Hohner 1040 Guitar Amp

[CJ]

just fixed a noisy transistor on this thing>

 

[CJ]

for a transistor amp, it sounds killer when over-driven.

uses BC 547 b transistors,

here is the schematic,

has the transformer phase splitter,

circuit board say "Marlboro" on it which is a cheap amp maker,

ok i'm out...

 

[Bo Deadly]

Not clear how the distortion switch works. If 4x4004 means 4 1N4004 diodes, it's not clear how that would do anything being that they would always be reverse biased. Maybe it's 4 in parallel and their capacitance creates a momentary increase in gain to add a little peak to the leading edge of the waveform? Probably very uninteresting compared to the distrotion created overdriving the output stage like in any pignose style amp.

 

[musipol]

I could see it adding some even order harmonics if the diode was reversed(and in parallel as you mentioned above) so as to be forward biased during signal peaks..........but as it stands, I agree with you. How could it work??

 

[JohnRoberts]

Not clear how the distortion switch works. If 4x4004 means 4 1N4004 diodes, it's not clear how that would do anything being that they would always be reverse biased. Maybe it's 4 in parallel and their capacitance creates a momentary increase in gain to add a little peak to the leading edge of the waveform? Probably very uninteresting compared to the distrotion created overdriving the output stage like in any pignose style amp.

Old hand drawn schematics often contain errors. It is clear when the diode anode is grounded the diode is cut off, but unclear what else it is connected to when active.

JR

 

[Newmarket]

just fixed a noisy transistor on this thing>

Oh Dear. You've gone wrong there. It should look like this

 

[panman]

Oh, but those Eminence square-mag speakers are very good sounding. They give a nice overdrive.