LUXKIT A3700II

Commentary

Chassis kit for power amplifier whose configuration can be changed by part set sold separately.

The A3700II is a chassis kit for a tube type stereo power amplifier with an effective output of up to 55Wx2.
It includes a chassis, a universal high-capacity power transformer, a high-current choke coil, and a high-voltage block capacitor.
The A3700II can be combined with a circuit part set (sold separately) to complete a tube type power amplifier. The circuit configuration can be selected from 3 connected NFB, 3 connected NON-NFB and UL connected push-pull circuits. In addition, there was a part set for push-pull to take advantage of the vacuum tubes and OY15 type output transformer.

The attached assembly manual lists a single circuit as a recommended circuit.

TCR88
Stereo configuration parts set combining KT88 large beam output tube and OY15-3.6K-HP high power output transformer with low insertion loss.
The first stage is a 3-connection low-noise tube 6267, and the driver circuit is a cathode-coupled phase inversion circuit with 6AQ8. It can be a 3-connection NFB, 3-connection NON-NFB or push-pull circuit with UL connection or a single circuit.

TCRAII
Stereo push-pull parts set combining 5-pole output tube 6CA7 6CA7 which is well-established for audio and new output transformer OY15-5K-HP of high power specification with very low insertion loss.
The first stage is a 3-connection low-noise tube 6267, and the driver circuit is a cathode-coupled phase inversion circuit with 6QA8. 3-connection NFB, 3-connection NON-NFB and UL connection can be made.

CP3700PII
This is a part set for mounting a stereo push-pull circuit using a vacuum tube or OY15. It is a set of resistors, capacitors, sockets, lug plates, and wiring materials. This makes it possible to use a large ST tube such as 2A3 as an output tube. The bonnet may not be used because the shape and height vary depending on the configuration.

I had a self-made tube panel sold separately.
VP-1 is a push-pull tube panel with 4 holes for GT tubes and 4 holes for MT tubes. VP-2 is also a push-pull tube panel with 4 holes for GT tubes and 3 holes for MT tubes.
VP-3 is a tube panel for single, with 2 holes for GT tubes and 3 holes for MT tubes.
VP-4 is a raw tube panel.

Model Rating

Type	Power amplifier kit
Kit Name	TCR88			TCRA7II
Circuit system	3-pole tube connection NON-NFB	3-pole tube connection With NFB	UL connection	3-pole tube connection NON-NFB	3-pole tube connection With NFB	UL connection
Maximum power output	30W	30W	55W	25W	25W	45W
Effective power	25W	25W	50W	20W	20W	40W
Total harmonic distortion factor	Not more than 2% (1 kHz, 25W)	Not more than 0.5% (1 kHz, 25W)	0.5%	Not more than 2% (1 kHz, 20W)	Not more than 0.5% (1 kHz, 20W)	Not more than 0.5% (1 kHz, 40W)
Frequency characteristic	20 Hz to 25 kHz (-1dB or less)	10 Hz to 40 kHz (-1dB or less)	10 Hz to 40 kHz (-1dB or less)	20 Hz to 25 kHz (-1dB or less)	10 Hz to 40 kHz (-1dB or less)	10 Hz to 40 kHz (-1dB or less)
Input Sensitivity / Impedance	650mV/50k Ω	700mV/100k Ω	850mV/100k Ω	600mV/50k Ω	700mV/100k Ω	760mV/100k Ω
Residual noise	1 mV or less	0.5 mV or less	0.5 mV or less	1 mV or less	0.5 mV or less	0.5 mV or less
<Others>
External dimensions	Width 410x Height 168x Depth 237 mm
Weight	17.7kg
Sold Separately	Push-Pull Tube Panel VP-1 (¥ 2,000) Push-Pull Tube Panel VP-2 (¥ 2,000) Tube Panel for Single VP-3 (¥ 2,000) Unprocessed Tube Panel VP-4 (¥ 1,500)