Contact Us About this Product

I own Bliss Hifi, a high-end audio boutique based in Minnesota. This Butler Audio TDB 5150 is a trade-in from a professional audio reviewer who received it as a review sample several years ago. The unit is in like-new condition with very light use and is in perfect working order. BK Butler designed the 6SL7GT tubes in this amplifier to last upwards of 10,000 hours, so with the minimal use this unit has seen, the tubes have a tremendous amount of life remaining.

The unit comes with its original box.

BK Butler is best known as the man who invented the Tube Driver guitar pedal, the effect that gave David Gilmour his iconic tone on The Division Bell and countless other recordings. What is less widely known is that Butler applied the same patented thermionic tube technology to a line of home audio amplifiers, and the TDB 5150 is the five-channel flagship. This is not a conventional tube hybrid where the tube is bolted onto a standard solid-state circuit for marketing purposes. Butler’s patented design uses the vacuum tube’s thermionic emissions to directly drive the output stage in a way that preserves the musical warmth, dimensionality, and harmonic richness of a tube amplifier while delivering serious power: 150 watts per channel into 8 ohms across all five channels simultaneously, 225 into 4, and stable into loads as low as 2 ohms. There is zero global negative feedback in the circuit, which is a significant contributor to the amplifier’s open, uncompressed, and dynamically alive presentation. Each channel operates as an independent modular amplifier with its own massive heatsink, independent AC secondary, rectifier, and 20,000 microfarads of filtering.

What makes the TDB 5150 particularly interesting for two-channel listeners is the bi-amping potential. With five independent amplifier channels, you can dedicate two channels per speaker, running one channel to the bass section and another to the midrange/tweeter section, and still have a fifth channel available for a center speaker or powered subwoofer connection. Bi-amping separates the demanding low-frequency workload from the more delicate midrange and treble reproduction, allowing each channel to operate with less stress and greater headroom. The result is tighter, more controlled bass, a cleaner midrange free from intermodulation distortion caused by bass signals, and an overall sense of the music opening up. Because each of the TDB 5150’s five channels has its own independent power supply with dedicated AC secondary winding and 20,000 microfarads of capacitance, there is genuine electrical isolation between channels, which means the bass channel’s heavy current demands never compromise the midrange/tweeter channel’s performance. That level of channel independence is exactly what makes passive bi-amping work at its best.

At its retail price, the TDB 5150 was already a remarkable value. At trade-in pricing in like-new condition from a reviewer who barely used it, this is an exceptional opportunity.

Happy to answer any questions. Thanks for your consideration.

Check my stellar feedback and buy with confidence. This listing includes free insured shipping across the CONUS. As this is a passthrough sale that I am brokering on behalf of my client, I prefer to accept payments via PayPal F&F, Venmo Gift, or personal check, but this also gives you the opportunity to attain this at my lowest possible price. Credit card payments are also possible for a 3.1% convenience charge.

More about the unit:

The Butler Audio TDB 5150 is a five-channel vacuum tube driven power amplifier designed by BK Butler, the inventor of the patented Tube Driver circuit that became famous through its adoption by guitarists including David Gilmour of Pink Floyd. The TDB (Tube Driven Buffer) designation refers to Butler’s patented Hermionic technology, which captures the pure thermionic vacuum tube emissions (the original “Edison Effect”) and uses them to drive the output stage. This is fundamentally different from conventional tube hybrid designs. The circuit operates with zero global negative feedback, preserving the natural dynamics and harmonic structure of the music signal. Each of the five channels is built as an independent modular power amplifier with its own hand-selected and matched 6SL7GT twin triode vacuum tube, massive oversized heatsink, independent AC secondary winding, independent rectifier, and 20,000 microfarads of filter capacitance. Tube heaters are fully regulated with a delayed soft start (10 to 15 second turn-on delay) for extended tube life. Butler Audio states that normal tube life is upwards of 10,000 hours. Power output is 150 watts RMS per channel into 8 ohms and 225 watts RMS per channel into 4 ohms, all channels driven simultaneously. The amplifier is load-independent and stable into loads as low as 2 ohms. Frequency response is 20Hz to 20kHz (plus/minus 0.5dB) with a power bandwidth of -3dB at 50kHz. THD is less than 0.10% at 8 ohms and less than 0.15% at 4 ohms. Signal-to-noise ratio is better than 110dB (A-weighted). Slew rate is 15V per microsecond. Input sensitivity is 1.5V for 150 watts into 8 ohms. Input impedance is 47k ohms. DC fault and short circuit protection circuitry is built in, with diagnostic LEDs (red indicates fault). Inputs are custom-made hard gold-plated eutectic brass RCA connectors, one per channel. Speaker outputs are custom-made hard gold-plated eutectic brass five-way binding posts, one pair per channel. The chassis is finished in frosted platinum with internal blue LED tube illumination. Idling consumption is approximately 120 watts. Dimensions: approximately 19 x 7 x 16 inches. Weight: approximately 48 lbs. Concept and design by BK Butler, USA. The TDB 5150 has earned praise from Audiogon reviewers as a definite value in the multi-channel amplifier category, with one reviewer noting he had not found comparably priced stereo amplifiers that matched the TDB 5150 in sonic character, control, or bass response.

Contact Us About this Product

Indexed by