Filter cap values for a Classic 30?

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Ravenhaller
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Filter cap values for a Classic 30?

Post by Ravenhaller » Mon Aug 14, 2017 10:21 pm

Hi guys. First post from me.

I just picked up a 2002-ish Classic 30 and so far i'm loving it. That said, it would be wise to give it an overhaul before punishing it too hard, and the first port of call is replacement of the filter/electrolytic caps.

I guess I can pull the amp apart to check the values of the caps, but i'm hoping someone can link/post me the information here.

I've been trying to google the schematic, trying to google high res pics, but all roads point back to a blueguitar.org PDF... lots of mod suggestions... not the right info for basic servicing.


Anyway, there appears to be 7 filter-sized electrolytic caps on the PCB - if you can help me out with their values, i'd be much appreciative.

Ravenhaller
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Re: Filter cap values for a Classic 30?

Post by Ravenhaller » Tue Aug 15, 2017 12:11 am

While i'm here I might as well ask about a new tube compliment for the amp. It has electroharmonix tubes which I assume were OEM installed (the amp has been sitting in storage for the last 10 years). They work, and they surely rattle - I think there's better suited tubes for what i'm chasing.

What I want - the clean channel gets dirty too early for my tastes - after 4 on the dial it basically becomes a gain channel. And the presence peak is horribly bitey as you ebb the volume higher - it needs to be cooled off.

Gain channel - wanting to get a better exploration of grit and crunch tones. As it is, I can't see myself using the 'pre' control beyond 5 or 6 - the gain on offer from here on would rarely be used under my command. Again, the presence on this channel can get a bit hot for my preferences.

FYI - I don't want to be spending countless hundreds on NOS RCA tubes here. At the end of the day, this is a workingman's amp.


Thanks guys.

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Enzo
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Re: Filter cap values for a Classic 30?

Post by Enzo » Tue Aug 15, 2017 12:36 am

Contact customer service at Peavey for any Peavey schematic.

But even at Blue Guitar, click on schematics on the left, then scroll down to Peavey in the list, and there is a GIF of the stock Classic 30 schematic as well as the stock layout for it. C30 schematics are all over the internet. The mod stuff is all in the articles section, rather than the schematics section.

Modern caps are SOOO much better than the ones we used in the 1960s and 1970s. Me personally, I'd not expect those caps need changing yet, but up to you.

There was no stock tube. During production you might see EH tubes and the next month JJs, and the next month Sovteks, etc. Used to see Ruby branded ones too.

It is normal for this amp to start distorting over about 4-5 on the clean channel. It is the phase inverter clipping.

ScottMarlowe
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Re: Filter cap values for a Classic 30?

Post by ScottMarlowe » Tue Aug 15, 2017 9:29 am

Enzo wrote: Modern caps are SOOO much better than the ones we used in the 1960s and 1970s. Me personally, I'd not expect those caps need changing yet, but up to you.
Agreed. I have two old Classic 50s (91 to 93 or so production). One, which has obvious seen a lot more action than the other is just starting to develop a 120Hz hum and my ESR says the filter caps are about twice as resistive as a new one, but they're not failing, just not perfect. VERY slight 120Hz hum. The other one is dead quiet, and the ESR meter says the caps are good as new. If you've got no 120Hz hum I'd just leave it. Note that C30s ARE harder on their caps than C50s since they run noticeably hotter. If you do have 120Hz hum then replace them. Here's the best video on the subject on the net:

http://i.imgur.com/H4ouQn5.jpg?2
There was no stock tube. During production you might see EH tubes and the next month JJs, and the next month Sovteks, etc. Used to see Ruby branded ones too.
And don't forget the old "Super 7" which was also any or all of those above restamped, and mine were Chinese (and darned good sounding tubes actually).
It is normal for this amp to start distorting over about 4-5 on the clean channel. It is the phase inverter clipping.
And it's glorious.

Ravenhaller
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Re: Filter cap values for a Classic 30?

Post by Ravenhaller » Tue Aug 15, 2017 2:35 pm

Enzo wrote:It is normal for this amp to start distorting over about 4-5 on the clean channel. It is the phase inverter clipping.
If that's the case I might try/buy a 5751 in the preamp stage and see what becomes of things. I mean, I really dig the clean channel with a single coil guitar in hand, but I want the amp to play friendly with my superstrats too - i'm hoping to extract a little more clean headroom from the normal channel.

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