audio leak issue

[pyonc]

Hi friends,

Even if I turn the preamp volume all the way down, I still hear some faint but audible sound from both speakers.
My preamp at the moment is vintage Marantz 3300 from the 1970s era. Is this kind of leak(or audio bleed?) something you typically experience with vintage preamps? I'm asking because I don't hear it at all when I test with my spare modern preamp.
Your feedback or comment welcome and much appreciated in advance.

[BMWCCA]

Is what you're hearing coming from the source/input selected on your pre-amp?
Do you still hear it when you switch your input to a source that's not connected or not playing program material?

When my Mac C20 did this I asked at a Mac Clinic decades ago and they told me the military-grade circuit boards they used back then simply had some cross-talk that seemed to increase with age and there was nothing that could be done about it other than to make sure there wasn't anything playing in one input while using another as a source. I'd say yours may be coming through the volume control pot, if what you're hearing is the source you've selected to play, even with the volume all the way down. If you like your Marantz and the bleed-through bothers you, just pause the source when you want silence.

[1audiohack]

Hell I have heard some OPPO pre's that pass signal when powered off!

It's hard to say where yours leaks but sometimes shorting plugs on unused inputs can pull the unwanted signal down some.

I don't think it's anything to loose sleep over.

Barry.

[Doctor_Electron]

Hi friends,

Even if I turn the preamp volume all the way down, I still hear some faint but audible sound from both speakers.
My preamp at the moment is vintage Marantz 3300 from the 1970s era. Is this kind of leak(or audio bleed?) something you typically experience with vintage preamps? I'm asking because I don't hear it at all when I test with my spare modern preamp.
Your feedback or comment welcome and much appreciated in advance.

Does this bleed-through occur with all selected input sources? If so, is the level the same for each source?

Are the signal connections to your power amp OK?

Any possibility it could be RF from a broadcast station or local small-time "pirate station? The legal and illegal use of in-house (and further) low-power (or more power) transmitters is growing like the proverbial weeds.

I had a 3300 back around 1978 but had no negative issues with it other than for some unknown reason ( well, I do know) in a horsetrade I lost posession of the 7T that preceded it. Is the 3300 a Los Angeles build? It's been a while...

i would try removing power and exercising all rotary controls (min to max and back at least 10 times) and switches (on - off at least 10 times). You could have a deteriorated portion of the volume pot(s) to where the wiper is not making full contact to signal ground at its lowest setting.

The 3300 may have input and/or output impedances or gain that are higher than the newer unit, with some interaction not heard on the latter.

What if any changes have been made to the system about the time the bleed-through first manifested? Any other sonic anomalies presenting themselves? Are all the input and output jacks in use tight and clean?

Regards, -D-E-

[pyonc]

Thanks much for your kind comments and feedback.
RE forum member BMWCCA's question:
Is what you're hearing coming from the source/input selected on your pre-amp?
Do you still hear it when you switch your input to a source that's not connected or not playing program material?

This is what I have found now:
I don't hear anything from the speakers when I switch my input to a source that's not connected or not playing program material.
For example, when I switch my input to Phono while the music plays on AUX (CD), I simply hear nothing like audio leak from the speakers.
When I switch it back to AUX and turn the volume all the way down, then do I begin to hear again that little audible leak.
Then, as BMWCCA said, what I'm hearing might be coming through the volume control pot itself.
So, I think I had better live with it, as BMWCCA had similar experience with his McIntosh C20.

[pioneer]

I have a fisher 400c preamp that also has sound that you can hear with the volume pot turned all the way down. I have learned to just live with it as my 400c has been recently totally rebuilt, so I know there is no known issue with it. I do have some adjustments that I could turn down but decided I did not want to do that so I keep them wide open. I am also using 4343's biamped with right now a Citation 2 (duece) on the top and two perreaux 2150's bridged on the bottom.

[pyonc]

I have a fisher 400c preamp that also has sound that you can hear with the volume pot turned all the way down. I have learned to just live with it as my 400c has been recently totally rebuilt, so I know there is no known issue with it. I do have some adjustments that I could turn down but decided I did not want to do that so I keep them wide open. I am also using 4343's biamped with right now a Citation 2 (duece) on the top and two perreaux 2150's bridged on the bottom.

Looks like this kind of audio leak is inevitable to some degree in vintage preamps like yours and mine. Glad to know that.
By the way, my main system is 4343, too, driven in bi-amp mode by Marantz preamp, SE400S & Krell KSA 50 power amps.