Re: Whistle Rock Audio ML12 preamp BUILD/HELP thread!
« Reply #140 on: March 09, 2020, 12:44:50 PM »
Why do you think that?
Whats the problem? you gave no information

The hum can be from a lot of different places and reasons.
Why do you think the PSU is noisy?

Hum can be from a bad ground connection, or a ground loop.
Hum can be also electromagnetic interference from the Power transformer,
it's better to understand first wheres the source for the noise, your PSU might be totally fine

I think you should probably do a seperate thread for your problems and for what you want to accomplish as this thread is for the "Whistle Rock Audio ML12 preamp" project only


Essentially, unless I turn a guitar amp up real loud, far louder than I wish to work, I get no signal. The guy who built it said it was for drums but I can’t get any useful signal in that context either as we just don’t play that loud.

Re: the hum; The actual PSU unit makes noise. There is also a grounding issue but I know about that. I mean that there is a low but audible hum from the power supply as a noise in the room.

My thought was that I would move the transformer and opamp to 4 ML12 cards. This posting here. But if that is not possible I’m back to the drawing board and will post elsewhere gladly. 


TillM

Re: Whistle Rock Audio ML12 preamp BUILD/HELP thread!
« Reply #141 on: March 09, 2020, 12:51:48 PM »
Yes you can build the ML12 with the Jensen transformers and the 990opamp.
But as far as I understand, your pre don’t work like it should.

Re: Whistle Rock Audio ML12 preamp BUILD/HELP thread!
« Reply #142 on: March 09, 2020, 01:02:46 PM »
Yes you can build the ML12 with the Jensen transformers and the 990opamp.
But as far as I understand, your pre don’t work like it should.

Indeed. But it seems more straight forward to me, not try to repair a preamp for which I have no schematic and to simply build a on a known and proven design.

Whoops

Re: Whistle Rock Audio ML12 preamp BUILD/HELP thread!
« Reply #143 on: March 09, 2020, 09:24:57 PM »
I know what you mean and feel.

I also was in th same situation in the past, and I find it's much more easy to build myself a project from scratch that to try to fix or repair an "almost complete project built by another person".

I don't think tracing the schematic would be hard as it seems a simple enough circuit but by the photo you shown it really seems like a huge wiring mess, it doesn't even look like a nice build.

I would do exactly what you suggested, dismantle everything and built another project with the parts from scratch.

I guess you still need an output transformer, no?


Re: Whistle Rock Audio ML12 preamp BUILD/HELP thread!
« Reply #144 on: March 12, 2020, 08:56:50 AM »
I would need an output transformer but I know there  are a lot of sources for those. I honestly wish I could find a way to move these into a 500 format simply... ahh well.