I had both of my amps set up side by side today and there was a BIG difference in volume between the 2 amps. One has an 8 ohm D-130 and the other has a 4ohm K-130. I figured this might have something to do with the difference in volume, so as a test I swapped speakers. This didn't make much of a difference, one amp was still way louder than the other. To give you an example, I had the louder one on 2 and I had to crank the other amp to get it close to the same volume. I've heard that Sho-Bud made 2 different models of these amps. One being 70 watts and the other being 100. If this is the reason for the difference between the 2 amps, could a good electronic guy peak out the 70 watt amp to make it 100 watts? I could probably figure it out but I'd rather take it to someone. Also, this may help in identifying which amp is a 70 watt model and which is a 100. There are several subtle differences in the amps. The louder one has a heat sink under the power amp section, the other one doesn't. The louder one also has a slightly larger front panel. The louder one only has one fuse where the other one has 3. I guess it's possible that there is something wrong with the quieter of the two. Any ideas?
Thanks
David
Sho-Bud Dual Channel (Christmas Tree) Amp
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David
I worked at Music City Mfg in the Mid 70's building amps and the only thing they were making at the time were single channel amps. I do know that the "production" Dual Channel did not have a Heat sink. That was probably added later or may have been an experimental model. The claim was that the single channels were 100 watts and the circuitry is that of a typical 50 watt amplifier. They experimented with different Transistor types and and emitter resistor values to get some power boost out of the 50 watt design.(2 output transistors). Does your dual Channel with the heat sink have 2 or 4 output transistors? It is possible to get 100, even 250 watts out of a 4 output transistor design. The best power amp design I ever saw was a Kustom power module that put out 250 watts with one set of output transistors and emitter resistors and 125 with another. I have been using one of the 250 watt versions since 1974 and it has never blown with some pretty hard abuse.Shorted speaker leads etc.
I have some Sho-bud Schematics of both the single channel and Dual channel(christmas tree) and planning to make some copies if I ever have time and will give copies to anyone on this forum. If you need them, send me a number where I can fax them and I can do that. I work in Chesapeake Virginia and by the time I get home from work the post office is closed and it hasn't opened before I head for work, so mailing is out of the question.
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John
I worked at Music City Mfg in the Mid 70's building amps and the only thing they were making at the time were single channel amps. I do know that the "production" Dual Channel did not have a Heat sink. That was probably added later or may have been an experimental model. The claim was that the single channels were 100 watts and the circuitry is that of a typical 50 watt amplifier. They experimented with different Transistor types and and emitter resistor values to get some power boost out of the 50 watt design.(2 output transistors). Does your dual Channel with the heat sink have 2 or 4 output transistors? It is possible to get 100, even 250 watts out of a 4 output transistor design. The best power amp design I ever saw was a Kustom power module that put out 250 watts with one set of output transistors and emitter resistors and 125 with another. I have been using one of the 250 watt versions since 1974 and it has never blown with some pretty hard abuse.Shorted speaker leads etc.
I have some Sho-bud Schematics of both the single channel and Dual channel(christmas tree) and planning to make some copies if I ever have time and will give copies to anyone on this forum. If you need them, send me a number where I can fax them and I can do that. I work in Chesapeake Virginia and by the time I get home from work the post office is closed and it hasn't opened before I head for work, so mailing is out of the question.
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John