[simmconn]

I remember that the middle box is filled with some kind of epoxy-like compound. I’m not sure if it is a good idea to open it. The capacitance measures about 150uF in my case, possibly some capacitors connected in parallel.

 

[Galapac]

Has anyone opened the middle 'transformer' shroud on the 339i variant? Wondering if it has the same components as the 339. I'll open mine up once I move but would be great if anyone can verify the values in there (if they are different from the 339) in the meantime if you have already explored.

Colin there may be pics on this thread where someone was in there, there were capacitors if I recall in that middle section.

 

[colinharding]

I remember that the middle box is filled with some kind of epoxy-like compound. I’m not sure if it is a good idea to open it. The capacitance measures about 150uF in my case, possibly some capacitors connected in parallel.

Wow so that sounds like a ton of fun. I had taken if off briefly and it looked like they just glued a plastic bottom plate on it to keep the caps from moving around. Didn't do any extra analysis to see if there was epoxy draped over everything in there as well. Maybe I'll tackle this another time. Though I imagine the coupling caps in there have a decent effect on the sound hence why most are changing to film caps.

Colin there may be pics on this thread where someone was in there, there were capacitors if I recall in that middle section.

I have found the pics - mainly from telecaster (he had another thread dedicated to it) but there was mention further in this thread that the capacitance may have been altered slightly for the 339i variant and I just wanted to be sure.

 

[simmconn]

I’m pretty sure they are film caps already.

 

[colinharding]

That works for me then! One less part to meddle with.

I believe the ones in telecaster’s 339 were ~47uF electrolytics in parallel for reference. I’d have to dig up the thread to be sure but they were definitely electrolytic.

EDIT - found the thread here. The caps he found in the original 339 were 4, 63µF @ 350V - I was wrong above.

 

[MJS242]

My custom amp has mundorf MKPs. Mine were too big and an extended cover had to be created. If I remember, you can use a range of uF and people who built custom amps did this in different ways.

 

[MJS242]

Other custom build parts

 

[colinharding]

@MJS242 - thanks for the pictures!

Believe most went with what you did at the 220uF value as a replacement for the 126uF which is currently there - better bass extension is what remember people reporting back.

Where are all the smaller caps in your pictures going? There's 8 multipcaps @ 30uF. Is he tying those all together for a 120uF per channel? Thought it wasn't the best practice to parallel that many caps together to create a larger value?

 

[Galapac]

My custom amp has mundorf MKPs. Mine were too big and an extended cover had to be created. If I remember, you can use a range of uF and people who built custom amps did this in different ways.

All those mundorfs must have cost more than the amp itself.

 

[MJS242]

@MJS242 - thanks for the pictures!

Believe most went with what you did at the 220uF value as a replacement for the 126uF which is currently there - better bass extension is what remember people reporting back.

Where are all the smaller caps in your pictures going? There's 8 multipcaps @ 30uF. Is he tying those all together for a 120uF per channel? Thought it wasn't the best practice to parallel that many caps together to create a larger value?

I have a completed picture somewhere, but this is all I can find right now. I also have a lot of specifications for different parts and acceptable ranges. I haven't been that active on here in years. I have a custom 339 (6J5), a 339i (6J4P) and a Zana Deux. That's all been keeping me happy and I see no reason to upgrade.

 

[MJS242]

All those mundorfs must have cost more than the amp itself.

Well, the amp didn't cost anything

 

[colinharding]

Your amp looks fabulous - I wouldn’t upgrade either

Still very interested in understanding the modifications required to convert for 6J5 use - the “warmer” version as I believe it’s described.

 

[MJS242]

I have a completed picture somewhere, but this is all I can find right now. I also have a lot of specifications for different parts and acceptable ranges. I haven't been that active on here in years. I have a custom 339 (6J5), a 339i (6J4P) and a Zana Deux. That's all been keeping me happy and I see no reason to upgrade.

Completed pics

 

[Galapac]

Nice clean lines. Always nice to hear when someone finds their endgame and gets off the hamster wheel.
Unfortunately for me, there is that one more kit to build...

 

[MJS242]

Nice clean lines. Always nice to hear when someone finds their endgame and gets off the hamster wheel.
Unfortunately for me, there is that one more kit to build...

Yeah, it's kind of this unhealthy, dopaminergic hobby where it's always more more and never enough. Having said that, I love building kits I've done the BH crack and the transcendent sound masterpiece. Always wanted to do an elekit but free time isn't something I have a lot of these days. Wish more companies would offer kits rather than outrageously priced amps. The whole industry has kind of left a sour taste in my mouth the last several years with how prices have increased. Might as well be in the speaker realm.

By the way, found the exact specs on my two large caps. They're Mundorf MCap EVO Aluminum, 220uF, 250VDC. Can't say I recommend them because they won't fit with the stock cover.