Stereo Vacuum Tube Amplifiers

EL34/KT88 Single-Ended Stereo Amplifier

Custom built to order - send a message for current price 

This is a premium single-ended Class-A hi-fi vacuum tube amplifier. The amplifier uses automatic-bias, no periodic adjustments are necessary. The mode of operation is switchable between triode and UL (ultralinear) by way of a rocker switch on the back panel. The power supply uses low-noise solid state diode rectification with MOSFET ripple filter for a ultra-quiet black background and features a 60 second soft-start circuit that brings up the power supply voltage slowly, allowing the tube heaters warm-up time before full voltage is applied.

The output transformers are oversized 20W custom designed units weighing over 5 lbs. each, rated ~50H@1kHz-1V for deep rich bass response. 

The amplifier is designed to use EL34, 6CA7, 6550, KT88, and 6L6GC power tubes. There is a selector switch on the top panel for each output tube to select between two different bias settings depending on the output tube in use. 

The driver tube can be 6N1P, 6922, 7308, 6N23P, 6BQ7 or 12AT7 with jumper change for alternate heater connection.

A NOS (new old stock) 6N1P-EV driver tube will be included with the amp. If you would like power tubes to be included, contact me for options. 

Power Output: ~5W per channel triode mode, ~10W per channel UL mode

Frequency Response: 20-20kHz +/- 1.5dB

Input Sensitivity: 1VRMS for rated output

Speaker Output:  8 ohm

Output Noise: less than 1mV

Power input: 120VAC @ 100 watts - 2A Slo-Blo Fuse

Size: 13.25"W x 11.25"D x 8"H with tubes installed 

Weight: 22 lbs.

• Bourns Input Attenuator Volume Control

• Fused IEC Power Entry Module

• Neutrik RCA input jacks

• Pomona 5-way speaker binding post

• Panasonic non-inductive metallized polypropylene coupling capacitors

• Metal Film/Wirewound Resistors as appropriate

• Vishay DC Link Metallized Polypropylene Filter Capacitors

• Nichicon 105°C main power supply capacitors

• All components sized conservatively for long life

Customer Comments:

"The sound, coupled with the dead quiet background noise, was highly dynamic and conveyed an effortless sense of accurate imaging and enormous soundstage. I was simply shocked at the performance of this unit and its pinpoint imaging throughout the listing area."

"If you are considering an SET amplifier, I would highly encourage you to give this amplifier a try, it is very well constructed, competitively priced, and simply sounds terrific! In fact, I enjoyed this SET amp so much that I decided to have Scott build me a duplicate 2nd unit; what more can be said!!" - Chris, Florida

"This is the second amp I purchased from Scott. (The first was more or less the same as this one. The main difference being the manufacturer of the output transformers.) ...what matters the most is concerned- to begin with the (high) quality of build and the selection of the right parts, they are musical jewels. I’m seriously considering purchasing another of Scott’s amps." - Scott, Utah

6CA7/EL34/6L6GC Push-Pull Stereo Amplifier

Custom built to order - send a message for current price 

This is a custom designed push-pull amplifier that uses 6CA7/EL34 or 6L6GC output tubes and is conservatively rated at 24 watts per channel. The amplifier is wired for ultralinear operation and the output tubes are biased Class A at ~85% plate dissipation for the 6CA7/EL34 and ~75% for the 6L6GC. The output tubes use automatic bias and require no adjustment.

The driver/phase splitter uses a 6922 dual triode. The 6922 driver section uses a MOSFET constant current source (CCS) as the plate load to provide a very linear drive signal that is direct-coupled via a step network to set the bias for the cathodyne phase splitter section of the 6922.

The output transformers used in this design are very high quality units rated for 40 watts and 44H inductance @ 120Hz for excellent rich bass response.

The amplifier presents a deep, wide soundstage and a dead quiet black background. Works great with all types of speaker systems including high-sensitivity, and full-range single driver designs.

Contact me here for available tube options. Chassis finish/color can be selected at time of order. 

Frequency Response: 20-20kHz +/- 1dB

Power Output: 24 Watts RMS per channel

Input Sensitivity: 1.6VRMS for rated output

Speaker Output:  8 ohm

Output Hum & Noise: less than 1mV - virtually non-existent

Power input: 120VAC @ 160 watts - fused @ 2.5A Slo-Blo

Size: 15.25"W x 12.25"D x 8"H with tubes installed 

Weight: 25 lbs.

• Automatic Output Tube Bias - no periodic adjustment required

• Bourns Input Attenuator Volume Control

• Fused IEC Power Entry Module

• Neutrik RCA input jacks

• Pomona 5-way speaker binding post

• Metal Film/Wirewound Resistors as appropriate

• Low-Noise Ultra-Fast Solid State Diode Rectified Power Supply

• Nichicon 105°C Power Supply Capacitors

• All components sized appropriately for wattage & voltage

• Power cord included