Thumper 12” Combo
7591A 10W Class A/A2
Reactor Follower Coupled
So a number of customers who were using the LunchBox during covid approached me to make something larger and louder to broadcast over the drums.
The 7591A was used by a number of companies that felt the tiny EL84 was a bit of a problem. The larger octal based tube could handle much more power, but still have that chime sound everyone was looking for.
The Thumper model (Thumper in Europe is known as a single cylinder engine) is a single 7591A output tube running in Reactor Follower Coupled (RFC) configuration which allows for almost 20% more power than other single ended designs. In Class A the amplifier will deliver 8W clean and in Class A2 up to 10W. Giving max output of over 120dB (Warehouse B&B).
This model as is all the others is all tube with a 6072A/12AY7A input section with volume between the two halves. Leading onto the full tone stack and finishing off with the master volume into half of the 12AU7A tube for make up gain. The other half is used in the RFC directly coupled into the 7591A output tube. The 5Y3 rectifier provides the power for the amplifier. The 6072A is DC heated and regulated for ultra quiet operation.
There are two speakers available for this model (others available on request):
Warehouse Black and Blue Alnico (32lbs total weight) 102dB/W
Celestion NEO (27lbs total weight) 98dB/W
Comes with the standard cover.