Simple MC Cartridge SUT Question

For those who have experienced active LOMC gain and active with a step up transformer-
Does a SUT provide cleaner gain that may allow for slightly more gain than a fully active phono preamp?

 

maybe not o simple :?

Can gain from a SUT be cleaner than an all active phono stage that would allow you to apply slightly more gain without distortion or ill effects?

I know adding a SUT may involve compromises- e.g. impedance matching / non-linear frequency response, etc. but in terms of gain, is a SUT cleaner - seems like it should be?

 

I have been using a SUT for the last five years or so. Once it is matched well to the cartridge, it is hard to ever go back to an active phono stage. I started with a really old Ortofon SUT that I used for a short while and then upgraded to an Audio Note AN-S2/H SUT. I was so impressed with the improvements that I was getting that I saved up for quite a while and bought the AN-S8/L SUT. Audio Note only makes one model above the S8 and it is well above my pay grade, so I am happily staying with my AN-S8/L for years to come.

I found that there are some active phono stages on the market that can be very good with a really low output cartridge like my Io Gold, which is 0.05 mv. But, the ones that I have heard that really impressed me were very, very expensive. One started at about $20k and the other was well above $40k. They were both great but that is a lot of money. The benefit of the SUT is that it raises the level of output of the MC cartridge by using transformers instead of active amplification. In my experience, that keeps the amp noise out of the system. I have experienced more 'black' backgrounds and more of the inner detail of the recording with a SUT. I also found that bass was improved and the tone was better/more natural. The other thing about a SUT that is good news is that as far as I am aware, you can't wear it out. They will last for years and years. So, that makes them a good investment in my books.

The downside of a SUT is that they can be affected by electrical noise, so you need to keep them away from other components. Basically you get better performance by hooking up the SUT and turning up the volume without a record on and then move it around the various places that it can sit while hooked up. Then leave it in the location with the lowest noise. I don't want to overstate the noise issue, it is just something to be aware of, not afraid of.

My AN-S2/H was dead quiet once I placed it on the floor behind and slightly away from the preamp and turntable. I could turn the volume way up and not hear any hum. My current AN-S8 is the same but I have to play with it a bit more as I can hear a bit of hum if the phono input is selected and the volume is way up. You don't hear it at all once music starts, but my OCD has me thinking that I can get the already low level of hum even lower : )
Also, the very best SUTs are expensive. They have to use the best quality transformers and those are expensive to make, as well as using silver versus copper, which is also more money.

If you are interested in one, I would look for a used AN-S2 SUT that is the correct match to your cartridge. Here is one for sale that the seller is asking for CDN $995.00 which is about US $750.00, I think. I owned one like this (except that it was the H model) and it matched my Dynavector DV20X2Lo very nicely.
Audio Note AN-S2 L Step Up Transformer SUT

Looking at your cartridges, it looks like the H version would be the best match. Your Cadenza Blue has an internal impedance of 5 ohms, which is ideal for the AN-S2/H. Here is the quote from Audio Note:

The 3 Ohm input of the ‘L’ version has been primarily designed to partner the AudioNote IO Moving Coil cartridges, and the 12 Ohm input is intended to be used with cartridges with an internal impedance of around 3 to 4 Ohms.

The 15 Ohm input of the ‘H’ version is designed to partner cartridges with an internalimpedance of around 4 to 5 Ohms; the 60 Ohm input is designed for cartridges with internal impedances in the region of 15 to 20 Ohms.

 

I forgot to mention that I had used various phono stages over the years, most with MC stages and not just an MM stage. The last active stage that I used was the Musical Surroundings Phenomena II phono stage. The AN-S2/H fed into an Audio Note phono stage was a big step up.

 

In general, you should notice a lower noise floor and blacker background with your LOMC going through an SUT before your phono amplifier. Some believe that SUTs are not as lively as using active amplification, but I disagree. A good SUT makes a huge difference with a LOMC.

 

I agree. I would say that dynamics were definitely improved in my system using the SUT. Of course, the SUT matched my AN cartridge perfectly, because it was designed to work together with the IoGold cartridge.

 

I got a (Rothwell) SUT to pair a Benz LOMC cart with AN phono stage. No surprise it sounded better then the iFi phono stage I used before.

What was surprising was, experimenting, just how much better the Benz>SUT> MM section of the iFi was vs Benz>MC section of the iFi. Not a high end stage but an otherwise competent and quiet one. Real enhanced dynamics and quietness/clarity especially at volume. Was definitely sold on the SUT thing at that point.

 

Some good discussion here:

To SUT or not to SUT with a Denon DL-103?

I really have no experience with MC stages having purchased my Bob's SUT 10 years ago when I got seriously back into vinyl. It seems from reading that the liveliness of a match is directly affected by impedance, and that some of the drawbacks noted for SUTs can be a result of too low an impedance while shooting for higher gain/step-up ratio.

The negatives on this page, for example: Elevator EXP - MC Step-up Amplifier

I can say, having switched to a lower (proper) step up ratio/higher impedance at Warren's suggestion, that my DL-103r did sound better and more extended/lively.

 

I prefer tube amplification, but, it is difficult to go completely active and not have noise issues absent the use of a step up transformer. Even solid state gear can struggle with noise when going completely active. I also, apparently, like the sound of iron. My linestage and my amplifier are completely transformer coupled (input transformers on the linestage, output transformers on the linestage, input transformers on the amplifier), and I heard basically the same linestage/amp combination coupled with capacitors and preferred transformer coupling.

My phonostage has a built in step up transformer and it is dead quiet. Most of the phonostages I've heard with built in step up transformers are quiet. But, I've witnessed problems with locating a remote step up transformer, particularly with avoiding hum. Whether it is the transformer itself or the necessary additional pair of interconnects, or both, location and orientation of the separate step up transformer can be a problem, as Don Parkerhurst mentioned above. My personal preference would be a properly shielded and located transformer built into a phonostage.

 

Art9, Sl1210gr, Project Tube box ds (don’t remember off hand which tubes) into McIntosh MA252 vs inexpensive handmade sut from eBay. In a blind test a friend with better ears than me picked out the sut 100% as being cleaner. The ebayer was recommended by someone on this site. Sut < $300

Found it:
For those considering SUT's for the first time.

 

In my limited experience a SUT in place of added stage/gain of MC active is an improvement in overall SQ. Overall Noise not an improvement for me, and I don't think you get away with more gain.

Avanti why are you looking to have more gain?

New equipment just arrived so can comment about it some more this week. Went from too much gain with a 1:20 Rothwell MCL to a 1:8 K&K premium SUT. Expecting improvement using this with new Art9. I have about 45 dB of gain with Pearl II phono stage. SUT can be switched to 1:16 so will try both positions.

 

Shiver,
May I ask which Benz low output cartridge you refer to?

Am researching if (or not) my ACE SL 0.4 mV can match well a SUT.

I understand this cartridge specifically benefits from a load impedance of 1000 ohm (or above) - not a typical value for a low output MC cartridge.

So, I wonder if this value can realistically be achieved with a SUT commercially available. Am not sure though.
Like 1000 ohm input impedance, with a regular MM phono having 47 kOhm input impedance, translates to 6 or 7 turns ratio as for the SUT. Any higher ratio means a lower load impedance for the cartridge, ie. below 1000 ohm.
From explanations I found on this.

Appreciate any thoughts, and guidance.

Thanks,

 

The Benz cartridges are actually more like 0.6mV output since they spec at 3.54cm/sec, versus most other manufacturers using 5.0cm/sec nowadays. As such, a 1:6 or 1:8 SUT is a good match. I use vintage Partridge 977 SUTs with my Benz Wood SL, which are available from the UK for about $220 pair at current rates (PARTRIDGE, MOVING COIL, MC STEP UP TRANSFORMERS VINTAGE, 6:1, 977. | eBay ), and I have the next stage termination set at 22K to load the Benz at around 600 ohms, which is the range I like best. In my case, I just mounted them in the back of my Conrad Johnson phono preamp ...




Some of the Lundahl transformers can be strapped for either 1:8 or 1:16 gain, and they do have a new low gain model too. I have a pair of Lundahl LL1933, which were $180 each from the US distributor, Kevin at K&K Audio. I built them into another SS Conrad Johnson phono preamp, and didn't want too much extra gain so have them wired for a gain of 8 (18dB), and run my preamp at either 40dB or 46dB gain setting, which is plenty since my CJ 17LS2 line preamp has 26dB gain. They can also be wired for gain of 16, and have other similar models with higher winding ratios. The base models are wound with Cardas copper, but there are much cheaper models too, and K&K also offers kit or pre-assembled versions in a box with PCB and selectable parameters.

 

Many thanks Davey for the very detailed note. Extremely helpful. Now I understand better the thing with my Benz ACE SL as for output level and input impedance I've been after.

I also read in an interview with Mr Lukaschek that the Wood and Ace cartridges are technically identical, inside, but in a different body.
So I hope my results will be comparable, with same setup as for SUT.

I was wondering why the Benz PP1 phono stage, nowadays Lukaschek, does not use a SUT. Also am aware that there is 1 cartridge in the whole Benz spectrum that is labelled TR, transformer, as I know. Would it have to do with anything specific for Benz cartridges, the way they are built?
This thread is the first and only I find mentioning an actual usage of a Benz Wood/Ace cartridge with a SUT with great results.

Note: I'm guessing those using a 1:10 SUT may use a resistor as to achieve a desired load impedance of the cartridge, for a Benz SL Ace or Wood, if they need more than ca. 470 ohm it may give naturally from the transformer.
But I do not know if resistor use is of any good as I guess just changes the natural flow how that would be without it.

Thanks for help.

 

"In theory" a SUT will present lower noise and greater micro-dynamics compared to active amplification since the SUT is passive. Always exceptions and variance by application.

 

I borrowed from a friend an older Bob's Devices SUT which has the Altec Peerless 4722 transformers and unfortunately, it did not start well. There was distortion at higher volume due to a probable dying Mullard 12ax7 signal tube in my phono pre and hum issues due to the placement of the SUT. While the hum hasn't been completely eliminated I changed the Mullard to a Telefunken 12ax7 and everything snapped into place. The most noticeable first impression is a fuller soundstage and a meatier 'in your face' sound but not at all forward.

My cart is a Hana SL and phono pre is a EE Minimax phono which has 58db of gain, based on KAB phono preamp calculator the Hana SL's .5mv output optimal gain is 56db so it is sufficient. I noticed on quieter records the Minimax sounds nice and refined, however, music doesn't engage me as much and can be a bit sleepy sounding. It's early days but I think the use of a SUT sans the hum is a definite upgrade, to my ears and in my system at least.

 

Edit: There is certainly more gain but as for it being cleaner I need more time, I'll revert back once I've done a proper comparison. I'm not entirely sure the SUT and my cart are matched as this is all new to me, there seems to be a hint of distortion once I crank up the volume when using the SUT. Perhaps someone knowledgeable with SUT matching can chime in?

 

For a Hana SL a bob’s devices sky20 sut with the cinemag transformers is a great match. Bob uses Hana carts in testing, and I love the way the sky20 pairs with my Hana SL.

 

So you are using the Peerless transformers into the MM inputs on the EE Minimax instead of using the internal transformers, right? So roughly 24-30dB gain from the 4722 SUT, plus another 42dB gain from the MM preamp? So maybe an extra 10dB or so gain compared to the MC inputs on the EE? Which setting do you use on the Bob's Devices, high or low? I think the high gain setting would load the Hana down way too much, so you'd only want to use the low gain.

 

Yes using the MM input of the Minimax, I've been switching between the high and low settings and haven't decided what sounds better yet. A quick google search and I found this about the Peerless 4722:
Gain:
1:16 (150 ohm) 24db gain
1:28 (34 ohm) 29db gain

Not sure if its the same spec model as the one I borrowed.

 

Did you experience any humming? I'm told its normal and I just have to tweak the placement.

 

Yea, I'm not sure on the Bob's, but the 4722 impedance ratio is 150:50K and 38:50K, so 1:18 and 1:36 step up ratios, but in either case, the high gain setting would provide a reflected impedance that is way below the minimum specified load resistance on the Hana.

 

Thank you. Does this mean the 4722 is not a match for the Hana SL even in low settings?

 

The low setting is a good match, it gives you about a 150 ohm load. More gain than I'd think you would need, but some of that is subjective. I'd still re-audition them against the built-in transformers using carefully matched volume levels (measured with a test record and voltmeter), it's hard to be objective when the volume is different. I'm not familiar with how good the transformers are on the Minimax, I suppose they couldn't be that expensive or it would cost a lot more, but the vintage 4722 mic transformers were pretty cheap before they got popular too.

 

Thank you for your nuanced answer, it is difficult to be objective with different volume levels. After some more listening, there seems to be a trade-off, SUT pros are more gain, bigger soundstage, fuller and fast sounding(?) however at a higher volume it sounds slightly harsh and edgy. The Minimax seems to sound better at a higher volume level, bass is also more textured and mids sound more delicate and refined. However, even at the higher volume level it still lacks the "meat on the bones" that the SUT has in spades. Which is the main reason why I'm experimenting with the SUT, Minimax uses permalloy core MC step-up transformers.