarkable difference. I get them from Canadian outfit that ships very quickly. Getting the right physical fit for the big electrolytics will be the biggest problem. Happy replacing. There's nothing like the smell of a hot soldering iron in the morning!

@johnss I just wanted to thank you for your comments on the RFTLYS tube amplifiers.  I've owned a RFTLYS A5 for two years now and I have never had any problems with it and after replacing the stock tubes, I'm very happy with how it sounds.  Your the first person I've come across that had anything good to say about RFTLYS. Most people have never even heard of RFTLYS much less ever seen or heard one.  The A5 is very well built with three large transformers that is reflected in it's weight of 51 lbs.  What a horrible name though, I think RFTLYS would sell a lot more amps if they could come up with a catcher name than RFTLYS.