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In 1918 Western Electric introduced the “Mother of all Power Triodes”, the famous 300B.

Since then, a lot of 300B amplifiers have been built, mainly single ended class A ones.

Generic production ceased in 1988.

The new JJ Electronic 300B tube made in the Slovak Republic is tremendous. Its top-quality construction gives superior sonic results. Although a bit microphonic, it seems to have the best balance of smooth mids with upper and lower frequency extension. Ambience and imaging are excellent.

Of course you may choose to equip your Diamond I with other brands’ 300B’s.

300B amplifier - the tube

300B amplifier - the Diamond I

Diamond I 300B

3.400,00 € — 3.885,00 €

To choose your Output Tubes,
please check our 300B’s info page.

Some technology choices in our 300B amplifier:

  • – NO global feedback.
  • – Oversized stabilized power supply.
  • Toroidal supply transformer
  • Lundahl high-grade audio output transformers.
  • Lundahl high-grade audio interstage transformers.
  • – Gold plated professionnal connectors.
  • ALPS Blue velvet 27mm potentiometer.
  • NO capacitor in the signal path.
  • – Amplifier is point-to-point wired, while the Power supply is built on a high grade double-sided Printed Circuit Board.
  • – Circuit board with 100 microns thick copper tracks.
  • – 2 mm steel sturdy inox steel top and rear plates, with noble wood side frame, mounted on gold spikes to minimize microphony.
  • – Tripod arrangement of the spike-shaped feet to ensure stability on any surface.

Technical specifications

  • – Mains : 110V-220V
  • – Output Power : 9 Wrms x 2, pure Class-A
  • – Output Tube : 300B x 2 (JJ as standard, other brands as options)
  • – Input Tube : Raytheon 5842 x 2
  • – Lundahl transformer Interstage coupling
  • – Frequency response : 10Hz-38KHz +/-3 dB
  • – Signal/Noise Ratio : 98dB
  • – Distortion : Less than 0.5% at full power
  • – Output impedance : 4 or 8 Ohms

300B amplifier

300B amplifier connectors

One might find that 2 x 9 Wrms isn’t a lot of power.

Though not very powerful, providing your speakers’ sensitivity is high enough (that is above 90 dB), our 300B amplifier will fill a room of about 40 square meters with a sound high enough to be somewhat uncomfortable.

And remember, we’re speaking about Watts RMS, not Watts “music”, or Watts “eff” (for efficient), or any other exotic Watts invented for commercial purposes.

Why shoud I buy a single ended tubes amplifier like the Diamond I valves amplifier ?

One answer would be: it sounds different from transistors amplifiers, but there is much more :
  • – Valve amplifiers will reduce the harsh sound in most hi-fi systems, without losing the treble and musical details.
  • – Class-A tubes amplifiers have no cross-over distortion.
  • – Valves amplifiers allow you to hear the “silence” between the notes, as tubes are less noisy than transistors.
  • – A valve amplifier allows you to hear a note, followed by silence (or the dying echo of the note in the concert hall).
  • – A tube amplifiers has much less components than a transistor amp, and all things being equals, the less components in the signal path, the better the sound and the better the THD+noise figure.

In my humble (and biased) opinion the soundstage is stable, clean, wide, really stunning. The positionning of the instruments in the acoustic scene is perfect. One can ‘see’ each instrument. Power is more than adequate for a good level of sound pressure. There are no compression effects at any volume. Low level details are precise. Bass are firm, not muddy at all.

Jacques Casier, designer, acdc audio

… At first I wasn’t that impressed, but after a day or two it was like if everything fell right in place. I discovered new things in records I’ve been listening for years… Some friends of mine are now really jealous… It’s not cheap, but it’s the kind of purchase you never regret…

Jane Markham, sales manager, Colchester, UK

See the owner’s manual here