Leftee
09-06-2006, 10:48 PM
Some of you guys know I have a soft spot for old PA amps. You can coax some sweet tube tones from them for very little money. Here's my latest. It's from the 1950's and made by Bell Sound Systems. It's an interesting little amp. It's tube compliment is:
6AV6 (like 1/2 of a 12AX7)
12AX7
5Y3
6L6GB
NOS 6AV6's are available all day long, every day for $3.00 each. I just ordered some NOS (U.S. Navy) 6L6GA's from Terry Kilgore. This single-ended 6L6 setup (cathode biased) has 270v B+.
The amp has a strange voicing setup via that "Acoustic Control" knob on the front panel. It is some sort of tuned feedback to V2B. It goes from a really rich and bassy tone to a mid-prominent tone at the other end of the knob.
I've tweaked the amp out to warm it up a bit, but it's no gain monster. Drop a Bad Monkey in front of it and it sounds stellar! Really cool little amp! The upper end of the Acoustic Control (mid-prominent) sounds really amazing with the Bad Monkey. It has that mid-rangey woody knock of an old Plexi - but at about 5 watts. Really a great tone.
The amp came to me recapped (electrolytics). I recapped the rest of the amp to get rid of the old ceramic disk caps throughout. Also found that the amp was built wrong. The Acoustic Control had an incorrect cap on it - built that way at the factory. Now the control works properly for the first time in it's 50 year life.
I painted the case a faux stone finish. Left the face plate on the amp unpainted. This is a smokin' little amp for cheap. :cool:
http://www.leftee.net/images/pacemaker2.jpg
http://www.leftee.net/images/pacemaker7.jpg
I've got $95 into it delivered to the house. A few more dollars in parts added to that. I've spent more on paint than parts. :D I'll probably add a impedance selector at some point.
6AV6 (like 1/2 of a 12AX7)
12AX7
5Y3
6L6GB
NOS 6AV6's are available all day long, every day for $3.00 each. I just ordered some NOS (U.S. Navy) 6L6GA's from Terry Kilgore. This single-ended 6L6 setup (cathode biased) has 270v B+.
The amp has a strange voicing setup via that "Acoustic Control" knob on the front panel. It is some sort of tuned feedback to V2B. It goes from a really rich and bassy tone to a mid-prominent tone at the other end of the knob.
I've tweaked the amp out to warm it up a bit, but it's no gain monster. Drop a Bad Monkey in front of it and it sounds stellar! Really cool little amp! The upper end of the Acoustic Control (mid-prominent) sounds really amazing with the Bad Monkey. It has that mid-rangey woody knock of an old Plexi - but at about 5 watts. Really a great tone.
The amp came to me recapped (electrolytics). I recapped the rest of the amp to get rid of the old ceramic disk caps throughout. Also found that the amp was built wrong. The Acoustic Control had an incorrect cap on it - built that way at the factory. Now the control works properly for the first time in it's 50 year life.
I painted the case a faux stone finish. Left the face plate on the amp unpainted. This is a smokin' little amp for cheap. :cool:
http://www.leftee.net/images/pacemaker2.jpg
http://www.leftee.net/images/pacemaker7.jpg
I've got $95 into it delivered to the house. A few more dollars in parts added to that. I've spent more on paint than parts. :D I'll probably add a impedance selector at some point.