Pass Labs “House Sound” vs. McIntosh “House Sound”

Not sure what might be causing that.

If the analog jumpers are set for too high an output the symptom would be distortion, not hum, and only when the combination of the volume of the music and the setting of the DEQX’s volume control is too high.

I assume that you don’t have the analog main outputs of the DEQX disabled in the configuration, and that you disconnected the XLR cables from the amps when you connected the RCA cables.

Beyond that, I see the following statement on page 160 of the latest version of the DEQX manual, regarding the 75 ohm specification of the output impedance of the unbalanced analog outputs:

[The unbalanced analog output impedance is 75 ohms] into an earth-referenced amplifier i.e. one where the RCA ground pin connects to mains ground. This is normally the case. The precise output impedance is 75 ohms, plus 75 ohms in parallel with whatever the amplifier puts in series between its RCA connector and mains ground. If the latter is open, then the impedance can be as high as 150 ohms (such as may happen with a two-pin power connector).

I’m not quite sure what to make of that, but perhaps there is some kind of incompatibility between the internal grounding schemes of the DEQX and the amps. Which in turn may only manifest itself when unbalanced interconnections are used between the two components, since balanced receiver circuits can be designed (and ideally should be designed) to ignore ground.

That’s about all I can think of at this point.

Best regards,
-- Al

I’m going RCA/sub preout from the DEQX into the REL.

OK. So presumably you are using the volume control of the DEQX to change volume, rather than the one in the preamp.

Assuming that is the case I would reiterate my suggestion of trying an unbalanced connection of the DEQX directly to the power amps. Given the experience I mentioned earlier that was reported to me by another member (who also used a Premate), it seems very conceivable that you might obtain better results that way than with the balanced interconnection I assume you tried previously. And if so, perhaps you can eliminate both the DAC and the preamp altogether.

BTW, I use the unbalanced analog outputs of my HDP-5 directly into my power amp. I’ve never tried its balanced analog outputs, as neither of the power amps I presently have provide balanced inputs.

Best regards,
-- Al

Best of luck with the new preamp, Todd.

Also, could you clarify your statement that "I’m using the RCA sub preout into the REL." As far as I can see the C2500 does not provide a single-channel sub-out, and the REL only accepts a single channel for its line-level input.

Best regards,
-- Al

I do have a REL sub, which is blended quite well into the overall presentation/soundstage, but I often think I’m missing some 200hz and below or it’s getting sucked out of the source material.

Hi Todd,

If I understand correctly the chain you are using is:

Digital Source >> DEQX >> DSJ >> C2500 >> BHK300 monoblocks >> Speakers

Is that correct? 

Also, I'm wondering where and how the REL R-528SE sub is connected.  Specifically, if you are connecting it at speaker level what is the black wire in the Speakon cable connected to, which can be an issue given both that the amps are monoblocks and I believe also have differentially balanced outputs?  And if you are connecting the sub at line-level, given that the sub only provides a line-level input for one channel how are the two channels being summed together?

Also, regarding the experiment you conducted with the C2500 and the DSJ removed from the chain, findings that were reported to me privately by one of the other members who participated in the "Is DEQX A Game-Changer" thread, who like you used a Premate, suggest to me the possibility that the Premate's unbalanced analog outputs **might** be sonically superior to its balanced analog outputs.  So assuming (as appears likely) that your experiment was conducted using the Premate's balanced outputs it might be worthwhile repeating it using the unbalanced outputs. 

Best regards,
-- Al