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Thread: Escoed Troika arrives. SUT advice

  1. #1
    Join Date: Feb 2008

    Location: Canaries

    Posts: 190

    Default Escoed Troika arrives. SUT advice

    Hi all,
    Well, the Troika has finally arrived and after about 30 seconds it was obvious that here was a much better match for my Ittok LViii than my previous 103Pro with its extra weight. It sounds much more refined with loads of texture and detail in the bass and also higher bass volume in the mix. Funnily enough, treble detail is also much improved and piano sounds so much more authoritative so I guess the Esco fineline tip is also doing its bit in comparison with a stock Troika.
    Anyway, not here to extoll the virtues but rather to ask for advice regarding SUTs. I already had my Audio-Technica AT-650 adjustable, always using the 40 ohm setting with the 103. Then I got hold of the Haufe transformers (also 40 ohms) and made my own little box of tricks up and I found it an improvement on the AT. Now with the Troika I have just tried my AT again and my first impression is that it sounds better than the Haufe job, especially on the 3 and/or 20 ohm ohms setting although that could be down to the fact that I seem to get greater gain on the 3 ohm setting, although perhaps a bit too bright. I believe these ohms settings on the AT are really meant to represent 10x their value as far as load impedance is concerned. Anyway, can anyone confirm what should be the correct setting for the Troika and IŽll take it from there.
    Chris

  2. #2
    Join Date: Jan 2009

    Location: Essex

    Posts: 26,377
    I'm openingabottleofwine.

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    Quote Originally Posted by Chris View Post
    Hi all,
    Well, the Troika has finally arrived and after about 30 seconds it was obvious that here was a much better match for my Ittok LViii than my previous 103Pro with its extra weight. It sounds much more refined with loads of texture and detail in the bass and also higher bass volume in the mix. Funnily enough, treble detail is also much improved and piano sounds so much more authoritative so I guess the Esco fineline tip is also doing its bit in comparison with a stock Troika.
    Anyway, not here to extoll the virtues but rather to ask for advice regarding SUTs. I already had my Audio-Technica AT-650 adjustable, always using the 40 ohm setting with the 103. Then I got hold of the Haufe transformers (also 40 ohms) and made my own little box of tricks up and I found it an improvement on the AT. Now with the Troika I have just tried my AT again and my first impression is that it sounds better than the Haufe job, especially on the 3 and/or 20 ohm ohms setting although that could be down to the fact that I seem to get greater gain on the 3 ohm setting, although perhaps a bit too bright. I believe these ohms settings on the AT are really meant to represent 10x their value as far as load impedance is concerned. Anyway, can anyone confirm what should be the correct setting for the Troika and IŽll take it from there.
    Chris
    Whilst I have no experience of the Linn Troika (the only Linn cartridge I have used was the Asak), in general all mc cartridges should be loaded by at least 100 Ohms. Moving coil cartridges are voltage sources and so have a comparatively low source impedance. They should be fed into a device offering a load impedance several times higher than that of the coil resistance. I have recently been playing with a Denon 103 and run it into 100 Ohm, but am thinking of trying 470 Ohm.

    If you know the turns ratio of your Haufe transformers and also the load impedance of the preamplifier into which they feed, then the load presented to your cartridge is the load impedance of the amp/(turns ratio)^2. Thus with the usual 47 kOhm preamp impedance and with a 10:1 turns ratio (i.e.10x or 20dB), the load presented to the cartridge will be 470 Ohm (i.e. 47000/100 = 470).

    As always your ear should be the final arbiter, but intially I would suggest you try something > 150 Ohm and see how you get on.

    Regards
    Barry

  3. #3
    Join Date: May 2008

    Location: A Strangely Isolated Place in Suffolk with far away trains passing by...

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    I'm David.

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    Linn and Naim always loaded the Troika at about 470 Ohms as I remember and I believe naim tinkered around with the EHF response a little, hence their "K" boards.

    Am I right in saying that under-loading such a cartridge may make it a little bass-light by comparison? I don't know how much extra top that EsCo put back (Troika's lose it as they age...) but re-built as it has been, it should be a great sound.

    I've heard EsCo "do" good things to a 103 as well.......
    Tear down these walls; Cut the ties that held me
    Crying out at the top of my voice; Tell me now if you can hear me

  4. #4
    Join Date: Feb 2008

    Location: Canaries

    Posts: 190

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    I have reached the conclusion that this SUT business is a veritable minefield. I do wish that someone would just point to a trannie and say this is the one for the Troika but it would seem that when Troikas were kings, then SUTs were not in favour. I get the impression that I should be getting more bass slam than I am with my haufe DIY job and my AT-650 on any of its 3 settings. IŽll have to borrow a mateŽs Black Cube and see if I am missing out.

    Anyone heard the Hagerman Piccolo active head amp ?

  5. #5
    Join Date: May 2008

    Location: A Strangely Isolated Place in Suffolk with far away trains passing by...

    Posts: 14,557
    I'm David.

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    Oh for goodness sake, let me put you out of your misery

    Try asking Les at Avondale about his phono box based on Naim bits (no, don't spit!)

    The typical Troika had a rising bass and a presence dip (the EsCo one may have this tamed to a large degree, judging from one I had re-cantilevered years ago) which was countered in part by Naim's "K" boards. With a few well chosen cap replacements and an external power supply of good quality, they can sing very well I feel, without the rest of the bandwidth limited nightmare to slug them out of existance. Les does, I think, a little box for the boards to fit in and a not unreasonably priced power supply too to power it, which can be sited remotely.

    Well worth giving him a ring and having a chat about it. Even if you don't go down this route, you'll learn much from the conversation.......

    I'd also suggest the WD forum, as they've some real experts who can suggest a good transformer (their own?) and the proper way to adjust the loading.
    Tear down these walls; Cut the ties that held me
    Crying out at the top of my voice; Tell me now if you can hear me

  6. #6
    Join Date: Jan 2009

    Location: Essex

    Posts: 26,377
    I'm openingabottleofwine.

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    Quote Originally Posted by Chris View Post
    I have reached the conclusion that this SUT business is a veritable minefield. I do wish that someone would just point to a trannie and say this is the one for the Troika but it would seem that when Troikas were kings, then SUTs were not in favour. I get the impression that I should be getting more bass slam than I am with my haufe DIY job and my AT-650 on any of its 3 settings. IŽll have to borrow a mateŽs Black Cube and see if I am missing out.

    Anyone heard the Hagerman Piccolo active head amp ?
    The advice you are being given here is exactly the same as the advice you have been given on the pink fish media forum.

    The Linn Troika is quite happy to be loaded with 470 Ohm, and this is provided by the Naim K boards that have been suggested.

    In order to be able to help you further with your Haufe transformers, I would need to know the input impedance of the phono input of the pre amplifier you are using and the turns ratio of the Haufe transformers. If you don't know this, let me know the model number of the transformers.

    Barry

  7. #7
    Join Date: Feb 2008

    Location: Canaries

    Posts: 190

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    Hi Barry,
    The data sheet in german that Haufe gave me for my T-7833 capsules says :

    1:10
    Primary impedance 40 ohms
    Final impedance 47 Kohms
    primary Gauge 0.05V
    20 Hz-20Khz +/- 1db ref 1kHz
    1% (Klirrfaktor)
    6.8 kohm 1 khz+/-30% an rt-gn Farbe/pin
    Wicklungswiderstand 11.5 Ohms : 1.3 kohms +/- 10%

    Is this of any use ?

  8. #8
    Join Date: Jan 2009

    Location: Essex

    Posts: 26,377
    I'm openingabottleofwine.

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    Quote Originally Posted by Chris View Post
    Hi Barry,
    The data sheet in german that Haufe gave me for my T-7833 capsules says :

    1:10
    Primary impedance 40 ohms
    Final impedance 47 Kohms
    primary Gauge 0.05V
    20 Hz-20Khz +/- 1db ref 1kHz
    1% (Klirrfaktor)
    6.8 kohm 1 khz+/-30% an rt-gn Farbe/pin
    Wicklungswiderstand 11.5 Ohms : 1.3 kohms +/- 10%

    Is this of any use ?
    Chris
    Given this information, your transformer will present a load of 470 ohms to your cartridge if the transformer is in turn loaded by the 47Kohms of the phono input of your preamplifier.

    I don't understand what is meant by 'Primary impedance 40 ohms'. Are you sure this is correct, and not a misprint? (Iwould expect it to read 470 ohms)

    I did a bit of a search for the recommended loading for the Linn Troika. The results areas follows

    > 10 ohms, Nominal 150 ohms, 560 ohms recommended
    http://www.gb2001.it/sez/area51/sond...alogue_addicts

    nominal 150 ohm, 560 ohm recommended
    http://www.n.mackie.btinternet.co.uk/linn/tlp12faq.html

    500 ohm
    http://www.diyaudio.com/forums/showthread/t-81459.html

    So it would seem that 470 ohms is about right.

    Regards
    Barry

  9. #9
    Join Date: Jan 2009

    Location: Essex

    Posts: 26,377
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    Default Haufe T-7833 transformer

    Chris,

    I think I am beginning to understand your (and my) confusion over the terms 'primary impedance: 40 ohm' and 'final impedance: 47 Kohms'. Can you tell me if they are written in German as 'Quellewiderstand' and 'Abschlusswiderstand' respectively?

    If so, then these are the source and loading impedances that the transformer will see, when in use. In this case the 'primary' impedance refers to the coil resistance of your cartridge and not to the impedance presented to the cartridge by the transformer, which will be 470ohm.

    If you want to reduce the imput impedance to less than 470ohm, then let me know and I'll advise you on the values of the resistors that you can fit across the secondary winding of the transformers.

    Regards
    Barry

  10. #10
    Join Date: Feb 2008

    Location: Canaries

    Posts: 190

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    Hi Barry, thanks for going to so much bother. Yes, the 40 ohms value refers to the "quellwiderstand" but the 47Kohms is the value for the "Lastwiderstand"
    You can check the data sheet here

    http://audio.kubarth.com/rundfunk

    Once here, go to "all the rest" in red, top left and then flick quite a way down to the Haufe T-7883.

    By all means please advise of the best way to adapt the Haufes to the Troika. I am very grateful for any suggestions.
    Chris

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