Low-output vs. high-output moving coil cartridges - is the former really better?

[SIY]

But should we really consider wacky designs that have such flaws as hundreds of pF of Miller capacitance?

Dynaco, Marantz, Audio Research, Vendetta... then add in the cables.

 

[Michael Fidler]

Dynaco, Marantz, Audio Research, Vendetta... then add in the cables.

Which Marantz in particular? Even the Seven has a very low anode signal voltage, due to the wonders of negative feedback.

 

[SIY]

Which Marantz in particular? Even the Seven has a very low anode signal voltage, due to the wonders of negative feedback.

View attachment 413895

I measured the 7's circuit at slightly over 100pF. The Audio Research is almost the same circuit, but they actually added a couple small caps. Dyna pretty much the same as Marantz minus the cathode follower.

 

[Michael Fidler]

I measured the 7's circuit at slightly over 100pF. The Audio Research is almost the same circuit, but they actually added a couple small caps. Dyna pretty much the same as Marantz minus the cathode follower.

OK, but that's fine for most MM cartridges. I'm not sure what we're contending here!

I would say we shouldn't consider anything with more than a couple of hundred pF.

 

[SIY]

OK, but that's fine for most MM cartridges.

Barely, with the Marantz circuit. AR is significantly worse, ditto Dyna (the positive feedback they used to boost the marginal open loop gain didn't help). But you have to also add the cables... You can make this work with a V15 or 681EE, but with a 150MLX, it's very, very difficult to get preamp plus cables to be as low as the 150pF it requires (cables alone tend to be in the 100pF or a little higher range). Thus its (undeserved) reputation for being "bright."

Edit: the MM preamp I ended up using with the 150MLX had an input capacitance of about 15pF. I could have lowered it a bit by cascoding the source followers, but 15
pF was good enough considering the lowish capacitance of the balanced cables I used.

 

[sq225917]

While it's interesting looking at gain and noise, why not include distortion, after all that extra mass resisting stulus input has to have some downsides. Surely

 

[Michael Fidler]

While it's interesting looking at gain and noise, why not include distortion, after all that extra mass resisting stulus input has to have some downsides. Surely

But wouldn't that be reflected in the frequency response and channel tracking issues, if it were significant?

Barely, with the Marantz circuit. AR is significantly worse, ditto Dyna (the positive feedback they used to boost the marginal open loop gain didn't help). But you have to also add the cables... You can make this work with a V15 or 681EE, but with a 150MLX, it's very, very difficult to get preamp plus cables to be as low as the 150pF it requires (cables alone tend to be in the 100pF or a little higher range). Thus its (undeserved) reputation for being "bright."

Edit: the MM preamp I ended up using with the 150MLX had an input capacitance of about 15pF. I could have lowered it a bit by cascoding the source followers, but 15
pF was good enough considering the lowish capacitance of the balanced cables I used.

I'm not sure if a reputation for 'brightness' could be considered undeserved if apparent with a typical total load capacitance of 200pF. Sort of like saying that British classic cars of the 1970s are unfairly monikered as 'rot boxes', as they stay so lovely and solid in Arizona (until they're re-imported back into the UK, of course)!

 

[SIY]

I'm not sure if a reputation for 'brightness' could be considered undeserved if apparent with a typical total load capacitance of 200pF. Sort of like saying that British classic cars of the 1970s are unfairly monikered as 'rot boxes', as they stay so lovely and solid in Arizona (until they're re-imported back into the UK, of course)!

Putting aside car analogies, it is unfortunate that this was the second best cartridge I have ever had a chance to listen to or use. I wish it were more load tolerant. But it isn't, so one needs to take some care with both wiring and preamp.

I bought a second one just in case; apparently, they have disappeared. Now that I've pretty much abandoned vinyl, it's going to eBay.

 

[Michael Fidler]

Putting aside car analogies, it is unfortunate that this was the second best cartridge I have ever had a chance to listen to or use. I wish it were more load tolerant. But it isn't, so one needs to take some care with both wiring and preamp.

I bought a second one just in case; apparently, they have disappeared. Now that I've pretty much abandoned vinyl, it's going to eBay.

So maybe we not only need high-output MC, but also low-output MM, with inductance low enough that LC resonance is out of the audio band?

I reckon this would be quite a good idea: lowering the number of turns to bring the output down to the 2mV mark, but moving the resonance point up past 30kHz.

 

[SIY]

So maybe we not only need high-output MC, but also low-output MM, with inductance low enough that LC resonance is out of the audio band?

What you mean is the best phono cartridge I've ever encountered, the great Technics EPC-100C Mk4. 33mH, 1.2mV DCR of 30R.

 

[DSJR]

Stanton/Pickering had such low output mm models. All reviewed in 'Choice books now on world radio history's UK pages.

 

[Michael Fidler]

What you mean is the best phono cartridge I've ever encountered, the great Technics EPC-100C Mk4. 33mH, 1.2mV DCR of 30R.

Not made anymore

Stanton/Pickering had such low output mm models. All reviewed in 'Choice books now on world radio history's UK pages.

Why are they not still making them? Why are we still putting so many windings on as if we're still stuck with the gain/noise impedance limitations of valves?

 

[JP]

I'm not sure if a reputation for 'brightness' could be considered undeserved if apparent with a typical total load capacitance of 200pF. Sort of like saying that British classic cars of the 1970s are unfairly monikered as 'rot boxes', as they stay so lovely and solid in Arizona (until they're re-imported back into the UK, of course)!

Pretty much all AT four-coil MM generators benefit from low Cl, and some combinations also benefit from lower Rl as well. I run them ~55pF all-in, and for the latter (440/540/740, etc.) 34-36k. Conversely, the two-coil like the VM95 do best around 200-300pF.

May be worth a gander at the cartridge measurement library here.

 

[SIY]

I knew you'd pop up.

 

[JP]

So little opportunity to share useless knowledge here - I gotta jump in where I can.

 

[DSJR]

What you mean is the best phono cartridge I've ever encountered, the great Technics EPC-100C Mk4. 33mH, 1.2mV DCR of 30R.

Not made anymore



Why are they not still making them? Why are we still putting so many windings on as if we're still stuck with the gain/noise impedance limitations of valves?

I cannot say sir, and the issue is that testers Martin Colloms and Paul Messenger (r.i.p.) tended to have an agenda of sorts, even if they didn't mean to (we've discussed this kind of thing many times here and all of us have fallen into this trap on occasion I'm sure).

https://www.worldradiohistory.com/UK/Hi-Fi-Choice/1975-1982/Hi-Fi%20Choice%20Iss.%20028%20Cartridges%20&%20Headphones%201982.pdf

Book page 100, pdf page 102.

I think that conventional MC pickups have a well defined 'hinge-point' of the cantilever. I appreciate B&O/Soundsmith*, AT VM types over the decades and Grado designs are also very similar in that the different cantilevers have a fixed precise hinge, rather than being poassed through a rubbery 'tube,' but in the past, stylus quality varied hugely and much work has been done to get the diamond finish better. Expensive MC types often have superb diamonds on them (best I ever saw via a proper microscope was a Dynavector Diamond model (living on as a 17D I believe), where the 'diamond' cantilever was better formed and finished than most styli (I'm looking at you Shure and Empire... )

I have no idea of the expensive Soundsmith re-realisations of the B&O MMC designs, but the originals are temerature sensitive (I have MMC20EN and MMC20CL in 'as new' condition and in the summer here, the 20CL especially is delightful, but dull and bland in the winter).

 

[SIY]

I cannot say sir, and the issue is that testers Martin Colloms and Paul Messenger (r.i.p.) tended to have an agenda of sorts, even if they didn't mean to (we've discussed this kind of thing many times here and all of us have fallen into this trap on occasion I'm sure).

https://www.worldradiohistory.com/UK/Hi-Fi-Choice/1975-1982/Hi-Fi%20Choice%20Iss.%20028%20Cartridges%20&%20Headphones%201982.pdf
Book page 100, pdf page 102.

I note that they had the little brother of the great EPC-100CMk4 in the mix, the EPC205CMk3. I had one of those as well and it was a terrific cartridge in its own right. Check out the square wave: the only ringing is from the cutter head.

 

[Michael Fidler]

It looks like we just need to e-mail Audio Technica and ask why they won't make a version of what they're currently making with fewer turns.

I've had a few VM95s apart - not much in the main body. How many do you reckon their minimum order quantity would be?

 

[JP]

I note that they had the little brother of the great EPC-100CMk4 in the mix, the EPC205CMk3. I had one of those as well and it was a terrific cartridge in its own right. Check out the square wave: the only ringing is from the cutter head.

Elastomer in my 100CMK3 perished. Still have one good 100CMK4, though. For now.

 

[SIY]

Elastomer in my 100CMK3 perished. Still have one good 100CMK4, though. For now.

I'm getting a new student who has the reputation of being a master of 3D printing. I'll ask him about tiny work.