Golden era MMs in the 21st century

the thin end of the wedge
wolfie62
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Re: Golden era MMs in the 21st century

Post by wolfie62 » 04 Nov 2019 20:33

You do know that black paint is very inexpensive, right?

Bertel69
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Re: Golden era MMs in the 21st century

Post by Bertel69 » 04 Nov 2019 20:38

Yes, and the other bodies are Sterling silver and 24 karat gold ;-)

tep392
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Re: Golden era MMs in the 21st century

Post by tep392 » 08 Nov 2019 20:29

Those ADC carts have high inductance, so need low capacitance loading. Make sure your using low capacitance cables and if your phono stage is adjustable, set it for the lowest capacitance.

wolfie62
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Re: Golden era MMs in the 21st century

Post by wolfie62 » 08 Nov 2019 20:40

High inductance? Some have 300 mH. Others have 580 mH. Not all that high. If you’re in the 150-250 pF range, you’re ok.

tep392
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Re: Golden era MMs in the 21st century

Post by tep392 » 08 Nov 2019 20:56

wolfie62 wrote:
08 Nov 2019 20:40
High inductance? Some have 300 mH. Others have 580 mH. Not all that high. If you’re in the 150-250 pF range, you’re ok.
The ZLM that Bertel69 is saying is rolling off would have 580 mH, which is high in my opinion. The recommended 275 pf is low enough that you can't get away with generic audio cable and have to be carefull about the rest of the circuit. I'll give you an example.

My QLM36 MKiii is 580 mH. I was using some generic cables measuring 300 pF with a 90's era receiver with a healthy 260 pf phono input. Add in the 110 pf in Dual's tonearm wire and I was way over the ADC recommended 275 pf load. I had a very pronouced rolloff above 8 kHz. My Audio Technica 3003 had no problems with this amount of capacitance. I've since changed receivers and cables getting my total down to 290 pf and my frequency response with the QLM36 is now very flat out to 20 kHz.

wolfie62
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Re: Golden era MMs in the 21st century

Post by wolfie62 » 08 Nov 2019 21:28

My 1977 Hitachi table measures 135 pF cart to end of RCA cables, factory supplied. My 1981 receiver has 110 pF at its input. 245 pF total. My setup is nothing special. Your example appears abnormally high.

tep392
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Re: Golden era MMs in the 21st century

Post by tep392 » 08 Nov 2019 21:43

I have two Kenwood receivers from the 90's and they are both 260 pf. I can only guess that it was a good match for the turntables they were putting out at the time. I'm currently running a 1980 KR-7050 that is 120 pf. Regarding my Dual 1219, I don't know why the tonearm wire is so high at 110pf. Seems like a lot for a foot and a half of wire and I was pretty surprised when I first measured it. I haven't studied the construction of the wire. My audio cables are now Mogami at only 20pf/ft and quite affordable.

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Re: Golden era MMs in the 21st century

Post by wolfie62 » 08 Nov 2019 22:25

Changing lanes. At work still, but got delivery on an AcuTex cartridge. MI, 3-pole design. Not the Shibata tipped, but the elliptical version. I’ve been intrigued by the design for decades; now I will finally get to hear one.
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BMRR
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Re: Golden era MMs in the 21st century

Post by BMRR » 09 Nov 2019 02:41

I'm not so sure that high(er) inductance always necessitates low(er) capacitance. Take for example the Stanton 680/681 and Pickering XV-15: these carts are rated at over 900 mH inductance, yet the recommended load capacitance is 275 pF, exactly the same as what ADC recommended for their carts. Likewise, if you look at some of Shure's cartridges which were rated at 600-700 mH inductance, the recommended load capacitance was as high as 500 pF for some of them. Then there are the Audio-Technica carts with inductances ranging from 360 mH all the way up to 1000 mH, and Audio-Technica recommended 100-200 pF load capacitance for all of them.

mamakasou
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Re: Golden era MMs in the 21st century

Post by mamakasou » 09 Nov 2019 08:20

Yeah, as BMRR says, it varies with manufacturer and with each model.

I suppose it's more related to factory 'tuning' of each pickup than to actual mH.

Bertel69
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Re: Golden era MMs in the 21st century

Post by Bertel69 » 09 Nov 2019 10:02

Gents, thanks for your considerations and suggestions, appreciate it.

I use a Restek MiniRIA+ as phono pre, both capacitance and impedance can be adjusted, so for my MMs I always use the lowest capacitance (which is labelled 100pF, so doesn't add any additional capacitance, just that of RCA plugs and teflon shielded internal wire which is around 100pF). The only available setting for proper high impedance is 47kOhm.

I don't know the exact capacitance of wiring and cable of My SME Series 2 Improved, should be around 150pF in total, but I don't care really, as I have my rewired SME Series III coming. Will solder the wiring directly onto the board of the MiniRIA+, so I then have a total capacitance of 40-50pF to start with, which I then can adjust up to 600pF in steps of 50pF via dip switches.

Will also replace the 47k resistor in the MiniRIA+ with a 100k linear pot (plus serial resistor of 10k, just to be safe), so I then can also fine tune the correct impedance loading, e.g. my Empire 4000D/III would rather want to see something like 100k, as many of the Quadro cartridges with their wide frequency band.

I have not yet put together the proper setup for impedance measurement (as e.g. detailed here: https://sound-au.com/articles/cartridge-loading.html) so that I can do my own precise measurements, but assuming that my ZLM has an inductance of 580 mH as you say (which sounds pretty high to me, but will see), with my current total impedance of around 250 pF the optimum load resistance is 48.2k, which is almost exactly the 47k I use. Resonance frequency is at 13.2 kHz, so well in the audio band. However that's not what the frequency measurement with Adjust+ says (pink noise, calibrated):
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There's no peak in the high frequencies, it all seems properly loaded, just a steady decline…

Will measure again when my SME Series III is here with lower total capacitance - if I can get away with say 70pF in total, the resonance frequency would be at 25 kHz and the optimal resistance at 91k. Will report back when all is in place.

Bertel69
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Re: Golden era MMs in the 21st century

Post by Bertel69 » 09 Nov 2019 10:09

wolfie62 wrote:
08 Nov 2019 22:25
AcuTex cartridge. MI, 3-pole design
Very nice find Wolfie - enjoy!

I have this guy sitting here, kind of the younger sibling:
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You've got me intrigued now, will put it on my SME right now :-)

Bertel69
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Re: Golden era MMs in the 21st century

Post by Bertel69 » 09 Nov 2019 12:36

Wow, this is really light:
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With a compliance of 42 and that little weight, I took the heaviest headshell I have, the entré (a good vintage match as well) and ended up with a resonance frequency of around 9Hz which is nice
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And oh my god, does this thing play great! Lots of detail and dynamics, amazing. I‘m currently listening to the excellent EMI Quadro recording of Mozart‘s Zauberflöte / Magic Flute with Sawallisch and the Bavarian State Opera, which my father had received as a present back in 1980 and which is still in excellent condition, and I‘m like just there, in the middle of the scenery, all detail and presence and „live“, a great joy :-)

wolfie62
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Re: Golden era MMs in the 21st century

Post by wolfie62 » 09 Nov 2019 21:01

There are mixed opinions on the AcuTex 3XX series vs the 4XX series.

My 310 is a disappointment overall. Sounds like an MI version of an Audio Technica cartridge. No air, just a very straight forward presentation. No pizazz.

I’ve been playing the 1970 ADC 10E MK IV. The AcuTex 310 IIIE seems to hit the frequencies, but no wide soundstage, very little depth or width.

billshurv
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Re: Golden era MMs in the 21st century

Post by billshurv » 09 Nov 2019 23:53

Bertel69 wrote:
09 Nov 2019 10:02


I have not yet put together the proper setup for impedance measurement (as e.g. detailed here: https://sound-au.com/articles/cartridge-loading.html) so that I can do my own precise measurements,
Although a step in the right direction Rod missed something with that, which is measuring all the way up to the generator self-resonance. But it's a start. My personal view is that being able to change resistive as well as capacitive loading is vital to get the best out of a MM/MI cartridge. But that's just me :)

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