Classic Vacuum Tube Phono Stage (MM / MC)
Status: Wait List for assembled units. Please send us an email if you would like to purchase one, and we'll put your name on the list, with an estimated ship date. Sorry for the delay. Please contact us at Tavish Design if you have any questions (firstname.lastname@example.org). Thanks!
Tavish Design’s Classic Vacuum-Tube Phono Stage is a passively-equalized, two-gain-stage design whose basic circuit topology has remained popular for more than 55 years. The reason for its endurance is simple: with appropriate updates, it is very difficult to beat without going to elaborate multi-tube circuits. In fact, this simple phono stage outperforms many (if not most) high-end products.
Our update of this classic circuit includes optimized RIAA equalization that makes the circuit less sensitive to variations between tubes, as well as a relay-selected JFET pre-preamplifier for low-output moving coil cartridges. It retains the extremely high overload margin inherent to high-voltage vacuum tube circuits.
Our design also includes linear, regulated high-voltage and heater supplies for low noise and low operating drift. The 200 volt supply rail operates the tubes in their intended range - we don’t starve the tubes by operating them at low voltages. And, we completely avoid the use of switching power supplies. The unit is powered from an external AC wall transformer, using a small internal step-up transformer for the high voltage supply. This puts the larger, high-current transformer outside (and well away from) the enclosure. A sophisticated circuit board design with multiple ground domains eliminates coupled noise. Finally, we use a low-noise 5751 input tube (you can substitute a 12AX7 if you prefer). The result of all this is exceptionally low noise and hum for a tube phono stage, in a compact and low-cost package.
Vinyl LPs sound better than ever, and Tavish Design’s Classic Vacuum-Tube Phono Stage lets you get the most out of your LPs for a reasonable price. It’s not your grandfather’s phono stage - it offers high-end sound and performance, and exceptional value.
For ambitious do-it-yourself enthusiasts, we offer the blank printed circuit board (with or without the surface mount JFETs pre-installed). We suggest downloading the Assembly and Setup Manual before ordering the circuit board, to be sure you are comfortable with the assembly process.
We also offer a premium assembled version, with RIAA equalization trimmed to within ±0.3 dB (30Hz – 20kHz) and supplied with an individually measured RIAA curve for the unit. It also includes a selected low-noise 5751 that achieves >81 dBA (ref. 5mV) signal-to-noise ratio on the moving magnet input (signal-to-noise ratios on the MC input are not significantly affected). The premium version is not always available - it depends on the tubes we have in stock.
- Designed to accommodate any cartridge (Moving Magnet, High-Output Moving Coil, or Low-Output Moving Coil) with an output of approximately 0.25 mV or more
- Gain: 41 dB Moving Magnet, 61 dB or 53 dB Moving Coil (switch selected)
- RIAA equalization accuracy ±0.5 dB, 30Hz – 20kHz
- Signal-to-noise, moving magnet (MM) input: >79 dBA, ref 5 mV @ 1 kHz
- Signal-to-noise, moving coil (MC) input, 53 dB gain: >79 dBA, ref 1.25 mV @ 1kHz
- Signal-to-noise, moving coil (MC) input, 61 dB gain: >76 dBA, ref 0.5 mV @ 1 kHz
- Reference output level: 560 mV RMS (-2.8 dBu)
- Total harmonic distortion <0.02% at reference output level into 22k ohms, 1kHz
- Output level for 1% THD: >19 VRMS into 10k ohms, 1 kHz (31dB overload margin)
- Adjustable cartridge loading on both MM and MC inputs
- Linear regulated high voltage and heater supplies (No Switching Power Supplies)
- OMRON low-signal relays for MM/MC selection and output muting
- 14 gauge powder-coated aluminum chassis
- Tube complement: 5751 (x1), 12AX7A (x1), 12AU7A (x1) (MM input has an all vacuum tube signal path)
- Transistor complement (for MC preamp): 2SK209 (x2) Toshiba low-noise audio n-channel JFET, MMBFJ270 (x2) p-channel JFET
- Easy kit assembly with hum-free, single circuit board design
- Power Consumption: 18W, 120V, 60Hz using an 18VAC wall transformer
- Size: 9” wide, 6” deep, 1.5” high (3” high to top of tube guard)
- Weight: 3.5 lbs. including wall transformer (6 lbs. shipping weight)
- Made in U.S.A.
- 6 year limited warranty