Push Pull 300B

Push Pull 300B Mono Blocks

My favorite power tube is the 300B. I have always loved my SET 300B amp. It has the largest, sweetest sound stage of any tube out there. But like a true audiophile, if some is good, more is better. S0---, here it is! 25 Watts of butt kicking 300B power. The bass, the detail, the huge sound stage, they are all there but with more of everything. 25 watts through high efficiency speakers sounds like 500 Watts through low efficiency speakers. Adhering to my less is more ideas, I do not quite understand the need for mega amps. When designing mega amps, you must adhere to certain design criteria to meet the output goals. This limits many options.

As usual any amp starts with the power supply. Pulling 120ma @ 400v, two 300b's need a good transformer. I use a Kilovolt (500-0-500) power supply. This allows the use of a choke input filtering system. A less expensive unit will use a capacitor input filter. This allows the use of a smaller (cheaper) transformer. The capacitor system is an on and off type system. The caps fill up and then shut off until they need more and then they turn back on. This tends to be an all or nothing system. By using a choke input, the flow of electricity is constant and the caps are always full. The result is better bass, quieter running, more detail, and cooler running as well.

A push pull amplifier actually takes the analogue signal and splits it in half. The top part of the analogue waveform is sent to one tube and the bottom part is sent to the other. This allows each tube to amplify 1/2 the signal and you get a greater output. As an added bonus, a push pull amplifier is usually very quiet. The two signals tend to cancel out noise when reassembled. This amplifier also uses a fixed bias. You are able to adjust the bias with a screwdriver and meter right on the front of the unit. It is very easy to do. A fixed bias has tighter bass, detail, and clarity as well as negating the need for matched tubes.

This amp is so special because of the transformers that I use. Each mono bloc has five separate transformers. By using separate transformers, the sound is cleaner with less cross talk. Of coarse transformers are not cheap but are worth the investment for the ultimate sound. Using so many separate transformers also takes a lot more time to construct. All the power leads must be well routed and positioned to prevent induced hums.

To use solid state rectification or tube rectification, that is the question. Every amp that I offer for sale has been developed over years of experimentation. I always make each amp in various configurations and listen during development. I actually build my final product by ear, not engineering expectations. Each part has a signature sound. A solid state rectifier (changes AC to DC) sounds, well, more solid state. More bass and tighter transient attack it can sound a little brittle on some amplifiers. On others, it may be the right choice for just that reason. It is the total sonic experience that I listen for. By listening to each possibility I mix and match until I get what I want. Choices include AC or DC filament heating, choke or RC filter, fixed bias, type of power supply, regulated supplies, etc. The choices are endless and I have listened to them all.

These mono blocks are supplied with all tubes. Different brands of tubes makes a big difference in sound and we all have our favorites, or tubes that we can afford. The signal tube is a 6dJ8, 6922. The rectifier is the well known 5U4G. It can handle the load and give long service and a gigantic sound stage. An IEC connector is standard so that after market power cords can be used with great effect.

These amps are a once in a lifetime purchase and as such will provide many years of service with little or no maintenance. The sound stage is gigantic and very tube like. Rich and deep. After initial adjustment, the tubes do not need constant biasing. Tube life is very long as I do not stress them. Output taps available are 4, 8, 16 Ohms which will handle most speakers. All amplifiers carry a 1 year warranty. Email auralthrillsaudio@gmail.com for details.

$4999.00

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