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View Full Version : Beresford Caiman preamp problems



magiccarpetride
14-05-2010, 16:42
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
14-05-2010, 16:46
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
14-05-2010, 16:47
How does it sound using the fixed output? :scratch:

StanleyB
14-05-2010, 16:49
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
14-05-2010, 16:53
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
14-05-2010, 16:53
How does it sound using the fixed output? :scratch:

Sounds amazing!

magiccarpetride
14-05-2010, 16:54
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
14-05-2010, 16:56
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
14-05-2010, 17:38
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
16-05-2010, 15:51
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!

magiccarpetride
17-05-2010, 15:56
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.

No, everything's cool now, I've managed to wrestle down the ground loop problem. My review coming later...

Stratmangler
17-05-2010, 16:00
No, everything's cool now, I've managed to wrestle down the ground loop problem. My review coming later...

Excellent !
What was causing the ground loop ? It would be nice to know for future reference, 'cos it's not exactly an exact science.

Codifus
17-05-2010, 16:25
No, everything's cool now, I've managed to wrestle down the ground loop problem. My review coming later...

Since you're now using your DAC as a pre-amp I'm pretty sure you're going on a magic carpet ride of sound right about now:)

CD

magiccarpetride
17-05-2010, 16:27
Excellent !
What was causing the ground loop ? It would be nice to know for future reference, 'cos it's not exactly an exact science.

In my case, it was as Stan had originally advised -- I had to connect the screw at the bottom of the power amp with the screw at the bottom of the Caiman. When I first attempted it, I was sheepish to unscrew the one at the bottom of the Caiman, and I left the wire kind of just touching the screw. That didn't work, but this time, when I actually firmly affixed the wire, the hum disappeared.

magiccarpetride
17-05-2010, 16:28
Since you're now using your DAC as a pre-amp I'm pretty sure you're going on a magic carpet ride of sound right about now:)

CD

Read my review (separate thread), and let me know your thoughts.

StanleyB
17-05-2010, 16:35
In my case, it was as Stan had originally advised --
Some call me a genius, others use less glowing terms :lolsign:.

magiccarpetride
17-05-2010, 16:42
Some call me a genius, others use less glowing terms :lolsign:.

Maestro?