THD

The THD UniValve is a Single-Ended Class A amplifier head with a single output tube that can be switched at will among many octal-based power tubes, including 6L6, EL34, 6550, KT90, KT88, KT77 and KT66, for different tones without re-biasing the amp. Likewise, the two preamp tubes can be any combination of 12AX7, 12AT7, 12AU7, 12AY7 or 12AZ7. The UniValve delivers tones from smooth and clear to very aggressive overdrive. It is easily capable of driving a 4 x 12" cabinet, yet quite small and light. It has a built-in Hot Plate® Power Attenuator that allows for full output distortion at almost any volume. And it doesn't cost as much as you might think
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Like the UniValve, the BiValve is a single-ended pure Class A design. However, it has two output valves which are wired in parallel and combined through a special output transformer to deliver up to around 30 watts. You can use almost any output valve you like without touching any kind of bias adjustment, and in the BiValve you can use them in any combination as well. Combined with the capability to take almost any preamp valve, this makes the BiValve even more of an guitarist's dream than its predecessor. Because there's such a wide range of tone available to you.

The THD Hot Plates are attenuators which allow you to drive your valve amp at maximum gain but at low volume. This makes it a great addition for recording or practice where you can get all the drive sounds you need without the need to have sound re-inforcement in your studio. Note each is optimized for a specific impedance (2, 2.7, 4, 8, or 16 ohms.). Choose the one that fits the impedance on your amp. See more information for a technical explanation of how an attenuator works.
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In our view, probably the finest 2 * 12 speaker cabinet you can buy. Beautifully made from 3/4" ply birch, the cabinet is rigid and resonant. Comes with 2 * 12 Celestion Vintage 80 speakers.
Guitar Player, magazine:
"Improved the sound of every amp we tested them with."
" these lightweight, musical THD cabs can improve your tone dramatically."
"…delivers solid lows without a hint of flab."
"…produced more bottom-end beef than our lovely reissue Marshall 4x12 with Greenback 25s."
"The THD is smaller and weighs a lot less too.If you want big sound without slipped disks, this is the answer."

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The THD Yellow Jackets are specialized adapters which permit the use of EL84/6BQ5 power tubes in place of 6V6, 6L6, EL34, 7027 6550 (under 520 volts) and 7591 types. They will work in any amplifier that takes these tube types, as long as the plate voltage is under 520 VDC. This accounts for over 98% of the tube guitar amplifiers on the market. (They also work in tube Hi-Fi equipment!) Because the Yellow Jackets ignore the amplifier's grid bias voltage, it is possible to take them in and out at will to adjust your power level and sound for the individual gig or session. Class-A With Any Amp!
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