Step Up Transformers? Pros / Cons?

[watchnerd]

Current cartridge: Audio Technica AT33/EV (moving coil, 0.3mV output, 10 ohm internal impedance)
Phono Stage: Phono input of Devialet Expert 400, set to 100 ohm loading, RIAA EQ. DSP-based, so involves ADC.

Issue:

The Devialet has the quietest active phono stage I've ever heard, but if I crank it really loud (0dB to +3dB), and there is no music playing, there is a large amount of hiss.

At moderate listening volumes that I typically use (-20dB to -10 dB), the hiss is not really audible unless I stick my ear close to the tweeter.

Other than this, the Devialet phono stage is provides state of the art configuration options and incredibly low distortion.

Question:

I have never used a SUT (step up transformer) in a phono system. I've read some subjective claims of which I'm skeptical (they improve soundstaging, air), or at least think, if they exist, might be caused by inadvertent changes in cartridge loading (because there are no magic pixies in a SUT). I've also read:

"Apart from the issue of noise, the sound quality of transformers is something their advocates swear by. The distortion produced by audio transformers is of a completely different nature to that produced by a transistor amplifier. The harmonic distortion in transformers is greatest at the lowest frequencies and falls rapidly as the frequency rises, whereas in transistor amplifiers distortion more usually rises as the frequency rises. More importantly, intermodulation distortion tends to be lower in transformers than it is transistor amplifiers. The outcome is that although transformers aren't absolutely free of distortion (nothing is), the distortion is very benign compared to the distortion produced by many transistor amplifiers. This explains why the sound produced when a moving coil cartridge is used with a good transformer is so sublime and can create an open and spacious soundstage with amazing separation between instruments.
The case against transformers is simply one of cost. Transistors can be as cheap as a few pennies (or less when bought in sufficient quantities) whereas transformers always cost a lot more, by as much as a factor of several thousand, due to the expensive materials used in the core and the cost of the copper windings in terms of both material and labour."

(Source: http://www.rothwellaudioproducts.co.uk/html/mc_step-up_transformers_explai.html)

SUTs seem to run in the range of $1000-$1500, which is shockingly expensive for a bunch of wound copper. In the context of my system, that's less than my turntable + tonearm, but more than my cartridge. Which makes me question if it's a good investment -- granted, a SUT won't wear out, like a cartridge, but does have a limited range of step up ratios, which means it won't work with every MC cart out there.

So....

Would moving to a SUT lower the noise with no price to pay elsewhere (other than $$$)?

Or would it just add more complexity (another device, another set of interconnects, more risk of hum), more cost, and little probable benefit?

 

[Ceburaska]

In the time honoured manner, I’ll fail to answer your question and instead ask another one.
Have you tried the AT VM540?
It’s a Moving Magnet with excellent test results and I’ve recently switched to it with great subjective experience.
It’s also pretty cheap.
https://hometheaterhifi.com/reviews...udio-technica-vm540ml-phono-cartridge-review/
Also worth reading the conclusion from this review
https://hometheaterhifi.com/feature...dio-technica-vm760slc-phono-cartridge-review/
I have had an AT33 in the past, and liked it, but subjectively rate the 540 as highly. Plus it is cheaper, replaceable (sort of), measures well and has no need for step ups, etc.
Of course, if you’ve already tried and dismissed it, forget about it!

 

[Ceburaska]

Second non answer.
In the past I used a Graham Slee Elevator pre pre amp. It has a lot of load options all accessible from front panel.
I believe it is technically not a SUT.
It worked fine, but I found no better than running my current phono amp.
I’d be doubtful that a SUT would improve on your current system.

 

[watchnerd]

In the time honoured manner, I’ll fail to answer your question and instead ask another one.
Have you tried the AT VM540?
It’s a Moving Magnet with excellent test results and I’ve recently switched to it with great subjective experience.
It’s also pretty cheap.
https://hometheaterhifi.com/reviews...udio-technica-vm540ml-phono-cartridge-review/
Also worth reading the conclusion from this review
https://hometheaterhifi.com/feature...dio-technica-vm760slc-phono-cartridge-review/
I have had an AT33 in the past, and liked it, but subjectively rate the 540 as highly. Plus it is cheaper, replaceable (sort of), measures well and has no need for step ups, etc.
Of course, if you’ve already tried and dismissed it, forget about it!

I haven't, but when I get in an MM mood, I swap in my Nagaoka MP-500.

If I were going to get an AT MM, I'd probably go for the VM750SH.

 

[watchnerd]

Second non answer.
In the past I used a Graham Slee Elevator pre pre amp. It has a lot of load options all accessible from front panel.
I believe it is technically not a SUT.
It worked fine, but I found no better than running my current phono amp.
I’d be doubtful that a SUT would improve on your current system.

What's a pre pre amp?

I think in the US we call that a headamp: an active device that boots MC up to MM voltages.

 

[watchnerd]

In the time honoured manner, I’ll fail to answer your question and instead ask another one.
Have you tried the AT VM540?
It’s a Moving Magnet with excellent test results and I’ve recently switched to it with great subjective experience.
It’s also pretty cheap.
https://hometheaterhifi.com/reviews...udio-technica-vm540ml-phono-cartridge-review/
Also worth reading the conclusion from this review
https://hometheaterhifi.com/feature...dio-technica-vm760slc-phono-cartridge-review/
I have had an AT33 in the past, and liked it, but subjectively rate the 540 as highly. Plus it is cheaper, replaceable (sort of), measures well and has no need for step ups, etc.
Of course, if you’ve already tried and dismissed it, forget about it!

I also like the AT33 series because of the matching true mono cart.

 

[Ceburaska]

What's a pre pre amp?

I think in the US we call that a headamp: an active device that boots MC up to MM voltages.

I am straying way past my knowledge here, but yes I believe it is quite different to SUTs, and I think I’ve heard it called a head amp.
Net effect is the same, MC into MM amps.

 

[Soniclife]

The Devialet has the quietest active phono stage I've ever heard, but if I crank it really loud (0dB to +3dB), and there is no music playing, there is a large amount of hiss.

I've heard quieter, but not as good, there seems to be some magic to the Devialet stage, and by magic I mean accuracy.
My cart is lower output, 0.28mV, and at high levels there is hiss, but once the stylus is in the groove I don't think I can hear it over the groove roar, I'm over worrying about it till it's cart replacement time, when I'll consider something with higher output, it's the simple solution.

 

[cjfrbw]

I would say if your cartridge output is .5 mV or higher, stick with active. If lower, then consider a SUT. However, you are entering another realm of subjective hell with them. Down to .3 mV, I think you could "post gain" after the fact of a standard MM output with a good gain stage and do OK.

With a Yamaha receiver, I cranked up the regular MM phono input with the volume and a .5 mV cartridge did great. If you think a SUT will add some elusive improvement in sound quality, I would say 'maybe, maybe not', it might just be a bit different. Your most detailed presentation will be with direct drive and no SUT.

My 'opinion' is that certain cartridge and SUT combinations can be wonderful. However, if you change cartridge or SUT, the 'magic' can also change for the worse (or better, depending). It's almost like every cartridge requires it's customized SUT, or a painful and expensive process of trial and error.

Yeah, been there, done that. I wouldn't believe that just because a SUT is expensive that it will work best with your cartridge, or necessarily be worse because it isn't expensive. I suppose they can be measured for ringing, impedance, and frequency response, but I seldom ever see those published because it so much easier to beguile the beguine with the subjectivist chaff. Get one that's good, but as usual steer away from the mythologized stuff aka expensive to be expensive and rare etc.

Vinyl is noisy, anyway, and if you can stay active with a bit of noise, I would recommend it if the noise isn't any more distracting than the groove noise etc. Some cartridges are so low in sensitivity that they have to have SUTs, but I really don't think those low sensitivity cartridges are at all necessary any more for sound quality.

 

[Pluto]

SUTs seem to run in the range of $1000-$1500, which is shockingly expensive for a bunch of wound copper.

If you fancy a play with transformers and don't mind mounting them yourself, at a rather more modest cost, take a look at Sowter Transformers site. This company actually makes and supplies the guts of many products sold at truly horrendous prices.

 

[kevinh]

Well I haven't used a TT in many years so this opinion may be dated.
SUT served 2 functions, Converting the High Current Output of a MC Cartridge to a higher Voltage
to drive a Phono stage. The second function is matching the low impedance of the MC cartridge to the
high impedance of the MM phono stage.

So check the input impedance and sensitivity of the phono stage, then the output impedance of the MC cartridge and it's voltage.
The Sowter suggestion is very good.
Not aware of how a MC amp stage compares to a good SUT back in the 80's a good SUT was superior to the MC stages of the day.
The late Peter Aczel was a fan of SUT over a MC stage.

 

[DonH56]

If the noise is not a problem at normal listening I would not worry about it. Especially considering the average noise floor of vinyl.

I always called it a pre-preamp as a headamp was something different back in the primordial past when I was more involved with this stuff. A pre-preamp boosted MC levels to MM; a head amp was on a guitar stack.

A transformer can do a great job or not; lots of variables (natch). It is sensitive to impedances, can pick up hum, and can add distortion due to normal transformer EM issues (hysteresis in the curve, core saturation, etc.) I agree that it is higher in distortion at LF compared to active devices, but the overall level of distortion can be low enough to not matter. Frequency response is usually a bit rolled-off at the very low end and again at the very high end (for different reasons -- core field capacity on the low end, shunt capacitance at HF). The wiring itself should not add significant (as in, none) noise and within its operating range is quite effective IME/IMO. No active devices means less added noise and no power source needed (which can add its own noise). I suspect the price is a combination of the small ("boutique") market and marketing but good transformers have always been pricey IME. And yah, it should last a lifetime, so you can amortize over a number of cartridges.

Back in the day (1980's) I used a transformer with a Denon 103 and was happy, usually happier than with the active stages I tried (or built). It missed a little of the deepest bass but was otherwise a good solution. It misbehaved a bit when heavily clipped (ticks and pops), but so did the most preamps at the time. My preamp (ARC SP3a1) actually handled ticks and pops pretty well, one positive attribute of tubes.

You can order from a place with a trial period and see if you like it. I do wonder if you really need one, however.

FWIWFM - Don

 

[SIY]

Advantages:

Voltage step up with essentially no noise penalty.
Opportunity to run your cartridge and wiring balanced (hum and common mode noise rejection)
Very low distortion at intended signal levels.

Disadvantages:

The loading of the secondary is almost never gotten right, which causes either rolloff or peaking in the treble. If you change cartridges, that loading will need to be redone unless the new cartridge has the same DCR as the old one. This should NOT be confused with cartridge loading, which (despite the chittering of chimps in the review magazines) is not very critical.

Costs:

A pair of top quality transformers can be had for under $500. And even less in most cases- the Sowters I use were under $300 the pair. But you have to put them in a box or (better) inside an existing phono preamp.

 

[debunker]

SUTs seem to run in the range of $1000-$1500, which is shockingly expensive for a bunch of wound copper. In the context of my system, that's less than my turntable + tonearm, but more than my cartridge. Which makes me question if it's a good investment -- granted, a SUT won't wear out, like a cartridge, but does have a limited range of step up ratios, which means it won't work with every MC cart out there.

That much for a SUT seems a bit insane. I have no experience with transformers in the phono path, but I do have a lot of experience with Jensen transformers in other applications and they are exceptionally well built and about as clean and transparent as you can get. So if you go the SUT route, here's one option to consider:

https://www.jensen-transformers.com/product/mc-2rr-l/

And if you wanted to go the DIY route and rig up your own box, you could probably do it even cheaper based on the price of the actual transformers:

https://www.jensen-transformers.com/transformers/moving-coil/

 

[LTig]

Current cartridge: Audio Technica AT33/EV (moving coil, 0.3mV output, 10 ohm internal impedance)
Phono Stage: Phono input of Devialet Expert 400, set to 100 ohm loading, RIAA EQ. DSP-based, so involves ADC.

Issue:

The Devialet has the quietest active phono stage I've ever heard, but if I crank it really loud (0dB to +3dB), and there is no music playing, there is a large amount of hiss.

At moderate listening volumes that I typically use (-20dB to -10 dB), the hiss is not really audible unless I stick my ear close to the tweeter.

Other than this, the Devialet phono stage is provides state of the art configuration options and incredibly low distortion.

My 2 cents: as long as the hiss does not disturb you while playing the best and quietest vinyl: just keep it and do not tamper with the preamp chain.

Question:

I have never used a SUT (step up transformer) in a phono system. I've read some subjective claims of which I'm skeptical (they improve soundstaging, air), or at least think, if they exist, might be caused by inadvertent changes in cartridge loading (because there are no magic pixies in a SUT).

I'm no expert in audio transformers at all, but one problem you can get with an SUT is hum. I'm not so sure about THD. The voltage levels are so low I can hardly imagine that they are able to drive the iron core into saturation. My active studio monitors have audio transformers in the XLR input and here the level is much higher and yet THD is no problem at all (subjective opinion).

I've also read:

"[..]The case against transformers is simply one of cost. Transistors can be as cheap as a few pennies (or less when bought in sufficient quantities) whereas transformers always cost a lot more, by as much as a factor of several thousand, due to the expensive materials used in the core and the cost of the copper windings in terms of both material and labour."

With a good matching audio opamp like the venerable AD797 it is no rocket science to build a headamp with 20 or 26 dB. I use an AD797 in the first stage of my DIY phono preamp (20 dB gain, for an MC-cartridge with 0.65 mV output) and its noise is below my hearing threshold for the highest usable SPL. When I pull up the volume so high that I can hear the hiss then dropping the needle is unbearable loud and the tracking noise swamps all amplifier noise by a large margin.

SUTs seem to run in the range of $1000-$1500, which is shockingly expensive for a bunch of wound copper. In the context of my system, that's less than my turntable + tonearm, but more than my cartridge. Which makes me question if it's a good investment -- granted, a SUT won't wear out, like a cartridge, but does have a limited range of step up ratios, which means it won't work with every MC cart out there.

If you really want to invest a lot of money then forget the SUT and get yourself a better MC cartridge with higher output level. Mine is the Van den Hul MC-One special with a very sharp needle cut. It traces vinyl with very low noise and clicks are more damped in comparison to all other cartridges I had used before ("dig" instead of "TOCK"). Beware though that its sound is more "digital" (clear and dynamic) than "analog" (warm and boomy) - regarding tonality my vinyl sounds very close to CD.

 

[SIY]

I'm no expert in audio transformers at all, but one problem you can get with an SUT is hum.

A decent SUT should have very high hum immunity. Certainly the ones I've used from Sowter, Jensen, and Cinemag have excellent shielding and very high CMR.

 

[watchnerd]

If you really want to invest a lot of money then forget the SUT and get yourself a better MC cartridge with higher output level. .

I thought HOMC sort of defeated the purpose of LOMC, namely lower moving mass.

If higher output is the answer, why not just go MM and avoid the whole issue?

 

[Soniclife]

I thought HOMC sort of defeated the purpose of LOMC, namely lower moving mass.

If higher output is the answer, why not just go MM and avoid the whole issue?

Define higher.

There is quite a different between 0.3 and 0.6 output, but you can easily work out where your own preferred high enough cut of is, turn on the amps, select phono, crank the volume up, and without playing a record go into the RAM settings and change the level setting. At what setting do you no longer care about the hiss? About 0.5mV is quiet enough for me, 0.6 even better, that's not HOMC levels.

 

[anmpr1]

Back in the day, the high priced transformer racket...I mean market...was defined by Mitchell Cotter. That said, I never heard anyone who heard Cotter's blue brick complain about its sound...just the price Mitch was asking for them. I couldn't afford that kind of lunch, so bought a 9 volt battery powered commercial design based on (or stolen from, depending upon who you ask) Marshall Leach's do it yourself Audio magazine project. I still have mine, and sometimes use it with a Denon 103. But I also have an add-on, el-cheap-o ProJect phono box featuring a switchable MM/MC phono stage that I mostly use with my DAC preamp.

From slumming the Net, my impression is that you are going to pay at least 5 or 6 hundred dollars in order to get into the current transformation thing. Whether whatever you get will be 'better' than amplifying voltage, who knows?

FWIW, I recently bought a Pickering XV-15 MI cartridge with a NOS 1200e (.2x.7) nude diamond. The sound from this +40 year old cartridge knocked me over. It is supposed to be the same as the Stanton 681EEE. I'd owned them back in the day, but never remembered them being this good. I'll never forgive Gibson for ruining the company. Gibson, the company that mucked up the Les Paul. What a joke. I guess Walter Stanton bailed at the right time.

 

[watchnerd]

Anpther wrinkle:

I see that some SUTs are stereo and some SUTs are mono:

VS

Since I also have a mono cart, would I need 2 different SUTs?

Or can I just run the mono cart into the stereo SUT with no downside?