Super Reverb SS Rect?

[buffalono]

Hello All,

I read alot of post here but only post about 1 a year. Recently I came across an odd Fender amp. I'm not sure if it has been modded or came from the factory like this. Here's the scoop.

A friend has a 1968 super reverb chassis that has ss rectification and a 4 ohm output transformer. He has done some research and came up with the following dates on the transformers....

Here are the transformer numbers:
1) Power – 125P7D (606-7-17) [year-1967], instead of 125P5D
2) Output – 125A6A (606-6-34) [year-1966], instead of 125A9A,
3) Choke – 125C1A (606-7-34) [year-1967],
4) Reverb – 022921 (606-7-40) [year-1967],
Chassis Back: A 28941 Under chassis stamp T020668 (1968 week 34).

The amp has had some mods to it, someone took out the tremolo and changed it to a gain stage. It also has 6CA7 tubes in it and it is missing the cabinetry, just an orphan chassis. He also noted that the face plate has "black vertical lines on the faceplate that indicates it to be a Pre-CBS (blackface equivalent) model"

Does anyone know if Fender made supers like this with the ss recto and 4 ohm tranny? He is offering it to me so cause he knows about my tube amp addiction and I've been looking for a chassis to do a Vibroverb clone. I already have a JBL 15 for it.

[Tom Phillips]

Seems like your chassis has Bandmaster power & output transformers installed.
I have seen the black stripe front panels before. They were short lived early silver face designs and I don’t associate any particular significance to them.

In 1968 the wiring was still very neat and well dressed like the blackface amps. Can you add photos of the inside of your amp clearly showing the condition of the wiring and components?

I don’t think that Fender ever made Super Reverbs with the ss recto and 4 ohm OT. However, this is still a good find. The cover plate over the unused octal tube socket hole is the type Fender used but I can't determine if it is stock for your chassis.

Chassis Back: A 28941 Under chassis stamp T020668 (1968 week 34).

How did your friend date the amp from that information? Can you post a close up photo of that area?

Regards,
Tom

[buffalono]

Here are some more pics, and you are right that does look like the little output tranny for a bandmaster. I used to have one and bought a bassman OT to replace it with. I still have the OT but sold the bandmaster so I get a 5f6a kit. To bad my JBL is 8 ohms and the bassman OT is 4.

[olddawg]

[ATTACH=CONFIG]17010[/ATTACH]Here are some more pics, and you are right that does look like the little output tranny for a bandmaster. I used to have one and bought a bassman OT to replace it with. I still have the OT but sold the bandmaster so I get a 5f6a kit. To bad my JBL is 8 ohms and the bassman OT is

There are much more knowledgeable techs concerning this on this board than me, but if it were mine I would use the 8 ohm OT. A one jump mismatch is common practice and it would be 4 ohms with an extension cab anyway. You might try it at least. It cost nothing to do and could save you some cash.

[Tom Phillips]

The inside looks like what I'd expect for a 1968 Fender. I'd agree that amp started its life with a blackface circuit and wiring workmanship. You didn't show the inside where the rectifier is so I can't comment further on what may be up with that. What happen to the 5AR4 rectifier is still a mystery. I see modifications with the brown shielded wire leading off from the 220k channel summing resistors. Looks like a master volume has been added.
I think you have a good chassis to do a Vibroverb clone. You take good photos but it would be nice to see all of the parts of the amp. Closeups are good but wide un cropped shots would help too.

[buffalono]

Thanks for the info guys! Once I get the chassis I'll take some more pics of the guts.
It looks like a project to keep me busy for the winter.

[buffalono]

Here is a close up of the recto board and a wide shot of the chassis from that end.

[Tom Phillips]

Interesting. The configuration you have sure seems like an oddity. The rectifier board is a Fender part and the cover plate on the unused octal tube socket chassis hole is consistent with Fender factory work. I'd be surprised if someone would have went to the trouble to do a conversion to that level of detail including the transformer change. So how and why it got to its current configuration is a mystery to me for now. Still, you have a good chassis to do a Vibroverb clone.
Have Fun,
Tom

[buffalono]

I think I'll leave the ss recto in and just put in the bassman ot I have. Do you think it will be ok to run my 8 ohm JBL 15 with the 4 ohm output trans?

[Tom Phillips]

I think I'll leave the ss recto in and just put in the bassman ot I have. Do you think it will be ok to run my 8 ohm JBL 15 with the 4 ohm output trans?

I agree with leaving the SS rectifier installed. That's the most practical decision given the power transformer installed.
At the risk of starting a can of worms discussion I think it is OK to use your 8 Ohm speaker with the 4 Ohm OT.

[buffalono]

Well, I got the chassis last week and will start on it in a couple weeks as soon as I get the other projects going off the deck.

I'll keep a picture diary to chronicle my adventures.

Thanks again for the helpful info!