Flatpicker
Well-known member
I?ve had this Bogen CHA-10 lying around for about 10 years and finally decided to take a look at it yesterday. I?d like to turn it into a nice little low wattage guitar amp without having to completely rebuild it, if possible.
If it used 12AX7(s) like most other Bogen amps, it would be simple, but this thing uses a 6AV6 triode for the mic input and a 6AU6 pentode for the gain stage. It also uses feedback and a 5-position switch to form an unique tone control that I have never seen before. Other than that, the rest looks like fairly common stuff.
I noticed that the 6BW4?s heater voltage uses the same winding as the other tubes. Does this make it prone to more hum or something?
Here?s a link to the schematic
If it used 12AX7(s) like most other Bogen amps, it would be simple, but this thing uses a 6AV6 triode for the mic input and a 6AU6 pentode for the gain stage. It also uses feedback and a 5-position switch to form an unique tone control that I have never seen before. Other than that, the rest looks like fairly common stuff.
I noticed that the 6BW4?s heater voltage uses the same winding as the other tubes. Does this make it prone to more hum or something?
Here?s a link to the schematic