To SUT or not to SUT?

Rdk777

Well-Known Member
Jul 9, 2019
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The tonearm cable goes into the SUT (single ended) and then from the SUT to the p/s (also single ended). I do however use balanced from the p/s to my integrated amp (that buys around 6dB of gain). I use the 47k setting on the p/s - which happens to be the most optimal setting for the ARC Ref 2SE. I don't have tap settings on my EMIA SUT.
 

bazelio

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Sep 26, 2016
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The gain produced by the SUT/cartridge can be too great for the MM RIAA stage that follows it. The 'dynamic envelope' (DE) produced by the SUT/cartridge can - if to great -overload the MM input . Also it compromises dynamics and reduces the level of the pre amp volume control. A SUT is not a one size fits all and needs to be carefully matched to the MC cartridge in use imho.

Absolutely correct.
 

Don_Camillo

Well-Known Member
Jun 26, 2022
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tempo333.blogspot.com
Old FR carts fr 1/fr7, Zyx low 0.24 and ortofon vienna, venice , vero
are made for suts,all from 1 ohm to 5 ohm.
Yes.
We always want to achieve the (technical) best. That's why you should always first look at this question from a technically correct perspective. The higher the gain, the more noise an amplifier circuit adds to the output signal. At the same time, with high amplification, you also have to contend with hum more severely. But hey, that's the advantage of a transformer; this is always noise and hum-free. Conversely, this means that you have to put in a correspondingly high amount of effort with an amplifier circuit in order to get it as good as with a transformer. Or to put it another way: If the output voltage of the MC is below 0.26 mV and the coil inductance is below 6 ohms, then a transformer always has an advantage.

Whether a transformer transmits the signal linearly depends on the internal structure of the transformer and the skills of the transformer winder.
 

Don_Camillo

Well-Known Member
Jun 26, 2022
158
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Vienna
tempo333.blogspot.com
The gain produced by the SUT/cartridge can be too great for the MM RIAA stage that follows it. The 'dynamic envelope' (DE) produced by the SUT/cartridge can - if to great -overload the MM input . Also it compromises dynamics and reduces the level of the pre amp volume control. A SUT is not a one size fits all and needs to be carefully matched to the MC cartridge in use imho.
But as you said before this is not an issue of SUTs in general but of the mismatch of SUT and MC output. Furthermore comprised dynamics is alos not an issue of SUTs but of this special situation and because the phono stage is overdriven.

I agree to there´s no SUT that fit´s all also but there´s no matching with ears but a matching by technical facts only with result of a total linear amplification
 

DasguteOhr

Well-Known Member
Sep 26, 2013
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Yes.
We always want to achieve the (technical) best. That's why you should always first look at this question from a technically correct perspective. The higher the gain, the more noise an amplifier circuit adds to the output signal. At the same time, with high amplification, you also have to contend with hum more severely. But hey, that's the advantage of a transformer; this is always noise and hum-free. Conversely, this means that you have to put in a correspondingly high amount of effort with an amplifier circuit in order to get it as good as with a transformer. Or to put it another way: If the output voltage of the MC is below 0.26 mV and the coil inductance is below 6 ohms, then a transformer always has an advantage.

Whether a transformer transmits the signal linearly depends on the internal structure of the transformer and the skills of the transformer winder.
yes, the most important points for that are the input capacity of the phonoamp, the bandwidth of the sut (example 5hz-300khz silvercore sut) the dc resistance of the coils provides information about the quality of the material and the winding technique. all of these factors are crucial for good results. I'm not a fan of high step-up ratio usually reduces the bandwidth of the sut, it's better to choose a higher gain on the phonoamp if possible.
 

Walter66

Active Member
Aug 22, 2022
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There are transformers for low impedance pickup systems which have the same winding resistance, but different winding methods. So how would one know what winding style is being applied just from reading the resistance on primary or secondary?
One has to rewind the transformer to know which technique was applied and one has to reverse the stacking of the lamms to know what the core is being made from. And even then, there is no knowledge on how the annealing process has been done.
Too much of this knowledge on how to produce good transformers is unknown without an exact production plan. And even with that, Western Electric is still not being able to produce the same quality in tubes that once was being produced.
 

DasguteOhr

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Sep 26, 2013
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of course you can draw conclusions with the help of the dc resistance and the bandwidth. the lower limit frequency indicates when the core is saturated. the deeper the better. the dc resistance of the primary winding should be as low as possible. this can only be achieved with a few winding layers. Conversely, this means that the secondary side requires less winding to achieve the transmission ratio.
mathematical formula
That means the winding ratio N1/N2 = ü; The impedances behave like ü²=Z1/Z2. It doesn't matter whether Z1 or Z2 is the primary or secondary winding.
this benefits the bandwidth at the high frequencies. As far as I know, only dynamo sheets with a thickness of 0.5-1.0mm are used most with such transformers.
we can argue for hours, but if the Sut has this requirement, it works better. whether you like the sound is another question.
 

Walter66

Active Member
Aug 22, 2022
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Ohmic resistance will say nothing about the windings itself. If a coil is layer wound or random (cheap method), no ohmic resistance will tell you.
If a coil has pied secondaries or not (special winding method), no ohmic meter will tell you.
What materials were used for isolation, no ohmic resistance will tell you. What annealing process for the lamms, same.
The simplest things may be calculable with an ohmmeter, for others you'll need a capacitance meter. And for all other aspects of a quality SUT just reverse engineering will do. And even then sometimes its not easy to replicate. Btw, perfect measurements don't even tell about perfect sound at all.

A WE 618B may have such a limited bandwith and such bad measurements compared to some SUT today, I would prefer this seven days a week to modern transformers. Just because it has the magic and realism in the midrange of the tone spectrum, it sounds so real. I don't need either 5Hz or 300Khz, just because thats not where the hot spot of all audio appears to happen. The better measurements don't have brought us better and more trustworthy sound. Same thing has happened as in the audio amp section. A five hundred transistors amp may have better specs in the end, but it doesn't sound as pure to me like a handfull of tubes put together oldschool to make up for a full function pre- or power amp. Just my two cents on this topic.

What appears on first look like easy math will become much more complex in the end, when it comes to all things that can destroy or enhance good sound in every audio unit. Its not simple as math alone and the formulas will tell you just the surface complecity of the task. Math is always a much simplified model of the real physical world.
 
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ctlmdphd

New Member
Nov 5, 2023
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I just bought a MSL Signature Gold cartridge and need a new phono pre with or without a SUT. It seems a MSL SUT 1030 would be the logical choice. I don't have a voltage-based/MM phono stage. What would you recommend?
 

melomane99

Well-Known Member
Aug 17, 2016
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IMHO you have bought an MC cartridge that would be very difficult to match to most SUTs as you have a very low internal impedance - 1.4 ohms and a very high output 0.5mv. A SUT to match the cartridge's gain would be around x10 to give you 5 mv for your MM stage.The SUT's input impedance is 470 ohms which could be too high for the cartridge's 1.4 ohms impedance. MSL's SUT should be made to match it's cartridges. Surely a dealer would loan you one to try in your system?
 
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Solypsa

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MSL website states that the ideal loading is around 400 ohms for the Signature Gold.

I would ask at which loading other users of same cart landed with satisfaction.
 

bazelio

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Sep 26, 2016
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IMHO you have bought an MC cartridge that would be very difficult to match to most SUTs as you have a very low internal impedance - 1.4 ohms and a very high output 0.5mv. A SUT to match the cartridge's gain would be around x10 to give you 5 mv for your MM stage.The SUT's input impedance is 470 ohms which could be too high for the cartridge's 1.4 ohms impedance. MSL's SUT should be made to match it's cartridges. Surely a dealer would loan you one to try in your system?

Sorry, this is incorrect information. You'll want to appropriately match the SUT's DC resistance for a low impedance cart in this case. 470 ohms is the reflected load impedance from the phono input to the cart, through the SUT. Two different things. Most SUT winders will offer at least two options for DCR, and some will offer three for cart matching. Lastly, many (most?) SUTs have two input pairs so that you can utilize load plugs on the SUT primaries and affect the final load seen by the cart accordingly.
 
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SOS

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Jun 20, 2015
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@bazelio can you give some examples of SUTs that have 2 input pairs so that you can utilize load plugs? Thanks in advance.
 

bazelio

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@bazelio can you give some examples of SUTs that have 2 input pairs so that you can utilize load plugs? Thanks in advance.
Intact Audio, Consolidated Audio, Ypsilon off the top of my head, with strong preference for Intact Audio. There's the EAR MC4 which has multiple inputs but has already loaded them differently internally. I'd probably modify one of those inputs to use as my own variable load but you want to run square waves through it and evaluate that on an oscilloscope to make sure the SUT behaves well with a non-standard load. It should be fine if they're loading the primaries and not the secondaries. There's also the Zesto Audio SUT which has a 10-step load switch to select between ten different internal load options. Useful, but less useful to me than just a second pair of RCA inputs. I don't know, but I'm sure there are others I'm forgetting. Also, I've seen phono stages that have MC and MM inputs which provides loading options or load plug inputs for both signal inputs.
 
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