Testing MC step up transformers

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Testing MC step up transformers

Post by lejonklou » 2019-08-22 12:27

Today my tests of various MC step up transformers started. Very very very exciting, as the perhaps worlds best manufacturer kindly allowed me to borrow all of their models to listen to! I've been wanting to do this for many years and now it's finally happening. How good can it get?

I have wiring schemes for each model, variable loads for input and output, a slightly modified Slipsik 7 phono stage, a test flowchart, a long list of questions, pen, paper and a big stack of records in front of me.

It's like Christmas in August!

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Re: Testing MC step up transformers

Post by maffe » 2019-08-22 13:30

Merry X-mas to you!
Sitting here with a bunch of jazz and classic music that my 70 year old neighbor lended me, and a very disappointed cat sins his sleeping place gets up ever 20 minutes or so changing record:)

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Re: Testing MC step up transformers

Post by mrco99 » 2019-08-22 14:27

Wow!
That sounds very exciting indeed!
Have a great session and no Christmas records in between your pile I assume :-)

What is your first test track?
Happy listening and we're all eager to hear the outcome!
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Re: Testing MC step up transformers

Post by ThomasOK » 2019-08-22 16:10

It will be very interesting to find out how they compare to the other MC stage work you've been doing. It is great that you view all this work as being like Christmas, as the end results are presents for us!

By the way, you might as well mention the brand since it is quite obvious in your Instagram photo.
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Re: Testing MC step up transformers

Post by lejonklou » 2019-08-22 19:20

Thanks everyone!

I spent the whole day comparing, the differences are big and really interesting! Will continue tomorrow and during the weekend.
mrco99 wrote:
2019-08-22 14:27
What is your first test track?
The Beatles 'Help'. I ended up listening to all tracks of the album before I moved on.

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Re: Testing MC step up transformers

Post by matthias » 2019-08-22 20:05

lejonklou wrote:
2019-08-22 19:20
I spent the whole day comparing, the differences are big and really interesting! Will continue tomorrow and during the weekend.
Great,
maybe you have a transformer that is optimised for EMT cartridges as well?
That means gain around 56dB as combo with Slipsik.

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Re: Testing MC step up transformers

Post by Charlie1 » 2019-08-22 20:51

Enjoy your dream job Fredrik. I quite like mine (overall) but it's no dream - you're a lucky man!!!

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Re: Testing MC step up transformers

Post by lejonklou » 2019-08-22 21:08

matthias wrote:
2019-08-22 20:05
maybe you have a transformer that is optimised for EMT cartridges as well?
That means gain around 56dB as combo with Slipsik.
As Slipsik has 40 dB of gain, that leaves 16, which is 6 times. Not much!

The lowest ratio of the ones I'm testing is 1:5. Level wise that should fit. The second lowest is 1:8 and the third lowest is 1:10 (overload? the total with Slipsik would be 60 dB).
Charlie1 wrote:
2019-08-22 20:51
Enjoy your dream job Fredrik. I quite like mine (overall) but it's no dream - you're a lucky man!!!
Thank you! It's true, I'm extremely lucky.

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Re: Testing MC step up transformers

Post by FalseMetal666 » 2019-08-23 21:12

My set up is modest, and I've only ever had budget equipment until now, but I am surely very happy with my Gaio v1, fed by a humble Bellari STU and Denon DL103.

Beats the pants off of my previous Clearaudio Nano v2 (as it should).

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Re: Testing MC step up transformers

Post by David Neel » 2019-08-30 09:43

I'm intrigued by this approach. Way back in the 1970s I had a step up transformer with an FR-1 cartridge. How does the use of a transformer and a modified Slipsik 7 contrast with the "MC Slipsik" previously discussed?
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Re: Testing MC step up transformers

Post by lejonklou » 2019-08-31 21:34

Report coming soon

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Re: Testing MC step up transformers

Post by lejonklou » 2019-09-02 00:04

OK, time to share some impressions!

I will not mention any specific models in this report, but rather my general conclusions after five days of testing these transformers.

My first conclusion is that the more expensive models from Lundahl are really a lot better than their less expensive models. I skipped testing the versions that use silver wire, mainly because I have never had any good experience with silver, always finding copper to sound more natural. Both when it comes to wires, plating of connectors (where gold or tin is better than silver IMO) and as heat sinks (although a professor in metallurgy, which I met at a party, pointed out to me the need for annealing pure silver after every process of machining, cutting or drilling, due to its rapidly hardening properties, so my conclusions of the pure silver heat sink tests might very well be invalid). As I told Lundahl after the tests, this situation of the most expensive models being the best is highly commendable and atypical for most audio companies in my experience.

Transformers have a certain sound character, which leans toward the soft in a rather charming "analogue" way. The more expensive oversized models have less of this colouration and preserve the dynamics in the music, while the smaller and less expensive models have more colouration. A good active first stage of amplification of the signal from the MC can excel in dynamics, but it also adds a little noise and distortion. A transformer can sound very open and musical, but it also adds some soft colouration and a little hum. I have now learned that the problems of both can be minimized with a really good design.

My second conclusion is that Lundahl's unique uncut amorphous cobalt core design is quite a bit better than the mu-metal cored alternatives that they (and many others) also manufacture. I had read that some audiophiles describe the amorphous core character as "more musical and detailed" and the mu-metal core character as "more analytical and mid-bass punchy", which didn't really help me understand anything. But now that I've listened to them myself, I can confidently state that I'll pick the uncut amorphous cores any day of the week. This applies to the more expensive oversized designs, while with the less expensive models these differences were not as easily divided into better and worse. In general, the mu-metal cores sound more "straight and clean" but they also lack the fine nuances of the musical performance, which the amorphous cores deliver in spades.

My third conclusion is how to optimally connect these step up transformers (SUT) to a high level phono (MM) stage. As mentioned before, I used a slightly modified Slipsik 7 and the main part of the modification was that I made its input load variable and switchable. The standard input load of Slipsik 7 is 47k ohms and 68 pF. The standard way of using an SUT is to leave this MM load as is it and use no load on the primary side of the transformer (where the MC cartridge connects). An MC normally requires a lot less resistance and a lot more capacitance to sound good. Now, the transformer will not only transform the voltage of the MC from low to high, it will also transform the resistive part of the input load of Slipsik (47k) from high to low. The resulting primary side load varies with the ratio of the transformer, so if it's for instance 1:10, the load as seen by the MC cartridge will be a lot higher than if the transformer is 1:20. For this reason, I made the resistance and capacitance variable at both ends of the transformers.

And the conclusion of these test was that for optimal performance, the cartridge load should be on the primary side of the transformer. Instead of no load on the primary and 47k ohms on the secondary (the standard way of using an SUT), there should be 180 ohms on the primary (which is the optimal value for Linn Krystal) and no load on the secondary. And something similar happens with the capacitive load: On the secondary side, the typical 68-200 pF of the MM stage doesn't do anything for the MC, which will sound a bit nervous as a result, while adding 10 nF on the primary side calms the cartridge and makes the music flow more harmoniously.

These test were mainly done with Lundahl's more expensive amorphous cores and the results may not be perfectly translatable to all SUT:s. Lundahl told me that having the load on the primary side would not present any problems, it might in fact be an advantage, as it would likely tame a slight ringing in the waveform of the transformed signal. I did all the loading tests by ear and didn't do any measurements, but my impressions confirmed their thoughts on this. With the standard way of using a SUT and keeping the MM input load (even if you adjust it to the optimal resistance, which is rarely 47k but can be anywhere from 18k to 72k), the music is more messy than when the load is on the primary side of the transformer, directly on the MC cartridge output.

So how good can it get with an SUT? Really good! The best setup I tested couldn't touch SINGularity, but the small and affordable MC stage that I am working on got some stiff competition. One thing that surprised me was how similar the two actually sounded, one leaning towards the gentler side (the SUT+Slipsik 7) and the other being a little more upfront and direct (my small MC stage), but these differences in character were really minor. They both made me want to listen to just about any record I put on all the way to the end. I did a quick calculation of what an integrated SUT+Slipsik 7 design would cost and sadly it's more than twice the cost of my small MC stage. So at the moment, this is not a given future product of mine. And the cartridge load thing excludes it from becoming an add-on-box to a Slipsik 7, it would have to be an integrated one-box design.

We'll see what happens. At least I have now learned that audio transformers have the potential to perform really well. And also that the very best ones are not cheap! Apart from being used as SUT's, they have a number of other possible usages in audio electronics, some of which I've tested in the past, but never anywhere near this level of performance. Lundahl apparently know what they're doing!

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Re: Testing MC step up transformers

Post by Charlie1 » 2019-09-02 12:18

Fascinating read - thanks Fredrik.

SUT offers a nice upgrade path for Slipsik owners moving to MC but it also makes sense that you don't want too many products. I guess the SUT market is also much smaller than traditional MC phono.

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Re: Testing MC step up transformers

Post by matthias » 2019-09-02 13:11

Charlie1 wrote:
2019-09-02 12:18
Fascinating read - thanks Fredrik.
+1

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Re: Testing MC step up transformers

Post by David Neel » 2019-09-02 16:21

Thank you Fredrik for the write-up!

Apart from increasing my knowledge of audio design/configuration, the post has made me more eager than ever to hear the new MC stage.
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Re: Testing MC step up transformers

Post by Defender » 2019-09-04 19:04

I really appreciate the honesty and openness in sharing all your findings there other companies try to keep those findings a secret for a competitive advantage - actually that openness is driving me to buy your products.
I see you dont like silver and you state it does not sound natural - can you elaborate more?
Does it shift the music towards more restless, more forward more sparkle but bright? Sorry to use hifi terms but I have no other description for what I think I hear with silver interconnects.

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Re: Testing MC step up transformers

Post by ThomasOK » 2019-09-04 19:36

Thanks, Fredrik! A lot of interesting information on the SUT trials. Considering the expected price range for the lower cost MC stage in the Slipsik case, the SUT unit would be pretty high - probably more than a Sagatun. From the reading I've done about those who are fans of SUTs they seem to be picky about matching the loading and windings of the SUT to the cartridges such that they recommend different SUTs for different cartridges. I was recently reading about one SUT that was specifically designed for the Denon 103 cartridge so some of them get quite specific. With this in mind I expect that the typical SUT customer would expect to at least have adjustable loading and incorporating a system such as the one in SINGularity would cause a further significant increase in price. So unless it had really world beating musicality it seems the entry level MC stage is likely a better way to go for most, especially with such close sound quality.

It sounds like the SUT/modified Sipsik phono stage could end up getting close to SINGularity in aluminum cases with more standard construction. I would have to guess that this would be the superior product.

It is great that you enjoy your work so much as that is a lot of work. I agree that it is very cool, and rather unusual, for a manufacturer to share so much of how design is accomplished. Honest HiFi indeed!
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Re: Testing MC step up transformers

Post by lejonklou » 2019-09-05 12:33

Charlie1 wrote:
2019-09-02 12:18
SUT offers a nice upgrade path for Slipsik owners moving to MC but it also makes sense that you don't want too many products. I guess the SUT market is also much smaller than traditional MC phono.
Thank you for your comments! I don't mind having many products, but each one needs to make sense. The SUT market that you refer to is when people add a SUT to their MM phono stage. As I wrote, this is a suboptimal solution due to the cartridge load becoming very imprecise. If I was to make a product with SUTs, they would be integrated with the phono stage (hidden inside) and have an adjustable cartridge load. I don't think such a product would be regarded as belonging to the SUT market. It would simply be an MC stage.
David Neel wrote:
2019-09-02 16:21
Apart from increasing my knowledge of audio design/configuration, the post has made me more eager than ever to hear the new MC stage.
Thanks! I have one really tricky problem left to solve to be able to build it in larger numbers than one at a time. I hope to figure out a solution as soon as possible, because this baby is ready to fly! The prototype will be playing at XFI in Veldhoven, the Netherlands, the 28-29th of September.
Defender wrote:
2019-09-04 19:04
I really appreciate the honesty and openness in sharing all your findings there other companies try to keep those findings a secret for a competitive advantage - actually that openness is driving me to buy your products. I see you dont like silver and you state it does not sound natural - can you elaborate more?
Does it shift the music towards more restless, more forward more sparkle but bright? Sorry to use hifi terms but I have no other description for what I think I hear with silver interconnects.
Thank you! Yes, silver conductors, connectors and parts always seem to have a bright sparkling character in the treble that isn't well timed with the rest of the music.
ThomasOK wrote:
2019-09-04 19:36
From the reading I've done about those who are fans of SUTs they seem to be picky about matching the loading and windings of the SUT to the cartridges such that they recommend different SUTs for different cartridges. I was recently reading about one SUT that was specifically designed for the Denon 103 cartridge so some of them get quite specific.
Yes, the reason why the SUT+MM phono stage enthusiasts are so picky about exactly which SUT to use is that the transformer ratio determines both the signal level (MC cartridges vary a lot in their output level) and the cartridge load. This really complicates things, as if you get one right, the other might be wrong. By removing the 47k ohm load of the MM and placing the cartridge load on the input side of the SUT, these two parameters will become separate instead of interdependent. And the choice of SUT will be much easier and mainly depend on which level suits the cartridge.

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Re: Testing MC step up transformers

Post by tokenbrit » 2019-09-07 18:17

Any potential to transform the power supplies in Sagatun or Tundra arising from your MC SUT tests?

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Re: Testing MC step up transformers

Post by lejonklou » 2019-09-07 19:06

tokenbrit wrote:
2019-09-07 18:17
Any potential to transform the power supplies in Sagatun or Tundra arising from your MC SUT tests?
I'm not sure what you mean by this. The SUTs have nothing to do with power supplies. The principles and technologies involved are so vastly different that it's a fun exercise to try to find what they have in common.

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Re: Testing MC step up transformers

Post by tokenbrit » 2019-09-07 23:02

lejonklou wrote:
2019-09-07 19:06
tokenbrit wrote:
2019-09-07 18:17
Any potential to transform the power supplies in Sagatun or Tundra arising from your MC SUT tests?
I'm not sure what you mean by this. The SUTs have nothing to do with power supplies. The principles and technologies involved are so vastly different that it's a fun exercise to try to find what they have in common.
I have no knowledge beyond the awareness that transformers can be used in both, so was just curious whether any transformer technology was common between the two applications, or whether Lundahl make any transformers that could be used to make a musically superior power supply...

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Re: Testing MC step up transformers

Post by lejonklou » 2019-09-08 00:43

OK! True, both use transformers. But very different in design, materials and practical use.

I doubt there's any cross pollination possible here, but as I said, it's fun and perhaps, at least maybe somewhere far down the line, worthwhile thinking of what they have in common.

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Re: Testing MC step up transformers

Post by Defender » 2019-09-08 11:13

Hi Tokenbrit,

those transformers can be used in output stages of source components as Linn does in the Klimax DS range. Others try to tune output stages of CD-Players and DAC‘s with output transformers.
So there might be the question coming up if it would make sense to try it in the output stage of a pre-amp.
But I think signals entering the pre amp are even too high so the pre amp wouldnt really need a step up transformer.

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Re: Testing MC step up transformers

Post by lejonklou » 2019-09-08 11:33

The line level transformers and the SUTs are two separate ranges from Lundahl, as the required levels and ratios are different. But they're both analogue signal transformers and therefore similar, while the switch mode power supplies in Boazu, Sagatun /Mono and Tundra /Mono use a completely different type of transformer.

I have tried using transformers on the audio output of my phono stages and preamps, but have never been really happy with the results.

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