Up for sale are my favorite amps . Unfortunately , finances force me to sell. I have had them about 8 months or so . During that time i have collected many tubes for these. I had planned on keeping these and never selling them. This is the reason for all of the extra tubes .
Here is a review of the 861. The 864 is much improved on the 861.
https://www.audioasylum.com/reviews/Amplifier-Tube/Granite-Audio/861/amp/65018.html

http://www.graniteaudio.com/

I also replaced all of the coupling capacitors with the "Outstanding" Jupiter Copper Foil Paper and Wax. They were all matched to each other and it required 4 for each amp.. The cost for this was close to $1000.00 . They have taken these amps to another level. You will be amazed by the detail, the excellent Midrange , and Bass that plumbs Very Deep and very articulate. When my funds permit , I would like to own some again. These amps perform flawlessly , and i have not had any issues
All of the tubes are matched sets.
I have many extra tubes.

All tubes are included in the Sale
There is over $1000.00 in tubes.

The is 4 total 6F8G to 6SN7 adapters . This is so you can use 6F8G in place of 6SN7. I like most 6F8G tubes better than most 6SN7 tubes
There is 3 pairs of Sylvania VT-231 (6SN7)
1 matched pair of Arcturus 6SN7
2 matched pairs of Raytheon VT-99 (6F8G)
1 matched pair of 6F8G RCA tubes
There is 2 sets of matched pairs of JAN 6SN7WGTA tubes (short bottle ) These were the original tubes that they shipped with.
1 matched pair of Chatham 5R4WGY Rectifiers
1 matched pair of JAN Cetron 5R4WGB Rectifiers
2 matched quads of Svetlana 6L6GC output tubes
1 Quad of Shuguang Black Treasure KT-88-Z
I will also include the original yellow coupling capacitors.

The 864 has a dramatically improved signal-to-noise ratio of 102dB at rated output. This is due to the all new filament, plate, and volume control circuits. And the THD Total Harmonic Distortion measurement is also improved 50%. Then the 864SR Silver Reference 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. Of course we also offer the 864 without the internal silver wire to give you the choice.

We debuted the all new 864SR at CES in Las Vegas. And everyone was blown away by our sound. You will be too when you hear the 864SR Silver Reference."

These amps are switchable between PENTODE (60 watts each) and TRIODE (30 watts each). The TRIODE presentation is not to be believed. So pure. PENTODE gives slightly better dynamics. Your choice. Further, they have a rotary switch to dial in FEEDBACK or none at all. Finally, each monoblock has a ALPS rotary VOLUME CONTROL so you don't need a preamp with these amps. Really thoughtfully done. All switches gold/silver contacts.
They can run KT-88, 6550A, EL34, and 6L6GC output tubes .

MORE INFO:
Main Details
Maker Granite Audio Brand Don Hoglund Designer Jeff Kida Designer
Function
Amplifier, Power
Additional Model ID 864SR Silver Reference
Channels/Tracks
1 Channel
Form Factor Standard Width
Signal Path Analog Hardware
Date Produced 2012-2018
Dimensions 9"x9"x13" (HxWxD)
Weight 30lbs
Frequency Response 9Hz-48kHz
Notes Silver wiring used on internal signal path.
Additional Specifications
Output Power (Triode) 30W
Output Power (Pentode) 60W
Output Tube KT88 Can use 6550A, EL34, 6L6GC
Tube Complement KT88 (x2), 6SN7 (x2), 5R4-WGB
Input Impedance 100kΩ
SNR 102dB At 7.0V into 4Ω Load
Power Consumption 220W
MSRP $7,500/pr
Connections
Input RCA (Phono, Cinch) Unbalanced, Stereo, Socket (Female)
Output (16, 8, and 4Ω Taps) Binding Post Stereo