Cap Upgrade: DIY

[jimbones]

Has anyone upgraded caps in their amplifier? I own Premier 12's and I was told that there are 4 specific caps that I could upgrade to get the most sonic benefit without recapping the entire unit. They are 0.15uf 600v caps. I have the schematic as well with the target caps marked on the schematic. I'd like to know if you did, what type cap did you use? I am comfortable with my soldering skills ( I am mil spec certified as having worked in the defense industry).

[admin]

I haven't done specific cap upgrades in CJ gear but I have with other gear (phono preamps and speaker crossovers). You may want to check of solen, they are very good.

[jimbones]

I haven't done specific cap upgrades in CJ gear but I have with other gear (phono preamps and speaker crossovers). You may want to check of solen, they are very good.

I was thinking if higher end like jupiter Janzen etc.

[admin]

Lots of good choices out there. I've had good experience with Solen in the past but that certainly is not the only viable option.

[jimbones]

reviving this thread. Does anyone have any pcb layout to id key caps that I could replace as part of a cap upgrade on my P12? I have a schematic but not sure which cap would yield the best results. I dont want to go replacing every cap lol. Also if you know of a resource, person or website its much appreciated

[admin]

CJ doesn't offer any formal upgrades to the Premier 12 so it's hard to say. I couldn't really say which are "more important" caps relative to others. As the unit is getting up there in age, I would maybe do a visual inspection and if you see if any of the caps are not looking their best, maybe go with those first. You may get more bang for your buck by replacing a near failing cap than replacing a "more important" cap but that is still working at spec.

The other thing you could do is set a budget. Then see how many caps you can upgrade with that budget. Smaller caps are obviously typically cheaper so you may be able to replace the vast majority of the caps and that may get you better performance than just replacing a few large ones.

[jimbones]

as I understand it CJ uses a lot of 0.22uf caps so i cant just start changing them willy nilly (is that even a saying today lol) I have decent funds, it not so much budget as much as it is that I dont want to disassemble more than I need to.

[admin]

I hear you. I think one issue is that every cap is going to be on the audio pathway on an amp like the Premier 12. Which means every cap could have a significant influence on the sound. How does one really know which ones are degrading after +20 years?

[jimbones]

No thats not what I meant. For example: I have a very nice Phonostage. I called the manufacturer. They said that the caps they were using were all pretty good but in the particular circuit they said there were 2 that would give me 90% of any improvement I was looking for.
I was thinking "maybe" that may be the case here. If they are equally important then so be it. I am leaning towards the Solen caps.

[admin]

I'm sure there are some caps that are "more important than others." I wish I knew which ones were those. I think in some audio equipment there can be components that simply don't influence the sound. Things like digital volume control, input/output switching, etc... but when the components are in the direct audio path (as they are with the Premier 12), it becomes difficult to tell.

I don't think you can go wrong with Solen. I've used them in upgrades to my equipment in the past. I highly recommend them.

[jimbones]

there a crap load of them in there. not every one is IN the audio path, but a lot are

[SolderSlinger]

CJ does offer a cap upgrade. It is C1. The latest version of the C1 upgrade does not include replacing the B+ voltage supply bypass caps with TEFLON capacitors. It is still possible to get them but it costs extra.

The 4 caps that provide the most improvement the output tube coupling caps. The 5th is the driver stage -input grid AC RC filter.

[admin]

I wasn't aware that the Premier 12 is still CJ upgradable. I don't remember it being listed on their upgrade page. But if it is, that is great to hear.

[RJKflyer]

Looking at the Prem 12 schematic, my immediate choices for caps to upgrade would be:
1. The 0µ15 600V in each grid of the 6550s
2. The 1µ 400V with 0µ15 400V bypass in the 6FQ7 grids to ground

These are arguably the 'most' audible. I would suggest Solen FEP (Tin/PTFE).

In my MV-55 I did the No.1 caps with Solen FEP, and the No.22 caps with V-CAp ODAM due to space limitations. It was a most excellent upgrade, although I appreciate the Prem 12 is a much fancier amp to start with.

Naturally caps in the PSU are also eligible, as we are of course modulating the PSU, but if you wish to do things one step at at a time (esp. given the prices of these), the above would be my recommendation.

[jimbones]

Looking at the Prem 12 schematic, my immediate choices for caps to upgrade would be:
1. The 0µ15 600V in each grid of the 6550s
2. The 1µ 400V with 0µ15 400V bypass in the 6FQ7 grids to ground

These are arguably the 'most' audible. I would suggest Solen FEP (Tin/PTFE).

In my MV-55 I did the No.1 caps with Solen FEP, and the No.22 caps with V-CAp ODAM due to space limitations. It was a most excellent upgrade, although I appreciate the Prem 12 is a much fancier amp to start with.

Naturally caps in the PSU are also eligible, as we are of course modulating the PSU, but if you wish to do things one step at at a time (esp. given the prices of these), the above would be my recommendation.

Thank you RJKFlyer I will check the schematic