Best Phase Inverter tewb for JMP 2203

Vostre Roy

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Can't say about the JMP in particular, but so far I've been very happy with an 12AX7 ECC803S gold pin Tung Sol in any of my marshall clone builds. Seems to open the dynamic without adding too much fizz (as a regular ECC83S would do)
 

Joshabr1

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Telefunken smooth plate is the best phase inverter tube ever made for any amp.
 

keennay

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Sylvania or Raytheon... whichever one has the green lettering on the tube.
 

ampmadscientist

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Tell me ...

ANY good 12AX7, makes no difference they all will work.
You don't need a special 12AX7 tube.

Telefunken, JJ, etc...they are all good ones.
My standard choice is JJ. Very Rarely have a single problem.

Chinese Sino: lots of gain crunch and sizzle, good for metal.
Sold as Electro Harmonix, Groove Tubes 12AX7CH, and Sino China.
BUT more noise.
 

FutureProf88

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One that works. Honest. V1 is what you hear the most of in the signal. The other two are more functional. I've started using Mesa branded 12AX7's in the PI slot becaus of Mesa's selection procedures. You typically get a reliable, consistent tube from them.
 

chee16

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I like a nice old stock (don't care about NOS, old stock that tests 80% or better from a reputable seller) Sylvania or GE in the PI. A good old stock tube will be much more durable then anything new and that is the main concern with the PI. No need to go rare old stock though.

For new tubes anything will work, but again they won't be as durable in the long run. You might read that you shouldn't use Tung Sol's for the PI but I think the issue was sorted out a while ago. And EH are Russian made tubes, not Chinese.
 

FutureProf88

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Honestly I would think that cathode follower and phase inverter slots would be ideal places for those "I can't believe they're not preamp tubes" like the RetroValves.
 

charveldan

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Running a wet/dry rig today, time based & modulation running thru the DSL loop.

FRIEDMAN is dry and low gain, endless combinations, someone get me a venue ...

I emailed Dave Friedman, he said put 2 of the new [never used] 1963' Mullards in the first 2 slots of the JMP, that has 4 pre's.

Mullards in V1 & V2, Amperex 7025 in V3 and a used Mullard in V4 [PI}.

Big sound, amazing in every way.
 

FutureProf88

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Running a wet/dry rig today, time based & modulation running thru the DSL loop.

FRIEDMAN is dry and low gain, endless combinations, someone get me a venue ...

I emailed Dave Friedman, he said put 2 of the new [never used] 1963' Mullards in the first 2 slots of the JMP, that has 4 pre's.

Mullards in V1 & V2, Amperex 7025 in V3 and a used Mullard in V4 [PI}.

Big sound, amazing in every way.

You could probably put empty Coca Cola bottles in the Friedman and it would sound big.
 

charveldan

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You could probably put empty Coca Cola bottles in the Friedman and it would sound big.
Well i had issues today cuz last nite i put a new Mullard in V1 of both the DSL & JMP and it was an incredible difference.

So Dave told me to put the last new tube in V2 of the JMP and i did but it was like something not making contact well.

So for about an hour i swapped tubes, cleaned jacks with contact cleaner, sanded tewb pins, switched cables, it had something to do with my Holy Grail EH reverb pedal.

Ive had problems with that before.

I pulled the pedal from my board and bought a new TC Electronics mini verb.

TC-Electronic-Hall-Of-Fame-Mini_WEB.jpg


But to be honest with the wet/dry setup the DSL reverb does a good enough job in a pinch.

I could mess with this rig trying options til next year and still have options i havent tried.
 

pedecamp

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Marty always preached putting a lopsided tube in the PI, whatever that means. I never tried it.
 

stalefish

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Tubes don't matter as much when you never leave your apartment or turn up past 1.
 

Joshabr1

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Well this talk that the phase inverter is not as important as other pre amp spots is rubbish. Untill you put in a good telefunken Raytheon black plate or sylvania all long plates you won't know. I like a long plate in v2 and 3. I don't know exactly why but they do shine in these spots. You can put any tube in v3 and then put a nos telefunken in there. If u can't hear the difference you are wasting your time with old tubes to begin with.
 

chee16

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Lopsided PI means that the triodes don't test at the same gain factor. At one point people said a balanced PI is best, and then other well known opinions said unbalanced was best. I have a GE 12ax7wa in the PI of my TSL602 mostly because I bought it off of ebay for a good price and then realized that it's not the most musical tube as far as V1 goes. My preamp is as follows: Mullard I63, Raytheon Black Plate, GE long grey plate and GE 12ax7wa. These sound great. It really does make a difference for the type of music I play, which is low/mid gain blues/rock.
 

Joshabr1

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It's best to try a bunch starting at v1 and see what ur ear likes instead over anyone else's opinion. We all hear a different tune. Hell I got a friend that thinks kossoffs tone sucked. That's a ludicrous statement to me but be believes it! Goes to show you we all hear a different tunes. Some more than others hear this different tune
 

LPMarshall hack

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So let me see if I have this right...

In my 2500 (I assume in most tube amps, the preamp tube sequence is the same?), if I'm looking at the rear of the amp, V1 is the left tube, V2 is the middle tube (duh), and V3 is the tube on the right (the one closest to the power tubes)?

And would V3 be the PI?
 

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