2. tech-talk
  3. 1227416784

Background noise problems

Hi,

I posted around 2 months ago on this issue, but like an idiot, I was due for vacation in Bali a few days after I posted and missed most of the conversation. Anyways, I have tried a few more things and was hoping for some feedback....

Here is my situation: I am getting upper-frequency "snow" coming out of my speakers. My current setup is a Gold-level McCormack DNA-125 amp, Herron VTSP-1a/166 preamp, and Sony 9000es CDP that has been upgraded to VSE Level 6, with Tyler Acoustics Linbrook Signature speakers. Except for the snow that I am getting (sounds like a snowy TV) the system sounds great. Unfortunately, I am hearing the hiss around 20 feet away.

Here is what I have tried so far:
1) substituting a Eastern Electric Minimax preamp for the Herron: less of the hiss sound, but still present. I am assuming the preamp has less gain?
2) Substitute a Consonance CDP for the Sony. Not much change in background hiss
3) substitute a Jolida integrated amp for the Herron/McCormack combo, input from the Sony: this virtually eliminated the hiss

I have had the Herron checked over by Keith, replaced tubes, and everything has checked out. The McCormack was recently upgraded, but it is possible something is wrong there. The Sony unit was also recently upgraded from Level 5 to Level 6, but the hiss was there before the upgrade and still remains.

A few notes: I hear the hiss as soon as the Herron is engaged, whether or not it is receiving an input. The hiss is the same on all inputs, whether or not they have an active input or are not connected. The speakers are basically dead silent when only the amp is engaged.

It makes me think that I have some issue with compatibility in my system with the Herron, but as I am still getting some background noise on the substitute preamp, I am wondering where to go from here. The Jolida intergrated was basically quiet, which is a good sign.

Where should I go from here? I have the makings of a superb-sounding system, but need to get rid of this background noise. It can be heard easily in the music. Thanks in advance!
dawgcatching
mr_hosehead
210 posts
 
I thought you pretty much had your answer after try #3. It's based around the McCormack and the connection w/ the Herron. Sorry, but I don't know enough of the details on input & output of those two, but the easy approach would simply be "how did you like the sound with that Jolida?", 'cause that gave you the lack of hiss you wanted.
thorman
1,262 posts
 
Have you tried changing interconnects? Is it possible its a i/c connection between the problem piece...Just a guess...........
Post removed 
mlsstl
1,438 posts
 
The specs on the McCormack show a 98 dB S/N ratio with a 1 volt input sensitivity for full output. The Herron has an 80 dB S/N ratio (for moving coil input) and the speakers show a sensitivity of 92 dB.

The rushing noise you hear is white noise and is typical of the residual background noise you get from gain circuits. All electronics produce this noise, but it is usually inaudible.

Since all the electronics have been checked or recently upgraded, the assumption is they are working correctly. (You also didn't mention any channel imbalance with the noise which could indicate an aging or faulty tube in one channel.)

That leaves the strong suspicion that you have a gain mismatch at work. Speakers a bit more sensitive than usual. A relatively powerful amp. A tube preamp (which often tend to have a bit more residual noise than solid states).

Are there any internal gain setting switches in either the preamp or amp? If there are, try some different settings. If that doesn't help, I'd simply try some different preamps and see if the noise disappears. You'd also want to try some different power amps with the Herron. (Looks like you've already tried different music sources.)

While each piece of equipment you listed is good stuff and has excellent reviews, it may be they are just not suited for each other.
More to discover