I recently bought a Fender Super Reverb that has a solid-state rectifier instead of a tube rectifier. I cannot find any schematic for a Fender Super Reverb with a solid-state rectifier. Every single schematic shows a tube rectifier. Do I have an oddball amp? It is rated at 70 watts has a 2 1/2 slo-blo fuse and has a 2 ohm speaker output; is there a schematic out there for this amp so I can do some repairs?.

- Joe Landi

Hey Joe,

Well, it sounds like you’ve got yourself a mid-‘70s to early ‘80s silverface Super Reverb. These were the last of the silverface versions prior to the release of the totally re-designed “Riviera era” blackface amps. These 70 watt circuits were offered as a Super Reverb as well as a Pro Reverb and Bandmaster Reverb, and on the bass side as the Bassman 10 and Bassman 70.

Regarding the solid-state rectifier, yes, that is correct for these amps. In a continuing effort to produce amps that were louder and cleaner (because CBS of course knew that that’s what we all wanted from our amps at that time, haha), they moved away from the compression of a tube rectifier to the stability and increased voltage output of a solid-state rectifier. They also redesigned the power transformer to supply yet more high voltage (plate voltage in the area of 500V), and installed the very hifi sounding “Ultra-Linear” output transformer. While these amps retain some of the old familiar names of the Fender amps from the ‘60s and early ‘70s, they are substantially different animals, both in electrical design, as well as tone and response.

As far as a schematic goes, I do have one, so shoot me an e-mail. Hopefully it will help you get your 70 watter from the ‘70s back to new ... or maybe better!

I have a Crate Blue Voodoo 150HB and all the little lights in the back are blown (the little orange lights behind the tubes), now my problem is I need to know the voltage and wattage of the little lights so I can get some new ones. Unfortunately I haven''t been able to find anyone who can tell me the voltage and wattage. The lights that are already in it don''t say anything on them except for the number “47.” They don''t affect the sound, but when they all light up the amp looks so hot. If you could help me out that would be awesome.

– Tom

Hi Tom,

I don’t know why anyone else couldn’t help you, as you already have the answer. They are the ubiquitous #47 lamp (6.3V, 150mA) that has been used as a pilot lamp in many a guitar amp for the last 50 years. It is a very common lamp in most electronic parts stores (if you can find one now-adays), and I think possibly Radio Shack may stock them as well (although probably not for long). You might also simply try going back to the shop you originally took it to and purchasing some #47 lamps. If they’ve ever replaced the pilot lamp in a Fender amp, they should have them in stock. By the way, the orange look to the lamp is simply a rubber sleeve that slips over the glass bulb.

Now you can put the orange glow back in the Blue Voodoo.

I own a mid eighties JCM 2205 Split Channel Marshall. Can you suggest a tube that will help boost my gain? Also, can you suggest a pedal that might do the same i.e. the new BBE pedals?

Thanks. - Loren


While (theoretically) all of the same type of tubes are supposed to be manufactured to the same type of specifications, there are some tubes that wind up exhibiting greater gain characteristics than others. You could try Chinese 12AX7s, or the new Mullard reissue 12AX7. You should be able to source these thru a good amp tech in your area, or they are also available thru Groove Tubes as the GT-12AX7-C and GT-12AX7-M. Groove Tubes also offers sets of Special Application Group tubes. A hi-gain set for a Marshall can be ordered as SAG-MHG. As far as boosting the gain thru a pedal, there is a veritable cornucopia of pedals out there that can perform this function.While I’m not familiar with the new line of BBE pedals, I’m sure my friends Josh and John at Voodoo Labs (voodoolab.com) or Dave at Barber Electronics (barberelectronics.com) can help you find a pedal that fits the bill. Of course, you could always pick up a Budda Phatman or Zenman tube overdrive pedal and be in true sonic nirvana.

Good luck in your quest.

Jeff Bober