Phono Loco Coming From Sutherland Engineering

The usually conservative (engineering-wise, don't know his politics) Ron Sutherland has thrown all electronic caution to the wind and will shortly introduce the Phono Loco, his first venture into what's commonly called a "current mode" phono preamplifier.

As with a few others on the market the Phono Loco requires a balanced signal from the cartridge and an XLR terminated phono cable. Now, cartridges are inherently "balanced", with no reference to ground but some tone arm manufacturers, Rega for one, ties ground to the RCA plug's outer ring so an RCA to XLR adapter will not work but others that separate ground (SME's DIN connector among others) can be used with an adapter and Sutherland supplies one but only for use until you can get a replacement cable or have your arm re-wired if necessary.

Why go through this hassle? And why manufacture a phono preamp that can only be used with balanced XLR equipped tone arms?

As anyone who uses or has used such a device, which Sutherland calls a "tran-simpedance" circuit, the moving coil cartridge sees a virtual short circuit. The input signal is the cartridge's current output. The good news is that "low output" (voltage) moving coil cartridges put out a good dose of current. The lower the cartridge's internal impedance, the more current it outputs (and usually the lower the voltage output, but that doesn't matter!).

Noise isn't generally an issue and there's no loading options because there's no loading! There are three gain settings on Sutherland's Loco: a medium gain said to be good for most cartridges and low (-6dB) and high (+6dB) settings if needed. The output is single-ended (RCA).

Mr. Sutherland cites the CH Precision P1 as an example of a current mode phono preamplifier "currently" on the market. It sells for $31,000. I own one along with the extra cost X1 outboard power supply. Sutherland claims his Loco is better than the P1 because it is totally focused on one task and has no flexibility or options, which the P1 most certainly does.

Will the Loco better the performance of CH Precision's P1/X1 combo? I will be the judge of that! How much will Loco cost? $8200.

Zardoz's picture

for your review on this. I'm using a Krell KPE Reference phono with with upgraded caps that sounds great, but I have been looking for something better to come along, in a price I could conceivably afford. I had been looking at trying to find a used mono block, but this might be even better.

isaacrivera's picture

I wonder, Sutherland at this price point... is the power supply external? Are the gain choices selectable externally? Or do we have to open the box and use dip switches?

JohnG's picture

"As anyone who uses or has used such a device, which Sutherland calls a "tran-simpedance" circuit, the moving coil cartridge sees a virtual short circuit."

DC Bruce's picture

Wasn't the Acqvox phono stage that you (MF) reviewed some years ago, a current-mode preamp? Or at least current mode for MC cartridges. I recall that the unit's performance with MM carts was nothing special; but the MC cart performance was pretty good. The product was made in Germany, and I think it's still available by on-line order. It was something like $2K

vinyl listener's picture

i always thought his preamps and amplifiers were anything but conservatively designed.
from the early days of those pint-sized amps, the auto-switching preamps, battery power supplies etc.

dr vinyl's picture

I think its and alternative to impedance matching, that people sometimes use as and equalizer or tone control for there systems