Recent sound deterioration shrillness, ringing


Because of recent speaker changes I've been flooding the forums trying to accommodate these changes and have run into a problem. First, for purposes of this discussion, the chain of components that I'm dealing with is this: Apple TV - Peachtree Audio preamp - RCA TO XLR CABLES - Behringer Ultracurve DEQ2496 EQ - XLR cables to Peachtree 220 power amp - speakers. Using other sources, the problem is the same.

With straightforward RCA connection from preamp to power amp everything sounds great and when I first hooked up everything as described above, it also sounded good. However, that's no longer the case; when hooked up through the EQ the sound turns somewhat shrill with what I would call a somewhat "ringing" effect to it even with the EQ power off which defaults to signal pass through. I've checked all connections for proper polarity and found them all to be properly connected.

Leaving the EQ out of the chain would be the first obvious choice for resolution but using it is the only way I have for connecting a subwoofer. One thing that crossed my mind is that, during setup I accidentally connected the preamp output to line out instead of pre out and thought my walls were going to cave in before I got it shut off.

I hope I've provided enough info for, at least some speculation and will appreciate any ideas that come to mind.
128x128broadstone
The Behringer is a very powerful unit, but it is not considered very good sounding. Check to make sure all the effects are bypassed.
Broadstone...I've been following your dilemma on some of
your other posts.

Why can't you hook up your sub via the high level inputs
and use your amp to connect it? You just parallel the
speaker wires coming out of the amp. Or you could even
run a set of speaker cables from the speakers to the sub,
if that's easier. If your sub has both high level inputs and
then outputs to the speakers, that would be even better.

That would be the solution, unless I'm missing
something?

What kind of sub do you have? Make and model.
Jim (Broadstone), how have you been connecting the sub to the Behringer? If by any chance you have been using an XLR-to-RCA adapter or adapter cable at an output of the Behringer, most such adapters short the inverted signal on XLR pin 3 to ground (XLR pin 1). The output circuits of some components will not be happy under that condition, and damage could conceivably even result in some cases. (There is no problem using such an adapter at XLR inputs, as you indicated you are doing).

Regarding the possibility of connecting the sub to amplifier outputs, assuming the sub can accept speaker-level inputs, your amp is class D, and apparently uses some version of the ICEPower class D modules. Some ICEPower versions have large DC voltages on both their + and - output terminals. I would therefore not connect a powered sub to the outputs of your amp without first getting an ok from Peachtree. Or if Peachtree indicates that the 220 has that kind of an output, using specialized adapters that have been available which utilize capacitors to block the DC.

Best regards,
-- Al