Capacitance loading question

[Puma Cat]

Jeff:

I admittedly don't know much about things like loading for cartridges either. I know that MM cartridges like to see an impedance of 47K ohms, and if I understand it, are more sensitive to capacitive loading than MCs. Is the converse true for MCs, where they are more sensitive to impedance loading and less sensitive to capacitance or???

Just trying to determine what the optimal loading for my Koetsu would be.

Thanks,
Stephen aka PC

[Removed]

Originally Posted by Puma Cat

Jeff:

I admittedly don't know much about things like loading for cartridges either. I know that MM cartridges like to see an impedance of 47K ohms, and if I understand it, are more sensitive to capacitive loading than MCs. Is the converse true for MCs, where they are more sensitive to impedance loading and less sensitive to capacitance or???

Just trying to determine what the optimal loading for my Koetsu would be.

Thanks,
Stephen aka PC

Puma Cat......yes your pretty much correct with MM cartridges and with MC cartridges a good place to start with loading MC cartis is mulitiply the internal impedance by a factor of 10.......I think your Koetsu has a internal impedance of 5 ohms so I would start at around 50 ohms and go up from there......try it wide open too. If you find the Koestu needing a bit more sparkle load it higher, it really is what you like in sonics.

[Puma Cat]

Originally Posted by A/V Solutions

Puma Cat......yes your pretty much correct with MM cartridges and with MC cartridges a good place to start with loading MC cartis is mulitiply the internal impedance by a factor of 10.......I think your Koetsu has a internal impedance of 5 ohms so I would start at around 50 ohms and go up from there......try it wide open too. If you find the Koestu needing a bit more sparkle load it higher, it really is what you like in sonics.

Thanks, Jeff,
When you say try it wide open, what exactly do you mean? The plan is to plug my Cinemag SUT into my EAR and use the MM setting, which will give me 47 k ohms, is that what you mean by "wide open"?

I am trying to find out what the impedance is in the EAR834 MC circuit, I've read that Stereophile tested it around 530 ohm, whereas Dan Meinwald of EAR USA says that it is 100 ohm, regardless of what Atkinson's tests showed. I imagine that the SUT contributes a bit of impedance as well?

I'm wondering if I go into the MM circuit of the EAR, I should have the impedance of that changed to give 100 ohms, which is what I've read is optimal for Koetsus. I can have Scott Frankland of MFA/Wavestream mod my EAR to provide optimal loading in combination with the SUT.

Where do you get the USB microscope and how do you measure SRA accurately?

Thanks,
Stephen.

[Removed]

Originally Posted by Puma Cat

Thanks, Jeff,
When you say try it wide open, what exactly do you mean? The plan is to plug my Cinemag SUT into my EAR and use the MM setting, which will give me 47 k ohms, is that what you mean by "wide open"?

I am trying to find out what the impedance is in the EAR834 MC circuit, I've read that Stereophile tested it around 530 ohm, whereas Dan Meinwald of EAR USA says that it is 100 ohm, regardless of what Atkinson's tests showed. I imagine that the SUT contributes a bit of impedance as well?

I'm wondering if I go into the MM circuit of the EAR, I should have the impedance of that changed to give 100 ohms, which is what I've read is optimal for Koetsus. I can have Scott Frankland of MFA/Wavestream mod my EAR to provide optimal loading in combination with the SUT.

Where do you get the USB microscope and how do you measure SRA accurately?

Thanks,
Stephen.

Puma Cat......47K is wide open YMMV though

I had the 834 and it was nice but didn't allow the flexibility.......if you mod it then your locked into fewer cartridges......you can go the SUT route but it will be hit or miss. Honestly I would spend the money on a phono stage that had flexibility.....

Contact Mitch Singerman he is the expert on EAR (310) 823-5145

Dino-Lite--Digital Microscope

Buy one that zooms to at least 200x.....also get the goosneck stand

When you measure for SRA your adjusting the angle of the stylus to be approx. 90-92 degrees in relation to the LP or there abouts.......so adjusting VTA effects SRA......starting out the arm level just puts you in the ball park but very seldom the optinum position.

What I do is position the USB microscope at the stylus so I have a nice shot on the lap top, then use a protractor to get my adjustment closer.......Fremer did a write up in the June issue last year when he had the Ortofon A90 in for review......there is some good info on the microscopes there.

Here is the info I posted awhile back

Michael Fremer discusses VTA, SRA in June 2010 Stereophile.....

[Tonepub]

But doesn't the EAR already use a transformer for the MC input? So why get another one for the MM input?

[Puma Cat]

Originally Posted by tonepub

But doesn't the EAR already use a transformer for the MC input? So why get another one for the MM input?

Yes, but the step-up on the EAR is not sufficient to get a voltage into the EAR that is in it's optimal functional range for the preamp section. The Vermilion is a 0.2mV output (unlike your Blue which is 0.4mV), and the 1:10 SUT on the EAR provides 20dB of gain, which gets the voltage coming in to the phono gain stage only to 2.0mV. The RIAA equalization standard is based on a spec of 5.0mV of gain, and the recommendations I've discovered from articles by Bob Sattin of Bob's devices is that you want the input voltage coming into your phono stage to be at a minimum, higher than 2.5mV to avoid S/N problems and no more than 10mV to avoid clipping/headroom problems. The ideal target voltage would be right about 5 mV per the RIAA spec, and I am 2.5X below that with the step ratio of the transformers in the EAR. The 1:30 SUT should get well into the range of input voltage I need for the gain stage in the EAR...

This from my correspondence with Bob:
"The EAR hasa 1:10 step up (20db) which will bring your effective output to 2.0mV which is below the sensitivity floor of the preamp circuitry in the EAR. Ipersonally owned the Urishi Vermillion and it was my cartridge of choice. I was able to try out many SUTs with it. I ended up using the CineMag with
it. It works best with 1:30 (30dB) which gives the best balance between voltage output and impedance loading."

[Puma Cat]

Originally Posted by A/V Solutions

Puma Cat......47K is wide open YMMV though

I had the 834 and it was nice but didn't allow the flexibility.......if you mod it then your locked into fewer cartridges......you can go the SUT route but it will be hit or miss. Honestly I would spend the money on a phono stage that had flexibility.....

Contact Mitch Singerman he is the expert on EAR (310) 823-5145

Dino-Lite--Digital Microscope

Buy one that zooms to at least 200x.....also get the goosneck stand

When you measure for SRA your adjusting the angle of the stylus to be approx. 90-92 degrees in relation to the LP or there abouts.......so adjusting VTA effects SRA......starting out the arm level just puts you in the ball park but very seldom the optinum position.

What I do is position the USB microscope at the stylus so I have a nice shot on the lap top, then use a protractor to get my adjustment closer.......Fremer did a write up in the June issue last year when he had the Ortofon A90 in for review......there is some good info on the microscopes there.

Here is the info I posted awhile back

Michael Fremer discusses VTA, SRA in June 2010 Stereophile.....

Jeff, did you get the Dino-Lite AM3013T or the AM413T for your microscope? My understanding is you need one of the "13T"-model series to get the measurment/calibration software to do the SRA measurement.

Thanks,
Stephen.

[Removed]

I got the AM3013T

[jdandy]

Jeff.......I did as you suggested and moved the tracking force for the 2M Black from 1.5 grams to 1.7 grams. I also took Fremer's suggestion of using a jeweler's loop and a bright flash light and was able to see my Shibata stylus rake angle quite clearly. Surprisingly I am extremely close, if not right on 92 degrees to the record surface. The loop was a huge help, and a nice tip from MF.

I have adjusted the capacitance for the phono stage on my C1000P preamp to 50 pf, and with the 300 pf of the Wireworld Silver Eclipse interconnects the 2M Black is loaded with 350 pf. That's a bit high, so I am going to look for some lower capacitance interconnects. I think I would prefer to be in the area of 250 pf total load capacitance.

Thanks for you help.

[Formerly YB-2]

Great thread and very informative links. Gotta luv Mikey's comments. Take no prisoners. Am guessing he didn't sell any subscriptions to Stereophile to those two. Might have to join another forum or two. Unless I've misread, the optimized fine line contact stylus on my SoundSmith retipped DL303 will benefit significantly with proper setting of the SRA. Now I'll have to get a USB microscope and drag a computer somewhere near the vinyl rig. Ah, well. Perhaps that will provide the impetous to get me started on getting that Logitech Touch and RAID and start ripping my LP & CD collection. Just upgraded my phono preamp (thanks Jeff), so was thinking I could simply relax and clean some vinyl and do so heavy-duty listening. It never ends.