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All SAG kits are selected on a limited
basis. Please do not ask for next day or three day shipment. These
may not always be in stock. When they are ordered they will be built at
that time. This takes about two to four working days after receipt of the
order. If you order this kit with other items your other items will be
held until the kit is done. We prefer not to do partial shipments with
backorders.
Specially selected from premium Groove Tubes preamp tubes which have been
tested in our normal rigorous fashion to meet the GT standard. Special
Applications Group (SAG) provides further testing and grading for certain
performance characteristics.
This three tube set is optimized for your Marshall,
Bogner, Rivera, Mesa or British type amps which use (or will benefit
from) the ECC83 (12AX7) preamp tubes. SAG-MHG includes two
high output preamp tubes to be used in the V1 and V2 positions, and one MPI
(matched
phase inverter) tube for the V3 position. The matched phase inverter may be
a 12AX7 or an ECC83, as it will be matched for it's response curves
with the other two tubes. The phase inverter is not part
of the tone generation stage, it is a current
driver.
The V1 and V2 tubes will increase the front end output structure of your
amplifier from about 10% to as much as 25% or more, over the typical stock tubes
you may have now. Output ranges over 20% need to be discussed as there are
specific aspects which need to be discussed..
The V3, matched phase inverter tube will assure a balanced output section
when used with matched power tubes (highly recommended) which will assure
sustain across the entire range of your instrument.
The MPI (Matched Phase Inverter) is a SAG selected
12AX7 or ECC83, as this tube is not part of the tone generation stage, but part of
the output section and is chosen for its current drive and rise time
characteristics.
Use this MPI in any application where a phase inverter / driver of the
ECC83/12AX7/7025 tube is specified. The phase inverter / driver position
of a guitar or bass amp is a current driving position, and not part of the tone
generation stage. These tubes are selected for specific characteristics,
so may be a 12AX7R, 12AX7C, 12AX7M or another 12AX7 type that has been
selected for specific curve traces as the objective. This tube cannot be
specified as to type in the kit.
These kits also work particularly well
in Fender Blackface and Silverface amps where the increased gain and current out
of the first gain stage combined with a switch from the 12AT7 in the phase
inverter to a 12AX7 will yield a much more agressive tone. These amps
which are normally considered to be on the "clean" side will become more
agressive with this kit.
These kits are very popular in the
Fender Hot Rod series amps.
Each of the three kit tubes is marked as to it's specific rating. In
the future if you wish to change your gain structure, it is a simple matter to
request a higher or lower value as the actual characteristics of your
amplifier's gain stage is now known.
For specific applications, feel free to email or contact
Groove Tubes Special Applications Group. Other SAG (Special Applications
Group) products can be seen at http://www.groovetubes.com/product.cfm?Product_ID=1773
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