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Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Step Up Transformers inside the turntable?
Step Up Transformers inside the turntable?
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Old 19th May 2019, 12:29 PM   #11
EUVL is offline EUVL  Europe
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If you put the SUT at the end of the tonearm, and then the phono pre right next to it.
That must be the best solution, not ?


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Old 19th May 2019, 08:44 PM   #12
billshurv is offline billshurv  United Kingdom
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Step Up Transformers inside the turntable?
Quote:
Originally Posted by davidsrsb View Post
Typical LO MC impedance is close to most cable impedance

What do you consider to be a typical LO MC?
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Old 21st May 2019, 01:36 AM   #13
davidsrsb is offline davidsrsb  Malaysia
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The MCs designed for ~100R rather than 47k loading
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Old 21st May 2019, 01:54 AM   #14
cyto is offline cyto  United States
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Quote:
Originally Posted by davidsrsb View Post
The MCs designed for ~100R rather than 47k loading
It is a reflected impedance based on the turns ratio of the step up transformers.
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Old 21st May 2019, 08:09 AM   #15
billshurv is offline billshurv  United Kingdom
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Step Up Transformers inside the turntable?
Quote:
Originally Posted by davidsrsb View Post
The MCs designed for ~100R rather than 47k loading

I don't believe any MC is designed for 100R loading and the ones that are recommended to be loaded with that are generally under 10Ohms. I'm possibly missing something but how is that close to the impedance of a 50 or 75Ohm coax?
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Old 22nd May 2019, 03:53 AM   #16
davidsrsb is offline davidsrsb  Malaysia
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Strictly the impedance of coax or twisted pair is only valid at high frequencies, where jwL and jwC dominate R and G and the 50/75R values don't apply at audio frequencies.
In practice twisted pair is in hundreds of Ohms in the audio band, so not going to cause impedance errors if you extend a long cable from the MC cartridge to a 100R stepup transformer
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Old 22nd May 2019, 05:30 AM   #17
PRR is offline PRR  United States
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Quote:
Originally Posted by cyto View Post
...the very low MC output signal would be travelling a minimal distance....
It is low VOLTAGE, true.

It is higher available *current* than a MM needle.

The available *POWER* is about the same MC or MM.

To a first rough approximation, the interference or signal loss is about the same either way, almost, roughly. Not like either is "weaker", though they are both weak.

After all: when you run MC through a transformer (power out equals power in) you get "MM signal".

47k MM signals suffer from capacitance of "long" lines, and the 47k ballpark seems to assume 3 foot leads. (90pFd in cables, 90pFd grid capacitance, makes very nearly 47k at 20KHz.)

50 Ohm MM needles can drive thousands of feet of wire but ohmic losses may matter at 1000' of heavy wire or 100' of skinny wire. If we had a good low-hiss 50r active amplifying device this might not matter (its Zin may be much higher than 50r). If driving a transformer (because good low-hiss@50r devices are scarce) we may need to sharp-pencil the situation.

As said, there is 50/60Hz everywhere, in turntable and often in preamp, and this gets into the audio transformer.

Personally I think I would run the low-Z line out and let the SUT be in the preamp.
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Old 22nd May 2019, 08:11 AM   #18
billshurv is offline billshurv  United Kingdom
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Step Up Transformers inside the turntable?
Quote:
Originally Posted by davidsrsb View Post
Strictly the impedance of coax or twisted pair is only valid at high frequencies, where jwL and jwC dominate R and G and the 50/75R values don't apply at audio frequencies.
In practice twisted pair is in hundreds of Ohms in the audio band, so not going to cause impedance errors if you extend a long cable from the MC cartridge to a 100R stepup transformer

I am now more confused. The majority of LOMC are 3-12Ohms with outliers down to 0.1Ohm and up to 40 Ohm. I don't see where you are going.
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Old 22nd May 2019, 09:37 AM   #19
davidsrsb is offline davidsrsb  Malaysia
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The stepup transformer or most MC preamps present a 100R load to a LO MC as standard.
Adding a ~100R twisted pair between them still means that the cartridge sees 100R.
The cable would have to be very long before its loss and actual impedance became significant, far more than 10m.
Telephone pair cables work at kilometers before they need equalising
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Old 22nd May 2019, 09:39 AM   #20
billshurv is offline billshurv  United Kingdom
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Step Up Transformers inside the turntable?
That's not what you originally said or what I have questioned.
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