Yesterday I was working on an old Sears Silvertone model 1474. A unique amplifier, two separate output transformers, two speakers, and a lot of bad leaky old capacitors (see photo below). In fact nearly all of these green caps were leaking and causing all sorts of trouble. It is fairly typical for old electrolytic capacitors to go bad with age, but somewhat more rare for coupling caps to go bad. For this brand of caps though, I have seen most of them fail.

Once I got it working right it is a nice amp. It has a loud full sound! (4 6L6 output tubes!).

Today I installed The BillM mods into a new-ish Blues Jr.

Seems to have livened it up a bit…..tighter bass response for sure!

1965 Blackface Super Reverb….it has the original electrolytic power supply caps still in it! It also had the orginal bias filter cap and cathode bypass caps. They are were in various states of degradation, so they were replaced with new ones. Amp brought back to its peppy self again! The tremelo circuit was causing a clicking sound, and we cleaned up that too.

A mean little distortion machine..yowzer!

I had a seriously misbehaving Blues Jr. in the shop. Some amplifier problems are intermittant, and that tyoe is more difficult to repair. Then there are the more obvious problems…see below!

blues_jr_before

blues_jr_after

Today I am working on a Fender 5E8 “Twin.” The one with dual rectifiers. Someone, in the amps long past, had removed the rectifier tubes and replaced them with solid state diodes. There is nothing wrong with doing that in general, but, in this specific case it resulted in power supply voltages that were too high for the typical 500V maximum voltage rating of the power supply capacitors. So, I removed the diode rectifier and put-in two nice NOS rectiifer tubes to restore the amp to its original design. This particular amp chassis was re-housed (in the past) in a Tweed Bassman-like 4×10 cabinet. So, it looks, at first glance like a 4×10 Tweed Bassman, but, it is not!

It’s “Fender Tuesday” here at Sunnyside Amps! I’ve got a Deluxe Reverb re-issue and a 1975 Princeton Reverb here in the shop for repairs/mods. They are made so differently.

Check out these two photos of the insides of the 1975 Princeton Reverb and the more recent  Deluxe Reverb re-issue. The Deluxe reverb is the larger of the two.

I have seen quite a very many (!) butchered Fender Hotrod amps. People get a mod kit (which would be fine if installed correctly) and try to install it without the proper skills and tools. Then, the PCB traces get damaged and sometimes the problem is very difficult to find.

I had one of these in last week and there was a PCB trace that looked fine, and tested as having continuity..yet, the amp popped and sputtered a lot until it had warmed-up. As it turns-out, there was a tear in the PCB trace. When the amp was warm the gap between the two segments made a good connection (since the metal traces expand when they get hot ), but when cold the connectiuon was not 100%. Pop Pop crackle….sputter..etc.

So please folks, be careful with your amp modding!

A neat little Valco, single output tube, tube rectified, one preamp tube..this thing screams when you crank it up. It needs a bias adjustment (it is running too hot as a result of todays higher wall voltages), and the owner wants an extension speaker jack..Since the amp has three input jacks we decided to convert one input jack to an ext. speaker output jack so that we could avoid drilling any holes into the vintage chassis!

Pictures and (possibly) video to come later….

Man, this amplifiers needs a lot of work. It was dead on arrival….it is so old that some of the wire has almost turned to dust…..bad pots, bad input jacks, and more!

Note the field coil speaker, and this amp uses octal pentode preamp tubes..they don’t make ’em like this anymore!

Nice woodwork and grille work!