Groove Tubes GT-5751M Specifications

GROOVE TUBES GT5751M DUAL TRIODE

The 5751 is slight variation of the popular 12AX7. It
is interchangeable in all circuits calling for a 12AX7.
It can be effectively used to “customize” the amp's
preamp stage to reduce gain when placed in the V1
position (first gain stage in the signal path). This
will also allow for more clean headroom before dis­tortion and soften the dynamics as well. Stevie Ray
Vaughan used NOS 5751 preamp tubes in many of
his Fender amps for this purpose.
Our exclusive GT5751M tube design, like its close
sister the 12AX7M, is an exact replica of the origi­nal British built Mullard ECC82/12AX7 dual triode
preamp tube, but with slightly lower 5751 Gain and
TC specs.
This famous Mullard dual triode design from the
late ‘60s has a unique four (different) mica spacer
design that reduces tube hum and microphonics by
suspending the Cathode in a complex mica layered

structure which acts like a shock mount. It is unlike
any other preamp tube ever made (most all preamp
tubes use just a single mica design!). This same
Mullard design was licensed by other tube factories,
such as Amperex, who used this design for its leg­endary Bugle Boy series of preamp tubes.
The GT 5751M has the same great rich classic
sound of the GT12AX7M; a distinct tone along with
high definition no other currently produced preamp
tube can match. It is Aspen’s (our founder’s) per­sonal favorite in ALL his modern high gain amps for
adding that softer vintage touch and tone.
We highly recommended this tube for the Fender
Hot Rod Deluxe amps to fatten up the tone and
“tame” the higher gain preamp stage. You will get
more natural power tube distortion that will be
controlled more so by the player’s touch, than the
Gain and Volume settings.

PINOUT DIAGRAM

All specifications subject to change without notice. All rights reserved. 0107-JKC-5751M

*SPECIFICATION MEASUREMENT PROCEDURES

The measurements on this sheet are actual test results of current production tubes made in a neutral and con­sistent manner for the purpose of fair comparisons. We decided not to use just reprinted “target specs” from
an old RCA book like most, if not all, current production spec sheets released today. If these specs do not meet
the old RCA or GE published spec sheets, do not be alarmed. In fact, NO tubes made today meet all these orig­inal specs, and only a few come even close in the critical areas of Transconductance and/or Gain.

We believe it is more important to provide our customers a meaningful standard by which ALL tubes made today
can be compared. So beginning with our 2007 spec sheets, our first ever published, ALL the tubes we manufac­ture and/or made in other factories and/or other tubes that are in our catalog will reflect actual test results and
averaged over at least 10 samples. As production quality rises and falls (frequently) we reserve the right to make
these results subject to change as and performance rises, or falls. Current data sheets reflecting latest produc­tions can be found on the GT website at www.groovetubes.com.

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SPECIFICATIONS*

Class A Amplifier

Plate Voltage: 250 V
Grid #1 Voltage: 3 V
Amplification Factor: 65
Plate Resistance: 48KΩ
Transconductance: 1300µ
Plate Current: 1.1mA
Heater Voltage: 12.6 V