One very interesting program at Silbatone is our effort to shine a spotlight on rare, seldom heard, and under-appreciated vacuum tubes. The Western Electric 252A power triode is the immediate predecessor of the famous WE300B and is best known to historians and collectors as the power tube used in the WE 59B amplifier. Sadly, this tube is extremely hard to find today and quite expensive on the auction block, so very few modern listeners will get to know the 252A tube.
Although a beautiful piece of engineering art and historically significant, the late-1920s WE 59B amplifier is not one of the greatest amps for today's music listening. Until now, no serious attempt at a world-class 252A amplifer has been made. Silbatone decided to create a worthy platform to explore the sound of this important and triode. This is our mission, because we love this fabulous tube and we need to experience and share her ancestral voice.
The Silbatone RP252 amplifier is based on a low distortion, directly-coupled topology with no feedback in the output stage. The voltage amplifier and driver tubes, 12AY7 and 6900, are selected from the best specimens in our tube locker. The output transformer is a special in-house wound silver foil unit with a Permalloy core. Our goal is to hear what the 252A can do so we tried our best to give it a proper stage on which to perform.
Our evaluation of the RP252 Amplifier is that it provides a very tasty eight watts and it sings with an authority and depth that engages the ear and commands respect. Not bad for an 80 year old tube!
A 300B version, the RP300. which shares the inspiration and design of the RP252 is also available. If you want to experience the highest level of performance available in a medium-power single triode amp, you must audition the RP-300 and RP-252. A revelation for newcomers and old hands alike!
This Mazinga amplifier takes simplicity and parts count to the extreme. The audio circuits consist of two transformers and one tube. No resistors, no capacitors. Yes, the current regulated power supply is somewhat sophisticated and complex but that is the price sometimes paid to get the best performance out of simple circuits.
While the parts in the Mazinga amplifier might be few in number, they are the finest quality pieces known to Man. The input transformer is silver wire on a high permeability core, the tube is a rare Bendix 6900 twin-triode which was only used in jet fighter avionics and the Nike Early Warning System of the Cold War. One of the highest-specification tubes ever made.
The output transformers are really special in this amp. They are Silbatone's unique silver foil secondary units using 2kg of silver wire on unobtainable huge Finemet cores. One literally has to “know somebody” connected at Hitachi to get these made, but fortunately we know him. Unbelievable material with unparallelled capability.
The end result of this adventurous project is a very lively amplifier with incredible resolution and a sense of speed and natural presentation that we found very impressive. Mazinga might earn the lowest power rating of any amplifier at the HighEnd show, but we invite you to experience what 850 milliwatts of rather ambitious simplicity can do paired with our high-sensitivity Western Electric systems, a mixture of old and new that we are happy to share with our visitors!
As an uncomprising entry in the phono amp market, the SQ100 features separate 10X and 20X silver litz step-up transformers for low and medium impedance MC inputs, silver coil nickel core inductors in the LCR RIAA EQ, and a triode silver wired output transformer line driver for balanced and unbalanced outputs.
The D3a transconductance gain stage employed in the SQ100 is our third generation effort in refining this approach and it is unexcelled in noise and distortion performance among tube circuits, as well as dynamic and colorful musical portrayal. A particular effort was made to eliminate series capacitors in all audio circuits to maintain signal purity. Analog conditioning circuits ensure optimal DC conditions and perfect balance for the operation of each vacuum tube stage.
In recent years, Silbatone engineers have focused diligently on the challenges of low level amplification. The SQ100 is the flower of this effort, incorporating out latest thinking in a generously appointed phono control center that will please even the most determined and demanding analog enthusiast.
SQ-105 Phono Amplifier
The Silbatone SQ105 offers a flexible phono amplifier that brings home the musical performance of our reference-grade preamplifiers for a relatively moderate investment. By engineering tube-based solutions for the expensive silver transformers of the reference units, we are able to offer an unmatched combination of high-performance and economic value in this new product. Aside from saving on the high cost of extremist silver transformers, the SQ105 was developed with the uncompromising attitude that inspires all Silbatone designs.
The SQ105 is our first phono amplifier to include an integral MC head amp. This advanced design gain stage provides variable gain up to 20dB gain at remarkably low noise (250ohm equivalent noise resistance) using a German Post D3a tube. The remaining circuitry was developed for our top of the line designs. The D3A transconductance gain stage, low distortion current feedback RIAA driver, and the powerful tube output buffer are all trickle-down technologies from our reference units.
The facilities of the SQ105 are tailored to provide flexibility for the needs of the avid phono listener. Selectable load resistance and capacitance at the MC input to optimize conditions for your favorite cartridge types and two additional MM inputs are provided for high output cartridges or step-up transformer inputs. An on-board volume control allows SQ105 to be used the stand-alone basis with any power amplifier and to adjust the gain structure of your system for ease of operation with shared line amplifiers.