Step up transformers, good, bad or maybe?

I've noticed that some folk use a Bob Devices SUT so I had a browse on his web site, nice looking units especial the wood plinth ones however I need educating where SUTs are concerned. I know what a step up transformer is but not really what its actual use is in this day of good MC/MM outboard/onboard phono amps. I believe they came into existence when users of valves with onboard MM inputs wanted to use MCs? What benefits do they bring? Also:

(a) Do they come before the seperate phono amp or after (I would imagine its after)?
(b) Where does arm cable earthing take place, I notice Bob's has a lift switch?
(c) Are these Step up transformers mains powered?
(d) If a pre or intergrated amp, such as Croft, has a MM input then a SUT would be mandatory if a MC is used?
(e) For users of SUTs what has been the improvement (or otherwise) of using these units?

Okay, I know I ask alot of questions but the purpose is to clarify my thinking and correct any misconceptions.

Thanks fellas :)

Ron :piano:

I have used a Denon AU300LC step up tranny with a DL103 cartridge and a Pro-ject Tube Box II phono stage. (I recently upgraded my phono stage and I no longer use this set up.) The Denon SUT was specifically designed for use with the DL103. I would run the Tube Box II in MM mode with the SUT transformer before the phono stage. The Denon SUT has a ground post for the ground wire from the turntable, and another ground wire to connect to the phono stage. It does not have a mains cable.

When using it I noticed the DL103 had just a little more presence, a little more soul. If I took the SUT out of the system and switched the Tube Box II to MC mode, it seemed to lack a little bit of life. I am by no means an expert on any of this, just sharing my personal experience. Regards, Jim

Thanks Jim for sharing your experience on the Denon SUT. They do appear to be a postive and well looking into a bit more.

Ron

Hello Ron,

Here's my experience:

(a) They come before the MM phono input.
(b) I've tried both on the SUT and the MM phono pre - I use whichever works best.
(c) SUTs require no external power, just the signal connections.
(d) Yes, a SUT or Head Amp is required, unless you are using a high output MC cartridge that works with MM inputs.
(e) I have always used a SUT so I can't compare.

You may want to check out K&K Audio SUTs. Hope this helps. Best regards.

Much appreciate the info Gerard, its looking a positive for using a SUT :)

Ron

Don't mix up SUT's & head amps though. A head amp for a cartridge will need mains power.

P.S. It's about time that vinyl users claimed back the term head amp from those pesky ear-muff users who seem to have appropriated the term because they're too bloody lazy to type headphone.

It is very good that we can discuss SUTs here on AoS without an electronics 'expert' chipping in that they are fundamentally inferior to a well-designed MC head amp. All I can say is that my Bob's Devices Cinemag SUT sounds way better than the MC input of my PS Audio GCPH, and paired with the MM only Paul Hynes Veron Concert is quite magnificent. So, the proof of the pudding is in the listening: if you get a SUT that will correctly load the cartridge, and is well designed and constructed, you are likely to have a most enjoyable listening experience. Marco will confirm this, as he uses (used?) the Auditorium A23 with the Denon 103. MartinT uses the same Bob's Devices SUT as me and is similarly pleased. All of us are content to ignore the theory and simply enjoy the music. It does help, though, to understand the maths to work out what the loading is - I don't have much of a clue but I think Martin does.

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Don't mix up SUT's & head amps though. A head amp for a cartridge will need mains power.

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Unless it's battery operated, Chris, like the Lentek ;)

I'll comment more on SUTs, later... It's interesting, though, that the real enthusiasts seem to use SUTs (often, after having compared them with high quality active MC stages) :)

Marco.

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Originally Posted by Marco

Unless it's battery operated, like the Lentek ;)

I'll comment more on SUTs, later :)

Marco.

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Yes, of course, I should have said 'an external source of power'.

Thanks again for more info. Do you have to decide on the actual cartridge to be used so that the SUT works in harmony (no pun ;)) with one another? what happens at a later date if you change to a different make of cartridge? Looks like I will have to finalise on cartridge to be used first???

I'm getting there, I think :scratch:

Ron

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Originally Posted by JazzBones

Thanks again for more info. Do you have to decide on the actual cartridge to be used so that the SUT works in harmony (no pun ;)) with one another? what happens at a later date if you change to a different make of cartridge? Looks like I will have to finalise on cartridge to be used first???

I'm getting there, I think :scratch:

Ron

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Not really, there are two main variables - step up ratio & loading. The ratio is the thing that could possibly limit future choice of cartridge if you decide to go for something with an incredibly low output, but it's usually nothing a twist of the volume knob won't cure.
The loading is usually easy to vary to very fine degrees by adding a resistor of an appropriate value - some SUT's have a bit of choice here as standard.

One advantage with SUTs that hasn't been mentioned is that you can run balanced wiring from the phono cartridge to the SUT & convert to a single ended output to your phono stage ;)

At the miniscule voltages we are talking about with an MC cartridge running balanced is a big advantage as it naturally cancels out interference picked up by the cables themselves.

I'm beginning to absorb more info on SUTs now than at the beginning of this thread, thanks all, but there is still alot more I can learn. I take it that a MM input, either intergrated or outboard is used as opposed to a MC input and then comes the SUT? Of course using my MC of choice.

Ron

No - we're still not quite there!
Think of it like this. A MM cartridge is an electrical generator and it produces a teeny weeny amount of energy. You need a normal, bog standard MM phono stage to get this up to the same sort of level as a CD player, tuner etc. That phono stage may be built into a preamp or an integrated amp, or it may be a seperate unit.

A moving coil is another flavour of electrical generator, but it's not quite as efficient, so it needs a little extra boost to get it up to the same level as an MM cartridge. This is what the SUT / head amp / MC stage will do.

So with a moving coil cartridge and a MM phono stage, you have several choices:

• Plug your arm cable into the MM stage & turn it up........way up. This can give you too much noise and it will make you fall out with your neighbours the day you forget to turn it down before playing a CD
  
• Plug your arm cable into an SUT & then plug the SUT into your MM stage
  
• Plug your arm cable into a head amp then into the MM stage
  
• By-pass the MM stage & get a dedicated moving coil phono stage & plug your arm cable into that, then plug it into a spare input on your amp
  
• Chuck away your MC cartridge & stick with a very good MM straight into the MM phono stage

All of the above have their proponents and there is no 'best' way. I've done all of the above, and nowadays I waver between a Bent Audio Mu step up into an MM phono stage and an LFD moving coil phono amp into an aux input.

Hi Ron

I have the luxury of connecting my low output MC cartridge either directly to my Whest phono amp, with suitable switch settings, or via my CineMags. Having compared them, there is no contest. The step-up correctly matches impedances to give the cartridge the correct loading and also drive the phono amp at a lower gain setting, giving less noise.

In real-world language, I find the step-up gives better dynamics and a more vivid and life-like sound with lower noise. I would not be easily persuaded to revert to direct input to the phono amp.

Hi Ron,

In my experience, SUTs work best when they've been designed from the ground up, along with a partnering MC cartridge, by the same manufacturer. You can get away with it though sometimes by mixing and matching, as Martin has done.

This allows the manufacturer not only to match the cartridge and SUT in an electrical sense (in terms of impedance and loading), but crucially in terms of voicing both in order that sonic synergy is achieved. That's the hard bit!

Denon, for example, have products which epitomise this approach, and it's one I would recommend.

It's all very well finding a transformer that matches a cartridge, electrically, but it may have a sonic signature that doesn't synergise well with the tonality of the cartridge (all transformers sound different, even those which measure the same), which is where experienced ears are needed in order to obtain a good match!

I believe that it took Keith Aschenbrenner in Germany years to find the optimal transformer (sonically) for the Denon DL-103 before he eventually came up with the A23, and I can well believe it.

There's an art to matching transformers with MC cartridges that goes beyond simply attending to the known electrical parameters, but if you get it right, vinyl replay will beguile you in a way that I've not heard yet from using an active MC stage :)

Marco.

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Originally Posted by Marco

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There's an art to matching transformers with MC cartridges that goes beyond simply attending to the known electrical parameters, but if you get it right, vinyl replay will beguile you in a way that I've not heard yet from using an active MC stage :)

Marco.

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Thanks Marco and forum family, it looks like I've got some seriously serious learning ahead of me, but I guess everyone starts from the beginning :)
Out of sheer curiosity what happens when vinylists have two arms on their decks with differing pickup cartridges? This is a minor question and can be ignored if you wish.

At the moment my AT OC9II is connected to the onboard S board MC input of my Avondale modded NAC72. There is a better solution for better fidelity and I would welcome suggestions but not at stratospheric cost.

Alex N's ANT (sold by Hi Fi Sound) gets good kudos from HFW mag but I have not come across anyone using one yet... are they worth it, sorry if this last question puts you on uneasy street?

The arm that my AT is bolted to is an Ekos 1 which has been completely worked on by Johnny 7/ AO ie: Kondo silver wiring from cartidge tags to SME arm connection, continuos. Damping of the arm and an AO gold plated * decoupled counter weight. (* a moment of sheer indulgence on my part but it does look good :) ) The TT is the Tek1210 with TS HE PSU, Copper sub platter, Acro mat, Isnoe feet and the whole caboodle sits on a Townshend Audio Seismic sink (bellows and spring type), there is an old Mana glass shelf between Isonoe feet and the Seismic sink, overkill maybe but in the interest of perfection one must experiment;) With the latter I thought I would go beyond the surgical glass disc and sorbathane footers... now can you follow what I'm trying to do??? :scratch:

Ron :piano:

Ron, it sounds as if you have everything set up for superb sound quality with the possible exception of the MC input to your NAC72. Since you have an AT-OC9 and the Bob's Devices CineMags are designed for it, I would suggest that this may be the route to go down. Can your NAC72 take MM inputs? You could be looking at a serious upgrade in sound with just one device introduction and a Mark Grant G1000HD cable between step-up and preamp.

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Originally Posted by MartinT

Ron, it sounds as if you have everything set up for superb sound quality with the possible exception of the MC input to your NAC72. Since you have an AT-OC9 and the Bob's Devices CineMags are designed for it, I would suggest that this may be the route to go down. Can your NAC72 take MM inputs? You could be looking at a serious upgrade in sound with just one device introduction and a Mark Grant G1000HD cable between step-up and preamp.

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Hi Martin, thanks for your words of encouragement. Yes, I do have Naim MM daughter boards that I can substitute for the MC ones. Would it be better to use the MM boards married to Bob's Devices SUT instead of the MC boards? On the other hand I could always put link wires which would make the vinyl input into just another line input and work from there.... hmmm, permutations are numerous. Incidently, one cartridge I've got my eye on and sticking loose change into a jar for is the gold Dynavetcor 17DR3, it has a very small/short cantiliver but many years ago Naim reckoned that one did not need to go beyond this one as it was real value for money, of course it cost less than today's asking price of £699.00p, any musings on the 17DR3 Martin?

Thanks again for your advice

Ron:)

Martin, since sending the preceding post I have got an education (further) on SUT, a must read for anyone who wants to learn more! I shall email Bob and give him details of my cartridge etc., also my pre-amp and then go with his suggestions... Bob looks like he has had alot of positive feedback, can't ask more than that. Luckily I have a set of MM inputs for my Avondale modded NAC72 thus saving me the expense of a MM head amp. Should be interesting with what Bob comes back with.

Ron :piano:

Hi Ron, yes you need the MM board as the SUT is expecting a standard 47k input to work with. A line input wouldn't work at all, far too low sensitivity and it wouldn't have the essential RIAA compensation curve for vinyl.

Gents,

A very timely thread!!

I just picked up a Conrad Johnson Premier 15 MkII phono stage with CJD teflon caps upgrade :)
http://www.theartofsound.net/forum/p...&pictureid=445

Now this phono stage has 53 db gain, as opposed to my Modwright SWP9.0SE phono stage which as 68db from the MC stage. I am using a Zyx cart with 0.34mv output.

So the CJ and the Modwright faced off today, with a good friend of mine adding his fine tuned ears to the evaluations.

The CJ proved the superior phono stage which I thought was no small feat compared to the Modwright. The CJ had more dynamic bass that is better defined and not slightly bloated like the Modwright. The mids are more fleshed out and the highs are more resolving, just a more transparent and natural presentation. The Mod sounded a bit CDish or solid stateish if that makes sense?

In the end we both agreed the CJ had the better presentation.

As with all things audio there are seldom all positives.

Now one advantage for the Modwright is that it has a lower noise floor. At matched listening levels the Modwright had no discernible hiss, while the CJ has some low level hiss which can be heard. Not too objectionable, unless you go for fairly loud listening levels, at which point the hiss becomes distracting on quiet passages.

I plan to put in some better tubes, and this may help somewhat, but ultimately I have been looking into step-up transformers for the CJ, which is essentially an MM phono stage, albeit an incredibly good sounding one.

I'm sure there are insanely priced SUTs, but I was looking into the Bobsdevices SUTs like others here. I had seen some reviews from Jerry Siegel on 10audio, and was intrigued. He had the same CJ phono stage and realized the virtual elimination of hiss and a positive sonic benefit from the higher signal levels going into the CJ.

Has anyone heard the Sowter transformers, or the Altecs that Bob sells?
How about other transformers and how they compare to Bobsdevices?

Cheers,
Pete

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Originally Posted by Pete

Has anyone heard the Sowter transformers, or the Altecs that Bob sells?
How about other transformers and how they compare to Bobsdevices?

Cheers,
Pete

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I use Altec 15095 transformers and I like them a lot. They are not from Bob's Devices, though - I bought the transformers and wired them up in a box myself. The 15095s are actually line transformers used in reverse, and they can probably still be bought more cheaply than the 4722 microphone transformers.
A pair of the latter currently on US eBay are nearly £200, and that's just the bare transformers.
The only other transformers I've tried were Newcomb, which are also sometimes sold by Bob's Devices. They sounded soft and rolled off at the top compared to the Altecs.

Pete - Bob will be able to tell you which transformers best match the Zyx. He is very friendly and helpful.

Hi Ron,

Sorry I missed this before...

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Out of sheer curiosity what happens when vinylists have two arms on their decks with differing pickup cartridges? This is a minor question and can be ignored if you wish.

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If they're serious, they will have dedicated SUTs for each of their MC cartridges! ;)

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At the moment my AT OC9II is connected to the onboard S board MC input of my Avondale modded NAC72. There is a better solution for better fidelity and I would welcome suggestions but not at stratospheric cost.

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The boards in Naim preamps are actually very good, especially since their performance will have benefited from the Avondale mods, so unless you have around £800 to spend on something like a Whest TWO (which works superbly well with Naim equipment), I'd leave things as they are.

The internal phono boards have the advantage of being hard-wired to the preamp circuit, at the closest point to the signal, and thus the subsequent sonic benefits of that, together with the removal of the external cables required when an off-board phono stage is used.

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Alex N's ANT (sold by Hi Fi Sound) gets good kudos from HFW mag but I have not come across anyone using one yet... are they worth it, sorry if this last question puts you on uneasy street?

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Nope - it's not a problem. I had the top model MM version, a Kora 3T Limited Edition, on an extended loan for some months, and compared it to the valve MM phono stage in my Croft, using my then A23 (103) SUT and DL-103SA with both.

I have to say that the Kora was superb, and one of the best solid-state phono stages I've heard.

It didn't sound thin and grainy, like some SS phono stages can sound, due to its use of FETs, which are a bit like the transistor equivalent of valves, and with the A23 SUT/DL-103, it produced an effortlessly musical sound full of insight and involvement.

Ultimately, though, I preferred my Croft's built-in MM valve phono stage, as it has particular strengths, musically, which are quite unique. Anyone who's heard a Croft phono stage will know what I mean.

I'd say at just under £800, in terms of SPPV, the Kora 3T Limited MM is a superb bit of kit, and in conjunction with a good SUT, would likely be an improvement on what you've got, although I'd advise you audition it against an active MC stage like the Whest TWO in order to hear which product/approach offers the best sound (and synergy) in your system.

DC's your man, as he has both in stock :cool:

Marco.