I received the Booz hound Labs JFET Moving Coil (MC) Pre-Preamp Kit a while back and I promptly assembled the small circuit board. I’m a sucker for a simple kit and a hot iron. That is where it all stopped. The circuit board remained complete and laying about for a few years. Recently I required another MC stage because the tube moving-magnet (MM) preamp I had just completed did not work all that well with the Jean HI raga MC stage I had been using for years. It appeared the HI raga had too much output and was over-driving the tube stage. So I needed another MC stage.
I borrowed a friends Denon MC step-up-transformer (SUT) unit. The system sounded better with the SUT driving the tube MM stage but also sounded a bit dull. This finally pushed me to complete the Booz hound Labs MC Pre-Preamp kit.
The Booz hound Laboratories JFET Moving Coil Pre-preamp kit includes PCB and all passive components to populate the PCB. Four Stand-offs for mounting the PCB are included. You have to provide your own chassis, power supply (12-24VDC), and various connectors. The Booz hound Laboratories JFET Moving Coil Pre-preamp kit features:
- Minimalist circuit using the 2SK170 JFET;
- ~30dB gain;
- Russian K40Y paper-in-oil coupling capacitors;
- Nichicon Muse electrolytic filter capacitors;
- nice quality PCB (made in USA);
- circuit requires external 12-24VDC power supply (batteries work well);
- Assembled dimensions (height with included standoffs): 4 x 2 x 1.625 (inches).
The MC Pre Pre kit only has a handful of components and for the practiced DIYer the whole soldering chore can be over in less than an hour. Some of the solder pads are quite small so a fine soldering tip and some soldering experience is required. Some solder points I found a challenge and I have been on the cooler end of a soldering iron for over forty years.
The schematic (shown in Figure 1 below) is from the kit assembly manual. If you take a look at the circuit you will see it is very simple. It is basically the Le Pacific MC Pre Pre designed with the usual Booz hound Lab tweaks. The tweaks I think have been quite smart and I believe have really advanced the basic Le Pacific designs.
Booz hound Labs is known for their designing and supplying audio kits around the Russian paper-in-oil (PIO) caps. Personally I have used these Russian PIO caps in many tube and solid state projects. In every case I have been pleased with the results. The Russian PIO caps are inexpensive and good sounding. A lot of other DIYers sing their praise also. The Booz hound Labs JFET RIAA Phono Preamp Kit is full of PIO caps and I liked the MM phono stage also.
Read More: JFET Moving Coil (MC) Pre-Preamp Kit