Challenger CH618 (Bogen 18 ?)

knockbill

Lunatic Member
Anyone have a schematic for this amp? A search found some info on Bogen 18 which looks similar in an old AK thread, but the links were removed,,,
Seems the difference is at least the rectifiers,,, 7Z4 on my chassis, 5Y3 on Bogen 18...
I found a semi-stripped chassis, and figured it would make a new project,,, I don't have the exact OPT, but the PT should be easy enough, with an accurate schematic...
Looks like its a PA type mono amp, that guys have used for guitar/harp, also...

Thanks...
 
Thanks Tom,,, I'll clean up the chassis in the mean time...
Update...
Seems a Bogen CH18 is different than Challenger CH618, which has 5 switches/pots...
Pic of the CH618 chassis...
 

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Did a little reading on this amp,,,Challenger was bought out by Bogen after this was made... Seems it was dual power,,, 120VAC or 6VDC battery... there were a couple of vibrators, one to run the phono motor, the other for HV for the amp... I found a PT that will probably work, and restuffing teh cans should be easy enough... only potential problem I see is the multi tapped OPT, but that's not really necessary to get it running...
We'll see how to progress with an accurate schematic... May be use a pair of 6L6s, there are a lot of Bogen amps using them, or a derivative...
 
Check out the attached hand drawn schematic for that CH618 amp. I had previously posted a link for it in this thread on the similar CH18 but it seems the link is now disabled.
 

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Thanks,
I found that thread quickly, but the links were missing,,, that hand drawn schem looks reasonable... I found a different schematic without enough details and voltages to be useful, however it showed 420V on the output plates, which didn't seem right... I don't have the txs for this thing, and have no reason to fool with the 6V supply, so this is a reasonable plan...
I may change it to 6L6s just for the heck of it, tho... Plan is to get it running with parts on hand...
I appreciate your effort!
 
Putting the amp back together using the hand drawn schematic, using a parts PT, and a 5U4 with better filtering ... Bypassing the mic stage for the time being... Other than some missing cap values, it should work... The tone stack is kind of strange as it modifies the FB... Looking fwd to seeing how that sounds!
I would like to try 6L6s since it has a PT that will support them,,, Looking for a CH30, or Bogen PA 30 watt PA schem, but haven't found one yet,,, anyone have a Bogen or Challenger schem that may work here?
Thanks...
 
I have the C-18, C-625 6L6 schematics; also the C-25. These are larger files and would need to be emailed.
 
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On that schematic there seems to be a dead short across the .003 cap on the top pole of the tone switch, what's up with that?
 
Didn't get that far yet,,, but FB is gonna need to be modified, as I don't have a 70V OPT, and that's the winding teh FB starts from... building it with an 8ohm, for now...
 
Yep,,,
I got it almost done with the 6V6 schematic,,, just gotta dial in the PS resistors,,, but I'm going to use one of the 6L6 schems Tinkerbelle sent me...
 
Update,,,
Got it running with 6V6s and an 18W Stancor multi tap OPT,,, basically used the hand drawn schem, but some of the voltages on that were pretty far off also... I used a 5U4 rectifier, and PT that will support it... It sounds surprisingly good, with no FB cobbled in yet... Left the AC heaters in, and its very quiet, just some tape hiss...
Not sure I can call it a Challenger or Bogen, tho!!!
Next try will be 6L6's...
 
Sams schematic below. As I don't think these are common, I entered this model at Radiomuseum.com, using your picture - hope you don't mind.
 

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Appreciate it,,, seems to be pretty rare, couldn't find much on it other than posted here,,, Seems it has two separate power cords, 120V and 6VDC with multiple pins that plugged into a jack on the side, I only built the AC PS... The power jack was also missing ...
I'll post a pic of it as I have it running now, before I convert it to 6L6s...

Still working on the big scratch on front,,, mixed the color pretty close, just needs more paint and wetsanding... My buddy rescued it going from truck load of scrap to dump!!!
OPT is under the chassis for now, I'll try to fit it with a bell and mount it on top..
Thanks again for the interest and schematics... We'll get it!
 

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Sams schematic below. As I don't think these are common, I entered this model at Radiomuseum.com, using your chassis picture - hope you don't mind.

That's the Challenger schem with the high voltage numbers on it...Other than the hand written one posted, I couldn't find one with reasonable readings... I could post a schem of the PS I built, but the PT is just something off the parts shelf...
 
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