I am not sure I properly appreciate MM, but clearly need to give them another go. My last MM play of a record was early 1988. Putting preference aside, so far we have had no solid evidence of why MC should be superior.
I clearly need a new test record. At this rate will have to ignore posts by SY as he costs me money!
My last MI was a Grado Reference Platinum and I much prefer my SPUs to that and the Benz Ebony H I really just ought to sell.
an ebony would look really nice on my main rig. and I know that knowing it was a model up from mine would make it sound better.
As soon as I am in a position to give you a sensible offer I will! Sadly that will not be for a while yet 🙁
Yes. The trick is that, once you account for the cable capacitance, the input C has to be really, really low. That's what led me to the Equal Opportunity preamp design.
My turntable (Roksan Xerxes) actually has a cutout for a factory phono module headamp to slide in. I had always thought that a good idea for noise and hum pickup reasons, but not considered the capacitance. Just checked the arm and total C for all cables is listed at 155pF, which compared to the cable specs gives 50pF in the connectors, which doesn't feel too wrong. Cable is twinax so I have the ability to run balanced as well.
hmmm food for thought.
hmmm food for thought.
I used to have an AT125LC which I quite liked, until someone's child got curious and snapped the lovely tapered cantilever. 🙁 It was at a time in my life when I couldn't afford the replacement stylus (which cost more than I had paid for the cartridge). A friend gave me a Grado, and I almost stopped listening to records.
I still have a Signet (made by AT) TK7E, which I would still be using if I hadn't gone over to the other side (Denon DL-311LC). They all sound good, except the Grado.
Two cheap'n'cheerful MM's I have owned were an Empire 2000-eIII and an Ortofon F15e. Both sounded better than they had any right to!
I bought the Leach jfet preamp in the 1970s because Dr. Leach claimed the input capacity was 20pF. That was believable because the fets have about 3pF Cgd and the jfets had about a gain of about 4 with that load resistor. This was a case where the low jfet transconductance was useful. I had a Shure V15V high inductance cartridge and the calculated load capacity for critical electrical damping with 47k was only 60 pF. That is probably less capacity than is in the cartridge equivalent shunt capacity and tone arm wiring.
http://users.ece.gatech.edu/mleach/papers/wbpreamp/feb77article.pdf
http://users.ece.gatech.edu/mleach/papers/wbpreamp/feb77article.pdf
I've only owned a few MC's in the past, but in my findings none of them were particularily good trackers. While all exhibited an added sparkle to the sound I could never get them to faithfully track the inner grooves well. MM overall is much more affordable and while they may not have the frequency extension of many MC's a good MM will generally be a much superior tracker all across the record with their higher compliance. I personally value tracking ability and it's ability to read with sure footing in the groove over the resonant air of MC. With a well engineered stylus and optimized loading I've been shocked at what MM cartridges can do sonically 🙂.
Colin
Colin
Interestingly one cannot take it for given that a MM phono preamp has automatically a low input capacitance.
The popular pearl phono preamp, for example, has a rather high input capacitance (4x K170 in parallel with cascode) of about 120pF or so. Adding the standard 100pF/m phono leads and the cartridge sees already 250pF or so without any loading cap installed. Way too much for the AT150's, but pretty perfect for a V15VxMR.
PS: SY - you should have a good look at the AT150ANV.
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The same with all the variations of the old RCA Manual and the Dynaco/Marantz/Audio Research preamps. High gain input devices generally mean high input C. Cascoding can help that at the expense of other design/performance issues (e.g., PSR). Buffering the input gets rid of the problem but then there's a noise trade-off.
Adding input cap switching capability (which one commonly sees in commercial designs) is fine as long as the user knows what the baseline is- but usually, he won't.
The cartridge-preamp interface is the biggest obstacle to high performance with MMs.
Adding input cap switching capability (which one commonly sees in commercial designs) is fine as long as the user knows what the baseline is- but usually, he won't.
The cartridge-preamp interface is the biggest obstacle to high performance with MMs.
I don't know what I am doing right, but I have never had an MC mistrack and I have some audiophool extravaganzas with serious modulation.
Great Thread
So, how does one go about properly measuring the input capacitance that the cartridge will see?
I am getting close to putting my AT440mla back in action and figured I should at least get it loaded correctly.
What kind of meter or instrument can one use (or reliably get away with)
Meaning, I dont have a parameter analyser sitting around here at home.
Come to think of it, I dont have any way of measuring capacitance, not even with one of the hand held meters I have here.
Gonna have to buy something I guess.
Does input capacitance vary with frequency, or at least the frequencies we are dealing with here for phono?
Ive got a few preamps but the one I was going to use was the Pearl 2 that I built from Pass DIY boards.
Many thanks
Curt
So, how does one go about properly measuring the input capacitance that the cartridge will see?
I am getting close to putting my AT440mla back in action and figured I should at least get it loaded correctly.
What kind of meter or instrument can one use (or reliably get away with)
Meaning, I dont have a parameter analyser sitting around here at home.
Come to think of it, I dont have any way of measuring capacitance, not even with one of the hand held meters I have here.
Gonna have to buy something I guess.
Does input capacitance vary with frequency, or at least the frequencies we are dealing with here for phono?
Ive got a few preamps but the one I was going to use was the Pearl 2 that I built from Pass DIY boards.
Many thanks
Curt
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