PreAmp Tubes

[carl-anton]

The reason I am looking into changing my tube is that I am loosing gain. So I think that my tube is going bad.

If you're loosing gain gradually there might be something wrong. I don't know anything about tubes, apart from how the ones I tried sounded, so I can't help you there. Maybe you could try one of your guitarists many used tubes to see if it's the tube. If your amp is behaving normally, the 5751 shouldn't be a problem. My gain is set at 5 o'clock, so it's pretty high, but it's where the sweet spot is, and I adjust volume with the master vol anyway.

Well, good luck!

 

[seamonkey]

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"This tube will
need replacing if it becomes noisy or microphonic (which sounds like glass tinkling in the background of
certain notes), or completely fails (causing no signal or signal at very low levels). The tube in your 750x
should last one to three years, depending on usage."

 

[iriegnome]

"This tube will need replacing if ...per week over the extent of the last 5 years.

 

[Jonesy4fnk]

any suggestions for replacing the stock tubes in the Ampeg SVP-Pro preamp? Looks like (4) 12ax7 and (1) 12au7 (I'm assuming that this is in the V1 slot. This preamp is a bit noisy so I'm looking for a less microphonic tube. Plus, my Brubaker output is pretty hot, so I might benefit from a little less gain (like from the GE NOS 5751) in the V1 slot.....any suggestions for the SVP-Pro?

While I'm at it I may try out some NOS tubes for my Demeter HBP-1 as well.....I've hear the Mullard (copies) sounds good for these.

 

[Stubb]

For slightly lower gain applications, I can wholeheartedly recommend the JAN GE 5751. Have two of them in my Bassman 100. The gain on the normal channel is right around 6.5. Sounds better to me than the "USA" 7025s that came in it. (What is "USA?")

I also replaced the driver tube with a NOS Mullard 12at7 (from a "USA" 12at7).

 

[tornadobass]

I've tried several preamp tubes in SM-400 and Bass 350 amps and keep coming back to JJ ECC83 for best tone and least noise.

Least favorite are the Sovteks, which tend to be both thin sounding and noisy. Not worth the small savings in cost.

I've also tried an EH that sounded good but had a low hum, and an old GE that sounded almost as good as the JJ, but not quite as full.

BTW, when I had an Eden WT-300, changing the tube had no noticeable difference in tone or other characteristics.

 

[tombowlus]

BTW, when I had an Eden WT-300, changing the tube had no noticeable difference in tone or other characteristics.

+1 I can usually hear something different when I swap preamp tubes, but my Eden Navigator (which I really like) is the only tube preamp I have tried where swapping tubes makes absolutely no difference to my ears.

Tom.