Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JB on March 27, 2022, 09:27:37 am

Title: Pro Reverb that says it's a Twin?
Post by: JB on March 27, 2022, 09:27:37 am

A friend of mine has asked me to repair and service his Fender Pro Reverb.  Apparently the Power switch doesn't work, i.e. shorted on, and now the amp has stopped working.  Not dead, he says the master volume pot makes the speakers crackle when turned, so there's hope.
Anyway, the odd thing is the face plate says it's a silver face Twin Reverb.  The tube chart shows 4 x 6L6.  However this amp only has 2 x 6L6. It appears therefore to be a Pro Reverb. The only schematic that, so far, appears to match is a Fender one that seems to cover the ultra linear versions of the Pro, Super and Bandmaster.   Amp serial number and pots date it to 1977.
Any idea why it would be labelled on the face plate and tube chart as a Twin?  My mate bought it secondhand in 1980 and apart from him saying the power switch had to be replaced once before it appears to be untouched inside.

Title: Re: Pro Reverb that says it's a Twin?
Post by: sluckey on March 27, 2022, 09:42:08 am

Fender did some crazy stuff with the Pro Reverbs. Can you provide some pics?

Title: Re: Pro Reverb that says it's a Twin?
Post by: punkykatt on March 27, 2022, 09:43:57 am

They make mistakes from time to time. The person who put the face plate on made the mistake, the person who put the sticker on just looked  at the faceplate is my guess.

Title: Re: Pro Reverb that says it's a Twin?
Post by: JB on March 27, 2022, 09:52:02 am

Quote from: sluckey on March 27, 2022, 09:42:08 am

Fender did some crazy stuff with the Pro Reverbs. Can you provide some pics?

I'll have a go, hold on....

Title: Re: Pro Reverb that says it's a Twin?
Post by: JB on March 27, 2022, 10:20:12 am

Here it is:
(https://live.staticflickr.com/65535/51964604294_f4aab4dda4_b.jpg)

(https://live.staticflickr.com/65535/51964604329_fc6944aa47_b.jpg)(https://live.staticflickr.com/65535/51964880020_1c83cd68b2_b.jpg)(https://live.staticflickr.com/65535/51963317647_ea7f4f24e5_c.jpg)(https://live.staticflickr.com/65535/51964386513_c0724cedaf_c.jpg)

Title: Re: Pro Reverb that says it's a Twin?
Post by: sluckey on March 27, 2022, 11:15:37 am

Definitely a Pro Reverb chassis (only 2 octal sockets) and the voltage selector switch indicates it is an export model.

This looks like the schematic...

     https://el34world.com/charts/Schematics/files/Fender/Fender_ultralinear_pro_rev.pdf

Title: Re: Pro Reverb that says it's a Twin?
Post by: JB on March 27, 2022, 11:23:18 am

Yes I'm in the UK so it's the export version and set to 240V.  I wonder if someone put the wrong faceplate on, and then whoever sticks the tube charts read the plate and slapped in the chart for a Twin.
Must have been made late on a friday afternoon...

Title: Re: Pro Reverb that says it's a Twin?
Post by: sluckey on March 27, 2022, 11:28:36 am

Nah, they only made Pro Reverbs on the midnight shift. Most of the workers loved Cheech and Chong.   :icon_biggrin:

Title: Re: Pro Reverb that says it's a Twin?
Post by: JB on March 27, 2022, 11:45:22 am

Quote from: sluckey on March 27, 2022, 11:28:36 am

Nah, they only made Pro Reverbs on the midnight shift. Most of the workers loved Cheech and Chong.   :icon_biggrin:

In which case it's a wonder it ever worked!
And yes I think that is the schematic.  I'm going to recap it, swap out the power and standby switches that he says are both faulty (the power switch does feel a bit odd) and then take it from there.