Small Block Amplifiers

Available in three styles:

  • RFC Reactor Follower Coupled, Single Ended Amplifier
  • MPC Magnetic Phase Coupled, Push Pull Amplifier
  • DHT Directly Heated Triode, Singe Ended Amplifier

All the Small Block Amplifiers start off the same way, with the same tone stack and gain stages. We use the wonderful 6072A/12AY7 for 2 stages of gain with a Main volume control in between them. This allows you to set the amplifier up to any type of sound you would like. The second stage drives the custom Bass, Mid and Treble controls with tons of variations in sound. Following that is the volume control heading into the post gain stage and the driver stage. Each of these final stages is determined to optimize the output of the amplifier.

The RFC has been used by Wavelength since the beginning. This is a novel approach of directly coupling the post gain stage to the output stage. This gives the design more than 20% more power than other single ended designs. As with all single ended designs this is a true Class A amplifier. But unlike others this is also an A2 amplifier. Because it is directly coupled the output grid of the tube (the tube input) can be driven positive which throws the output past overdrive into a whole new sound.

The MPC came about when someone asked for a nice small wattage push pull amplifier. I was going through transformer options when I saw prototypes for a magnetic phase inverter. I said to myself this could be interesting and it was. The MPC can be applied to may output tubes and create power up to 100W’s in larger chassis. We have been toying with amplifiers based on the 6V6 and there the power is between 15-18W’s.

Directly Heated Triodes were the very first tubes ever designed. These tubes have very weird 4 pin sockets as there are no cathodes to these tubes. You have the grid input and the plate and 2 filament pins. They are an extremely revealing tube and will show any flaw in the system. This is the ultimate of clean amplifiers with a sound stage that is huge. Wattage range from 1-12W’s depending on tube and output transformer.

All of these come with power and standby switches and in an assorted amount of available colors and tolexes. Real wood versions are also available on special request.