6L6SEST Vacuum Tube Stereo Amplifier

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In 1936, RCA developed the 6L6 vacuum tube for high power, high quality audio amplification. So, it just seemed right that my introductory amplifier should be based on the wonderful 6L6-GC vacuum tube. The 6L6SEST is a beautiful, high quality, 8-watt, single ended, hi-fidelity stereo amplifier, hand made in the USA and perfect for all hifi enthusiasts.

When developing the 6L6SEST, I had several goals in mind. I wanted to blend the best of the vacuum tube era’s circuit designs and methods with the best parts (including tubes) available today. I wanted to source as many parts as possible from high-quality, USA manufacturers, and it had to be practical to own and use.

The 6L6SEST starts with a precision engineered, 1/8" stainless steel chassis that is laser cut to exact specifications and provides a tough and durable, yet beautiful brushed steel finish. I use high-quality octal tube sockets for solid tube connections and long service life. The simple and visually authentic power switch is rated for heavy duty use and the volume control is a high-quality, Alps "Blue Velvet" potentiometer with a beautifully matched, machined aluminum control knob.

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Across the rear apron are standard analog RCA input connections, 8-ohm speaker output posts that will accept banana plugs, spades, or bare wire, 2 amp fuse protection, and a standard 120V IEC power jack.

Image description Inside, the 6L6SEST is hand-wired using authentic, point-to-point style wiring for reliability and easy service in the future, should your amp ever need it. The 6L6SEST is a full vacuum tube amplifier that uses a readily available Electro-Harmonix 5U4GB tube rectifier, not harsh sounding solid-state diodes. I use only high-quality Sprague Atom filter capacitors in the power supply chain for long life and smooth, extremely quiet operation.

The 6L6SEST preamp section is based on the sonically beautiful 6SL7-GT dual-triode. The 6SL7-GT was often used in the driver stages of audio power amplifiers from 1940 – 1955. I felt the 6SL7-GT was the perfect tube for this amplifier. The 6L6SEST comes stocked with the new production Tung-Sol 6SL7-GT, a very neutral sounding tube with great dynamics. However, there are many other new manufacture and new-old-stock (NOS) 6SL7 tubes around that you can try in the 6L6SEST to tailor the sound to your specific sonic preference.

Image description The 6L6SEST comes stocked with the new production Sovtek 6L6-WXT+. This variant of the 6L6 family is the high-power workhorse for several well respected guitar amplifier manufacturers. It is built tough, has a long lifetime, and provides wonderful sonics.

The 6L6 power tetrode has been in production since 1936. During that time, there have been several manufacturers of the 6L6 and it’s variants. There is a wide selection of new-old-stock (NOS) tubes at various prices in circulation and this leaves plenty of other 6L6 output tube options to try in the 6L6SEST to suit your tastes.

I tie all this tube goodness together with high-quality coupling capacitors from Mundorf and output transformers from Edcor USA, to create an exceptional sounding vacuum tube amplifier at an incredible value.

And of course, an amplifier of this caliber must be placed into a unique cabinet to add that extra flare and customized look. The base is hand constructed and finished from solid oak. Other customizations are available including half blind, dovetailed construction and a choice of wood including Oak, Cherry, Maple, and Walnut. Occasionally, more exotic wood choices come available. Popular exotics include Bubinga, Teak and Purple Heart. Finish options include hand rubbed flat, satin, or high gloss. Be sure to specify your choice at order time!

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The 6L6SEST is an 8-watt, single-ended audio amplifier and therefore is best suited to lower-powered, higher-efficiency speakers and small to medium-sized rooms. It will however, drive larger, higher-powered speakers systems to moderate volume levels with decent input drive. It’s single-ended audio characteristics are absolutely amazing with vinyl sources and sound great on all but the most demanding digital sources with deep bass requirements.


  • Weight – 18.2 lbs.
  • Dimensions – 7.0″ H x 13.75″ W x 12.0″ D
  • Power Requirement – 120V AC 1.0A (~90 Watts)
  • Circuit Type – Single-Ended, Ultra-Linear, Class A
  • Power Output – 8 Watts
  • Signal Input – 2.0V for max output
  • Frequency Response – 20~20,000 Hz
  • Total Harmonic Distortion – 0.7% @ 1,000 Hz, 1 watt

Tube Compliment – 5U4GB Rectifier / 6SL7-GT Preamp / 6L6-GT Power Output

Warranty – 1 year parts and labor (shipping charges not included – 90 day warranty on supplied tubes)

Price: $1799.00

To order email: riverty@gmail.com

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“Valve amps produce even harmonics which are, well, harmonious to our ears and are responsible for the ‘lushness’ we associate with tube amps. Solid state amps produce odd harmonics which sound harsh.”

“Well conceived tube amplifiers don’t have the “hard, brittle edginess” that can afflict solid state amps. If you value the emotion and the excitement of the music above all else, tube amps are the way to go. Carefully chosen, very expensive solid state amps can get close, but don’t quite match this euphonious presentation, especially in the mid-range.”

“I run my tube amp at a quarter to a third volume and even with its modest power output (only 16W) it subjectively sounds fuller and louder than my solid state amps. I think that a valve amp would make any ‘live’ or ‘unplugged’ recordings sound even more atmospheric and real.”

Links Of Interest:

How It’s Made – Audio Vacuum Tubes – https://youtu.be/PFQSdX1B-ic

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