Beresford Caiman preamp problems

[magiccarpetride]

I've mentioned this in another thread, and got a lot of good advice, which unfortunately didn't help. I'd like to address this problem in a separate thread, to see if I could fix it, or if I'm actually dealing with a faulty unit.

Basically, my Caiman works fantastically well, but when I try to use it as a preamp (connecting variable outs straight to my power amp), I get a very loud, terrible noise.

Initial diagnosis was that it was caused by the ground loop. Try as I might, I couldn't eliminate it. What's more, the noise is very loud and audible with the volume control all the way down, but when I crank it up, it really gets super loud and unbearable.

In addition, playing music via the already noisy Caiman preamp sounds heartbreakingly bad and retarded. There's barely any bass nor highs, and the mids are severely muffled. Is that how the ground loop problems manifest? I have a hunch that maybe variable outputs could be faulty. Is there a way to diagnose that?

I'd really hate to have to replace this unit, as it's been burning in for me quite nicely for the past 10 days or so.

[Stratmangler]

Hook the thing up to your pre as you already do, but connect the DAC to the pre via the variables, whack up the volume on your pre and adjust level with the pot on the Caiman.

That'll show if you have a fault causing the problem.

[Mike]

How does it sound using the fixed output?

[StanleyB]

I advised you to connect a piece of wire between a screw on the DAC and the amp. I assume you have done that and it did not work?
There is nothing else you can do to solve earth loop problems within an existing system if you have tried the various suggestions. I suggest that you send the DAC back and I'll give you a refund.

[magiccarpetride]

I advised you to connect a piece of wire between a screw on the DAC and the amp. I assume you have done that and it did not work?
There is nothing else you can do to solve earth loop problems within an existing system if you have tried the various suggestions. I suggest that you send the DAC back and I'll give you a refund.

Thanks for your generosity, but I don't want a refund, I want a fully functional Caiman!

P.S. I may have botched that piece of wire connection you've suggested (it may be wobbly and losing contact). Will ask a more crafty friend to give it a try.

[magiccarpetride]

How does it sound using the fixed output?

Sounds amazing!

[magiccarpetride]

Hook the thing up to your pre as you already do, but connect the DAC to the pre via the variables, whack up the volume on your pre and adjust level with the pot on the Caiman.

That'll show if you have a fault causing the problem.

Brilliant suggestion, will give it a go. Thanks for your help!

[Mike]

Sounds amazing!

Then I would suspect you're own 'hunch' of a faulty variable output could well be correct.

I'm sure Stan is by far the best person to advise!

[Stratmangler]

I've been having a nose around on the DPA site - apparently their amps are DC coupled.
They also only give out 1v output from the pre to power.
Does this point to the possible cause of the noise issues that Alex is experiencing.

[magiccarpetride]

Hook the thing up to your pre as you already do, but connect the DAC to the pre via the variables, whack up the volume on your pre and adjust level with the pot on the Caiman.

That'll show if you have a fault causing the problem.

OK, I've tried that and, indeed, there is no hum whatsoever! Pretty much sure at this point that the variable outs are working properly, so it's back to the ground/earth loop.

I'll try to implement Stan's advice in a more thorough fashion (fasten the wire between the Caiman and the power amp chassis).

Thanks for your help!