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Power Amp Upgrades

COMPONENTS
Power Amp  864
DECO Amp  864
Preamplifier  770
Amplifier  Upgrades

Discontinued Amps
Power Amp  860
Power Amp  861
Power Amp  860.1

Factory Upgrades
for Models
860 and 860.1 and 861

First ever power amp factory upgrades.


There are 3 basic upgrade options. When you get the upgrades you will receive a "Factory Certificate of Authenticity" that lists the upgrades, old model number, serial numbers, and the new model designation after the upgrades.  The official certificates have a detailed border and embossed corporate seal.  You will also get new metal labels on the chassis with the new upgrade model number.  The labels are gold colored text and logo on a black background.  The labels are placed on the top of the chassis just above the bias controls and next to the Contour control.  The metal labels and Certificate are your proof of the "Factory Authorized Upgrades" and will insure the resale value of your upgraded amps in the future.

The upgrades are ".3" or ".7" or ".8" . This upgrade number will be added to whatever the original model number was.
For example, if you already have the Model 861 amp and are getting the ".7" upgrades; the new model will become 861.7 .

All upgrades must be done at the Granite Audio factory because they are quite involved.  Each upgrade involves reworking circuits, adding new parts, and moving existing circuits.  However, the upgrades involve only the most minor changes to the music signal path.  The meat of the changes is in the power supply where it improves the music performance by lowering the noise floor without changing the music signal path.

Contact your nearest dealer to get more details and to get an RMA number to send your amps into the factory.  You must buy the upgrades through a dealer and arrange a time frame to ship the amps to the factory for the upgrades.  We highly recommend you ship the amps double-boxed in their original factory cartons.  If you no longer have the boxes, we can ship you replacement boxes for an added cost.  Please allow approximately 3 weeks plus travel time for the upgrades.




UPGRADES:

".3" Upgrade.  Input Circuit.
Make the input grid stopper a fixed value. Add grid bypass to V1-6SN7 tube. Modify volume control circuit.  This upgrade adds only 2 resistors to the music signal path.  This upgrade lowers the system noise floor, gives some sonic improvement, and makes the volume control work better.  Prior to the upgrade you may have noticed that the volume control would interact with some brands of 6SN7 tubes in the V1 tube socket.  Prior to this upgrade it was necessary to use only the highest quality tubes in the V1 socket.  This upgrade will cure that issue and allow you to use a wider selection of available 6SN7 tubes in the V1 socket.  It will also lower the signal-to-noise to -90dB.
MSRP   $500.00 pair



".7" Upgrade.  (Also includes the ".3" Upgrade.)
Plate Circuit. Add more isolation and filtration to 6SN7 plate circuit.
Filament Circuit. Convert 6SN7 filament circuit to DC voltage.
This upgrades does not add any parts to the music signal path.  This upgrade takes the amp to a whole new level. You will think you upgraded your speakers too.  This upgrade seriously stabilizes the filament and B+ voltage rails to a whole new level that also takes the signal-to-noise measurement to -99dB at 7.0 volts output.  The bass and vocals are even more clear and clean than before.  The bass is even fuller and richer.  The upper octaves of the piano are cleaner and more accurate.  The notes decay and ring even more realistically.  This upgrade will get your older amp closer to the performance of our newest Model 864 amp without spending $5,000.00.
MSRP   $1200.00 pair



".8" Upgrade.  (Also includes the ".3" and ".7" Upgrades.)
Silver Wire input circuit with #470 Pure Silver Interconnect.  The amp has its internal signal path wired with our world renowned 470 silver interconnect wire.  This wire is 99.9999% pure silver and double shielded to reject noise and make sure you have the cleanest purist path for your music.  Our customers have been asking us to internally wire our power amps with our 470 silver wire for years.  They've come to appreciate the great sonic benefits of the 470 silver interconnect between their top quality components and it only made sense that we finally carry that same super quality wire to the interior circuits that carry the precious music signal.  While this upgrade improves sonics with the better wire, it also improves the noise floor a few more decibels with the dual shielding.  The measured signal-to-noise is -102dB at 7.0 volts output.  (Note:  This silver upgrade is not available on the Model 860 amp because the RCA input jack is already located at the input of the V1-6SN7 tube and there is no wire there to upgrade to silver.)
MSRP   $1500.00  pair

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