Ypsilon Pre-amplifier & Phono Stages
PST-100 MK2
PST–100 MK2 is most certainly an impressive addition to YPSILON’s 100 series. It approaches the concept of pre amplification in an outstanding way. Its heart lies in the in house made transformers used for attenuation. In addition its valve state circuit combined with exquisite materials produce the finest and most elegant sound that any pre amp could ever achieve.
Conventional wisdom suggests that the most critical part of a preamplifier is the active circuit design. We, however, believe that the means of signal attenuation (the volume control) is the most critical to the overall sound of a preamplifier.
Most designers use resistor attenuators for volume control. We have used resistor attenuators with high quality resistors (Vishay, in the past, felt unsatisfied from the character they induced in the signal. We developed a very special transformer as the means of attenuation, using special winding techniques and highest quality wires and cores. Its performance suppassed that of the best resistor attenuators.
In a transformer the magnetic circuit can be ultra linear when the very best core materials are used. The sound of such materials is much more musical and detailed compared with the best resistors. A transformer attenuator with 31 taps is used in the PST-100 MK2 providing a total attenuation of 54db in its lowest tap.
The active gain stage is a no – feedback s.e. ,C3m triode, transformer coupled. The power supply uses valve rectification(using the 6CA4) and choke filter. Wiring is point to point with custom made pure silver wire. The transformer attenuator is placed after the valve stage, preserving the purity and micro details of the signal. The gain is 16db. Output impedance is 150 Ω max. PST 100 mk2 is the pinnacle in preamplification. It is a must have component for building a “no holds” system.
PST 100 TA PST 100 is also available without the valve stage for systems that don’t require additional gain. This version is equipped with the transformer attenuators and is called PST 100 TA. Notice that it is fully upgradeable to the full version at any time by returning to factory.
YPSILON PST 100
VPS-100 PHONO
The road to VPS-100 took many turns in our long and extensive evaluation of topologies and materials, design and implementation.
Passive RIAA equalization is preferred to active because in active RIAA equalization there is a feedback loop and the RIAA network is in this feedback loop. Usually RIAA equalizer circuits are implemented with capacitors and resistors (CR networks). Capacitors present the so called “dielectric absorption” -energy is stored in the dielectric material and is added to the signal with a small delay producing a ringing character in fundamental notes. This ringing behavior can be noticed in piano notes. In the past an alternative way of implementing a RIAA equalizer the LCR (Inductance-capacitance-resistance) circuit was proposed.
A long time ago TANGO transformers from Japan used to produce such a circuit working in 600Ohms. A few manufacturers are using LCR based phono stages using variations of the original TANGO LCR circuit. The challenge in 600ohm LCR eq is to drive the network properly; having no more than 2 gain stages with enough overall gain and low enough output impedance.
The best way of driving the LCR network is by using a transformer. We design and build ourselves the transformers using a special amorphous c-core material. Winding insulation is paper. A properly implemented LCR RIAA sounds much more natural, musical and open than CR networks with better defined macro and micro dynamics.
The LCR networks most commonly used are based in double T filter networks .One T filter forms the 50-500Hz poles and the second T filter forms the 2123Hz pole.
In the VPS-100 we took it one step further, the 2123Hz pole is formed by air core inductor with practically no stray capacitance at the first gain stage and the 50-500Hz poles are formed in high signal level directly at the output of the second gain stage. So this is a split RIAA design using two gain stages based on the SIEMENS C3g tube. These tubes are very reliable as they are specified for 10.000 hours.
The power supply uses the 6CA4 tube rectifier and a choke filter .The heaters for the tubes are AC in the second stage and DC passive regulated for the first stage. The construction uses no printed circuit boards and is point to point silver wired using our own extruded and annealed to spec silver wire. Special attention is paid to mechanically de-couple the first gain stage and 2123 pole coils using a specially designed decoupling system. The rest of the construction is mounted on a aluminium sub chassis that forms together with the aluminium bottom plate a very rigid platform.
Ypsilon VPS 100 Phono Stage, MC16 Step Up Transformer Review
MC STEP UP
MOVING COIL STEP UP TRANSFORMERS
The MC series moving coil step-up transformers are used to amplify the low level output signal from a moving coil cartridge bringing it to the appropriate level to drive a moving magnet phono preamp.
The MC5 provides 5 times transformation ratio or 14db of gain
The MC10 provides 10 times transformation ratio or 20db of gain.
The MC16 provides 16 times transformation ratio or 24db of gain.
The MC20 provides 20 times transformation ratio or 26db of gain.
When terminated in 47k which is the standard input impedance of MM phono preamps the equivalent input impedance of each one would be:
MC5 2K ohm
MC10 500 ohm
MC16 200 ohm
MC20 140 ohm
If additional loading is needed, it can be done through the parallel input RCA connectors.
The MC series transformers are large size single C-core double coil transformers using a proprietary amorphous core material. Special winding techniques were developed in order to minimize inter-winding capacitances and maintain wide frequency response. They are optimized sonically to be as invisible as possible.
The transformers are shielded with mu-metal and are potted in 10mm thick soft iron nickel coated enclosures providing immunity to outside magnetic fields and a quiet and noise free performance.
The MC transformers were developed in conjunction with the VPS100 phono preamp. They can be used with most of the moving coil cartridges. For optimum performance the MC transformers can be used within a specific range of cartridge output levels.
MC5 may be used with cartridges from 0,8-1,2mv
MC10 may be used with cartridges from 0.4-0.6mv
MC16 may be used with cartridges from 0.3-0.4mv
MC20 may be used with cartridges from 0.2-0.3mv