I picked up this dandy over Thanksgiving weekend for a hot $25. It seems to have been designed as an auxiliary unit for a console TV/radio/turntable, and is only a single channel. I'm enjoying it currently, but would like to get it into the best possible shape I can while keeping its limitations in mind. I typically work with vintage guitar and bass amps, so I've been having a lot of fun learning about tube gear made for clean headroom rather than overdrive.
![Click the image to open in full size.]()
This particular amp couldn't have been used in recent years considering the scratchy pots and overwhelming hum, so I cleaned it up, replaced the filter caps and added a grounded power cord and an inline fuse while I was in there. There is still some hum/buzz that I have to track down, so I'm digging through other posts before I ask questions that will get my primary reasons for posting off track.
Having not worked on anything quite like this, what can those more experienced than me tell me about the design itself? Anything good, bad, or otherwise that you can tell me? I haven't gone through everything point by point yet internally, but I can say all of the capacitors are ceramic discs, which I haven't worked with a whole lot. Any improvement to the tone stack by changing things for different values/types of capacitors? The only part that appears to be totally useless is the input switch (LP/RIAA/78), but correct me if I'm mistaken. The tubes seem to be doing well, and are all original USA or West German tubes rebranded "Dynamic Electronics".
![Click the image to open in full size.]()
Lastly, it has two full range 8" speakers in the open baffle cabinet wired in series running at ~6ohm. The schematic states "6-8ohm", which I've never really seen stated as a range... Any idea what an OT like this handle? I was looking at replacement options and came across the Wild Burro "Betsy". Running one of them would put me just shy of 6ohm, but a pair to fill the cabinet would get me just short of 12ohm. Bad idea on the latter, or not a big deal? I have never dealt with impedance mismatches before, so if I'm missing any important information I'd be happy to track it down.
Thanks in advance for your replies!
This particular amp couldn't have been used in recent years considering the scratchy pots and overwhelming hum, so I cleaned it up, replaced the filter caps and added a grounded power cord and an inline fuse while I was in there. There is still some hum/buzz that I have to track down, so I'm digging through other posts before I ask questions that will get my primary reasons for posting off track.
Having not worked on anything quite like this, what can those more experienced than me tell me about the design itself? Anything good, bad, or otherwise that you can tell me? I haven't gone through everything point by point yet internally, but I can say all of the capacitors are ceramic discs, which I haven't worked with a whole lot. Any improvement to the tone stack by changing things for different values/types of capacitors? The only part that appears to be totally useless is the input switch (LP/RIAA/78), but correct me if I'm mistaken. The tubes seem to be doing well, and are all original USA or West German tubes rebranded "Dynamic Electronics".
.JPG)
Lastly, it has two full range 8" speakers in the open baffle cabinet wired in series running at ~6ohm. The schematic states "6-8ohm", which I've never really seen stated as a range... Any idea what an OT like this handle? I was looking at replacement options and came across the Wild Burro "Betsy". Running one of them would put me just shy of 6ohm, but a pair to fill the cabinet would get me just short of 12ohm. Bad idea on the latter, or not a big deal? I have never dealt with impedance mismatches before, so if I'm missing any important information I'd be happy to track it down.
Thanks in advance for your replies!