Which caps for Dynacord MCX 16.2 output stage?

[HUBA]

I have a rediculously high noise floor on my Dynacord MCX 16.2 mixing desk and figured I could try a recap of the output stage. I have no kvowledge about this whatsoever, but I'm guessing it's simply a matter of switching from old to new with maybe some soldering, and I was hoping someone could point me to some suitable caps?

[henryf]

I don't have any information specific to the Dynacord MCX 16.2, but changing the output caps isn't going to fix a ridiculously high noise floor.

[HUBA]

No? Well it surely can't be the way it sounds when it's fully working. It's too much noise. Maybe I shouldn't have called it noise floor. It's not a wall either, but it's quite loud.

I had the impression that dried caps is a common reason for noise in older equipment(?)

Are there other things that are more likely to cause the noise?

[henryf]

Originally Posted by HUBA

No? Well it surely can't be the way it sounds when it's fully working. It's too much noise. Maybe I shouldn't have called it noise floor. It's not a wall either, but it's quite loud.

Does it sound like hiss? Does it sound like a power-frequency hum?

Originally Posted by HUBA

I had the impression that dried caps is a common reason for noise in older equipment(?)

If the filter caps in the power supply are bad, you could expect some hum.

Originally Posted by HUBA

Are there other things that are more likely to cause the noise?

Everything in the circuit that has resistance adds some thermal noise. Generally, the stuff nearest the head of the amplification chain contributes the most audible noise, since the following stages amplify it.

[HUBA]

Thanks for the help henryf

Originally Posted by henryf

Does it sound like hiss? Does it sound like a power-frequency hum?

It's both at the same time and both the hiss and the hum increases and decreases with volume.

Originally Posted by henryf

If the filter caps in the power supply are bad, you could expect some hum.

Ok thanks. I will look into that.

Originally Posted by henryf

Everything in the circuit that has resistance adds some thermal noise. Generally, the stuff nearest the head of the amplification chain contributes the most audible noise, since the following stages amplify it.

I see. Are there specific critical parts that it might help to replace? Is this doable for a novise? The way I figure, as long as I don't ruin anything in the process, I could just swap back to the original part(s) if replacing wont work or makes it worse.

[henryf]

Originally Posted by HUBA

Are there specific critical parts that it might help to replace? Is this doable for a novise? The way I figure, as long as I don't ruin anything in the process, I could just swap back to the original part(s) if replacing wont work or makes it worse.

If you had access to a user's manual or a schematic for the Dynacord MCX 16.2, that would help. I'm not sure if your mixer uses op amps. Can you locate any on the input circuitry of the mixer? If so, can you identify their type?

[HUBA]

Originally Posted by henryf

If you had access to a user's manual or a schematic for the Dynacord MCX 16.2, that would help. I'm not sure if your mixer uses op amps. Can you locate any on the input circuitry of the mixer? If so, can you identify their type?

Sorry for the late reply. Have been some trouble with my connection. I apprechiate your effort trying to help me on this. I'm trying to track down a service manual on ebay germany. The bidding has ended but it wasn't sold so I'm waiting for a reply from the seller. Until then, and since I'm probably not able to identify an op amp without the service manual, and therefore am reluctant to open up the thing, it will have to wait. Sorry for taking up your time. I will probably post some novise questions again when I get hold of a manual if you'd still like to help. Thanks again

[tinn]

Dear HUBA,
From where do you get a service manual?
I am looking for a DYNACORD EC280 servicemanual.
In old times it was easy, just call DYNACORD (Munich).
Now it is BOSCH and they are unable to supply any manuals of old gear.

Regards, Tinn