Butchered Fender Silverface super reverb

[pompeiisneaks]

Hey,

I've got a buddy having me look over an issue with his amp. I already got it, and added a three prong earthed power and removed the death cap quickly. I didn't have much time to do more. SOmeone had replaced only one of the cathode caps and two of the 5 in the doghouse with newer electrolytics and done some other oddities to it.

It's still working fine, but his complaint is as follows:

The tremolo works, but you have to turn it up to about seven or eight before you get anything and I'm just wondering if new caps or what do you think might actually do the trick?

Also he'd already mentioned the reverb also was good but not super strong. I.e. like the tremolo it almost becomes obvious at about max volume only.

The original blue astrons are in there as well as the original cathode caps (minus the one) and I'm wondering if there's an easy fix to make the reverb stronger, as well as the trem...

Is this a case of just trying new tubes that may be stronger to drive the tank for the reverb?

I'm not 100% sure what version it is, because the butchery someone did was convert it from a 100lb monster into a head, by chopping the top and bottom off and doing who knows what with the speakers.

Ideas of what to look at first?

Thanks in advance, just want to have thoughts on what might be the issue before I peek at it.

Or was the silverface super reverb known for less swampy reverb?

~Phil

[neskor]

Hi.
I have SF Super Reverb and reverb is very strong even on 4.
Try first to replace tubes and then check cathode capacitors in tremolo and reverb circuit.
Also try to replace tremolo Roach and check did you connect reverb tank in right direction.

[pompeiisneaks]

I thought if you placed the reverb connections backwards it wouldn't work? I can check but whoever had connected them had put some red coloring on the cable and the socket so I knew how to exactly put one of them back correctly how it 'was' but that doesn't mean it was right.

As for the trem, I thought the roach was more of a 'either it works or it doesn't' Does that mean they can just start getting weaker instead of full on fail?

I'm pretty confident the thought of new tubes and new cathode caps might help, as I'd suggested both to him, just trying to think of other possible issues before I take it on. Thanks!

~Phil

[Stevem]

You need to get at least one know strong / good testing 12AX7 and AT7 to trouble shoot any Fender amp like this.

The weak Tremolo could be the Optosensor going in south.

Also make note that on these amps if the foot switch jack for the reverb is not plugged in on the back of the amp then having the Tremolo side of the foot switch plugged in will allow activation of the Tremolo.

Basically the Tremolo gets it's on/ off ground path thru the reverb foot switches ground.

[pompeiisneaks]

Excellent info, thanks stevem!

~Phil

[pdf64]

Failing / failed cathode bypass caps may lose perhaps 18dB gain off the fx channel. Which is a lot. And 6dB off the reverb gain. So for a vintage amp, just replace all ecaps.
Most especially the bias supply reservoir, that’s the most critical ecap in the amp, it’s worth splashing out on a 25000 hour type there at least

[pompeiisneaks]

yeah I think I already told him I suspected the caps, and I told him the doghouse had all originals minus someone that replaced only 2 of them with cheap Illinois caps.

I told him right then, that I'd recommend a full recap of all electrolytics, but I think maybe he's trying to save as many pennies as he can on it... /sigh

Often he buys amps on trades he's an amazing bartering genius, and has new amps all the time, and often I think he wants me to fix up the bare minimum to clean their tone up a bit etc, and then he re-sells/trades them for an upgraded 'something else'

~Phil

[pdf64]

His remit wouldn’t leave me much opportunity for job satisfaction. I’m happy to work cheap on stuff I enjoy, but I don’t enjoy doing half a job.

[sonicmojo]

I've replaced the roach in about a dozen Fender amps like this and that is "likely" the problem for the weak trem in that amp.

[pompeiisneaks]

pdf64 agreed, but he's more a buddy than a customer, and it's hard to convince him to do more all the time, and harder yet to say no. He always pays so it's not free work or anything, but it can definitely be unfulfilling knowing I could have done more but he doesn't want it.

Thanks sonicmojo, I'll see if replacing the tube helps first, then go from there.

~Phil

[bmx]

yeah I think I already told him I suspected the caps, and I told him the doghouse had all originals minus someone that replaced only 2 of them with cheap Illinois caps.

I told him right then, that I'd recommend a full recap of all electrolytics, but I think maybe he's trying to save as many pennies as he can on it... /sigh

Often he buys amps on trades he's an amazing bartering genius, and has new amps all the time, and often I think he wants me to fix up the bare minimum to clean their tone up a bit etc, and then he re-sells/trades them for an upgraded 'something else'

~Phil

I have a motto that pertains to people who "Donate" their time. I say, "It ain't free, it's worthless!" No end of characters that have hard won skills that are willing to give away handcrafted pedals and fix old amps for free just for the joy of it. You should be the one piling up a beautiful amp collection. You are being bled! Next time he brings you a tube amp to fix, offer to fix it for $300 or offer to buy it from him for $50. It's probably too late for this guy. He has already priced your time at $0.02/hour. Set some boundaries, get some respect for yourself!

Hope that is helpful! - Ethan

[pompeiisneaks]

yeah I think I already told him I suspected the caps, and I told him the doghouse had all originals minus someone that replaced only 2 of them with cheap Illinois caps.

I told him right then, that I'd recommend a full recap of all electrolytics, but I think maybe he's trying to save as many pennies as he can on it... /sigh

Often he buys amps on trades he's an amazing bartering genius, and has new amps all the time, and often I think he wants me to fix up the bare minimum to clean their tone up a bit etc, and then he re-sells/trades them for an upgraded 'something else'

~Phil

I have a motto that pertains to people who "Donate" their time. I say, "It ain't free, it's worthless!" No end of characters that have hard won skills that are willing to give away handcrafted pedals and fix old amps for free just for the joy of it. You should be the one piling up a beautiful amp collection. You are being bled! Next time he brings you a tube amp to fix, offer to fix it for $300 or offer to buy it from him for $50. It's probably too late for this guy. He has already priced your time at $0.02/hour. Set some boundaries, get some respect for yourself!

Hope that is helpful! - Ethan

I don't know if you noted that I specifically said I charge him labor and he pays it... but I'm glad you think I need some self respect, we all do.

I've never done work like this for free, even to close friends.

~Phil

[bmx]

Hey Phil! I suppose it was as much a note to you as it was a note to myself!

[pompeiisneaks]

No worries just didn't know if you'd seen that I did say so before.

~Phil