# Service 80’s SuperChamp? + Photos



## keto (May 23, 2006)

Issue is, there’s a low volume buzz below the note, that fades as the note dies. Definitely not 60 cycle hum. I will but haven‘t yet try some different preamp tubes, I don‘t think I have other 6V6s to try. Pulled the chassis, I don’t see any burnt resistors or evidence of damage to any of the caps etc.

I will deoxit the jacks, tube sockets, and pots. Beyond that,
-is the buzz pointing to anything specific?
-what else should I be doing while I have it open?

Photo essay follows.
















I bet the junction below was/wasn’t fun, looks awesome.


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## cboutilier (Jan 12, 2016)

Those sure are ugly inside.


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## keto (May 23, 2006)

More pics. I didn’t realize that lip was there, the 2 screws hold the chassis in place even after the long vertical bolts are out, genius.








And the nuts and channels are built into the chassis, so much win.


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## keto (May 23, 2006)

cboutilier said:


> Those sure are ugly inside.


There is a lot going on, I’ll give you that much


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## Lincoln (Jun 2, 2008)

well, someone has been in there and possibly chasing the noise you described. It will be interesting to hear what the techs have to say.


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## keto (May 23, 2006)

Lincoln said:


> well, someone has been in there and possibly chasing the noise you described. It will be interesting to hear what the techs have to say.


The white plastic wire running power (I think?) and the modern resistor on the light, what else? The orange caps?


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## Alan Small (Dec 30, 2019)

your power filter cap(s) are way past due as mine were...as soon as i recapped my ring modulation issue( ghost notes) disappeared


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## Lincoln (Jun 2, 2008)

keto said:


> The white plastic wire running power (I think?) and the modern resistor on the light, what else? The orange caps?


Yes, those orange caps for sure. I also noticed a brown coloured capacitor that is identical to capacitors that a well know Edmonton tech sells on ebay. The brown cap on V1


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## jb welder (Sep 14, 2010)

Does it sound at all like the boost (maybe bleeding in a bit)?
Or like what @Alan Small mentioned?
I guess crossover distortion could also be possible but it would have to be biased very cold to be that noticeable.


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## keto (May 23, 2006)

jb welder said:


> Does it sound at all like the boost (maybe bleeding in a bit)?
> Or like what @Alan Small mentioned?
> I guess crossover distortion could also be possible but it would have to be biased very cold to be that noticeable.


It could be bleed, it’s not an unpleasant noise, just keeps the clean from being really clean at low volume. I’m not getting ghost notes.


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## StevieMac (Mar 4, 2006)

This is just a kick at the can but the last time I experienced something similar to what you're describing, it was traced to the PI tube. Obviously that may or may not address your issue but replacing that tube, tightening things up in the socket, and re-seating worked for me. YMMV.


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## Frenchy99 (Oct 15, 2016)

I would try different pre tubes first. Clean the sockets.


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## keto (May 23, 2006)

StevieMac said:


> This is just a kick at the can but the last time I experienced something similar to what you're describing, it was traced to the PI tube. Obviously that may or may not address your issue but replacing that tube, tightening things up in the socket, and re-seating worked for me. YMMV.





Frenchy99 said:


> I would try different pre tubes first. Clean the sockets.


Yeah, I want to hear it with a 12AT7 in place of the 7025, see it it tames it usably, and I’ll try a couple other AT7s in place of the original. And the deoxit regime I described above.


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## keto (May 23, 2006)

Lincoln said:


> Yes, those orange caps for sure. I also noticed a brown coloured capacitor that is identical to capacitors that a well know Edmonton tech sells on ebay. The brown cap on V1


Chuck? If he had his hands on it, I’m sure it’s fine.


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## Sneaky (Feb 14, 2006)

cboutilier said:


> Those sure are ugly inside.


What? You don’t like spaghetti?


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## Latole (Aug 11, 2020)

cboutilier said:


> Those sure are ugly inside.


I agree, all those wiring act like a antenna to capture noise.
A real rats nest. 
You need some experience to work ( and find issue) on this amp or to be very lucky.
Deoxit jack ?? Ok with the use of burnishing tool


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## Jamie McQuistin (Aug 20, 2018)

I have a Champ II which is a stripped down version of your Super Champ, and they look pretty similar on the inside. When running a 7025/12AX7 in V1, mine started to break up when the volume was set at 2. A 5751 increased the amount of clean by a bit, but I settled on a 12AY7 which keeps it clean up to 3-4 on the volume and usable overdrive up to 10. A bit of Deoxit for the pots and tube sockets helped too.



















Good luck!


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## Paul Running (Apr 12, 2020)

keto said:


> there’s a low volume buzz below the note, that fades as the note dies. Definitely not 60 cycle hum.


Ghost notes caused by inadequate power supply filtering.


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## Latole (Aug 11, 2020)

Paul Running said:


> Ghost notes caused by inadequate power supply filtering.


Right, this amp need a new filter caps: Multisection caps can and few single 'lytic caps looking bad in circuits


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## nonreverb (Sep 19, 2006)

Did you try plugging into a different speaker first to eliminate the possibility it's a bad speaker?....The reason I ask is sometimes a speaker with a damaged coil can have a similar effect.


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## Latole (Aug 11, 2020)

_courtesy of Doug Roccaforte_

_www.RoccaforteAmps.com_

Many amplifiers are prone to "ghost notes." It helps to know what kind of amp we're talking about.

Certain capacitor brands, like F+T, LCR have high leakage current. Other capacitors for coupling have ESR problems, sometimes caused by the physical construction, and lead type. Pure copper leads reduce this, and tubular capacitors are less prone. This is because they do not have any flat sides for the signal to bounce off of.

Some amplifiers like _Fender_ _Black/Silverface _models that have the _ghost note_ issue can be reduced by cutting the phase inverter "output" coupling capacitor values in half.

Others generally are just suffering from old, or leaky filters. Vintage amplifiers like _Vox_ _AC30s_ have very low filtering, I believe this was not because of design, but more as an economical approach to save money. The same is true with many amplifiers designed in the 1950s. Increasing the filtering can cure the _ghost note_ problem.

With _Marshalls_ there are two ways to help cancel this out:


Install a luf 600-1000V non-polar plastic capacitor across the last decoupling electrolytic in the line. This is the last filter, which filters the supply for the preamp. The capacitor will be wired to "by-pass" this filter, one lead to ground, the other to the capacitor lead.
Increase the filtering. On 50 watt models, it seems to take another 50mf across the main B+, and another 50mf for the screen supply.

For 100 watt _Marshalls_ expect to add another 100-150mf across the main B+, and at least another 100mf for the screen supply. Now, the amp will be stiffer on bass notes, if not acceptable, you can add anywhere from a 100-200 ohm 209 watt resistor in series with the output transformer center tap, this will give back a looser feel.


*____*


keto said:


> I don’t see any burnt resistors or evidence of damage to any of the caps etc.


To know, you must test caps , not only reading value with a professionnal capacitor checker.


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## Sneaky (Feb 14, 2006)

Suggestion for you while you’ve got it apart, you should install a 1/4” speaker jack on the back. Unrelated to your problem of course, but it’s a good thing to have if you ever want to use the amp with another speaker cabinet.


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## Paul Running (Apr 12, 2020)

Give that amp the time and love that it deserves and it will reward you...the more time that you spend on it, the closer your bond...that passion comes with time.


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## jb welder (Sep 14, 2010)

Latole said:


> _courtesy of Doug Roccaforte_
> _www.RoccaforteAmps.com_
> _..._
> tubular capacitors are less prone. This is because they do not have any flat sides for the signal to bounce off of.
> ...


If this guy figures signal is boucing around inside capacitors, I'm not sure I should trust much else he has to say.
And 1mF = 1,000uF, it's important.


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## nonreverb (Sep 19, 2006)

I think you should just give up and sell this sorry heap to me keto.


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## Paul Running (Apr 12, 2020)

jb welder said:


> If this guy figures signal is boucing around inside capacitors, I'm not sure I should trust much else he has to say.
> And 1mF = 1,000uF, it's important.


That can happen when you play too many games of Pong.
150mfd capacitor bank:


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## Gordie (Mar 22, 2014)

Paul Running said:


> Give that amp the time and love that it deserves and it will reward you...the more time that you spend on it, the closer your bond...that passion comes with time.


Do you own one? Is this your experience with the model?


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## Paul Running (Apr 12, 2020)

Gordie said:


> Do you own one? Is this your experience with the model?


No, I do not own that particular make and model. I speak mainly of antiquity. I have a passion for vintage electronics, especially at the component level.


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## Gordie (Mar 22, 2014)

I bought mine from new, and perhaps I've been guilty of "hacking" inside. I have noises and it needs love and new output tubes. I just wondered if you had some advice. Cheers!


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## keto (May 23, 2006)

Well, depends on budget entirely, and whether preamp or power. The latter, old RCA expensive or JJs current, you can’t go far wrong. The tough one is the 6C10, no longer in production and not that many around in the $100 range even. Lots say a 12AT7 instead of whichever the reverb driver is, I think the 7025. Tungsol current, RCA old/expensive for the 12AX7, and a dozen decent choices in between.


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