DavidK35
100+ Head-Fier
Hi greinedo, nice work!
I will reply to you as I have that APPJ, and there are only one or two people left on this thread now, partly because of the age of the amp and it has had several new versions since then, (which I'm rather sorry about)!
Glad you like the amp, it is pretty amazing! I am continually being shocked by it, even now after about 10 years of ownership!
The Jantzen caps you used look to be fine, the right values to boost bass performance and the cathode caps at 1000uF will give power a boost to avoid clipping and improve transient response, given that this is a relatively low power amp, (which is not a problem because low power often means clean power). Together with the bypasses to boost the faster treble frequencies is what is needed here.
I found burn in time improved the soundstage airiness and clarity especially, but for the Jupiter and Kaisei caps I have put in they need into the hundreds of hours before I really started to notice it big time.
The upgrades are really worth it for this little baby amp.
Changing the pot has been mentioned but as far as I know nobody has actually done it due to the lack of space, and if you're not getting any problems it's best left. As the amp is autobiasing you can't adjust it by any other means. Digital volume seems a fine compromise.
Good work on the DAC, did you make the speakers too?
Let us know your impressions through your speakers after more burn in time, I am interested to know as mine are only 87db but are absolutely stunning quite frankly!
Also any questions about tubes etc., but there is a lot about that back in the thread.
Still here, with the cap mod & original amp. Enjoying it as much as first day. After trying a whole host of tubes (earlier in the thread) settled on the 14N7 as driver & the unbeatable 6BG6G coke bottle
power tubes. Spacing very tight but works fine. Shame they changed the design, mine's a keeper.