Do I get a SUT?

[Barry]

The FRT-3 has two turns ratio options and true to form they're labelled in the most confusing way possible (to my mind at least). One option is labelled as "30 ohms" and it has a turns ratio of 1:20. That would be the option to use with the OP's Dynavector cartridge, despite the DV cartridge having an internal impedance of 5 ohms.
The second option is labelled as "10 ohms" and has a turns ratio of 1:40. That's too high a ratio for the Dynavector despite the labelled impedance being closer to the cartridge's source impedance.

Still, you can't do any damage by trying both options and it would be worth trying both just to find out what it sounds like when you get it "wrong". It usually doesn't sound all that wrong anyway.

Agree about the confusing labelling. I've always thought the labelling of Japanese SUTs was not the impedance presented to the cartridge by the SUT, but the source impedance of the cartridge for which the SUT setting is appropriate. But this does not seem to apply to the FR designs.

Taking 47KOhm as the load impedance of the phonostage, a 1:20 turns ratio SUT will present an impedance to the cartridge of ~ 120 Ohm (or 4x the labelled figure). A 1:20 turns ratio will reduce this figure to ~ 30 Ohm (or 3x the labelled figure).

However such speculations are academic because, as you rightly say, choose whichever setting sounds best.

[RothwellAudio]

I've always thought the labelling of Japanese SUTs was not the impedance presented to the cartridge by the SUT, but the source impedance of the cartridge for which the SUT setting is appropriate.

Yes, I think that is what they mean. However, they seem to pay no heed to the cartridge's output voltage as if that was irrelevant.

[lovejoy]

Thanks Dave - That was my supposition. The MM stage in the NAD seems very good indeed and I have been seriously enjoying what spending £70 on a vintage Shure has done on my deck. When I bought that DV cart though, I was very fond of it, but there's just no way of matching it into the MC stage of the NAD so it definitely sounds as if a SUT is the way to go.

Mark, as much as I like the DIY route and the potential savings, finishing things and putting them into boxes has never really been my strong point. I imagine a case is going to be a serious factor when it comes to something like a SUT as well, so I'd feel better sticking with the guys who know what they're doing in this instance, but thanks for the heads up on Sowter ;-).

Well that's another recommendation on the Rothwell, so there will be an order heading your way as soon as I have the hi-fi setup in the new house and the dust has settled... Thanks again all.

[OD1]

Hi Rich,
I use a Rothwell MCL with the same cartridge as yours, into a Croft 25R MM phono stage, it sounds great to my ears.
However, I had a problem with hum when I connected the earth lead from my TT to the MCL then to the Pre, which disappeared when I earthed the TT to the Pre only.

Andrew,
Will the SQ suffer if the MCL is not earthed ?

[RothwellAudio]

Andrew,
Will the SQ suffer if the MCL is not earthed ?

No, the SQ will not suffer. The way you have it connected is correct. The earth post is there if needed in other set-ups which are earthed differently. In your system removing the extra earth wire cured the hum, so that's correct.

[magiccarpetride]

Hi all,
Well, here's the story. I replaced my Dynavector L300/HX1.2 last year for the NAD Masters Series M12/M22 combination, which overall I've been over the moon with. The only drawback to the new amps is that they lack the widely configurable phono stage that the Dynavetor had that allowed me to set gain and capacitance settings for my DV20X2L MC cartridge perfectly. The NAD pre has an MC input, but there are no adjustments that can be made and given the low output of the DV, it gets a little noisy.

As an experiment earlier this year and having read lots of good things, I bought a Shure M55e MM. That has worked an absolute treat and I've been back enjoying my vinyl again. It has also illustrated how good the MM stage is on the NAD, even if it is sampling the incoming signal at 48KHz. I am kind of itching to return to my DV though, so I wondered whether a step up transformer may be the way to go. I'm loathe to buy an outboard phono stage as having reduced my box count after swapping the amps, I'd like to keep it that way, but accommodating a step up transformer would be fine.

If a SUT sounds to make good sense, can anyone offer any recommendations on particular units? I must admit it's something I'd never really considered before. Budget is 'don't go crazy' ;-).

Can't help you with recommendations for a particular brand, because my SUT was hand made for me. But I must say that it makes a difference in my setup. For the lack of a better word, I would describe the sound I'm getting with the SUT into the MM phono as more 'organic'. Switching back to the MC phono gives me a bit more 'electronic' type of sound (if those epithets even mean anything in the realm of sound reproduction quality).

[julesd68]

Agree about the confusing labelling. I've always thought the labelling of Japanese SUTs was not the impedance presented to the cartridge by the SUT, but the source impedance of the cartridge for which the SUT setting is appropriate. But this does not seem to apply to the FR designs.

Taking 47KOhm as the load impedance of the phonostage, a 1:20 turns ratio SUT will present an impedance to the cartridge of ~ 120 Ohm (or 4x the labelled figure). A 1:20 turns ratio will reduce this figure to ~ 30 Ohm (or 3x the labelled figure).

However such speculations are academic because, as you rightly say, choose whichever setting sounds best.

Yes I nearly drove myself mad trying to do the maths with my FRT-3.
Thing is it sounds wonderful so I stopped worrying about it. I tried both settings and one was just marginally preferable over the other ...

[Jason P]

I'm loving my Lounge Audio Copla variable SUT. I don't pretend to understand fully how it works, but work it does.

http://www.6moons.com/audioreviews2/lounge/2.html

[RothwellAudio]

I'm loving my Lounge Audio Copla variable SUT. I don't pretend to understand fully how it works, but work it does.

http://www.6moons.com/audioreviews2/lounge/2.html

That is not a step-up transformer - it's a headamp. Also, it's a headamp with one particular drawback in my opinion. One of the advantages of a headamp over a step-up transformer is that it's possible to set the gain and load impedance independently of each other, but the with Copla that isn't the case because changing the gain also changes the load impedance and vice versa.
I've never heard the Louge Audio Copla so I can't comment on its sound quality.

[bob4333]

Life is about to get interesting. The Rothwell Headspace is the piece of kit that I've had in my head for years thinking "If only someone made something that ........................", but didn't know anyone did. I'd considered SUT's but they seem a bit too bespoke, being tailored to a particular cartridge.

I want to hear what it does with my AT33 PTG/II, but more importantly to see what happens with an SAE 1000LT that I have. A HOMC (2,5mV @ 1kHz, 5cm/sec), an output too much for the MC input on my phono stage and not enough for the MM input. The MC input gives an extremely lively but ultimately slightly over driven distorted sound, whilst the MM input sounds a bit ordinary and lifeless. This is a staggeringly capable cartridge that can deliver dynamic range in spades when partnered well. I'm hoping the Headspace will give me the flexibility to adjust matters.

Just had a dip into the toy money pot and ordered one, delivery around Wednesday. We'll see.