FS: 4 Jan Phillips 12AT7 tubes $50

[Mikelamury]

I ended up with too many of these than I will ever use, trying to get rid of a few. New working order. Will ship all 4 tubes to Continental USA for $50 or $10 each plus $10 shipping.

[Demanic]

How are they compared to 12AX7's output wise.

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[beaubrummels]

12AT7s (a.k.a. ECC81) are a power factor of 60. 12AX7s are a power factor of 100. That is not a percentage, is a factor, or multiplier of whatever voltage it sees coming in.

Also have to consider, the 12AT7 is 250V 10mA plate with a -12v grid, transconductance is 5500 mhos, whereas a 12AX7 is 250v 1.2mA plate with a -2v grid and 1600 mhos transconductance.

Probably the best layman description for guitarists would be to say the 12AT7 is like turning the gain down by 2-3 numbers on the dial. But that's only if you are using it in V1. If you are using it in the phase inverter (V4 or V3, depending on the circuit), it's not changing the gain but the response of the amp.

(Calling Ewizard...)

[Demanic]

12AT7s (a.k.a. ECC81) are a power factor of 60. 12AX7s are a power factor of 100. That is not a percentage, is a factor, or multiplier of whatever voltage it sees coming in.

Also have to consider, the 12AT7 is 250V 10mA plate with a -12v grid, transconductance is 5500 mhos, whereas a 12AX7 is 250v 1.2mA plate with a -2v grid and 1600 mhos transconductance.

Probably the best layman description for guitarists would be to say the 12AT7 is like turning the gain down by 2-3 numbers on the dial. But that's only if you are using it in V1. If you are using it in the phase inverter (V4 or V3, depending on the circuit), it's not changing the gain but the response of the amp.

(Calling Ewizard...)

Right. I was just wondering if it is more or less powerful than the 12AU7.

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[beaubrummels]

Right. I was just wondering if it is more or less powerful than the 12AU7.

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For anyone's future reference, here's a list of common dual triodes sorted by their power factors
12AX7 - 100
12AT7 - 60
12AZ7 - 60
12AY7 - 44
12AV7 - 41
12AU7 - 20
12BH7 - 17

7025 - 100
6681 - 100
5751 - 70
6072 - 44
5814 - 20
6189 - 17

CV4004 - 95
CV4024 - 60

Sorry for derailing the OP, but if it helps make a decision for the sale...

[eclecticsynergy]

If you're not using your amp's input drive at ten (and who really does?), an AT7 is a good option.
The vintage Phillips are excellent sounding tubes, and the JAN designation means robust military-spec construction.
This is a great deal folks.

[Ascension]

I have been using 80's production Kodak labeled real Blackburn Mullard 4024's as loop or reverb drivers in several amps. These are the US equivalent and a great deal. Need to look in my tube box to see how many of the Mullards I have left. May grab these depending. These should work well in particular as reverb drives loop drivers and phase inverters.

[Mikelamury]

Update - there are still 3 available at this time. $10 each plus $10 shipping or $40 for all 3 shipped.

[Mikelamury]

3 still available - $40 shipped or $10 each plus $10 shipping.

[Mikelamury]

Meow...

[Mikelamury]

There are 2 of these JAN Phillips 12AT7 tubes left. $30 shipped to USA.

[jeremy]

these are some of my favorite pi tubes, especially in bf/sf fender amps. if i didnt have a stash, id have grabbed all four. great tubes!!

[Mikelamury]

these are some of my favorite pi tubes, especially in bf/sf fender amps. if i didnt have a stash, id have grabbed all four. great tubes!!

What would replacing a 12ax7 in the PI position with one of these do?

[jeremy]

the bf/sf amps im referring to all call for a 12at7 as the pi, but if you took a fender hot rod (which calls for a 12ax7) and put a 12at7 in there youd get a cleaner sound at the same volume setting, meaning the 12ax7 will break up earlier in most cases. it somewhat depends on what amp it is since not at pi circuits are the same

[Mikelamury]

2 still available- $30 shipped to USA