No Sound on a Solarus

[stargeezer]

Hi all,

  I was thinking about building my own tube amp but remembered an old SUNN I had for years that never worked in storage. A guy gave it to me many years ago and it did not work when I received it. I am pretty sure it is a 67 or 68 vintage Solarus combo. I pulled it out of storage and would really like to get it working again. My first step was to replace all of the tubes. Firing it up, all the tubes are lit but I get no sound. Wiggling the guitar cord in the sockets, I can hear a very faint "scratchy pot" sound coming from the speakers. The tubes are as follows (3) 12ax7, 7247, (2)6973, and a 6ca4. I have worked in digital electronics for years but this is my first stab at tubes. I do understand the voltages involved as well. Any road map to follow here?

Thanks,
Brian.

[loudthud]

You don't have the correct tubes. There should be one 12AX7, one 12AU7, one 7199, two 6CA7 (EL34), one 5AR4 (GZ34). There should be a piece of paper glued inside the head box with the correct tube numbers on it. You shouldn't even be able to plug 6973's and a 6CA4 in because they have 9 pins and the sockets are 8 pins unless your amp had some serious mods.

[stargeezer]

Actually, the tube names are factory etched right into the steel case in front of each socket. Every paper tag that was on this amp is gone. Only a tiny SUNN badge remains.

[loudthud]

If that's true, it's not like any Sunn I ever seen. Post some pictures.

[stargeezer]

Here are a few shots of the amp. I have never seen another one like it.

[loudthud]

I think what you have is a Univox, sometimes sold under other names notably Lafayette Radio. Go the link below and look for a schematic that matches the features and tubes of your amp.

http://www.schematicheaven.com/bargainbin.htm

[stargeezer]

I checked the Univox site. Looks like I have an "unknown model" Might be back in storage for this guy.

[stargeezer]

Well I dug a little further and followed a couple of threads. It looks like I have a Lafayette La-100r most likely made by Univox. Thanks for setting me on the right path. The guy I got it from must have put that SUNN label on it.

Brian.