Welborne Labs Ultrapath BP Tube Pre-Amp - 9/10 - Bubinga Wood/Black
If you're looking for a true high-end pre-amp, this is it. Not to mention, battery powered so there's no possiblilty of AC line interference. It is also remote control driven with all operations (power, volume, input, balance and mute) controlled by the remote. I've used this for the past 2 years and it's been ultra-quiet, amazingly musical, and a serious joy to own. The build quality is top notch and the woodwork is absolutely beautiful.
The unit was built by Welborne Labs (Jack Eliano or Ron Welborne) and was NOT a kit, although it was once available in that form.
Amperex Bugle Boy tubes are included as well as a recently purchased (July 2009) pair of 20aH batteries for longer playtime (10-18hrs between charges; upgraded from the 12aH stock batteries). The unit comes standard with a battery charger/AC power supply w/ all neccesary cabling neatly dressed in techflex style braiding (the braiding but not the wiring is a bit frayed near the connector).
I was also impressed with the documentation provided as it's extensive to say the least. Welborne describes the entire build, including complete component level schematics of the various stages in incredible detail in a 49 page Owners Manual. It comes with remote control and uses a trick 60 step attentuator design that includes it's own 26 page documentation describing various options and other aspects of the pre-amp guts.
I also modified the input/output scheme so the unit currently is set-up for 4 pairs of inputs and 2 pairs of outputs. It can easily be soldered back to it original configuration of 5 inputs and 1 output. Additionally, it also contains a set of low impedance transformer taps that can be used with headphones (all the details are contained in the manual).
Finally the pre-amp contains the ability to manually adjust the overall pre-amp gain from 0 db, 6db, 10db, or 15db of attenuation.
Specifications:
Frequency Response - 10 to 70Khz (+0, -2dB)
Harmonic Distortion - .045% @ 1V output, .07% @ 5V output
Voltage Output - 5.5V rms maximum
Gain - 10dB
S/N Ratio - ~90dB (tube dependent)
Voltage - 115/230Vac 50/60Hz
Input Impedence - 20kohms
Output Impedence - <600 ohms (<300 ohms headphone)
If you have any questions or comments, drop me a line. For AC'ers, I'll cover the shipping costs (two boxes)
Includes: Pre-Amp in Bubinga Wood, Bugle Boy Tubes, Power Supply/Battery Charger, Original Packaging, 20aH 6V Batteries, Original Documentation and all necesary cabling.
Please see my ad on audiogon for some stock pictures from the Welborne website....
Thanks for looking...
