Developing audio in Ireland
Custom IRISH handmade
Mk1 ~ 300B Single-ended Monoblock Triode Amplifier
Agents in Ireland for
Amplimo Transformers - ASC Capacitors - Silver Circle Audio cable - Emission Labs vacuum tubes - Soliloquy speakers - Phy Speakers

MK2 300B Amplifier
  • Single-ended 300B
  • Directly Heated Triode
  • Zero Global Feedback
  • Indirectly Heated Tube Rectifier
  • Oil filled PSU capacitors
  • Copper foil caps and Black Gate caps
  • All ironware and tube sockets mechanically isolated from chassis.
  • Monoblock construction
  • Hard wired
  • Single input
  • Left and right matching pair

Single-ended is as straightforward as you can get and despite the large number of available circuits that the are are out there, they are by the most part, similar in their topology. I also believe in the "Less is More" way of thinking and less in the way of the audio path the better. In the case of this amp there is only one capacitor in the signal path!

The 300B is one of the most linear amplifying devices ever made, despite the fact that Western Electric introduced this triode in 1935, it still has the absolute power to move hearts and souls. We have opted for AC as the heater supply for the 300b, - AC for the heater is preferable from a sonic point of view, but there are also other reasons why AC is preferred to DC. Directly heated tubes with dull emitters, such as the 300B, which have a barium oxide-coated filament, when subjected to DC can produce an uneven coating of metallic barium - whereas AC heaters will produce an even coating. This uneven coating can lessen emissivity and shorten the life of the tube.

Zero feedback is the only true route for the single-ended addict . Using feedback of an error signal is in itself erroneous ...I mean why should I put an error signal back into the circuit since this will create further errors and additional harmonics of a higher order. These higher order harmonics are more objectionable and audible themselves, despite the fact that the distortion levels are lower with feedback applied. By its nature, the error can never be eliminated...its the ever-decreasing circles thing...you never actually get to the end of it. Now that kind of philosophy does not appeal to me! And secondly, tube rectification is necessary to let the truth of tone breathe through naturally.

RCA Red Base 5692 - a sweet alternative to the usual 6SN7 family and one that some will say is the very best of its type. Absolutely superb and my best recomendation for this amp. Though very expensive, it has a wonderful midrange and better bass tonal definition.

The choice of ASC oil filled capacitors in the power supply is a worthwhile option and we have avoided the usual choice of electrolytic capacitors in the power supply in place we use self-healing high voltage ASC oil filled types, which are, in fact, true capacitors.

.....Listen to the feathers!...
"May you learn your lessons at a feather’s touch". .....Listen to the feathers...

Supplied as Left and Right hand pair
tubes front front tubes
Derek Walton
4 Tara place,
Co Meath,
Tel/Fax +35318351100

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