Will An Attenuator Help Reduce This Hiss?

thanks for all the great insights, all. to clarify a few questions...

the speaker i am hearing this trough is a Wilson Cub 2 used as a center channel. as ralph surmised, it is relatively efficient at 95 db.

Al, great memory! yes, at one point i was uing the W4S DAC2 as a preamp (can't say enough good things about that piece) however, i have since reconfigured my system enabling both 2-channel and multi-channel operation. the preamp driving the center channel is a Meridian 568.2mm and the power amp is a McCormack DNA-HT1. the interconnects between the amp and preamp are single ended, as the HT1 only offers RCA inputs.

Seems to me that the McCormick has about 30db of gain. This is going to be a bit of a trick.

Do you know how much output your source has? Is is enough to drive the amp directly?

Just to be different, Prometheus TVC's offer up to 54dB attenuation and isolation as well for under $500. Haven't read of any shipping backlogs for years. You can take a look at the Bent Audio stuff as well. If you're up for some DIY, I believe both Goldpoint and Dact have "fine tuning" naked attenuators. The problem with the inline attenuators is that they're only 10K Zin, which is not a problem in itself except in more complex parallel arrangements or with some tube and passive preamps.

NGJockey raises a good point about impedance compatibility. According to my not particularly accurate analog multimeter, though, my 10 db Rothwells consist of a resistor of about 22K in series between input and output, and a resistor of about 10K or 11K shunted from the output to ground. That will result in an overall input impedance, as seen by the preamp, in the vicinity of 30K, the exact value depending on the input impedance of the amp. As NG indicated, that shouldn't be any problem for a solid state component such as the Meridian.

The output impedance of the attenuator, seen "looking back" from the amp, will be in the vicinity of about 7K. Given that the attenuator plugs directly into the input jacks of the amp, with no intervening cable, that would only be a problem if the input impedance of the amp is low AND varies significantly as a function of frequency. Perhaps that is why some people report adverse effects from these things, and others don't?

Best regards,
-- Al

Hi Al, one of the things that causes confusion is the difference between PVCs and TVCs, and the various configurations of each and their interactions with the preamp, cables and amplifier.

The result is there is no single exact solution for every situation, often thus resulting in loss of bass, perhaps brightness, loss of dynamics, etc. One has to be careful!