Amplifier pre-amp valve replacement Question.

[KaosCill8r]

Hey guys, I have a Marshall Valvestate VS102r amp. It is a valve/solidstate hybrid and has a 12ax7 valve as its pre-amp valve. Has a bit too much early breakup. Was wanting to replace it with a smoother pre-amp valve. Something with a little more clean headroom. Also must be plug n play.

[bronzetalon]

Maybe try 12AT7 though I dont think you will see much of a difference.

[Holy Schnikes]

5751 or 12AY7 are other options. Here's a preamp gain chart as well:

http://www.thetubestore.com/Resources/G ... ain-Factor

[KaosCill8r]

Thank dudes. 5751 sounds like a winner to me. 30% less gain sounds about the result I am looking for.

[Holy Schnikes]

Thank dudes. 5751 sounds like a winner to me. 30% less gain sounds about the result I am looking for.

I've had really good luck with the 5751 in the past but some amps are more sensitive to preamp swaps than others. All just a matter of swapping it in there and trying it out. Good luck!

[rfurtkamp]

It's a Marshall solid state, probably using it as a glorified clippling diode.

Don't think you're going to get much (if ANY) change.

[grindonomicon]

Hey guys, I have a Marshall Valvestate VS102r amp. It is a valve/solidstate hybrid and has a 12ax7 valve as its pre-amp valve. Has a bit too much early breakup. Was wanting to replace it with a smoother pre-amp valve. Something with a little more clean headroom. Also must be plug n play.

Turn the volume up to noon or so, and then use the gain knob as your volume. That's the trick for the earliest Valvestates like the 8080 - 80V combo/ 8100 - 100V head. Works great with the killer Ampeg solid state amps (SSxxx or VH140C), and the better Crates like GX130C, Shockwave GT3500H, or "mini Shockwave" GT120HL.

Most of the Valvestate amps just use the tube on the Gain channel(s), the clean is all solid state / not using the 12AX7, so if you're using the clean changing the tube won't help.

[KaosCill8r]

Hey guys, I have a Marshall Valvestate VS102r amp. It is a valve/solidstate hybrid and has a 12ax7 valve as its pre-amp valve. Has a bit too much early breakup. Was wanting to replace it with a smoother pre-amp valve. Something with a little more clean headroom. Also must be plug n play.

Turn the volume up to noon or so, and then use the gain knob as your volume. That's the trick for the earliest Valvestates like the 8080 - 80V combo/ 8100 - 100V head. Works great with the killer Ampeg solid state amps (SSxxx or VH140C), and the better Crates like GX130C, Shockwave GT3500H, or "mini Shockwave" GT120HL.

Most of the Valvestate amps just use the tube on the Gain channel(s), the clean is all solid state / not using the 12AX7, so if you're using the clean changing the tube won't help.

Using the gain channel. Never use clean channel. Overdrive is always my clean.

[grindonomicon]

Then try the volume up in the noon to 3 o'clock range, and use the gain as the volume first. As mentioned above, the 12AX7 is for clipping, so a lower gain tube might help, but it also might reduce the volume of the amp when using the gain channel. You might try a 12AX7 with the lowest gain too - online vendors will be able to help you select one like that.

[KaosCill8r]

Thanks for your feedback guys. Much appreciated. Will let you know how it goes when I do some experimenting.