Transcendent Sound       Vacuum Tube OTL Audio Amp Kits

♦ 4 Watts Stereo-12 Watts Bridged

♦ Dead Quiet

♦ Unbelievable Clarity and Realism

♦ Drives Many Speakers

♦ No Bias Adjustments Ever

♦ No Calibration Required

♦ Matched Tubes Not Required

♦ Just Plug It In and Use It!

This amp has been tremendously popular.  It's been around a while but there is no reason to change it.  The circuity is simple with few components in the signal path.  It's easy to build and has excellent reliability.  

The sound is very smooth and musical.  The class A design has slightly more rounded transients than a push-pull class AB amp.  The difference is subtle, but noticeable.  With the extreme resolution of horn speakers, this amp will tame them and keep them from sounding brittle.  

Did we say quiet?  There is no chassis or transformer hum.  There are no turn-on thumps or buzzes.  

This kit is easy to build.  Notice the clean and open layout and lack of congestion.  The simplified circuit has minimal point-to-point wiring.  No adjustments or calibrations are ever required.  

The amp can be configured for either 120V or 220V-240V operation.  

Each channel is separately fused with only 3 tubes per fuse.  Speakers and the amp are fully protected regardless of component failure.

Many circuit refinements have been incorporated into this design.  The circuit is simpler making it easier to build and lower cost.  Fewer parts in the signal path reduce coloration and allow the music to come through undamaged.  Reliability, as with any Transcendent Sound product is the best.  Heat is always a problem in any Class A design but we have managed to minimize the waste heat to only 290 watts (2.4 amps at 120V).  Efficiency has been maximized.  With only 3 output tubes per channel, a failed tube is easy to find.  All tubes are current production and easily obtainable.

The driver section uses two 6H30pi tubes yielding incredible linearity.  The output stage uses the rugged octal based EL509 tube.  The big pentode is triode connected, minimizing distortion and providing the most musical sound possible.  This amp is fast, flat out to 100 kHz.  Hear music as it was meant to be.  


Power Output: 4 watts/CH stereo, 12 watts bridged in mono

Gain: 15 dB

Input Sensitivity: 1 volt for 4 watts and 1.8 volt for 12 watts

Output Impedance: 1 ohm

Input Impedance: 100K ohm

Distortion: 1% or less

Bandwidth: From 10 Hz to 100 kHz, flat less than 1 dB

Tube Compliment: 6-EL509, 2-6H30pi

Dimensions: 17 inches wide by 10 inches deep and 8 inches high

Weight: 23 pounds

Power Requirements:  290 watts, 120V, 220-240V, 50-60Hz

The Mini Beast

Pure Single Ended Class A OTL

Discontinued:  Under Redesign and will be Reintroduced.

Circuit Board and plans for $30.