BR-9

[Gaolee]

I found the schematics and have calls in to a tech I have used in the past, as well as a well recommended speaker repair and recone shop, but I figured I'd ask here about what to expect in making this thing work properly again. It's a late 1940s lap steel amp, and it is in pretty ratty condition. It's got plenty of "mojo," for what that's worth, but I'm more interested in getting it to work properly than what it looks like.

 

I plugged it in, and all of the tubes glow. After a short time warming up, it makes a whole lot of hum. It amplifies a guitar pretty well, too, although I wouldn't call it loud. The sound, what little there is over the hum, is great. Looking under the chassis, I found what appear to be the original components, most of them looking very tired. I didn't see anything which looked like singe marks, but through the grime, I can't be sure.

 

I'm told the original speaker cone is torn in a couple spots, so that's a given. Other than that, I would like to know what advice any of you have for combating the hum. Would new tubes be enough, or should I assume there are a whole lot of other components which will have to be replaced? Would something simple like installing a grounded cord solve the hum? Thanks in advance for any advice you can give.

[BobB]

Check out www.tubesandmore.com .......this is a great site for parts to restore vintage amps.........Tubes would be a good thing to change and should help the amp run with less hum. Some of the old capacitors may be adding to the hum. Visually inspect them to see if any appear to be leaking. (you may see a bit of corrosion on the surface of the capacitor if it is leaking)

[Gaolee]

Thanks for the reply. All of the parts inside the amp have cardboard tubes, and all of them appear to be oozing something or another. I guess everything should be replaced. I took it to a qualified amp guy, since I don't read schematics. It's going to be interesting to find out what it sounds like when its done. The speaker will be reconed, most likely, since there are a couple big rips in it and what's left is very brittle.

[Guest BentonC]

Let us know how it turns out when the repairs are done (and pics too)

[Gaolee]

Here it is, after being cleaned up a whole lot, but before any other work.

 

 

It is at the shop now, and I didn't give him any kind of deadline, since I don't have one, but I sure am interested to find out what it sounds like. Get a load of the electrical tape cord! I was very, very nervous about plugging it in. The cord is the first thing which has to get fixed.

[Guest BentonC]

Nice- looks like that amp has seen some road time. I'm sure it will be awesome once you get to plug it in!

[Gaolee]

It finally works. The two inputs were identical, but now the circuit is a bit different, and the sounds which come out of the amp are different, depending on which input you plug into. The only way to describe it is a Les Paul circuit (original) and a Strat circuit (modified). Both break up very nicely at fairly low sound levels, although that may be due to the currently mismatched 6L6 tubes. It is cathode biased and it doesn't run a whole lot of voltage, so I'm not concerned about the bias mismatch. The whole point of picking up this amp was to get a sweet sounding but not particularly loud amp. Mission accomplished.