Dynavector XV1-S and step-up

Hatari,

I recommend to you the Bent Audio Mu to use with what I hear is a wonderful phono in your Shindo. It is without a doubt the finest step up in my experience. This includes the copper version. I feel the cooper version is better than anything I have tried and I have tried many. Unbelievably, the silver version is a significant improvement over the copper.

I have own two XV-1s. I disagree with some of the opinions above. I have owned many of the top of line phonostages available today and all of them were improved upon by setting the phono stage to its lowest gain setting and introducing the Bent Silver Mu in front. IMHO there is no better way to control a MC cartridge then with a step up transformer. Also phonostages with out step ups that offer different load settings have always, in my experience, been a bit of a joke. Its as if either, the mc cartridge does not recognize the change in load or the phonostage isnt executing the change of load properly. In fact I have never seen a mc cartridge respond to load changes with out a Step up, like they do with a Step up. Period.

For example a phonostage with the option to switch from say 1000, 500, 200, 100 ohms and there is very little difference between 1000 and 100! Its ridiculous. If you place a resistor in my Bent Audio Silver mu's using the Stevens and Billington T-103 trannys you will notice a significant difference in cartridge performance. If you change the load by 10 ohms you will receive a response from the moving coil.

This is a copy and paste from another gentleman who pretty much nails it on the head with regards to moving coils and step up transformers.

In spite of the huge amount of gain possible with modern MC phonostages,
typically 1000 to 1800+ times amplification, the MC cartridge is a poor
voltage source to drive these amplifiers. Furthermore the low resonance
frequency of a MC causes them to have a rising frequency response
beginning well below 20KHz which gives them, all else considered, a
sharp, spitty and unpleasant treble. This is in turn damped with a low
input impedance which creates an even further problem for the weakly
output MC cartridge.
A matching step-up transformer solves all these problems.
The transformer "transforms" the MC from a voltage source to a current
source, the transformer steps up the voltage relieving the MC from this
task. As a current source the transformer presents the MC with an
impedance at or near (ideally) the impedance of the MC which naturally
damps the rising top end without creating a electro-mechanical damper as
in the case of the low impedance input of the direct drive amp, i.e.
without the transformer.

And the voltage amplification of 5 to 20 times makes for a much quieter
operation and vastly better signal to noise ratio than is possible in
the "direct drive" configuration.

Lastly, again all else being the same, the phonostage will usually use
less feedback and generally sound better with a lower gain than higher
gain.

I must agree, in my experience there is nothing better and I haven’t read one argument to convince me otherwise and I have read them all. Most of all, my experience tells me otherwise.

One must realize that transformers can be a very transparent device. Now with nickel and amorphous cores, silver wound and so forth, trannys are becoming down right nasty. I have heard some transformer based passive pre’s that are lovely! I don’t know if you ever experimented with amps. I tried many OTL amplifiers and none were as good as an amp with very good iron, like the vintage Acro TO 330, Tribute, Slagle, Tengo, Tamura, Electraprint, Audionote, lundahl, Sowter, magnequest, There is a lot of good transformer companies out there and all are striving for results beyond reproach. The Stevens and billington tx-103 transformer is, in my experience, is one of the most transparent devices in all of audio. By all means try a step up transformer with your XV-1s.

I have seen many people with lots of experience say, step up trannies are no good, this and that and that and this, and now they use step up trannies or own phonostages with them built in.

Rudolffzigray,
10/10 as far as my own experience goes and "another gentleman who pretty much nails it on the head"

I actually think that the "issues" arising in getting a proper impedance match has given SUTs a bit of a bad name(not mentioned by the other gentleman).

Also, as you pointed out, using an SUT shows up HUGHLY different loadings. It can sound absolutely impossible with e.g. 47ohm and really GREAT with 10ohm loading (as example with a 30dB unit).

Also there is the possibility of phono-pre overloading if wrongly matched. Some example scenarios I put see in: http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1248136396

Greetings,

Axel, In order to avoid confusing a novice, I would take issue only with the language you used in the post you referenced above. You wrote:

"Step 2: Find out the 'natural impedance' of the trannie.
Ratio^2 * phono-pre input impedance
e.g. 31.6 * 31.6 * 47k ohm = 47 ohm for a 30dB trannie
(this will be what the cart sees if you do not use secondary or primary loading of the trannie)"

47 ohms (or 47K ohms divided by ~1000, the approx square of the turns ratio of the transformer you described) is about what the cartridge "sees" as a load if there is a 47K ohm resistor across the secondaries of the SUT, i.e., on the preamp input side. A transformer, any transformer, has no "natural impedance" per se. Transformers merely reflect impedances from primary to secondary or vice-versa.

As to the rest of this argument, I would love to hear a very high quality SUT in my own system in order to make up my own mind as to their wonderfulness. I am keeping an open mind, but in principle there are about as many possible problems with a SUT amplifying the voltage output of a very LOMC as there are with an active gain stage. The problems are just different.

Hi Lewm,
y.s.:
>>> A transformer, any transformer, has no "natural impedance" per se. Transformers merely reflect impedances from primary to secondary or vice-versa. <<<

Sir, yes Sir! B U T, I did explain how 'natural impedance' comes about --- inverted commas and all.
Also 99% of phono-pres ARE using a de-facto impedance standard of 47k, hardly ever 50k, etc.

The calculation aught to make it clear that the 'natural impedance' of a 30dB trannie will be 50ohm for a 50k ohm input impedance or 100 ohm for a....

>>> ...in principle there are about as many possible problems with a SUT amplifying the voltage output of a very LOMC as there are with an active gain stage. <<<

The problems ARE different since some more insight is required with an SUT, which is often disregarded. Loading any MC 'straight' (no SUT) is pretty much 'dead easy', often by turn of a button.

As to the results, I dare say they are VERY much different, but this does not imply that you have to LIKE it. Raul's 'ear-equalization' comes to mind immediately.
Greetings,
PS: FM_Login (Roman Bessnow, alias 'Romy the Cat') swears by his trannie. This might be a MAJOR recommendation, or an equally major turn-off - depending where you stand with this expert source.

Axel, Sorry for being pedantic. I have to agree that a lot of folks who do use SUTs do not seem to take into account the matching of the SUT to both the cartridge and to the preamp. This is why I urged Hatari to first of all listen to his built-in SUT in his Shindo preamp, because that is undoubtedly set up properly to match the input stage. I dislike comparative testing of SUTs that we see in published articles, where a guy interposes several different SUTs between the cartridge and preamp, without regard for any special measures that might optimize frequency response, etc. The author then makes spurious judgements regarding which SUT sounds best. The Jensen transformer website has a couple of excellent "white papers" (I have no idea why we use that term in the US) on SUT electronics, from which one can learn a lot about this subject.