Hiss on a Pre-Amp

  • Thread starter Thread starter bmeador
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bmeador

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How much hiss is normal on a tube pre-amp?

So I just purchased a used PreSonus BlueTube 2 Channel Pre-Amp ( http://presonus.com/html/products/bluetube.html ). I had read some favorable reviews of the unit and thought the price was good.

The machine appears to have a substantial amount of hiss - if I turn up the gain at all (like, a quarter turn) I can hear it and it gets substantially worse as I a increase either the gain or the drive. I hear the annoying sound even when disconnecting the box from all other equipment and plugging my headphones directly into the output, so it's definitely generated by the pre-amp.

How normal is this for tube pre-amps? Should I expect this issue with a new BlueTube? Any recommendations for other models of affordable (i.e. under $200) pre-amps? I think I'm going to have to take this one back. I also don't like the fact that it is lacking an on/off switch.

Thanks for the advice to a newbie,
Brad.
 
Any tube pre will have more noise than it's comparably priced solid state counterparts.

It could just be a worn-out tube though. Try a quality replacement and see if there is an improvement. A lot of tubes that would work fine in a guitar amp wouldn't cut it in a mic pre.
 
if i were you i would take that one back and save up a little more money for something higher quality.
 
Oh. I thought this was "Pi$$ on a Pre-Amp". My mistake. Carry on.
-kent
 
What do you recommend?

Maskedman - what higher quality pre-amp do you recommend when you say "something higher quality"? I'm completely new to this and would appreciate the advice. Thanks.
 
From the Blue Tube manual:

The Blue Tube comes supplied with a 12AX7 vacuum tube that meets or exceeds the stated performance criteria for the unit. We expect some owners of the Blue Tube will try different tubes to investigate the various performance possibilities they might provide. Tube replacement can be
easily accomplished by first unplugging the unit from the electrical outlet and removing the screws which attach the top to the chassis. The tube is mounted in a transverse fashion and care should be taken to properly align the pins on the tube to the corresponding holes in the receptacle. Make sure the tube is completely seated in the receptacle and replace the top of the unit before restoring power to it.Remember: Tube life and performance are affected by how often a tube is used and by how hard the tube is driven when in use. Signs of wear may be exhibited by poor performance or by the tube becoming “microphonic”. Periodic replacement of vacuum tubes is recommended . The time between the suggested replacement varies greatly with use. If you notice a deterioration in sound quality then it’s time to change the tube.
 
Thanks for the advice

I returned it and got an ART. I'm very happy with it so far.
 
You were better off repacing the tube. I did and it solved the hiss problem.
 
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