Post by Owen Y on Jul 2, 2017 17:20:55 GMT 12
SUTs can be confusing, esp as there is probably quite a bit of not well-informed discussion out there. Essentially, a SUT is a (audio grade) transformer that provides gain from input to output - by having more wire turns on its 'secondary' winding (output), than on its 'primary' winding (input).  For Moving Coil cartridge SUTs, there are 2 main things to consider: 1) Gain (Gain ratio = SUT 'turns ratio') 2) Impedance (Impedance ratio = SUT turns ratio squared) eg, if you've got a 1:20 (26dB) SUT connected to the normal 47,000 ohm phono preamp input, then... 1) Gain = 1:20 = SUT turns ratio (prim:sec) 2) Impedance appearing at the primary (as seen by the cartridge) = secondary load divided by turns ratio squared => 47,000/400 = 117 ohms This is a typical choice for a medium output MC (say 0.4 - 0.6mVrms output), which will boost output up to 8-12mVrms. And provides a 117 ohm load, which will be around 10-15x the cartridge coil impedance (typically 8-12 ohms).
|
Post by Owen Y on Jul 2, 2017 17:33:17 GMT 12
Another example: For a low output MC cartridge (say 0.3mV), you might need a 1:30 (29.5dB) SUT. Gain 1:30 => 9mV output primary Impedance = 47,000/900 = 52 ohms (which again is around 10x the cartridge coil imped, typically 4-6 ohms for a low output MC).
|
Pundit
Post by SL1210 on Aug 6, 2017 19:13:04 GMT 12
Very helpful Owen!!
|
Pundit
Post by SL1210 on Dec 16, 2017 12:31:34 GMT 12
I am thinking about trying out an SUT. My Cartridge is the Benz Wood Low output Moving Coil and the Phono Stage is the Perreaux VP3  What sort of SUT would be suitable? For example Rothwell make one called the MCL and the specs for that are: turns ratio - 1:20 voltage gain - 26dB (x20) input impedance - 100 ohms optimum load impedance - 47k + 150pF bandwidth - 8Hz - 75kHz (+0/-3dB) cartridge compatibility (o/p) - 0.2mV - 0.7mV cartridge compatibility (imp.) - internal impedance <20 ohms The Perreaux offers MC and MM inputs. I understand the S/N ratio is better on the MM . I would be interested anyway to give it a try.
|
Pundit
Post by Gryffles on Dec 16, 2017 14:52:05 GMT 12
I found the Wood to sound best at 250ohm into MC on most phono stages
You could have pounced on the SAC Minute that was on Trademe and is now Fixed Offer of $300
|
Pundit
Post by SL1210 on Dec 16, 2017 16:07:45 GMT 12
x20 gives 4mV. Would that not result in 8mV. I will be first to acknowledge that things like ohms (or gnomes) appear to be one the Dark Arts.
|
Pundit
Post by Gryffles on Dec 16, 2017 17:54:55 GMT 12
|
Post by Owen Y on Dec 16, 2017 19:36:24 GMT 12
I am thinking about trying out an SUT. My Cartridge is the Benz Wood Low output Moving Coil and the Phono Stage is the Perreaux VP3 Hi SL1210 - the Benz Wood Low has Internal Imped of 12 ohms, so yes, i would agree, loading around 20x or 250 ohms. To achieve that with 47k ohms attached to the SUT's output winding, you need SUT gain = sq rt of 47k/250 = 14x. (Remember, SUT Imped ratio = Gain ratio squared.) So, a 1:15 (23dB) SUT should be close. Maybe not too many of those around?
|
Pundit
Post by Gryffles on Feb 11, 2018 22:18:57 GMT 12
I couldn't resist buying a Denon AU-340 from TM recently. Thought it would be versatile with 1:10 and 1:33 available. Of course I opened it up and the transformers look very similar to Tamura. Even the printing on them looks the same. Nothing to try it out on yet though 
|
Pundit
Post by Gryffles on Feb 11, 2018 22:20:47 GMT 12
Oh, even the specs are the same as Tamura TKS83. Who wouldn't be happy with Tamura 
|
Post by Owen Y on Feb 12, 2018 9:20:30 GMT 12
A nice quality SUT it looks, Gryffles. The 1:10 ratio is obviously for their DL-103 (& other Denons of that era - which is why it's labelled 40Ω)- giving 470 ohms load into a 47k input. OTOH 1:33 would offer around 40 ohms load - to suit super low imped/output MCs (3Ω internal imped). Of course the cartridge load appearing at the SUT input can be adjusted if your 47k at phono input lends itself to adjustment. eg. Depending on whether you prefer 1:10 or higher 1:33 gain, you could adjust the 47k down to 10k or up to 110k - in order to achieve say 100 ohms cart load.
|
Pundit
Post by Gryffles on Feb 12, 2018 17:08:14 GMT 12
Yes, I'm pleased with it Owen YWith the above in mind. How do you think I'll get on with a Dynavector DV20X2L which is .3 output and 5 ohms impedance. 1:33 will be to much gain but the load will be better in theory. 1:10 the gain will better suited but the load will be 470ohm unless I load with resistor. There is a lot of chatter around loading SUT's with resistors, a lot of it bad. Any experience from members here?
|
Post by Owen Y on Feb 12, 2018 19:20:21 GMT 12
Others of course can chip in, but I like phono stages where I can change the input load R (from the usual 47k ohms). Any resistor attached to the phono stage input (& thus the SUT output) will be very audible - normally this is the 47k factory installed R. Any R/s in this location affect not only the loading for the cartridge but, as the SUT is a magnetic coil (as is the MC cartridge), it also can have some effect on the 'damping' of the SUT's (& MC cart's) HF response - & thus affects the sonics. DV20X2L - my thinking would be this - DV say that it's internal imped is 5 ohms & to load it with at least 30 ohms. 1:33 would get the 0.3mV up to 10mV & depending on the phonostage gain, you could end up with around 1.3V at the input of your power amp - might be OK? Always better to have too much gain than too little, IMHO.
|
Pundit
Post by Gryffles on Feb 12, 2018 19:24:34 GMT 12
Thank Owen.
I can easily change the 47k resistor. I have a Pass design Pearl phono so lots of info and different builds around.
Guess I'll see what happens when the Lenco is ready.
|
Post by Owen Y on Feb 12, 2018 19:55:10 GMT 12
Yes play with the input load - change the R, rather than parallel or add Rs. A rebuilt Lenco should be a revelation, compared to a VPI(?) 
|
Pundit
Post by Gryffles on Feb 12, 2018 20:37:02 GMT 12
I'm hoping so, at the very least, the Lenco will suit my tastes better
|
Post by Owen Y on Feb 13, 2018 11:10:40 GMT 12
For anyone who wishes to change input loading on your phono preamp, without opening up the preamp & changing the input R, this may be useful.... daveyw.edsstuff.org/vinyl/loading/ Obvious added complexity & connections, but a useful way at least to trial load settings.
|
Post by Graham on Sept 14, 2018 10:18:55 GMT 12
I'm quite happy the sound of my Denon DL103R feeding into the MC stage of my ProJect Phonobox SE II set to 100 ohm load but would like to experiment with using an SUT.
Due to the 103R's rather unusual internal resistance of 14 ohms what suggestions have you guys got for a suitable SUT ?
|
Post by Owen Y on Sept 14, 2018 11:40:27 GMT 12
Hi Graham - 14 ohms is not unusual for low output MCs. It's the regular DL103 that is unusual, with its 40 ohms coil impedance (due I think to its AlNiCo magnets, which are less 'efficient' than modern magnets). Phonobox SE - MC/MM gain is 60/40dB, so the difference in gain you need is 20dB right?
|
Post by Graham on Sept 14, 2018 12:40:49 GMT 12
The DL103R sound fine into the MC stage with the volume control at about 1/3 to 1/2 setting so yes I figure about 20db gain would be ideal.
The MM stage is 40db and the MC is 60db.
|
Post by Owen Y on Sept 14, 2018 14:20:13 GMT 12
A 1:10 (20dB) SUT would give you 47000/100 = 470 ohms primary load for the cartridge - not quite the same as your 100 ohms presently) If you prefer to stick with 100 ohms (have you noticed much difference at the 220 ohms offered by the Phonobox SE's MC loadings?), then a 1:20 (26dB) SUT would give you a more matching 47000/400 = 117 ohms cartridge load. The extra gain of such a 1:20 SUT would however require you to drop your volume control down by 6dB. Which ever way your prefer, we may be able to rustle up some options for you - let me know.
|
Post by michaelw on Sept 14, 2018 18:13:54 GMT 12
graham - did your 103r come with the little test record showing output and frequency response ? below is the one with my dl-a100, a souped up regular 103. 
|
Post by Graham on Sept 14, 2018 20:54:17 GMT 12
Hi Michael. No test report with mine.
|
Pundit
Post by nakmad on Sept 14, 2018 21:17:10 GMT 12
Never play Leapfrog with a Unicorn.
Cassette Fetishist
219 posts
|
Pundit
Post by nakmad on Sept 14, 2018 21:25:23 GMT 12
Thanks Owen, I now understand SUT's a weenie bit better!.. Only a weenie mind. For what it is worth, I tack a Parks Audio Budgie SUT onto the front of my Nak 610 pre when using MC's through it. Mainly used with my DL103R using the low gain 1:9 setting.. and quite happy with the sound
Never play Leapfrog with a Unicorn.
Cassette Fetishist
219 posts
|
Post by michaelw on Sept 14, 2018 21:58:03 GMT 12
interesting how denon uses a higher than normal load for testing.
to inflate the output measurement ?
|
Pundit
Post by nakmad on Sept 14, 2018 22:08:10 GMT 12
interesting, 1K load for the A100 and 47K for the 103R.. and as I know more about (garden) gnomes than ohms, I'll leave that to the cognoscienti to explain
Never play Leapfrog with a Unicorn.
Cassette Fetishist
219 posts
|
Post by sub on Jul 7, 2019 14:14:03 GMT 12
I’ve been keeping an eye out for an affordable SUT to use with my Denon DL103R, Affordable being an important part of the equation!
The 103R output is .25mv, thus if I understand the above discussion, I need a sut with ratio at least 1:20, which will give a boost to 5mv, although have read elsewhere that a ratio of 1:40 would be better.
They don’t come up on T:M very often, but there is a Silvercore 1:10 currently listed, and at $500 is right at the top of my budget. Reading up on the Silvercore I find recommendations for using it with the 103R, even though the boost would be to only 2.5mv
The Silvercore seems to be well regarded, but would it work with my Pure Audio Vinyl - which is a preproduction Model for MM only, although all the jumper switches for changing input values are operative?
Any recommendations?
|
Post by michaelw on Jul 7, 2019 16:47:18 GMT 12
my dl-a100 was happy into 47k on the pav 
|
Post by Owen Y on Jul 7, 2019 17:41:48 GMT 12
I’ve been keeping an eye out for an affordable SUT to use with my Denon DL103R, Affordable being an important part of the equation! The 103R output is .25mv, thus if I understand the above discussion, I need a sut with ratio at least 1:20, which will give a boost to 5mv, although have read elsewhere that a ratio of 1:40 would be better. They don’t come up on T:M very often, but there is a Silvercore 1:10 currently listed, and at $500 is right at the top of my budget. Reading up on the Silvercore I find recommendations for using it with the 103R, even though the boost would be to only 2.5mv The Silvercore seems to be well regarded, but would it work with my Pure Audio Vinyl - which is a preproduction Model for MM only, although all the jumper switches for changing input values are operative? Any recommendations? Hi sub - Denon specify for the 103R either '100 ohms min.' or '40 ohms when using a transformer'. (An aside - traditionally the Japanese specify SUTs by the cartridge coil impedance - so the above '40 ohms' means that a SUT that is suitable for a cartridge with 40 ohms coil imped. - which is around 17dB or 1:7 - which (if you do the voltage ratio-squared sums) gives a cartridge load of around 1000 ohms, when connected to a 47k preamp.) Scanning quickly some forums, it seems that 103R owners are using anything from 50 ohms - 1000 ohms to load their 103Rs. So, given Denon's recommendation above, & the 14 ohms cartr coil imped., I would start with 10-15x the latter, ie. 150-200 ohms up to 1000 ohms. (Doing the ratio-squared sums again) this means a SUT of between 1:18 to 1:7 ratio. So, a Silvercore 1:10 should work, loading-wise. (Long explanation sorry.)
|
