Moving coil phono?

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robinje

Moving coil phono?
« on: 24 Oct 2008, 02:34 pm »
Hey, Frank...  Do you intend to ever produce a low output moving coil phono preamp?  Surely, you could produce something superior to a vast majority of available step-up transformers and head amps on the market.  Just curious...

JerryM

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Re: Moving coil phono?
« Reply #1 on: 25 Oct 2008, 01:53 am »
rob,

I may be wrong, but I'm thinking Frank has offered these for quite some time. From Insight to Ultra with a Transcendence in between. Check it out: http://www.avahifi.com/root/equipment/phono_preamplifier/index.htm
As RIAA Phono Preamps, Frank specifically states that each will work with a moving coil set up.

Score!!!   :thumb:

Have fun,
Jerry

dB Cooper

Re: Moving coil phono?
« Reply #2 on: 25 Oct 2008, 03:26 am »
From the link:

All AVA RIAA phono preamps are suitable for any normal output phono cartridge, head amp, or moving coil step-up transformer.

It can be used with head amps and step-ups; it doesn't act as either of those. From the old Audio Basics, I seem to remember Frank  being not particularly a fan of MC cartridges in general.

robinje

Re: Moving coil phono?
« Reply #3 on: 25 Oct 2008, 03:52 am »
From the old Audio Basics, I seem to remember Frank  being not particularly a fan of MC cartridges in general.

Okay, so maybe that explains why AVA doesn't have step-up transformers or sufficient active circuit gain in the existing AVA phono preamps to accomodate low output moving coil cartridges.  I guess those folks wanting to explore this realm of vinyl experience are forced to employ 3rd party (non-AVA) means to get low output moving coils to work with AVA equipment.  That's unfortunate, because without a doubt Frank and crew have the expertise to build this type of circuitry, more than likely in a superior manner to many of the existing alternatives currently available.  On the other hand, there currently seems to be quite a few choices of apparently fine sounding, relatively inexpensive moving magnet and moving iron cartridges available with sufficient output to drive an AVA phono preamp.  I guess if there weren't so many of these cartridges available, it would be more of an issue. 

JerryM

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Re: Moving coil phono?
« Reply #4 on: 25 Oct 2008, 09:15 pm »
From the old Audio Basics, I seem to remember Frank  being not particularly a fan of MC cartridges in general.

Okay, so maybe that explains why AVA doesn't have step-up transformers or sufficient active circuit gain in the existing AVA phono preamps to accommodate low output moving coil cartridges.  I guess those folks wanting to explore this realm of vinyl experience are forced to employ 3rd party (non-AVA) means to get low output moving coils to work with AVA equipment.  That's unfortunate, because without a doubt Frank and crew have the expertise to build this type of circuitry, more than likely in a superior manner to many of the existing alternatives currently available.  On the other hand, there currently seems to be quite a few choices of apparently fine sounding, relatively inexpensive moving magnet and moving iron cartridges available with sufficient output to drive an AVA phono preamp.  I guess if there weren't so many of these cartridges available, it would be more of an issue. 

rob,
Once again, I may be wrong and correct me if I am, but Frank offers a full selection of RIAA Preamps.
RIAA is a standard. Kinda like ANSI or ASME. Each of AVA's phono preamps are listed as capable of preamping a moving coil cartridge. Presumably, this means a moving coil cartridge that meets RIAA standards.
If one is to R&D and build to a non-standard, to which non-standard should one build? This nears factory one-offs.
If your MC set up meets RIAA standards, I'm thinking Frank's preamps will work just dandy. If your MC does not, why?  :dunno:
Seriously, I'm kinda curious,
Jerry

Panelman

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Re: Moving coil phono?
« Reply #5 on: 25 Oct 2008, 10:41 pm »

Jerry, the issue isn't the RIAA standard but rather the output level of the cartridge. I used a high output MC(Dynavector 10X5) with my AVA T6 preamp and the combination worked just fine. However that cartridge is a high output MC at 2.5mv and many MCs have much less output. With a low output MC and no step-up transformer the sound level using a AVA phono preamp may not be loud enough for normal listening levels. There are many quality MC step-up transformers that can feed the AVA phono section.

Sean

JerryM

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Re: Moving coil phono?
« Reply #6 on: 26 Oct 2008, 12:31 am »

Jerry, the issue isn't the RIAA standard but rather the output level of the cartridge.
Sean

Sean,
Thanks for the reply.
But when dealing within the parameters of the RIAA standard, what is the nominal input level from any cartridge feeding a RIAA phono preamp? It's standardized, isn't it? When dealing outside of this standard, what exactly should a phono preamp be capable of? I'm guessing it would be to bring the non-standardized signal back to some recognized standard.
Questions: What non-standard should a designer/builder aim to achieve? Could you imagine digital formats without the Redbook standard? Does music sound better from a device that cannot properly provide RIAA specified nominal input into a phono preamp? Does music sound better if you run it through another device first to achieve the standard level of normal RIAA output/input?
I think once one steps away from recognized industry standards one cannot expect a designer/builder to jump head long into the fold. You're talking one-off, or so.
What sonic benefit is realized by operating a MC cart outside of the RIAA specs for output to a phono pre?
Just curious,
Jerry

robinje

Re: Moving coil phono?
« Reply #7 on: 26 Oct 2008, 01:12 am »
Ummm...  you've completely lost me.   :scratch:

My original inquiry was whether or not AVA intends to ever consider building a phono stage to accomodate a low output moving coil cartridge directly without the need for external transformers or head amps. 

Panelman

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Re: Moving coil phono?
« Reply #8 on: 26 Oct 2008, 03:13 am »

Robinje, did not mean to hijack your thread with a discussion of the RIAA equalization curve.

JerryM,

The RIAA curve is used to create a flat response from the phono output not to specify a minimum output value from the cartridge.   

Sean

avahifi

Re: Moving coil phono?
« Reply #9 on: 26 Oct 2008, 11:18 am »
Panelman is correct, the RIAA curve is about frequency response, not gain.

We do not build a step up device for low output moving coil cartridges because the choice of active devices that we favor for outstanding linearity and dynamic range simply are not quiet enough for that task.  Trying to get an additional 20 dB of gain for low output cartridges requires playing around near the noise floor of the devices and design compromises favoring low noise over linearity.  We don't do this because there are so many relatively inexpensive normal gain cartridges available.

If you must use a low gain moving coil cartridge, we suggest using a step up transformer ahead of our phono section for best results.

Regards,

Frank Van Alstine

Wayner

Re: Moving coil phono?
« Reply #10 on: 26 Oct 2008, 11:22 am »
I just wanted to add that Frank's phono section works really well with high-output moving coil. I run a Sumiko Blue Point Special (2.5mv) with absolutely no problem, but probably wouldn't go with a cartridge with much lower output.

Wayner  8)

Wayner

Re: Moving coil phono?
« Reply #11 on: 26 Oct 2008, 11:23 am »
 aa

avahifi

Re: Moving coil phono?
« Reply #12 on: 26 Oct 2008, 11:34 am »
What are you doing up so early in the morning Wayne?

Frank



Big Red Machine

Re: Moving coil phono?
« Reply #13 on: 26 Oct 2008, 12:02 pm »
Don't you guys sleep?  I had to let the dog out so I have been up.  Not sure which is worse; the cat crying to be fed or the dog moaning to be let out!


Wayner

Re: Moving coil phono?
« Reply #14 on: 26 Oct 2008, 12:19 pm »
I couldn't wait to turn the AVA stuff on and start listening! Were going to Spicer for brerakfest if anyone is interest. Bus leaves at 8:00.

Wayner :lol:

robinje

Re: Moving coil phono?
« Reply #15 on: 26 Oct 2008, 01:17 pm »
Panelman is correct, the RIAA curve is about frequency response, not gain.

We do not build a step up device for low output moving coil cartridges because the choice of active devices that we favor for outstanding linearity and dynamic range simply are not quiet enough for that task.  Trying to get an additional 20 dB of gain for low output cartridges requires playing around near the noise floor of the devices and design compromises favoring low noise over linearity.  We don't do this because there are so many relatively inexpensive normal gain cartridges available.

If you must use a low gain moving coil cartridge, we suggest using a step up transformer ahead of our phono section for best results.

Regards,

Frank Van Alstine

Thanks!  That's the explanation I was looking for...   :D