QUICKLY: best price/performance ratio, Phase Invertor tube

guitarslinger

guitarslinger

New member
I decided I don't want to be wasting Sino, Square getter Chinese on something like the PI tube if it could better serve me as V1.

Out of these, what would you use as a PI?

JJ ECC83S
Shuguang 9th Gen
Sovtek 12AX7A
Sovtek 12AX7B
Electro Harmonix 12AX7
old RCA 12AT7
old GE 12AT7
 
I have limited personal experience with PI tube swapping - but have done a ton of reading over the years.

What PI tube spec does your amp require ax7 or at7? My inclination would be in this order of preference for an ax7 PI

Electro Harmonix 12AX7
JJ ECC83S
Sovtek 12AX7B
Sovtek 12AX7A
Shuguang 9th Gen (great in some V1 positions)

the GE and RCA at7 would be about the same. I've heard that you should use 'fresh" tubes for PI and replace PI tubes same time as replacing power tubes.

Mike
 
No easy answer here IMO. I haven't jacked around with the PI in the Eggs yet but we switched one out in a Voxcc and it made a dramatic difference. I believe we used a Sylvania 12AU7. This is really a big time matter of preference IMO. Of all the stuff listed I would honestly stay away from the Russian and Chinese and would actually suggest the RCA or GE. I guess my answer is mainly contingent upon level of use as you're indicating both are "old" and not NOS. Pop 'em in and play around. You should notice a big change in how the amp feels. Please report back with your findings as I am interested.
 
I recently tried some 12AT7s as phase inverters, and I can't put a finger on if I like it or not...

Mind you, it was at lower volume levels in my Randall RM20, but still... I could hear a difference.

Are 12AT7s safe to use in that amp?
 
RockStarNick":uejkmnab said:
I recently tried some 12AT7s as phase inverters, and I can't put a finger on if I like it or not...

Mind you, it was at lower volume levels in my Randall RM20, but still... I could hear a difference.

Are 12AT7s safe to use in that amp?
Click to expand...

Yeah they are. I've been using a JP 12at7 in my M4 for a long time, and have been very happy with it. Might have to try the 5751 in there next, as in my Mod50. I turned on my Mod50 for the first time in about a month or so today...It so needs 6550s put back in it. :)

But, in my M4, I've been running a TS 12ax7 and a JP 12AT7 in there for a few months with great results so far. Maybe I'll throw 2-5751s in there and see how that changes things, or just a 5751 to replace the TS 12ax7.

Eric
 
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