The AM RT-1 Preamplifier. (We will be showing them at the Hi Fi Show at the Intercontinental Hotel at the Rialto. 21-23/10)

Great new Hi Fi+ (UK) review.
6 Moons Review

This quite substantial Preamplifier is an upgraded version of the quite stunning Stereo Knight Magnetic Enigma Silver.
This is a minimalist in operation, but no effort spared, quite over the top, nothing to degrade the audio, everything previously learned Preamp.  The RT-1.   
It was needed to to drive AM's Crowning Glory.  The Nothing spared, whatever it takes to achieve the absolute in music reproduction. The AM 833S Monoblocks.

It is a stunning piece of design and engineering. The multi selector 33 step volume pots are painstakingly constructed in house for the ultimate in quality. Many years of research and development has gone into these pots. They operate multiple windings on transformers, which are also constructed in house, and give the first level of amplification, the same as the extremely impressive R-S Transformer passive preamp. This then drives the nothing compromised, nothing spared tube amplifier section, with a simply humungous power supply weighing about 25kG. The monstrous transformers have a bandwidth exceeding 15hZ to 122KhZ.
The Preamplifier works in Pure Class A, Single Ended mode using two 6H30 as the drivers, two 6922 valves as the amplifiers.
The preamp is a dual mono design, so that the transformers, power supply and voltage regulation are completely separated, so avoiding noise and cross talk. They use a large number of high value U-Cap copper foil capacitors, which were carefully chosen for their natural, analytical sound. The output transformers bandwidth can extend to between 15 HZ to 120KHZ

The design of the new tube preampis quite unique. The name "Magnetic AM R-T1" can be implied from the prefix: "magnetic", which indicates its direct origin from the AM magnetic passive preamp. Not only does the AM R-T1 utilize transformers for volume attenuation, but also another 2 transformers for the signal output and two more for power supplies.
The remarkable level of performance has been achieved with an all new audio and power supply circuit design. This new audio circuit is all tube, Class-A, with zero feedback, utilizing a total of four long-life tubes (2 6H30 as the drivers and 2 6922 as the amplifiers); and furthermore, it is a truly balanced circuit design in both the input and output stage, with the support of 2 volume control transformers.
The Magnetic R-TI is a direct upgrade from the AM reference version of the magnetic passive preamp, which already delivers an exceptional performance, by utilizing both tube amplifiers and output transformers. One great advantage of this magnetic feature is that it is capability of optimally matching with any amps and interconnects, while accepting input from any sources, at various impedance levels, with the least possible interference to the signal.
The power supply is divided into two separate parts: The main power transformer, which is used to power the audio circuit, and Mosfets, that are used for both the voltage stabilization and for a constant current supply. This enhances the reliability, and makes the tube amplification as linear as possible.
With its great build quality, audiophile grade components, versatility and the ability to musically transform every system, not only does the AM R-TI deliver striking clarity and detail that presents instrumental timbres and textures in an amazingly lifelike way, but it also represents great value, with great reliability and vision.

Feature summary of the R-T1 preamplifier
Technical details about magnetic AM R-T1
* 2 transformers for volume attenuation with 33 steps.
* Transformer output.
* Independent regulated power supply.
* The left and right channels are a completely independent design.
* Pure tube, Class-A, with a zero feedback audio circuit.
* Versatility to match all kinds of amplifier and interconnects, based on a fully magnetic or transformers implemented design.
* MOSFETS for voltage stabilization and constant current supply.
* U-cap capacitor in signal path.
* Detachable IEC power cord. High quality gold-plated AM custom binding posts and RCA jacks. TEFLON insulated wire and Japanese made POCC rectangular solid core copper wire all the way.
* A fully machined aluminum alloy chassis and exceptional build quality.

Here is the conclusion to the RT-1 review by 6 Moons
Conclusion. The R-T1 should be of particular interest to people of either hi-eff systems where deep attenuation is the order of the day; or those who routinely listen quietly but presently belabour a significant loss of substance whenever they do. Here the transformer-based volume controls excel at maximizing drive at very low signal voltages. It really was just a matter of time. Reference Chi-Fi has arrived. Audio Music's R-T1 TVC valve preamp belongs into the top echelon of performance as do its assembly and finish quality. It might take a few more years for this new reality to sink in. The few adventurous souls open-minded enough to already give this machine an audition should simply agree that this future is here now!...







Power Supply


 

Specifications

 Tube complement Two 6H30 as the drivers, two 6922 as the amplifiers
 Frequence response 20 Hz ~ 100KHz
 Input Impedance 47k ohms variable depending on the source
Volume control 33-position volume control
Output Impedance 600 ohms . RCA output & BAL output.
Input selections 3 pairs RCA single-ended ; 3 pairs balanced / XLR
Gain Input 0.5V output 2.5V
S / N > 98dB
Distortion rate under 0.5% / 5V
Power consumption 45 watts
Dimensions (W * D * H) 380W*340D*110H*(mm)
Weight 38 Kg shipping weight







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