Just got an Expression from a member here. Digging the tone, touch sensitivity and dynamics, but one of the preamp tubes is going microphonic. Looking to replace the bunch, but thought I would see who has what where.

What are your favorite pre-amp tubes for your Expressions?

Thanks Poi.

I found a box of older preamp tubes last night, gonna rotate a few in and out of there.

The Expression is a beast, played it for a bit yesterday. Amazing amount of gain, almost uncontrollable at times, this was with my strat!

Problems seem to arise when I touch the treble control or bright switch, microphonics pop up.

It's a tube I'm sure. Unfortunately all of my replacements are crappy too! Looking for some Amperex's now, where did you find yours?

Yeah, I'm leery about eBay and tubes, especially "NOS" there. But I was pricing them on a few different reputable places on-line, $75 a tube is a bit more than I want to spend!

Any suggestions for current day manufacturers? Sovtech? JJ? EH?

Ordered 3 tubes from Doug's Tubes: Sovtek 12AX7WA, Sovtek LPS, Tung Sol 12AX7 re-issue. These are all "low noise, high gain" types that I have read up on and people recommended for the Express style amps. They should be here tomorrow, I'll let you know how it goes...

I recently built my TW Express and it is really a fire breathing monster!
Have experimented with several tube sets including: 6v6, 6CA7 and EL34s.

Judging from the TW clips on YouTube, the original TW cleaned up amazingly and could go from clean to insane with the swell of one's guitar volume. The main problem with the TW Express by default is that it is way over gained, there is no possibility of cleaning up or dialing in any workable tone past volume one (7:00). I would seriously bring this to Nik's attention however I have never played through an original TW and Nik is god in some circles

Here is an original 1989 TW:

I was a little discouraged until I experimented with several preamp tube configurations I have found something that is more versatile from liquid lead to clean. Try using a Tung Sol 12ax7 in V1 and an EH12AT7 in V2. This brought down the gain by 40%. You can further reduce the gain using 12AU7. Check out: http://thetubestore.com/gainfactor.html  The newly designed TungSol 12ax7 have no discernable microphonics! You can tap the EH or JJ 12ax7 and hear how microphonic they really are.


In my experience, I'd further recommend humbuckers as single coils don't drive the TW that well.

Having built the TW I later installed the PVIMV Type II, I personally like the sound of the 6CA7 biased at 40ma. They have a lot more bottom than the EL34s and sound great through my Marshall 4x12 with greenbacks. This is indeed TW nirvana.

I'm reviving an old thread in the hopes that someone might benefit from my trial and error.

 I tried a TON of different combinations of tubes in my Expression and by far the best I've found are V1: either NOS RFT or new production Tung Sol 12ax7 V2: JJecc83s V3: Sovtek12ax7LPS, preamp tubes are important for sure, but the biggest tonal differences I found with trying different EL34s.

 I tried Winged Cs( not bad, but shrill and honky), EHX 6CA7( thin, shrill, and honky), new production Mullard( AWFUL), JJ EL34( ok, but honky), JJ E34L ( a little sluggish and honky), and a few more almost all of them made the amp sound harsh or harsh and honky.

 By far the best I've found are the Shuguang EL34B, sold as Sino EL34B via Tubedepot. Smooth, no harshness, no honkiness. Sounds like a nicely balanced EL34.

A couple other things to note: The PPIMV is almost useless and only sounds good at 3 o'clock or above and sounds best turned all the way up. I found the parallel ceramic and poly caps between V1 makes things too mushy on the low end, especially for humbuckers and even more especially for higher output humbuckers so I removed the .002 ceramic cap. I went from having the bass dialed all the way off to being able to use it between 9 o'clock and noon without any flub or mud. If I used the PPIMV I'd probably not remove the cap however as things get thin quickly once PPIMV is turned down.