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Thread: step up transformers and active head amps

  1. #1
    Join Date: Jan 2008

    Location: Los Angeles, USA

    Posts: 2
    I'm Warren.

    Default step up transformers and active head amps

    What MC step ups and head amps has anyone tried, and what differences did they hear? I have 4 transformers and 3 head amps now, doing comparisons, and ulimately confusing myself about which I like best.

  2. #2
    Join Date: Jan 2008

    Location: Ledegem Belgium

    Posts: 86

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    Could you tell us which preamps (and the rest of your amplifying chain) you have? And, of course which cartridge!

    John

  3. #3
    Join Date: Jan 2008

    Posts: 505

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    Quote Originally Posted by WarJarrett View Post
    What MC step ups and head amps has anyone tried, and what differences did they hear? I have 4 transformers and 3 head amps now, doing comparisons, and ulimately confusing myself about which I like best.
    Ever tried the Supex 'SDT-722' step up transformer, never tried it myself.

  4. #4
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

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    Guys,

    This is a subject dear to my heart - I'll get to it later!

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


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  5. #5
    Join Date: Jan 2008

    Posts: 505

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    Mayware 'T24' Transformer which uses a technique called 'reflected shunt equalisation' which uses a low inductance transformer enabling the use of carts from 2-40 Ohm.Has user changeable tappings ( Not really a good thing, but!)This was one of my best trannies regardless..
    gain varies from 30dB for 2/3 Ohm to 20dB for 40 Ohm carts..I did use this with the Mayware 'MC-7V' cart to superb effect.Superb dynamics also.Just another one of my past exploits...Funny how we de-grade as we up-grade!
    Last edited by Vinyl Grinder; 23-01-2008 at 02:09.

  6. #6
    Join Date: Jan 2008

    Location: South West England

    Posts: 958
    I'm Guy.

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    I'm developing an odd fascination with MC impedance matching transformers. This is particularly strange as the cartridge I use (Audionote Io) dictates the use of a very high ratio (100:1) transformer and the only people to make such a device are Audionote or Kondo. I found some loose transformers from the old silver wired Audionote Japan S6 on ebay which I put into a box and which suit that cartridge perfectly. Kondo still makes a version of this called the SFz (v. expensive) as do ANUK with several models.

    ANS6


    Internal View


    Loose transformers


    So why the interest in others?

    There were many different manufacturers of high quality studio equipment in the 50's and 60's. Most of these produced (or had produced) microphone matching transformers which facilitated the use of low impedance microphones with high impedance inputs. People have realised that these are applicable to use with MC cartridges and the prices of these loose transformers is creeping up. Models such as those by Altec, peerless, Jensen, RCA, UTC, Dukane all offer outstanding performance and are relatively simple to wire into a chassis. I recently bought a pair of Dukane 3A25's for a few pounds. These gave glorious results with an AT OC9 that I'd never previously wanted to listen to for more than a few minutes at a time.

    Dukanes



    A friend has some UTC A10's and has just bought a pair of the danish Jorgen Schou transformers which I'm keen to hear. It seems that the core materials used in the laminations as well as the winding techniques used (particularly in some of these older designs) can really preserve an incredible depth of tone from an MC cartridge in a way that wouldn't have seemed possible based on listening to the cartridge under normal circumstances.

    Have a look here for more inspiration

    http://members.myactv.net/~je2a3/mic-mcstep-up.htm

    Keep an eye out for auctions like this.
    http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=018


    From the Pure Sound point of view, I've found a European supplier of a goodish quality 1:15 transformer which would certainly do for most newcomers to the joys of MC's and which would go well with our phono stage.

    I've also found a UK transformer supplier who can make me some custom wound 'specials' with fancy core material and winding arrangements. The only problem with these is the outlay involved and the fact that they would cost half as much again as the phono stage we make! For me its not a problem as I appreciate the difference a good transformer can make but whether there's really much of a market for a £600-700 transformer remains to be seen.
    Last edited by pure sound; 23-01-2008 at 11:04.

  7. #7
    Join Date: Jan 2008

    Location: Ledegem Belgium

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    If there's a good set up with a (mostly expensive) MC cartridge that price is not a problem. A problem though is the quality of the transformer, the shielding and the room it takes. In the past a transformer had the advantage, over tube and transistor amps, of a low noise level. But that time is past! Nowadays it's easy to construct a MC preamp with a noise level of -75 dB at 0,3 mV//100 Ohm.

    John

  8. #8
    Join Date: Jan 2008

    Posts: 505

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    Quote Originally Posted by johnrtd View Post
    If there's a good set up with a (mostly expensive) MC cartridge that price is not a problem. A problem though is the quality of the transformer, the shielding and the room it takes. In the past a transformer had the advantage, over tube and transistor amps, of a low noise level. But that time is past! Nowadays it's easy to construct a MC preamp with a noise level of -75 dB at 0,3 mV//100 Ohm.

    John
    Maybe so John but they do not sound as good.As is nowadays.

  9. #9
    Join Date: Jan 2008

    Location: Ledegem Belgium

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    Dear Vinyllist
    Nothing is perfect. And every configurattion has it's advantages and disadvantages. So there are always some kind of consessions when designing an item.
    Now let's have a look at some of the possible (!) qualities of both.

    The step-up transformer:
    1. It's passive so there's hardly any non-linear distortion
    2. Bandwidth is ALWAYS limited
    3. A good one is relatively big and needs space
    4. It's supsceptible for "fields"

    The active solution:
    1. Distortion can be very low, around <0,01%
    2. Bandwidth is wider then any vinyl record holds
    3. If the "lay out of the PCB" is okay no shielding is needed
    4. It needs a power supply and that supply should not be coupled with the RIAA pre-amp thereafter.

    In the end it all comes at a price. A good MC step-up transformer will cost >1500 € and an active MC pre-amp, including RIAA, comes at around the same price. At present we offer a complete pre-amp kit, without the cabinet, for 895 €.
    Music is an emotional experience. Without it, living would be a dull habit...

  10. #10
    Join Date: Jan 2008

    Posts: 505

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    John

    A precisely matched high grade step up transformer is far superior to any MC stage. Fact!

    I can see your trying to sell your products, but please put that aside..

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