MC Cart Phono Stage Journey - amazing finding

[ohbythebay]

You guys will find this interesting...

A good phono stage is a must for anyone running an MC cart right? But what to get. You don't want something that is going to "color" the music, you want it to be a natural and NEUTRAL unit that will do its job - Bring the LOMC up to line level and pass on the signal untouched from its original quality without adding noise or subtraction of frequency. Pretty simple, right?

Not so much. SO many of the phono stages (mid level to low level) make assumptions about cart loading. Like 200 or 220pf fits all...NOT. Only higher end units give you selectable loading. Another drawback is how they have their own flavor, what they use for opamps, etc. Loss of detail may be a symptom. Loss of bass clarity. Mid loss. The list goes on.

Finally, there needs to be a synergy between cart and phono stage. I just witnessed a test on a phono stage where the poster tried various carts on the same stage (maybe 12?). It liked 9 or 10 of the carts and hated the others. Again this may be due to cart loading.

So my journey was in mid-lo fi..up to several hundred dollars on a phono stage. They fit my budget and matched what I had in equipment. I was not going to spend $800-$1000 on a phono stage for a $600 MC cart.

Well, I discovered synergy in the oddest of places that beats out anything I have heard INCLUDING a custom made phono stage made for my setup. I have gone back to this setup and I swear it sounds incredible.

It is an AT630 SUT (made in the 70's I think) that go for about $70 to $100 if you can find them - Into a $49 Art DJ Pre II. Laugh now...but this combo is killer.

First the SUT - It steps up the LOMC signal with zero noise, zero loss. It is the happy sister to any Audio Technica MC cart. Loading is perfect. I could then carry this in to my phono stage on my Marantz, but my table is a bit too far for that (doesn't have to be but it is) . So it goes to the ART DJ Pre II.

People have tried and tried to rag on the little ART but dang it all, it does what it is SUPPOSED to ...passes that signal and does not discolor, lose clarity, add noise, no drawbacks. The specs are incredible (especially for the price). And at least it lets you choose 200pf or 100pf loading. Not a wide range but SOMETHING and my cart prefers 100pf.

I have no doubt an $800 or higher phono stage would beat it (one would hope) but I don't need to spend that. and I spent $39 on mine before they raised the prices to a whopping $49...LOL

So maybe its just synergy of my system, but the noiseless, uncolored clarity and detail I hear is incredible. It also works well with a MM cart (no SUT needed first)...anyway..thanks for listening...

Specs and Pictures of the SUT and the Phono Pre

AT630Audio-Technica AT 630, Transformer for MC phono cartridges
Some technical data:
Manufacturer: AUDIO-TECHNICA, Japan
Input impedance: 20 ohms or less
Output impedance: 47 kohms
Gain: 20 dB
Frequency response: 15 Hz - 100 kHz
THD: 0.05%, 15 - 100000 Hz

ART DJ Pre II - ART Pro Audio
Signal To Noise Ratio > 90dB below clipping
Frequency Bands FILTER TYPE: Switchable, Low Cut, -3dB @22Hz
Maximum Gain 45dB @1KHz
Input Impedance 47k Ohms in parallel with either 100pF or 200pF
Maximum Input Level 40mVrms @1KHz
Maximum Output Level +6dBu (1.4Vrms)
Input Connectors RCA
Output Connectors RCA
Total Harmonic Distortion .01% Typical @1KHz
Frequency Response 10Hz -50KHz, +/-.5dB

 

[Myles B. Astor]

I am curious about your observation that capacitive loading affects the sound of your MC cartridge. Usually MCs are sensitive to resistive loading and MM and MIs to capacitive losding. In all my years, I've only heard one MC affected by capacitance. Perhaps there's something weird with your phono cable?

 

[ohbythebay]

I am curious about your observation that capacitive loading affects the sound of your MC cartridge. Usually MCs are sensitive to resistive loading and MM and MIs to capacitive losding. In all my years, I've only heard one MC affected by capacitance. Perhaps there's something weird with your phono cable?

Actually, its the opposite ...maybe I am mixing my terms but MC carts have preferred loading..I guess I should have said input impedance rather than loading....MM's are pretty much standard, 47K. Loading via Y cables and resistors in null RCA plugs is possible (for example if a cart tends to be bright)..but MC carts like different loads ..example of a high end unit with different settings for MM and MC:

Musical Fidelity - M1 ViNL - MM/MC Phono Stage-Audio Advisor

 

[Myles B. Astor]

Actually, its the opposite ...maybe I am mixing my terms but MC carts have preferred loading..I guess I should have said input impedance rather than loading....MM's are pretty much standard, 47K. Loading via Y cables and resistors in null RCA plugs is possible (for example if a cart tends to be bright)..but MC carts like different loads ..example of a high end unit with different settings for MM and MC:

Musical Fidelity - M1 ViNL - MM/MC Phono Stage-Audio Advisor

Sorry but you have it backwards. MCs can be loaded anywhere from around 40 ohms to 47 k-ohms. MCs are pretty much insensitive to capacitive loading, just the opposite of MMs. That's why even the phono cable cap needs to be considered with MMs.

Quoted from your Link:

"The M1 ViNL has extraordinary input flexibility. With MM moving magnet phono cartridges, it offers 47k or 68k input impedance. Input capacitance has seven values; 50PF, 100PF, 150PF, 200PF, 250PF, 300PF, 350PF, 400PF. This extraordinary flexibility means perfect matching for almost any MM cartridge.

The MC moving coil phono cartridge stage has ultra flexible input impedance switching, offering settings of 10R, 18R, 25R, 50R, 100R, 200R, 400R, 800R, 1600R and 47K."

Ergo 200 or 400 pf should have little or no effect on your AT.

And for MC cartridges, the rough guide for setting loading is about 10X the cartridge's internal impedance to provide optimal braking.

 

[ohbythebay]

The mistake I made was the term...INPUT IMPEDENCE. I said loading but that term is often used interchangeable. MC Carts are MORE sensitive to this than MM. Most MM's run at 47k RIAA and are never loaded different. Phono stage in receivers, 47k. MC carts vary in what they like and many MC Phono Stages default to 200r - 220 (200 - 220ohm) which is too high for some.

Example
The CA Azure 651P defaults to 220PF. No settings. Azur 651P Moving Magnet & Moving Coil Phono Pre-amplifier

Way too high for my AT OC9/III which prefers 100pf

Here is an MC Pre SUT that shows CART LOADING - note, this is for MC not MM
Pre Preamplifier | Elevator EXP | Graham Slee

More on MC cart loading
http://www.bobsdevices.com/Impedance.htm



Anyway, forgetting all of this...the setup works for me quietly and much better than products like the Azure

 

[Myles B. Astor]

The mistake I made was the term...INPUT IMPEDENCE. I said loading but that term is often used interchangeable. MC Carts are MORE sensitive to this than MM. Most MM's run at 47k RIAA and are never loaded different. Phono stage in receivers, 47k. MC carts vary in what they like and many MC Phono Stages default to 200r - 220 (200 - 220ohm) which is too high for some.

Example
The CA Azure 651P defaults to 220PF. No settings. Azur 651P Moving Magnet & Moving Coil Phono Pre-amplifier

Way too high for my AT OC9/III which prefers 100pf

Here is an MC Pre SUT that shows CART LOADING - note, this is for MC not MM
Pre Preamplifier | Elevator EXP | Graham Slee

More on MC cart loading
impedance matching moving coil mc cartridge impedance ratio SUT Step-up Transformers for MC Moving Coil Cartridges CineMag Altec Sowter UTC Western Electric Newcomb TBB-103 4722 15095 15095A Bob's Devices



Anyway, forgetting all of this...the setup works for me quietly and much better than products like the Azure

Thanks am more than aware.

 

[ohbythebay]

Thanks am more than aware.

Maybe I am not aware Myles, am I confusing things here ?..seriously, maybe I am misunderstanding how the whole loading/impedance thing works...I can be WRONG...(lol)

You seem like you know what you are talking about so if I am off base, educate me. This is not debate, this is a genuine request to learn...Thanks