SU-7: Active J-FET Head Amp +12dB to +26dB Moving Coil SUT Step-Up for LOMC w/Variable Gain and Variable Loading
Our Active Step-Up / Head Amp , an alternative to a physical Step Up Transformer or a combo MC preamp, for use with Low-Output Moving Coil cartridges, offers improved bass response and dynamics compared to coil-based SUTs while maintaining a rich, musical, naturally-detailed presentation.
Unlike transformers, it is highly adjustable to get the most from your cartridge with the best match to your system.
The SU-7 features eight current-matched low-noise high-transconductance Pure J-FETs in its input stage, operating in a single-ended mode (no Differential FET operation). Those are combined with an exceedingly high-dynamic-range linear output stage. It has user-adjustable gain and loading, offering exceptionally high headroom with a low and monotonic distortion residual.
The fully-discrete low-feedback audio path is coupled to sextuple-regulated discrete final dual-rail power supply regulation which provides dynamics and immersive soundstaging along with low-noise. The SU-7 is optimally paired with our MP-7 +40dB RIAA preamp for a complete LOMC solution.
Simplified Configurations as of 4/24/23 (Silver Fronts, Black available on special request; LED configuration can be made to match your existing MM/MP unit at no extra cost, email with special requests):
SPECS:
GAIN: +12dB, 18dB, 23dB, or 26dB, user-selected via internal DIP headers.
LOADING: 47 ohms, 100 ohms, 220 ohms, 470 ohms, 1K, 5K, or 47K, user-selected via internal gold-plated DIP headers, in parallel with 0.001uF. Soundsmith loading options including 750 ohms are available; email for info).
FREQ. RESPONSE: 20Hz - 20kHz +/-0.1dB.
THD: <0.01% at normal operating level of 5mV out. <0.02% up to +20dB above normal operating level; second harmonic predominates (quoted at +23dB gain).
S/N: >73dB A-Wtd re: 0.4mV input.
Optimum Cartridge Match: 0.18mV to 1.2mV output LOMC (Low-Output Moving Coil).
Headroom: 64dB above a nominal 5mV output (assuming the following RIAA stage has infinite headroom)…not a misprint.
Example: SU-7 set for +23dB gain: 0.35mV cartridge input results in 5mV at SU-7 output subsequently driving a +40dB RIAA gain stage with a line-level output of 500mV (0.5V) at 1kHz.
Maximum Out: >8V (+20dBu) into 10K load.
External Power Supply Cube: 24VAC 500mA, available in US 120V, EU 230V, UK 230V or AUS/NZ 230V.
Chassis: 5-inch wide, Silver front/black exterior aluminum chassis matching other current products..
Warranty: 1 year.
Matching Products: Designed especially to work alongside our MP8B, MP7B and MM6B RIAA units.
15-day Money-Back Guarantee from date of receipt, with 10% restocking fee. NOTE: Purchase of an SU-7 by a user of an existing MP or MM series who then returns the SU-7 (in the 15-day windows) does NOT entitle the buyer to also return the MP/MM for refund if the MM/MP was purchased more than 15 days ago and/or the MM/MP was purchased used or not directly from Darlington Labs.
1 year Limited Warranty. “Best Efforts” out-of-warranty support.
We reserve the right to make continuous technical improvements without notice. Refunds may be subject to a delay of up to 5 to 10 days due to payment processor times.