fired up the super champ

[scole]

after about 6 years i finally fired up the super champ, i was afraid the caps were bad but it sounds as good as ever. now for the 68 vibroluxe. i wonder if that will run.

[matndona]

OK- why'd it take 6yrs?

I have one, everything original & it's great! I did get a spare 6C10...which is getting harder to come buy though.

[scole]

i started building my own amps, plus i have other amps. since i started reading about amps i learned electrolytic caps only last about 7 years so im afraid to play my older amps.

[matndona]

I have an amp fantasy to find a PrincetonII and a DeluxeII to have a set. These seem to be in the $600+ range now on EBay though. I've always liked the sound of the SuperChamp thru bigger speakers. I'm thinking the versions with 12" speakers have to be pretty ideal.

Ever play either of those?

[Analog Assassin]

I just put a speaker out jack on the Super Champ...I'm going to try an Eminence Ragin Cajun speaker. They sound absolutely HUGE in my Super Reverb, more like a 12" speaker, it has a big bottom. Real efficient, I think they might be just what is needed in the Super Champ.
Does anyone have any mods to smooth out the treble on the amp? It kind of goes from dull to raspy pretty quickly.

[stokes]

i started building my own amps, plus i have other amps. since i started reading about amps i learned electrolytic caps only last about 7 years so im afraid to play my older amps.

Scole,I am a firm believer in changing old caps before they fail,but 7 years is a little short,I try to shoot for about ten years,but that is not a hard and fast rule by any means.But an amp that hasnt been fired up at all for 5 to 10 years should be considered suspect as the caps will dry out faster when they are not used for a long time,regular use will keep the caps "formed" and lengthen their useful life.When firing up an amp as you described,after a long idle period it is advisable to use a current limiter or a variac to "re-form" the caps before hitting them with full volts.If the Vibrolux you have hasnt been used in 6 yrs or so I would suggest bringing it up slow with a variac or current limiter,if the caps fail,they could cause other components to fail with them.A current limiter is very easy to make and good insurance against frying a vintage amp like the '68 Vibrolux.

[Analog Assassin]

I just noticed that it had a 47pf cap in parallel to the 330k resistor in the reverb section. The blackface standard is 10pf.

[stokes]

I just noticed that it had a 47pf cap in parallel to the 330k resistor in the reverb section. The blackface standard is 10pf.

Which amp are you refering to?Do you mean the 3.3meg before the grid of the stage after the reverb return?If that is what you are refering to,I dont think you will see much difference in tone between the 10 or 47pf,but the SF's value may have been increased slightly to eliminate a HF oscillation.Before getting into changing anything in the circuit to "smooth" out the harshness you describe,you may want to try a 5751 in place of the 12AX7(7025) in the first stage,I have never used it in that particular amp but have used it in many other amps for just that purpose,in fact of the dozen or so of my own amps most of them have this tube.It has a little less gain than the AX7 type and is not as harsh when pushed.If you do try this tube,get a NOS,the current production Sovtek I tried once is not as effective.Dougs Tubes has the JAN Nos 5751 for about $20.