Wavelength Audio, ltd. Thumper SE 7591A class A/A2 8/10W amplifier, B&B Alnico 12" Pink

Thumper 7591A Single Ended Class A/A2 8/10W guitar amplifier

Wavelength Audio, ltd.

I was asked to make a more powerful amp than the LunchBox (3W all tube, 8" alnico, DI, 9V stomp supply) but it needed to be a combo and less than 35 pounds. Well my first thought was 12" as compared to an 8" is probably double the output per watt (+6dB). Second I thought ok maybe EL84 or 6V6 both tubes I like. Then I thought why did Ampeg use the 7591A instead of the EL84? Probably because it was beefier and didn't blow as much.

Thumper name derived from a single stroke engine (keeping with the guitar-engines.com theme).

This is an all tube amp like the rest of mine. I am not a big fan of 12AX7 instead the front end uses a 6072A/12AY7 tube with regulated DC filaments for the gain between the volume knob. This goes to a full tone stack (bass, mid, treble) which then goes to the master volume, then the magic happens.

RFC or reactor follower coupled is a direct coupled amplifier idea I was told on many occasions that I could patent. Who cares! Anyway this allows the amplifier to gain an extra 20% power as now the tube can go from class A to class A2. Make up gain from the Tone Stack is done by 1/2 of a 12AU7A/ECC82 and the second 1/2 is used in the reactor follower stage.

Power is done by a GZ34/5AR4 vacuum tube and caps are all top shelf.

This is #2, first one wen to front man Ed Robertson of Barenaked Ladies.

It comes with the CoverAmps cover seen in the picture. All cabinets for my products are made special by Mojotone.

Specifications: 21" high x 9" deep and 17" wide.

Weight 32 pounds with Warehouse Black & Blue Alnico driver 103dB per watt rated.

Weight 27 pounds with the Celestion NEO V driver 98dB per watt rated.

If you have questions, don't hesitate to ask.

Thanks,
Gordon

Wavelength Audio, ltd.