Audio science review Schiit Skoll Balanced Phono Stage Review
This is a review and detailed measurements of the Schiit Skoll balanced phono preamplifier. It was sent to me by the company .
Touch controls select everything from loading of the input (resistance and capacitance) to input type (RCA or XLR), gain and filtering. A remote control is supposed to come with to let you do this remotely but my box had none in it. Back panel shows what is unusual about this phono stage:
XLRs for input and output! Love that as in this day and age, most systems also have computer connectivity for streaming and that is just asking for ground loop. So even if you don’t need it in a phono stage, it is a very good idea from system perspective.
Power is provided through a hefty AC transformer which provides dual voltages (24 and 5 volts nominally).
Company’s marketing message is around a discrete implementation (as opposed to IC op-amps) and that enabling high voltage operation/high headroom. We will test for that.
Note that there is no explicit Moving Coil/Moving Magnet setting. You select a gain from 40 dB to 70 in 10 dB increments. For my testing I used 40 dB to represent MM and 60 dB for MC. I performed all my testing with XLR input and output. I did briefly test with RCA out but that lowers the gain. Performance roughly remained the same though.
Schiit SKOLL Phono Preamp Measurements
Let’s start with our usual dashboard with 5 mv input and 40 dB gain:
I was impressed by almost total lack of mains noise and no reason to mess with any grounding as I always have to with other phono stages! Indeed grounding the unit or not made no difference at all. This is why you want balanced I/O.
Distortion is below -100 dB so SINAD is dominated by noise, ranking Skoll near the top of the class:
We can confirm that with SNR measurement:
The phono stages at the top of the chart eek out another 5 or 6 dB of noise performance, mostly at higher frequencies.
Performances drops fair bit with 60 dB gain but that is to be expected:
RIAA EQ implementation is very good:
I like having high pass filter but like to see it not eat into audible band so much with sharper response.
Distortion by itself (no noise) is far lower than the LP/cartridge:
Let’s test for headroom at 1 kHz:
Clipping point is well above average which is nice. That is offset by gradual rise in distortion however. Competing solutions haver a downward graph and then they suddenly shoot up.
Sweeping frequencies, I was pleased that performance was maintained up to 10 kHz:
Conclusions
The Skoll is a very flexible phono stage and I love the fact that it has balanced I/O which sharply reduced mains noise in my testing. Its discrete implementation allows higher operating voltages than some IC based solutions. Alas, distortion rises with level, likely courtesy of “zero feedback gain stages” as the company states. RIAA implementation is very good and I like the inclusion of high pass filtering. Better measured performance is available elsewhere but whether the LP format needs it, is another story.
I am going to recommend Schiit SKOLL phono stage.
Manufacturer Specifications:
Gain: 40db
THD: <0.006%, ref 4V RMS balanced, 2V RMS SE
SNR: >102dB, A-weighted, ref 4V RMS balanced, 2V RMS SE
Crosstalk: -100dB, 20-20kHz
Sensitivity: 2.85mV for 300mV output at 1kHz
Gain: 50dB
THD: <0.02%, ref 4V RMS balanced, 2V RMS SE
SNR: >90dB, A-weighted, ref 4V RMS,2V RMS SE
Crosstalk: -98dB, 20-20kHz
Sensitivity: 0.78mV for 300mV output at 1kHz
Gain: 60dB
THD: <0.03%, ref 4V RMS balanced, 2V RMS SE
SNR: >85dB, A-weighted, ref 4V RMS balanced, 2V RMS SE
Crosstalk: -95dB, 20-20kHz
Sensitivity: 0.34mV for 300mV output at 1kHz
Gain: 70dB
THD: <0.06%, ref 4V RMS balanced, 2V RMS SE
SNR: >70dB, A-weighted, ref 4V RMS
Crosstalk: -84dB, 20-20kHz
Sensitivity: 0.09mV for 300mV output at 1kHz
Maximum Output: 20V RMS balanced, 10V RMS SE
Overload Margin: >20dB
RIAA Accuracy: +/- 0.15dB, 20-20kHz
Low Frequency Filter: switchable 2 pole at 15 Hz, fully passive, for balanced XLR outputs
Output Impedance: 10 ohms
Input Loading: 10, 50, 100, 150, and 47k ohms resistive, and 50, 100, 150, or 200pF capacitive, switched via remote or front-panel button
Topology: Equipoise™ balanced, differential, fully discrete zero feedback gain stages, passive RIAA, 0.1% thin-film resistors, and 1-2% film capacitors, switchable passive CR LF filter, microprocessor oversight and relay switching, remote control
Power Supply: “wall wart” style 24/6VAC transformer, dual-filtered, regulated +45V/-19V rails, plus 5V/3.3V supply for microprocessor and relays
Power Consumption: 7W
Size: 9 x 6 x 1.5”
Weight: 2 lb
