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Anyone heard of Bogen Amps?

7/18/1997 3:21 PM
Erik M. Wood
Anyone heard of Bogen Amps?
Has anyone ever heard of a company called Bogen? It was apparently based in Paramus New Jersey in the 60's. I am not sure when it went out of business, but I recently picked up a tube PA system at a flea market which bears it's name. The front panel says Bogen Challenger, with the model number CHB-35. It works, the tubes light up and everything, but I don't have the user's manual or a schamatic of the thing for reference. I am interested in tinkering with the thing. It has some interesting features, like a 70 Volt output along with the preamp output. I have been told this is to power remote distribution amps for long cable runs without signal degradation. If anyone knows anything about this company or can give me some suggestions on where to get more information/ manual/schematics, please reply here. I would really appreciate it.  
7/19/1997 9:26 PM
You bet! I'll bet three quarters of the  
small p.a. systems ever installed in  
schools, churches,and the like used  
Bogen amps. I used to play in a garage  
band in high school that used one for  
an organ amp, of all things. Most of the ones  
I ever saw were less than 50 watts, but they no  
doubt made bigger ones.  
The 70 volt tap is used for distributed  
speaker systems such as in a school where  
you have a speaker in every classroom, or  
lots of small speakers spread around a  
large room. Each speaker would have a transformer  
that matched the output of the amp to  
the speaker. I don't think it was ever used  
to drive separate amps. This is still  
pretty much the way that's done - look at  
most small p.a. mixer/amps intended for this  
type application, and chances are you'll find  
a 70V output along with the usual speaker outputs.  
I don't think this output is of much use otherwise.  
Schematics...don't know about that - there's  
an article by Joe Jasniewski that addresses  
conversion of P.A. and integrated amps into guitar amps  
If you haven't seen it, check it out, it's very  
informative and has lots of ideas on what to do  
with this kind of iron.  
His e-mail address is at the bottom of his  
article - as many of these types of amps as he  
has probably seen, he may be of some help.  
Sounds like fun! Good luck, Steve Fillipp
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7/21/1997 1:33 PM
Steve M.

I have a Bogen CHB-100 chassis that came with  
four 7868 tubes, I'm guessing that it puts out  
about 50 to 100 watts. I had a heck of a time  
finding a schematic for it. I finally found it  
in the fourth edition of Jack Darr's Guitar amp  
repair book.  
Anyone have any idea wha the plate load impedence,  
i.e. the output transformer primary would be  
for four 7868s? It is not marked on the schematic. I want to rebuild this as a guitar  
amp, but don't know which tubes to use.  
7/21/1997 2:53 PM
Erik M. Wood

Steve, your CHB-100 sounds exactly like my CHB-35 except that yours has an extra pair of output tubes. They are of the same variety -7868. I am curious, in the book you mentioned, was there a schematic for the 35 watt version? I need one of those, myself. If not, in your travels, did you come across any info on Bogen which might prove useful?  
7/21/1997 6:48 PM
David Axr

Erik, Steve,  
Why don't you try and e-mail them your request for schematics. Let me know what you find out.  
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