RFC MC1 step up transformer - member review

[losenotaminute]

The RFC MC1 step-up is a relatively new product, hand built by Paul Coupe of Reference Fidelity Components.



This is what it looks like plumbed into my Puresound P10 MM valve phone stage, the source being a Linn LP12 with a Dynavector DV20X2-L MC cartidge.



Specifications are on the RFC website.

I was looking for an SUT as an alternative to my Lentek, the main reason being that the Lentek requires a 9v battery. I was finding that the performance of the Lentek degrades slightly unless the battery is fairly new, so a fully passive SUT seemed to be the solution and the RFC1 prototype had been extremely well received on AOS.

I feel it's important firstly to complement Paul on his communication and customer care. All emails were answered promptly, we discussed and agreed the appropriate gain settings for my cartridge, he kept me fully informed about how long it would take to manufacture (I believe the transformers are hand-wound by a supplier), I was offered a trial first and the unit was manufactured and delivered exactly as promised.

When I first plumbed everything in I had the dreaded issue of hum. This took a bit of tracking down, with a lot of help from Paul and a modification to the grounding arrangements inside the MC1 that was carried out extremely quickly and free of charge.

Now I have completely eliminated the hum (even at full volume it is silent) I have been enjoying experiencing what the MC1 can bring to the party. Describing what one hears is never easy, the sound stage is still there and very three-dimensional, the treble sounds clean and realistic (cymbals sound like cymbals) and the base is natural and well balanced. I am enjoying working through my record collection again, finding myself enjoying the music rather than listening out for the performance of different components. This for me is an excellent outcome.

Once again, I can't say enough about how helpful, polite and professional I have found RFC to be and heartily recommend the RFC MC1 for those of you wanting to use a low output MC cartridge into an MM phono stage.

Lawrence

[hifi_dave]

I hope that Pani ( 6 posts below ) is reading this.

[Tarzan]

Welcome to the RFC SUT1 club Lawrence, it really is a good unit, does not get in the way of the music! Well pleased with mine.

[Marco]

Nice one, Lawrence. Glad that the unit is hitting the spot! Paul makes some very nice stuff

Marco.

[bob4333]

Interesting review Lawrence thanks. Does this mean the SUT needs to go back to RFC if you change from your Dynavector or are there any user configurable bits inside?

[losenotaminute]

Interesting review Lawrence thanks. Does this mean the SUT needs to go back to RFC if you change from your Dynavector or are there any user configurable bits inside?

Hi Bob,

The unit would need to go back to RFC if you needed to alter the gain. There's nothing user configurable inside - no dip switches. According to the RFC website "The MC1 will suit a wide variety of low output moving coil cartridges from 0.25mV to 0.8mV output with a self impedance up to 40 Ohms. The SUT comes standard loaded for 100 Ohms cartridge loading but can also be loaded to any other value for no extra charge. "
If I recall correctly, my cartridge is 0.3mV and is towards the lower end of the range. Paul also has a design that produces even more gain than mine, it's a little more expensive due to the nature of the internals required to achieve this.

Lawrence

[Reffc]

Hi gents;

thank you for your thoughts on the MC1 Lawrence, just delighted that it's hitting the spot for you.

To answer Bob's point, I provide a fee service to re-configure the unit for a change of cartridge within the standard 24 month warranty period. Loading is a very mis-understood area when it comes to SUTs. The reason that minimum loading is specified is more to do with protecting the tiny wiring of the cartridge coils than for SQ reasons. It's to prevent current over-draw which might otherwise damage the wiring.

The secondary loading issue is the effect, particularly HF on SUT performance...some SUTs prefer 2ndary loading as it adds electrical damping which reduces HF ringing, whereas some perform best with primary loading. The reasons are connected to the SUT design and specification and the leakage reactance of the SUT. Where possible, there are benefits to using a low step up ratio over a high one, providing that your amp has sufficient gain. The HF correction is often easier to deal with. I've successfully used a 1:10 with cart outputs as low as 0.25mV with no issues. As Lawrence says, there are higher outputs which can be provided, but these require more work/circuitry on the secondary windings side. Also, just to clear up one point, the SUTs are made to my required specifications but I'm doubtful that they are actually hand wound. As far as I am aware, they are wound on a machine programmed for some fairly exacting spec's in a multi-leaf high bandwidth design. This machine does not reside in China and has never been there on holiday by the way