Will An Attenuator Help Reduce This Hiss?


i've got a little bit of tweeter 'HASSSHHHH' that i'm looking to reduce. as soon as i turn on the amp and preamp it becomes audible. placing the preamp into standby, mute, or on an unused input does nothing to change the level. changing the volume of the preamp does nothing to change the level. the only thing i've found that changes it is fully powering down the preamp - this eliminates it entirely.

i've been advised to insert a line level attenuator (endler, goldenjack, etc) between the amp and preamp at the amp inputs to bleed off some gain and reduce this noise.

will an attenuator reduce the 'HASSSHHHH' sound when reducing the level, or even muting the preamp, does not change things at all?

thanks for any inputs,
Scott
128x128srosenberg
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!
If it were me I'd shy away from buying an attenuator until going over the entire system architecture from top to bottom and, as thoroughly as possible, give it the full measure of attention paid to impedence and gain matching that (from what you've described) was evidently never successfully done to start with. Review and replace any and all components that can be said to be violating Ohm's Law so that you'll be able to get back to square one and you won't be eternally confronted with trying to buy expensive bandaids to put on something that needs surgery, knowwhaddamean, Verne?? I really think this is actually the best way forward for anyone in this situation and it will give you better performance for it, to boot!