bogen c-100 PA (solid state)

[oogared]

Ok, I got my hands on an old SS mono PA that Id like to use as a spare/backup/practice? guitar amp. I already modified the outputs and inputs to accept 1/4" jacks, installed a power plug socket from an old 'puter power supply so I wouldnt have that cord to trip over, and so far its working ok... as a clean amp, once I turn up the volume, it starts to turn into ugly farty fuzz. I was wondering A. if anyone knows where I can find a schematic for it, and B. what I could change in order to de-fuzzify it a bit.
I know that changing/upgrading capacitors and switching diodes for LEDs can have an effect on the distortion, and that carbon comp resistors can fail over time and make bad things happen (I noticed a few on the board) but I havent had the guts to dismantle the amp without a schematic, and even then what to change. Like I said, this is a spare amp, and I got it for free, so Im willing to tear it apart and mess/experiment with it with some guidance.
Thanks for reading all that.

[Enzo]

My first impression is that since it works OK at lower volume, when you turn it up you are simply overdriving the input so it distorts. It isn't a defect, it is just an unappealing distortion. Unless designed for it like in a distortion pedal, I have never found overdriven solid state circuits to sound pleasant at all.

[oogared]

well, ok ill give you that it is only SS, and with that horrible for distortion, but dangit there must be some way to clean it up... maybe i should have posted this in the SS section instead of Musical instruments... it never dawned on me til now

[Nigel Goodwin]

I've always found these types of PA amps are pretty poor for musical PA purposes - but your main problem is that they don't have guitar inputs. You say you've changes the sockets for jacks, but have you altered them for guitar use?.

A guitar requires a high input impedance, and a medium gain - the mike inputs are low impedance and high gain, and the aux inputs are low gain and probably medium impedance. Neither are suitable for a guitar.

I'm presuming you're probably using a mike input?, this will load the guitar excessively (due to it's low impedance) and distort horribly due to it's excessive gain.

You might try using one of the aux inputs?, which will probably be better, but I would suggest building a preamp to place between the guitar and aux input.

[oogared]

ohhhhhhh... that makes sense. so i should try to use the aux input with maybe a distortion pedal set to low gain as a preamp?

[Nigel Goodwin]

You could certainly try it, it depends on how the pedal is designed really - but as you've probably got one already?, it's worth a go!.

[vintagekiki]

I have service manuals with schematics for
Bogen Public Address

Models CTS-1035, CTS-1060 and CTS-1100
Models C35C, C60C and C100C
Models CT35, CT60 and CT100

send me PA model and your email

vintagekiki

[xstephanx]

actually, a while ago me and my friend were palying guitar really loduly, and we got the idea to try the stereo as a gutiar amp. so we wired 3 cheapie 3 ways mono and stuck it in the one channel of the cheapy amp that worked, and cranked it to the MAX, and cranked the distortion pedal. what i heard, was not good. It was actually amazing, it was a really wicked distorted fuzzy tone, and you could really shape the tone with the EQ. although it was a one trick horse and cou ldnt really do cleans or anything, it DID sound nice. Could be useful with an AB switching box.

oh and it was the loudest 20 watts solid state i had EVER heard, it was almost keeping up with my friends 60 watt (tube)guild thunderbass head into a 1x15" cabinet

dont mean to threadjack, just sharing my experiences.

[djedi]

Vintagekiki:
Any chance I can get a copy of the ct60 manual from you?
Thanks
Djedi

[unclejed613]

i guess all of us have tried this at one time or another...... but in audio, just as in other fields of endeavor, use the right tool for the job....... when i got started playing bass, i used an old bogen 50watt pa amp through a stereo speaker..... made a nasty farting sound, but it was better than nothing...... soon i fried the bogen, because it wasn't heat sinked for 50+watts overdriven and near 100% duty cycle. so i went to a pawn shop and paid $50 for a used Traynor YBA-1 and a trashed bass cabinet. i rescued a Jensen 15" woofer from something else and put it in the cabinet. now i had 60 watts clean bass that sounded a whole lot better (still not loud enough, but it could be heard)