[AKSAphile]

SP100 is still one of the most neutral sounding, zero gain, zero feedback preamplifiers (buffers) available. The author of design was Sten Warren, who works for PS Audio for some time. Interesting thing about this buffer is, that it does not have any capacitor in signal path. Instead of them, this circuit use trimmer and DC servo made with LF411 IC. Here you can read few things about SP100 and also newer preamp:


http://www.positive-feedback.com/Issue23/superphon.htm


My kit consist of two SP100 boards which are already assembled + two empty PSU boards + all capacitors needed. PSU boards are not asembled, but kit already include all capacitors. You have to add few resisors and regulators which could be LM or LT type. The PSU works as a cascode with two series regulators per rail. Recommended transformer should have around 30VA 2x18V per channel to obtain final +-15 Volts. All capacitors are from Panasonic...FM and FC ones for smaller value and TSHA for bigger 4700/35V ones.


Kit include original schematic. Tranzistors are original ones and are matched. Buffer was tested and it is in perfect working condition.


Price 45 EUR + post costs

My email: moonaudio@gmail.com

[*Scotty*]

It should be noted that the Superphon SP 100 was never offered as a kit and both channels of the original circuit and power supply were contained on a single board. Hopefully this is an accurate clone of the original circuit. If the circuit of the SP 100 was accurately copied than the resulting kit will probably sound superior to any number of newer preamps. The same kit is also offered for sale on the diy Audio forum.  http://www.diyaudio.com/forums/showthread.php?threadid=148552

Scotty

[ltr317]

I had a Superhon Revelation II preamp with the space case.  It was the best sounding preamp I've ever had, including many others that cost a lot more.  The only negative was that it was not as dynamic as an active preamp because of it's passive line stage.  Also, I wanted an entire tube based preamp and amp combo.  I'm still sorry I sold it. 

[AKSAphile]

Hopefully this is an accurate clone of the original circuit. If the circuit of the SP 100 was accurately copied than the resulting kit will probably sound superior to any number of newer preamps. The same kit is also offered for sale on the diy Audio forum.  http://www.diyaudio.com/forums/showthread.php?threadid=148552

Yes, it is true. This pcb on the photo was made from original schematic. I use the same transistors and components values. Only difference is better PSU and better dc servo IC - LF411. I would describe the sound like piece of wire without gain. Just simple impedance transformer. This kit on diyaudio is mine.

[AKSAphile]

I especially recommend this buffer to owners of high gain power amplifiers. In my case this buffer was tested together with AKSA 100N amplifier with superb results.