Mikelamury
New member
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.
FS: 4 Jan Phillips 12AT7 tubes $50
- Thread starter Mikelamury
- Start date
beaubrummels
Well-known member
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...)
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
PenultimateTone Member
Right. I was just wondering if it is more or less powerful than the 12AU7.
Sent from my SM-A115A using Tapatalk
beaubrummels
Well-known member
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
Well-known member
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.
The vintage Phillips are excellent sounding tubes, and the JAN designation means robust military-spec construction.
This is a great deal folks.
Ascension
Well-known member
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
New member
Update - there are still 3 available at this time. $10 each plus $10 shipping or $40 for all 3 shipped.
Mikelamury
New member
3 still available - $40 shipped or $10 each plus $10 shipping.
Mikelamury
New member
Meow...
Mikelamury
New member
There are 2 of these JAN Phillips 12AT7 tubes left. $30 shipped to USA.
Mikelamury
New member
What would replacing a 12ax7 in the PI position with one of these do?
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
New member
2 still available- $30 shipped to USA
