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Join date: Dec 2011
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Ι want to replace my stock tube on my AMT ss-20 (preamp) and I've been suggested those by the local guitar tech:

For starters all of those are 12ax7 preamp tubes (right?!)

Which would you suggest for blues/rock to heavy metal (80s era)?
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Join date: Dec 2009
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yes they are all the right tube.

the music you play will be more determined by the amp and then guitar / pedals. 1 12ax7 will not make our amp a blues amp and another a metal amp.

there is not that much difference, rather than subtle ones or flavors if you will that some people find preferences.

now if you change the tube type, like a 12au7....that will kill your metal, as it will drop the gain about 70%.

those are all very nice tubes. i have no experience with TAD and stray away from GT just cause i want the original, not a rebranded. however that in no way makes it less good, thats just me.

i like tung sol tubes and think tehy do have a nice bite that would be good for metal. that is a high end one with gold pins etc. even the standard new production tung sol would work well.

perhaps somebody else can speak for the TAD and GT.
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Join date: Jul 2008
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Groove Tubes are rebranded. Personally I avoid rebrands because I'd rather know exactly what I'm getting.
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The Name's Devon! ;)
Join date: Sep 2007
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First off, don't buy gold pins. That's just snake oil.

Second, I would avoid Groove Tubes, like said, because they're just other tube brands that say "Groove Tubes" on them.

Personally, I would go JJ ECC83S It's a great all-around tube. Most users on here agree that JJ makes some of the best current production tubes on the market. Tung Sol's are fine, too, but some people say that they are too thin or a little harsh. Personally, I use a few in my amp's preamp, with the rest being JJ.

What did you amp have in it before? If you were happy with the sound, you could always just put the same thing in it
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Join date: Dec 2011
633 IQ
The power amp which is a marshall 20/20 has el84s and an ecc82 preamp valve. I want to change my preamp's tube (an SS-20 AMT preamp) because I've heard from other owners (of the amt preamp) that it improves the tone qualities. The stock valve inside the AMT is an Electro Harmonix ecc83 12ax7. So ecc803 can't be used at ecc83 sockets?

I want to do this to experiment and may be improve my "toanz", while changing something on the more mobile side of my rig (I don't like carrying a rack along my guitar and pedal-board at every live)

Sorry for being clueless :\ and thanks for your answers..
The Name's Devon! ;)
Join date: Sep 2007
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ECC803's are the same as 12ax7's except for tube dimensions, iirc. I don't have any, but Cathbard would be who I would ask about this. It might not fit in the enclosure, if anything. Also, that 12ax7 in the power amp is not a preamp tube, it's the Phase Inverter, which is a part of the Power section. If I were you, I would put a JAN Philips 5751 in that slot. For the preamp, if you really want good tone, go NOS. It's pretty expensive, though. If not, JJ ECC83S

I would also retube the power tubes with JJ's
Grumpy Old Tech
Join date: Oct 2009
2,565 IQ
That groove tube is a rebranded eletro-harmonix. They aren't a bad tube but can be a little tinny compared to a JJ. They aren't the worst of the Sovtek factory's tubes but you can do better.

The TAD is a Mullard reissue, also out of the Sovtek factory. Very similar to the one above.

The Tungsol ECC803 is also out of the Sovtek factory. They are a low noise variant of the 12AX7. Most ECC803 tubes can have a tendency to be microphonic so you avoid using them in a combo, it would be fine in your preamp. They are slightly lower gain than a 12AX7 but normally not by enough to notice by ear. I am a big fan of ECC803 tubes but I have never tried the Tungsol reissue one. It's probably decent.

The TAD RT001 looks like it may be a Chinese Shuguang. If they are then the C version would be quite good and the A and B versions would be shit.

My recommendation in a stand alone preamp unit would be the JJ ECC803.

PS. For future reference here is the Groove Tube chart for identifying which one is which.
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Last edited by Cathbard at Dec 10, 2012,