bogen chb 100

[cancon]

I've found two schematics for this amp here:

This is an early version which matches my amplifier:
http://rh-tech.org/public/Bogen_chb100.gif

And this is a later version with updated power supply (though they removed the balance control):
http://music-electronics-forum.com/attachments/1432d1198906962-chb100.jpg



If I'm going out of my way to rebuild the power supply, does it make sense to add a diode bridge and upgrade the filter caps to those on the later version?

I'm also curious about the possibility of moving the master volume to a more useful point in the circuit, as well as potentially coupling V1A and B.

Any thoughts?

Thanks!
adam

 

[Enzo]

I don't see a bridge to add. Both circuits use two diodes in the main power supply. Whether they are two discrete diodes or one dual diode block hardly matters. The main diference I see is they went from 40uf to 100uf for the reservoir caps. And increased the second node to 50uf from 20uf. You want to put the larger value caps in? Go ahead.


If you plan to turn this into a guitar amp, as many have done, then think of it as a power amp plus four triodes. make the triodes into any sort of preamp you like.

 

[cancon]

Thanks enzo. Guitar, keys, doesn't matter. You may have opened the links in reverse order, those cap value changes are backwards. To be honest, the only guitar amp I covet are the old fender bassman amps. The main problem I see with this (aside from having the tube layout for a single channel amp), is the phase inverter is totally different. Aside from changing the tube socket, would there be many obstacles in converting the phase inverter/driver to a bassman style long-tailed phase inverter (dual triode)?

 

[Enzo]

Yes, it is a split load PI now. Of you want it to be a LTP, it will use up a dual triode, leaving one more in there for a preamp. If that is not enough triodes, then remove the 6C4 socket, enlarge the hole and install another 9 pinner.