MC Step Up Transformer Dilemma (Choosing Right SUT)

[Tharbamar]

For my musical enjoyment and trying to improve the sound of vinyl playback in my 2 channel system,
I wanted to try step up transformers (some says it's magical)but I'm not planning to pay mega bucks for simple step up transformers.

I went ahead and tried a few step up transformers for my Denon DL301mkII.

I have found a few interesting things/observation about using step up transformers in my 2 channel system,
SUTs are good up to certain level but may not be the best suited for all kinds of music playback in my experience but I do enjoy my using SUTs in my system.
This is eye opening experience for me in my 20+ years of being an audio guy.

I spent a lot of time futzing around with these step up transformers.
They all sounded good with different characters.
I think it's all comes down to personal taste and musical preference.
None of SUT I tried sounded bad in anyway but as always, different folks have different strokes and somebody might say/hear differently than I am, not everyone set up will sound the same.

This is not a review of SUTs.
I'm just sharing my experience for the people who may wonder into the SUT world like I did.


Left to right: Entre ET-100, DIY OneCent SUT, Denon AU-320,Denon AU-103

DIY: OneCent Step Up Transformer
(Softone PLT-1 SUT)

This is my first ever experience with DIY MC step up transformers it was such a great experience.
Overall I'm very impressed with quality of the sound.
I would described it for natural, effortless, transparency with good tonal balance but I would like a tad more dynamism with a little more bottom end and darker background for my liking.
My fist DIY SUT is up against well proven players and did very well in my opinion in some case I prefer this one over other SUTs.


Denon AU-320 Step Up Transformer

This is very good all around step up transformer may be suitable for any kind of system.
I would described it as lively well balanced sound from 40 years old technology and this could be one of best budget SUT for Denon MC cartridges.
I loved how it sound in my set up and match very well with my SS amplification.
Treble is near perfect, voices sounded natural and beautiful, letting me hear different layers and timbres of music, bass and lower midrange is well pronounce, allows me to hear the music as artist created without even the slightest hint of boom in lower region.


Denon AU-103 Step Up Transformer (In Japanese)

This is a another very good SUT from Denon,
It's kind of expensive but build quality of enclosure is better than any SUT I have ever seen.
It seems to be matching well with my DL-301mkII cartridge.
Most noticeable thing about AU-103 is absolute quietness, background is so dark (may be something to do with Meruton Class1 LC-OFC wiring).
Music just float in the room with 3D like sound stage with rich music, transparent sound.
This is first SUT that gave WOW factor and makes me want to keep on listening.
Treble is near perfect, voices sounded very natural and beautiful, letting me hear different layers and timbres of music, bass and lower midrange well pronounce, allows me to hear air and warmth of music without slightest hint of boom, looseness, may be a tad more define than AU-320.


Entre ET-100 Step Up Transformer (In Japanese)

This one is smooth, lush and very pleasing to listen.
It doesn't draw attention but everything is in please with smooth warm rich sound and bottom end is really good.
Very much comparable to Denon SUTs in sound quality, just being a little warmer.
Highs may not be sparkling but I do enjoy listening smooth lush tone of this SUT.
I only tried it in 40Ω setting for my Denon cartridge, very quiet SUT.
There is no bad thing to say about this SUT other than the size of the unit.

I have read and heard people saying most SUT are sensitive to EMI or hum if not set up correctly but I did not find this to be the case with any of SUT I've tried in my system.
There was absolutely no noise with it sitting only a few inches away from Apple TV, which was worst noise maker for my Parasound phono stage.
I can live with any of these SUTs but I think Denon AU-103 matched the best with my cartridge and I will also keep Denon AU-320 for me.

I hope this help for someone who is about to try Step Up Transformers.
My next step is to try DIY Cinemags.
Happy Listening !


​

 

[rothwellaudio]

Denon cartridges seem to be very popular and since Denon make step-up transformers it's tempting to think that their cartridges are ideally suited for use with transformers, but they're not ideal at all. The problem with a lot of Denon cartridges is their high(ish) output impedance, and to compound the problem they often have a low output signal - the worst of both worlds. Most modern MCs from other manufacturers are a lot more transformer-friendly.
Still, despite the numbers it's possible to get a good sound from a Denon cartridge with a transformer. I would expect a turns ratio of 1:10 or a little higher to be best for your DL-301mkII, and most of your transformers offer that.
Here's some info which might be useful
http://www.rothwellaudioproducts.co.uk/html/step-up_transformers_for_denon.html

 

[MickeySmile]

Great post with demo! LOVE it!!!
I happen to have a pair UTC A-10 transformer and I built SUT from it using 100% silver wire. It sounds very similar to your 1 cent SUT but my cartridge is DL-103.

 

[Duane]

Your presentations are outstanding. Have always liked the look of the Denon DP-47F with the silver trim.

 

[bobins08]

Denon cartridges seem to be very popular and since Denon make step-up transformers it's tempting to think that their cartridges are ideally suited for use with transformers, but they're not ideal at all. The problem with a lot of Denon cartridges is their high(ish) output impedance, and to compound the problem they often have a low output signal - the worst of both worlds. Most modern MCs from other manufacturers are a lot more transformer-friendly.
Still, despite the numbers it's possible to get a good sound from a Denon cartridge with a transformer. I would expect a turns ratio of 1:10 or a little higher to be best for your DL-301mkII, and most of your transformers offer that.
Here's some info which might be useful
http://www.rothwellaudioproducts.co.uk/html/step-up_transformers_for_denon.html

My recent experience says you are correct. I was given a K&K SUT with Lundahl transformer to try with my 301 MK II. The DL 301 has a 0.4 mv output, a 33 ohm output impedance, and the manufacturer specs call for a load of >100 ohm. The SUT was set up for 1:20 step up and there was a 30k load resistor in parallel. The sound was not great. Too hot, too much gain, and even some midrange suck-out.

First I removed the 30K resistor. The previous user must have installed it to create a 45 - 50 ohm load reflected back to the cartridge. The DL 301 likes >100 ohms and many say the 400-600 ohms is the sweet spot.
Removing the resistor changes the load to 118 ohms and provided a noticeable improvement. Still the sound was hot, the 1:20 step up is too high, and I was not to use my preamp volume.

I changed the step up to 1:10 and the result was fantastic. Due to the change in windings ratio the load the cartridge sees is now 470 ohm, the input signal to the preamp was halved, and the volume level and sonic quality is much better.

I think that anybody that uses a SUT needs to know the specs I covered here and the basics on what the SUT does to the cartridge so as not to overdrive the preamp and to properly load the cartridge.

To the OP: thank you for the interesting demos. It would be interesting to include the step up ratio used and any other loading consideration for the various set up.

cheers, Bob

 

[Tharbamar]

Fun weekend project.
All the extra connection on this step up transformer is not necessary for me and bypass all the toggle switches on the front panel of my Denon AU-320.

This mod takes this SUT to the next level.
Bigger sound stage, the music opens up nicely.
Overall nice warm tone is still intact.
The main improvement is clearer highs, everything sounds more realistic.
Probably the best improvement mod for Denon AU-320 step up transformer.


Removed all old dusty foams and treated with some Dynamat.


Input independence is fixed.


Now more front panel cartridge selection.

I would recommend it to anyone who does like their Denon AU-320.
Happy Listening.​

 

[Paulix]

Fun weekend project.
All the extra connection on this step up transformer is not necessary for me and bypass all the toggle switches on the front panel of my Denon AU-320.

This mod takes this SUT to the next level.
Bigger sound stage, the music opens up nicely.
Overall nice warm tone is still intact.
The main improvement is clearer highs, everything sounds more realistic.
Probably the best improvement mod for Denon AU-320 step up transformer.


Removed all old dusty foams and treated with some Dynamat.


Input independence is fixed.


Now more front panel cartridge selection.

I would recommend it to anyone who does like their Denon AU-320.
Happy Listening.​

Hello, I have the same model and wondered if you would share how to do this mod?
Thank you!

 

[RubberDuck52]

In late April 2024, I purchased a Ortofon ST-80 SE for my Hana ML. One of the best and most successful upgrades I ever did, as playback is now a lot more detailed, natural, balanced, transparent, snappy and pleasant. Been listening to records every day since, and for many hours.

I had two yards of low capacitance Audio Note AN-C COAX interconnects lying around, so I had my HiFi shop cut them in half and mount Neutrik RCA plugs on both sets. I also asked them to solder the two center wires together in parallel in order to further reduce the resistance. Now I have short, low capacitance, low resistance cables added to my Furutech phono interconnects. This makes a lot of sense with SUTs.
My phono stage is a Primare R-35, running at 47 kOhms, 100 pF and 40 dB gain. The SUT delivers 27 dB gain (1:20).

 

[Sleiven]

Fun weekend project.
All the extra connection on this step up transformer is not necessary for me and bypass all the toggle switches on the front panel of my Denon AU-320.

This mod takes this SUT to the next level.
Bigger sound stage, the music opens up nicely.
Overall nice warm tone is still intact.
The main improvement is clearer highs, everything sounds more realistic.
Probably the best improvement mod for Denon AU-320 step up transformer.


Removed all old dusty foams and treated with some Dynamat.


Input independence is fixed.


Now more front panel cartridge selection.

I would recommend it to anyone who does like their Denon AU-320.
Happy Listening.​

You will ruin your resale value and gain absolutely nothing. Have you measured the frequency response and distortion and noise level before and after mod? If so please post it here to document the effect.

 

[twiiii]

Having dealt with transformers and repeat coils back in the 60's and 70's at radio stations where all your tube electronics used out put transformers. You needed repeat coils to send signals over Ma Bell's phone lines and from one studio to another and so many other applications you can find your self having to deal with a real can of worms when setting up and using trans formers properly. You have to know when to bridge the signal and when to terminate the signal to get the best results. For best energy transfer you terminate by matching impedances. But with MC cartridges the higher the load impedance the less you you reduce the output of the cartridge. The question becomes how much does lowering the load presented to the cartridge effects the properties of the cartridge. Some say very little. I tend to agree. Its not like changing the capacitance to a MM cartridge that can compromise the frequency response and the capabilities of the cartridge when it comes to tracking grooves.

The issue with transformers is their own non-linearities. . This is where I had difficulties back in the 60's and 70's with different SUT's from Ortofon etc. Plus they are hum, noise and RF magnets. With tracking issues back then I finally gave up on Ortofon MC cartridges. But today having gone back to MC for all the big pluses they now give I have chosen a Mcintosh MC level to Line level preamp with impedance adjustments. It also has a separate input for MM cartridges with capacitance loading. Using Cook test records and selecting different loads for MC only reduces out put levels with small fractions in change of the frequency response. Noise does increase with lowering the impedance and separation issues are not changed.

Changing capacitance can have quite an influence on MM cartridges frequency response is what I notice the most. It doesn't seem to effect the sound of HO moving coil Dynavectors in the slightest is my opinion. Maybe it should. I just haven't noticed the extreme change you get with MM cartridges.