Bogen CHB14A conversion help needed

[billdramp]

Hello everyone! This is my first post, and ... first amp conversion. I have built one amp kit so far (a Weber 6o100), and also, one clone amp from schematics online ( a JMP MV 100watter)... just to give you an idea of where I stand.

I know some things about building amps, and know how to follow a layout / schematics... but do not really "understand" how/why things work yet... I'm still learning.

Anyway... I came across a BOGEN CHB14A amp today, and would love to turn it into a Marshall style amp...

I would love any advice or insight that some of your members may have with helping a newbie make this conversion... Please keep in mind my skill level, and bear with me with any "stupid" questions I may have.

Thanks so much for reading this, and taking the time to help me learn about this great hobby.

Cheers from Portland, OR.

Billy

[olive2sing]

Welcome Billy, I'm not one of the experts here I'm one of the students. I converted a Bogen MX30A about ten years ago and what I wanted was a clean and a dirty channel. So I looked up schematics and built 2 channels one from a black face Fender, and one a JCM800. I lucked out and got the sound I was looking for. I'll share some of the mistakes. The MX series had what I thought was a perfect place to put the input jacks until I heard the hum. I had them mounted next to the transformers.(stop that laughing guys) I learned why latout is so important. I kept the Power amp the same but I replaced all the caps.
The other mistake I made was in the JCM channel, when I first put it together the clean channel sounded great and the dirty channel was crap. I had spent so much time on it I waited a long time to fix the other channel when I decided to find the problem it turned out one cathode resistor was not 2.7K but 27K. I cant believe I waited so long for such a simple fix. I've had that Bogen since it was new in 73. And to think back in the eighties I tried to sell it but no one wanted it. Now you couldn't buy it if you tried.
Good luck

[billdramp]

No sound

Thanks alot for the welcome! And now down to business...

Today I tried to rewire the input and output jacks... afterwards I plugged in a guitar and acheived no sound. All I am hearing is a faint clicking noise when I strum the guitar, sounds like it is coming from the output transformer area?.

Any thoughts on where to start looking next?

There was also no sound in the aux input either...

Any thoughts would be helpful... maybe I wired the outputs wrong, it was a little confusing with the three prong speaker wiring.

Thanks for reading, and hopefully for being able to help me work through this project.

Cheers,

Billy

[billdramp]

It lives!

Well... I solved my own problem. I had the output jack wired up wrong. Once I sorted that out... Plugged in the guitar and strummed a chord. This thing sounds pretty good on its own, but Im ready to take suggestions on how to get the most out of this little 14 watts.

Thanks in advance for your ideas...

Billy

[olive2sing]

If I remember the CHB is a 2 channel amp Plus the aux channel. The aux is probably looking for a higher level signal than a guitar can put out. If the two mic channels use both sides of a 12ax7 you could remove them both and use the tube for 1 channel with two gain stages. Do you have a schematic for the CHB14? That could tell you what you have to work with and then you can see what you can turn it into.

[olive2sing]

I found a schematic on another thread and I was wrong it is a single channel using a 6au6 for the preamp. It might have been a CHB20 I remember using, whatever it was it had 2 mic channels. Check out this thread for more info and the schematic: Bogen CHB14A project