Bogen Challenger Ch 8

[silat]

Hey Guys,
I recently bought an old  Bogen Challenger 8 watt tube amp for 5.00 from  old guy, it has 5y3 rectifier, a 6l6, and two other tubes. I guess I will send the  Schematic and see if you have time to tell me what my best route would be for making it a decent guitar amp? I added a three prong plug and a fuse it did not have also an input and output speaker jack. It only had  microphone and a headphone jacks  i had gotten rid of. I am not sure how I should go about wiring the input for the best tone. I have sound but it is pretty weak and low... If any of you could help I would appreciate it, if not, I understand how busy you all are.

[eleventeen]

It largely depends upon how much work you want to do, how much skills & tools you have, both in electronics and metalworking, and how much you want to spend. You certainly got a great deal on the bare amp! Oh yeah, and what you'd like to end up with!


Many people here like to preserve the old amp as much as possible and of course change as little as possible. I'm not especially in that camp.


One simple approach would be to gut it and convert it to a Fender Champ, with the twist of having a 6L6 output tube versus a 6V6 (a few more watts) Older, tweed Champs have no tone controls are are truly very-low-parts-count amps. More recent blackface Champs have vol-treb-bass controls and some prefer that flexibility. A Champ w/a 6L6 output tube could be a fairly interesting amp and there have been some threads on that topic here which I am sure users can dig up.


Do you want a Tweedish amp? Do you want tremolo?


Maybe take a pix or two; some thing that matter would be whether the 6L6 is a metal tube, the amount of room you have to work with, whether you want to keep the thing as a bare chassis or install it somehow in a cabinet w/speaker to form a combo amp.


I advocate thinking about it for a while. The amp is probably 60 years old. It will patiently wait while you figure out just how you plan to molest it.

[silat]

Thanks for answering eleventeen! I am not interested in preserving it. But I do not want to gut it either. I want to make it as simple as possible. I have a Tweed 5e3 Deluxe and a Princeton tweed so i am tweeded out right now.

[silat]

Here are two more.

[Toxophilite]

I like conversions
Looks like it has a multitap OT
That's useful.
First get rid of all those nasty leprous wax paper caps!!!
That'll make a pretty big diference to volume, function and clarity etc


I'd just yank what wasn't needed(likely the switch that looks like a function switch, tape, record player ,etc)
and then rewire the signal path with a tone stack between the two preamp tubes
That might turn out neat

[DummyLoad]

I like conversions
Looks like it has a multitap OT
That's useful.
First get rid of all those nasty leprous wax paper caps!!!
That'll make a pretty big diference to volume, function and clarity etc


I'd just yank what wasn't needed(likely the switch that looks like a function switch, tape, record player ,etc)

that's a switched tone control network... i'd leave it be and cascade the two pentodes, each with it's own power rail tap with a bypass switch for the second pentode. you'll need a divider network or level control between the two to tame it down some when desired.

--pete

[silat]

Thanks  Toxophilite and DummyLoad! Yes, I also thought it might be good to leave that switch, as I had seen someone on youtube left it and just rewired it and it sounded really good.

[silat]

I like conversions
Looks like it has a multitap OT
That's useful.
First get rid of all those nasty leprous wax paper caps!!!
That'll make a pretty big diference to volume, function and clarity etc


I'd just yank what wasn't needed(likely the switch that looks like a function switch, tape, record player ,etc)

that's a switched tone control network... i'd leave it be and cascade the two pentodes, each with it's own power rail tap with a bypass switch for the second pentode. you'll need a divider network or level control between the two to tame it down some when desired.

--pete

Pete, do you have a schematic on how to do that? Or know where I can find it here that someone has already done?

[Toxophilite]

 
Why I shouldn't give advice!!
Well you learn something everyday
Still, those caps....ick!

[silat]

Why I shouldn't give advice!!
Well you learn something everyday
Still, those caps....ick!

Those caps I will replace, they are about 60 years old and are more than likely not doing what they are supposed to.

[DummyLoad]

I like conversions
Looks like it has a multitap OT
That's useful.
First get rid of all those nasty leprous wax paper caps!!!
That'll make a pretty big diference to volume, function and clarity etc


I'd just yank what wasn't needed(likely the switch that looks like a function switch, tape, record player ,etc)

that's a switched tone control network... i'd leave it be and cascade the two pentodes, each with it's own power rail tap with a bypass switch for the second pentode. you'll need a divider network or level control between the two to tame it down some when desired.

--pete

Pete, do you have a schematic on how to do that? Or know where I can find it here that someone has already done?

i'll see what i can find. as far as what i recommended goes, i just reverse engineer the amp if i can't find a schematic, then formulate what to i believe would be the best fit for the playing style desired and what'll fit with minimum reworking.


do leave the output stage and power supply as-is but do replace the power supply caps and 6L6 bypass cap. adding a another power tap is simple enough. another thought was to make the second stage pentode switchable to triode mode. IIRC typical mu of 6SJ7 in triode mode is 35-40ish.


--pete

[silat]

I like conversions
Looks like it has a multitap OT
That's useful.
First get rid of all those nasty leprous wax paper caps!!!
That'll make a pretty big diference to volume, function and clarity etc


I'd just yank what wasn't needed(likely the switch that looks like a function switch, tape, record player ,etc)

that's a switched tone control network... i'd leave it be and cascade the two pentodes, each with it's own power rail tap with a bypass switch for the second pentode. you'll need a divider network or level control between the two to tame it down some when desired.

--pete

Pete, do you have a schematic on how to do that? Or know where I can find it here that someone has already done?

i'll see what i can find. as far as what i recommended goes, i just reverse engineer the amp if i can't find a schematic, then formulate what to i believe would be the best fit for the playing style desired and what'll fit with minimum reworking.


do leave the output stage and power supply as-is but do replace the power supply caps and 6L6 bypass cap. adding a another power tap is simple enough. another thought was to make the second stage pentode switchable to triode mode. IIRC typical mu of 6SJ7 in triode mode is 35-40ish.


--pete

Reverse engineering was a lot of what I had in mind anyhow. I am going to leave power supply and output as is.I will change the caps also.  Thanks for your help Pete!