General Information
There are 26 A-10 Thunderbolt IIs in existence right now (excluding 2 Ray uses as his personal systems). Mine was picked up earlier in December 2020 leaving only 2 possible A-10 left to be produced by Ray.
Below is a summary of the A-10 Thunderbolt II design from Ray Samuels himself in a Head-Fi thread:
The A-10, Electrostatic Amp/Pre-amp has a fully balanced input to output circuitry, with two balanced inputs, XLRs, and three SE, RCAs. The input/gain stage incorporates two 12AX7 tubes that handle balanced input signals via four section balanced DAC attenuator. In the Pre-amp mode, the signal is passed to two 6SN7 tubes, via relays, which are used as pre-amp output stage ONLY. If electrostatic phones have been selected, the input of the two 6SN7 is grounded to minimize noise and the signal is routed to four 5687 tubes, via relays, which are used as drivers for the phones. When a single ended signal is used, it is routed, via relays, to a single 12AX7, center tube. This tube is used as a phase splitter with a gain of two for both channels. Then the signal is routed to the balanced attenuator which passes it to the two 12AX7 in the gain stage. Because of this design the preamp XLR output will always be in balance even though the SE input source has been used. Also the SE outputs will be available at all time. The A-10 has a balanced and a SE tape loop. The selected source input will be present at these outputs without pre-amplifications to the signals.
The four 5687 tubes are configured in a SRPP topology, each tube drives one phase of the signal. When the Pre-amp is selected the inputs of all four 5687 tubes are shorted to ground to minimize noise. All resistors used are of the highest quality 1% 3 watts film resistors by Vishay. The A-10 also incorporates caps made by Hoovland, the Musicap are the best sounding polypropylene caps in the audiophile world, they are use where needed with a great result. The A-10 uses the mil specs boards that are meant to last a life time, these boards don’t come cheap, with these boards, a mil specs solder is used. All parts are hand selected, matched and soldered. There are no cut corners when it comes to the method of implementing the parts. We match them 100% value wise in all four sections of this amp.
All signal paths and power lanes are separated from each other. They are laid the proper way to ensure that the signal travels clean without any noise added to the output. Parts that are not used during the pre-amplification their inputs are shorted to ground the same is true when electrostatic phones are used, all pre-amplification inputs that are not used are shorted to ground thus the amp becomes a dedicated amp to the mode you select.
The A-10 is designed to work with HE90, HE60, SR007 and the Jade. It is capable of driving all these headphones with utmost authority and control to levels beyond what the human ear can handle without any hesitation, clipping or distortion. You can run two phones at the same time without any problem of loss in quality of sound reproduction.
There are four different voltages in the power supply of the A-10. The bias voltages are fully regulated, no changes as the AC line fluctuates. The A-10 power supply hosts many stages of rectifications & voltage regulation to ensure that the A-10 is always ready to deliver the right voltage & current when needed. There is no compromise when it comes to the heart of the power supply, as we implemented a custom built, to our specs, Toroidal transformer from Plitron.
All the resistors used in the power supply are of the highest quality with Mil specs and 1% tolerance. We also used the high temperature Panasonic electrolytic caps as filters.
Both chassis are made from solid aluminum. They cost a lot. Every part is made to our specs with ultimate accuracy and 100% precision.
Below is a summary of the A-10 Thunderbolt II design from Ray Samuels himself in a Head-Fi thread:
The A-10, Electrostatic Amp/Pre-amp has a fully balanced input to output circuitry, with two balanced inputs, XLRs, and three SE, RCAs. The input/gain stage incorporates two 12AX7 tubes that handle balanced input signals via four section balanced DAC attenuator. In the Pre-amp mode, the signal is passed to two 6SN7 tubes, via relays, which are used as pre-amp output stage ONLY. If electrostatic phones have been selected, the input of the two 6SN7 is grounded to minimize noise and the signal is routed to four 5687 tubes, via relays, which are used as drivers for the phones. When a single ended signal is used, it is routed, via relays, to a single 12AX7, center tube. This tube is used as a phase splitter with a gain of two for both channels. Then the signal is routed to the balanced attenuator which passes it to the two 12AX7 in the gain stage. Because of this design the preamp XLR output will always be in balance even though the SE input source has been used. Also the SE outputs will be available at all time. The A-10 has a balanced and a SE tape loop. The selected source input will be present at these outputs without pre-amplifications to the signals.
The four 5687 tubes are configured in a SRPP topology, each tube drives one phase of the signal. When the Pre-amp is selected the inputs of all four 5687 tubes are shorted to ground to minimize noise. All resistors used are of the highest quality 1% 3 watts film resistors by Vishay. The A-10 also incorporates caps made by Hoovland, the Musicap are the best sounding polypropylene caps in the audiophile world, they are use where needed with a great result. The A-10 uses the mil specs boards that are meant to last a life time, these boards don’t come cheap, with these boards, a mil specs solder is used. All parts are hand selected, matched and soldered. There are no cut corners when it comes to the method of implementing the parts. We match them 100% value wise in all four sections of this amp.
All signal paths and power lanes are separated from each other. They are laid the proper way to ensure that the signal travels clean without any noise added to the output. Parts that are not used during the pre-amplification their inputs are shorted to ground the same is true when electrostatic phones are used, all pre-amplification inputs that are not used are shorted to ground thus the amp becomes a dedicated amp to the mode you select.
The A-10 is designed to work with HE90, HE60, SR007 and the Jade. It is capable of driving all these headphones with utmost authority and control to levels beyond what the human ear can handle without any hesitation, clipping or distortion. You can run two phones at the same time without any problem of loss in quality of sound reproduction.
There are four different voltages in the power supply of the A-10. The bias voltages are fully regulated, no changes as the AC line fluctuates. The A-10 power supply hosts many stages of rectifications & voltage regulation to ensure that the A-10 is always ready to deliver the right voltage & current when needed. There is no compromise when it comes to the heart of the power supply, as we implemented a custom built, to our specs, Toroidal transformer from Plitron.
All the resistors used in the power supply are of the highest quality with Mil specs and 1% tolerance. We also used the high temperature Panasonic electrolytic caps as filters.
Both chassis are made from solid aluminum. They cost a lot. Every part is made to our specs with ultimate accuracy and 100% precision.
