2. analog
  3. 126327-1998

Coincident phono stage - cartridge compatibility (EMT)?

I've got the Coincident phono stage and can't say enough good things about it. Currently running a Miyajima Kansui which sounds wonderful, but I'm feeling the itch for a bit more gain and dynamic punch. I've got my eye on the EMT carts, sound like exactly what I'm looking for, but am a bit nervous about the fact they've got a whopping 1.0mV of output (22 ohms internal impedance), while the Coincident has a total gain of 66dB.

So, my question might really be a technical one about compatibility. I read on Arthur Salvatore's blog that the on-board SUTs of the Coincident have a gain of 26dB, which might imply a 1:20 turn ratio. That, in turn, would imply a full 20mV going into the phono stage with the EMT, which seems like an awful lot. That said, an old review by Jeff Dorgay seemed to yield good results from the 0.9mV Clearaudio Goldfinger.

So, I suppose I'm mainly looking for thoughts on whether the EMT-Coincident combo would be just dandy, and if so, why should I not worry (e.g. - super-high voltage overload threshold)? Or, is it to be avoided because of potential overload, despite the Coincident's switchable impedance settings? (There appears to be a contingent that insists on the EMT being coupled with the special A23 SUT, noting that the EMT was originally coupled with an SUT with a 1:8 turn ratio, I believe.)

If the answer is the latter, open to alternative suggestions for other cartridges that mate well with the Coincident and which pack dynamic punch. Thanks in advance!
128x128cfluxa
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cfluxa's avatar
cfluxa OP
127 posts
 
A belated thanks to all of you for the thoughtful responses. I will indeed query Mr. Blume, armed with your insights, and report back.
lewm
13,095 posts
 
I just read a review of the Coincident and something about the specs.  This seems to be a dedicated MC phono stage, despite any pretext about using an MM cartridge with it.  There does not seem to be any way to bypass the built-in SUTs, in other words.  Then, as regards the 66 db of gain as claimed, I see that on the rear panel there is a 5 or 6-position switch to select for loading an MC cartridge.  When the input impedance is thus varied, I would normally assume it works by varying the turns ratio of the SUT, as seen by the cartridge output.  But if that is the case, then total gain is also going to vary depending upon the position of that selector.  Alternatively, I suppose it is possible that the selector switches among various discrete resistors soldered across the secondaries of the SUT, thereby altering impedance while holding gain constant.  This is a not so fine distinction that you might want to make if you have a conversation with Israel Blume.  And finally, the 5 cm/sec standard for stating cartridge output is relatively new on the scene; in the good old days, the velocity at which cartridge output was measured was 3.54 cm/sec.  By that standard, the EMT output is not so so high, at around 0.7mV.  But 66 db of gain is substantial even for that much output.  I agree with Almarg; you probably should have a conversation with IB.
nandric's avatar
nandric
4,086 posts
 

cfluxa, Your SUT's are the added amplification to your MM stage.

Your MM stage must be very good; the SUT's can't improve

mediocre MM stage. Besides each added amplification adds to  the

distortions. It is curious that you can't bypass the SUT's.

Otherwise you would own both MM and MC phono-pres.

Consequently the EMT in combination with the MM stage may

sound better than with added SUT's.

 


almarg's avatar
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almarg
9,670 posts
 
The phono stage is indicated as having an overall gain of 66 db and a maximum output capability of 30 volts.  66 db corresponds to a voltage gain of 2000x, which would seem to say that the phono stage can handle an input voltage of 30/2000 = 15 mv.  That would provide an overload margin of about 15x relative to the cartridge's specified nominal output, which certainly seems comfortable.  (As I understand it a margin of 10x or more is considered to be ideal, and somewhat less than that will be adequate with most recordings).

However, depending on the gains and sensitivities of the rest of your system I would have some concern that you **might** be forced to use the volume control on the phono stage and/or the volume control on your preamp or integrated amp (if your system includes either of those) at undesirably low settings.  Also, I have no knowledge as to whether the resistive load choices that are provided by the phono stage would be optimal with the particular combination of cartridge and phono stage.

A communication with Mr. Blume of Coincident would seem to be in order, if you already haven't done that.

Good luck.  Regards,
-- Al
 
cfluxa's avatar
cfluxa OP
127 posts
 
Nandric - thanks for the response. the .21mV spec you cite is indeed at 1 cm/s, which equates to 1.05mV at 5cm/s, which is the more typical standard of measurement in the US. My concern is that this looks like a big bite for the typical MC phono stage, hence my question. 

There's no way to bypass the included SUTs here, and I wouldn't want to in any case, so magical are their virtues. A key question, perhaps, is whether the Coincident's 41-lb power supply obviates any concerns about overload from what could be a 20mV signal coming from the SUT?


nandric's avatar
nandric
4,086 posts
 

We obviously assume that the carts outputs satisfy some universal

''norm'' or rule. This is not the case. In this sense the output depends

from the used test records. According to EMT own user manual

the output of the most EMT carts is 0,21 mV. According to what

we are used to : 1 mV.  So you can probaly use your phono-pre

without the included SUT(s). 

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