Which SUTs go well with Croft Phono stages?

[Elephantears]

Just recently I've had a Croft RIAA R on loan. I've been a fan of Croft pre-amps for some time, but rarely got the chance to use the phono stages they are famous for. Now the RIAA R has really impressed me. It has such a superb balance of qualities; great tonal colour without being euphonic; great mid-range presence without being too forward, a very naturalistic sense of space, and good dynamics without being pushy.

Now I also had a Puresound T10 step up transformer on loan and found the combination worked really well. After trying various cartridges I finally came to my AT50ANV and the results were amazing. Valve phono stage plus SUT is clearly the way forward with a low output cart like this.

I realise many of you know this already, but I've come to this SUT thing late, and would appreciate any suggestions. The T10 works really well, but I'm wondering if I could do even better - it's the first SUT I've tried.

A friend is going to Japan soon, so I'm wondering whether to get one of the Yamamotos. Anyone tried those? More generally, any experience of SUT with Croft would be really interesting.

[The Black Adder]

The Ortofon that Marco had would go well I'm sure, ST-80 SE.. ? a bit minty though.

[anubisgrau]

you would do a better job matching it to your pickup first. that's where things are screwed most of the times.

if you can get a SUT from japan, than i would go for a bare hashimotos (HM-3). they are about 30% less than in the UK. you would need to case them but that doesn't hurt....

if you need an advice where to look for them, let me know. i've recently visited akihabara in tokyo, you would need to order them a bit in advance, say 2-3 weeks. though one famous shop for transformers had exactly a pair of these...

[chris@panteg]

I use the Puresound T10 with my AT33EV, I've no intention of trying a more expensive SUT, perfectly happy with it.

Just enjoy it and buy more vinyl, my advice.

[loo]

Buy a pair of Sowter sut's and get Glenn to fit them inside your Croft
Save on extra connections
Paul

[Audio Al]

The Ortofon that Marco had would go well I'm sure, ST-80 SE.. ? a bit minty though.


That I now have :D

Sounds rather splendid running through my Croft 25 basic with built in phono stage ;)


PS don't tell Marco or he will be along soon with comments :lol:

Yes it is the ST 80se

[The Black Adder]

That I now have :D

Sounds rather splendid running through my Croft 25 basic with built in phono stage ;)


PS don't tell Marco or he will be along soon with comments :lol:

Yes it is the ST 80se


lol.. I don't think we can stop the man... :) :)

Great, I'm glad your enjoying the ST-80SE... It would be my choice with an MC me thinks... well, certainly one in the top 5 to try anyhoo.


Buy a pair of Sowter sut's and get Glenn to fit them inside your Croft
Save on extra connections
Paul

Yep... another good idea. Also, give Nick Gorham a shout (Lurcher) Andrew, he would do you a very nice job on one I'm sure.

[Elephantears]

Buy a pair of Sowter sut's and get Glenn to fit them inside your Croft
Save on extra connections
Paul

It's an interesting idea. Of course I'd have to admit to Glenn that I'm using an MC cartridge! And I have so nearly gone down the true MI way recently. But in reality I don't think there would be room for SUTs either in the RIAA R, or in my Tekni-Fi Pre.

My unusual Tekni-Fi/Croft pre doesn't have a phono stage, but after my trial of the RIAA R and I am certainly going to ask Glenn to fit one. But that is used in my second system, so it could be an RIAA R with SUT for the main system.

Regarding Chris's point; yes I do think the T10 is very good and a bargain. However my cart is much lower output than the AT33EV (which I used previously, incidentally), and anything I can do to reduce noise is a bonus. Mind you, I suspect all the excess noise is due to the Croft rather than the T10 so this is a moot point.

[Elephantears]

Also, give Nick Gorham a shout (Lurcher) Andrew, he would do you a very nice job on one I'm sure.

Yes, I might follow that up, thanks.

[DSJR]

I don't think Glenn cares what cartridge you use, as long as you're happy with the gear he's made.

Just to bring things down to earth for a skinflint like me, I've used an Audio Technica 630 SUT with my old Croft with no issues. Hum is reasonable, if not as quiet as a proper modern combination, but it's quite acceptable and never annoying.

[Elephantears]

Following Gordan's point above, I should have mentioned that my cartridge is 0.12mV and loaded at minimum 100 Ohms, although I'm not certain what loading is ideal. So perhaps I'm asking the wrong question here, and I should be looking at the cart. The fact that the T10 did seem to work surprisingly well in terms of loading and gain suggests that I might be wiser to stick that twist. But I'd like to know what my options are.

[anubisgrau]

i'm wondering what version of T10 you tried, the one with two hi/low switches or the one with a rotary loading selector with (i think) 5 options.

the first gives options of 1:18 or 1:36 loading, given your AT parameters i guess you used the 1:18 option with about 140ohm which probably functions well.

the second option has 5 steps between 30 to 200 ohm so it would be good to know what you used if you had that one.

overall, for 0.12 mV i would say you are very fine with 1:20 (or near, like 1:18) ratio so you won't overload your phono stage plus you will be in the zone of the recommended impedance. though, if i may say so, most of the AT carts are in the zone of 10ohm impedance so they would work fine with a bit lesser loading than recommended 100 ohm.

[NRG]

1:20 would be the absolute minimum ratio I'd go for with the AT50ANV, 1:30 would be much better. As for loading anything between approx 7~10x the cart impedance will work just fine IME. At 1:20 at 36K loading res gives 90R loading and at 1:30 75K gives 83R loading....

[Elephantears]

i'm wondering what version of T10 you tried, the one with two hi/low switches or the one with a rotary loading selector with (i think) 5 options.

the first gives options of 1:18 or 1:36 loading, given your AT parameters i guess you used the 1:18 option with about 140ohm which probably functions well.

the second option has 5 steps between 30 to 200 ohm so it would be good to know what you used if you had that one.

overall, for 0.12 mV i would say you are very fine with 1:20 (or near, like 1:18) ratio so you won't overload your phono stage plus you will be in the zone of the recommended impedance. though, if i may say so, most of the AT carts are in the zone of 10ohm impedance so they would work fine with a bit lesser loading than recommended 100 ohm.

This is very useful to know about the loading on the T10, thanks. I had the version with the 2 high/low switches and had them both on low. I think I tried one on high as well but can't remember if it made a difference. So I guess I was loaded at 140 ohms. On my Diablo I use 100 ohms with the AT50ANV. The Diablo also has a 33 ohms option which sounds just wrong, deadening the sound. I've forgotten what the 1Kohm sounds like but I'd be keen to try around 300-400 ohms.

Regarding gain, the T10 with the Croft has plenty. I accidentally discovered that the Croft can amplify a 0.3mV MC cart to an acceptable volume, which came as a bit of a shock.

[Reffc]

This is very useful to know about the loading on the T10, thanks. I had the version with the 2 high/low switches and had them both on low. I think I tried one on high as well but can't remember if it made a difference. So I guess I was loaded at 140 ohms. On my Diablo I use 100 ohms with the AT50ANV. The Diablo also has a 33 ohms option which sounds just wrong, deadening the sound. I've forgotten what the 1Kohm sounds like but I'd be keen to try around 300-400 ohms.

Regarding gain, the T10 with the Croft has plenty. I accidentally discovered that the Croft can amplify a 0.3mV MC cart to an acceptable volume, which came as a bit of a shock.

Bare in mind Andrew that cartridge loading isn't primarily for balance of sound, but to protect the windings on your MC cartridge. Too low a loading will allow too much current draw from the cart and can burn out or damage the tiny windings. The minimum recommended loading given by most manufactures is 10 x cartridge impedance. You can go as high as you like on loading without fear of damaging anything. With some cartridges and SUTs increasing loading has very little if any bearing on sound, whereas with others you will get a shift in tonal balance.

[walpurgis]

Too low a loading will allow too much current draw from the cart and can burn out or damage the tiny windings..

As an aside. Talking of burning out windings, I've come across several MCs and Deccas with burnt copper wires, i.e., open circuit. This is likely to be from continuity testing with a meter. So best not use a meter (I'm sure there may be meters safe to use here, but which one's?).

Usually this kind of damage occurs at the tiny lead out wires going from the coil to the terminal pins, due to nothing being there to sink the heat away. If the wire ends can be located at the coil, there is a chance of repair (very fiddly though).

[NRG]

I have never ever heard of too low a load causing a MC to burn out a coil. Even with a 10R load for the OPs cart the current is 12uA. I've run an Ortofon KB with a 10R load before for 47uA and its survived just fine. Even shorting the output the current would be limited by the MC coil resistance or am I missing something? :scratch:

What a low load does do is damp the stylus and reduce output due to the potential divider formed by the load and the MC coil some make like this sort of presentation, I know NK at HFW ran his Kontra B like this for years with something like a 10R load.

[Elephantears]

I've borrowed another T10 so I've got the Croft back in the system. I must say I am having serious difficulties getting rid of hum. It is very tricky to earth the whole system with so many cables, many of them crossing. This is one of the reasons I've shied away from SUTs before, but I'll persist.

[Sondekker]

I've been using a Cinemag 3440A (Red Label) SUT with a Lyra Delos into my Croft 25R without any problem. In fact it sounds very good.

The Cinemag has switchable high (x30) and low (x16) gain settings as well as a ground lift switch and at the time I purchased it was a reasonably priced (around £400 I think) and well reviewed unit. It was built by Bob's Devices in America who still supplies a range of SUT's based on Cinemag transformers.

After I'd acquired it then no matter where I placed it or how I dressed the various interconnects and power kords comprising my system I always got audible hum. I spoke with Bob who suggested I disconnect the screen at one end of each of the interconnects connecting the SUT into my previous preamp and Bingo, the hum completely disappeared.

Always worth a try.

[Elephantears]

That's really good to know John, thanks. I'll try that. I tried the Croft again today and loved it. It's actually quite difficult to get a hum free situation with any phono stage I've tried, including my Diablo, but very low output carts are new to me so I've lots to learn.