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Tube Amp Help/Problem

I have a new preamp. I notice when I turn the volume past 11:00 there is a very audible loud hiss.no hum. It increaes as I turn up the volume and at 11:00 is very audible from a listening position of about 7 feet away with no music playing. Is this a white noise issue? I tried switching the tubes to different positions (12AX7's) and no change/moving cables/interconnects away from power cords etc. This has a phono section built in which is exhibiting this issue. The other inputs do not hiss nearly as much or very little even with the volume cranked up which leads my to believe its not an impedence mismatch with my amp. I have read some of the posts that state they can hear hiss if they put thier ears next to the speaker. Mine is very audible 7 feet away. This is my first tube preamp so maybe this is normal.
autodexr

Showing 1 response by newbee

newbee
4,811 posts
 
Nothing particularily unusual about your situation but it is quite possible to reduce the noise by getting 'low noise' tubes (assuming that you don't have them, or that you present ones are worn out). They cost more but are worth it.

BTW, tube phono sections are often noiser than line stages, and matching the output of a cartridge and the output of a phono stage can make a difference, especially if you are using a low output MC cartridge.

You don't mention your other components but some tube pre-amps have high output and when coupled with amps with high sensitivity and with speakers of high efficiency you will have a hard time correcting pre-amp tube noise without some specific effort.
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