Compliance and Arms and Carts, Oh My!

Compliance and Arms and Carts, Oh My!

Postby bhjazz » Sun Feb 26, 2017 7:26 pm

I'm roughing out some of the details which might help me determine which turntable to buy. Fund-wise, I am in the middle of the Scout and the Prime. I intend on also purchasing a Dynavector DV-20X2L.

But a wrinkle came up recently. It's staring quietly at me. Yes, it's my old Stanton D6800EE. I know these models were ca. early 1970s, but I have fond memories of the sound, and was rather hoping to be able to swap it on to one of these tables now and then. So I started reading.

It appears the Dynavector is a low compliance cartridge at 12 x 10-6cm/dyne. It also appears that the Stanton is a high compliance cartridge at 25 x 10-6cm/dyne. I have a "Compliance For Dummies" understanding of compliance. Maybe less. But what it looks like is that one would mate a high compliance arm with a low compliance cartridge, and vice versa. I'm totally aware that it's not as simple as I am making it.

I was not able to determine many of the specs for the JMW 10 3D Arm on the Prime, and was unsure about which arm would be on the 2017 Scout/Baby Prime. Are there mass specs or compliance measurements?

I see quite a few forum posts with folks using Dynavector cartridges, so I am guessing that the associated arms on these 'tables are of high compliance.

So my questions are: what are the compliance thoughts/specs for these two tonearms? If they are both high compliance, is there any way to use my old high compliance cartridge? Is there a different tonearm I could swap in instead?

Many thanks!

Brian
Last edited by bhjazz on Mon Feb 27, 2017 1:06 am, edited 1 time in total.
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Re: Compliance and Arms and Carts, Oh My!

Postby Brf » Sun Feb 26, 2017 9:00 pm

The Staton is not the best match with any of the JMW tonearms. I had the 680 on a Black Widow tonearm about a thousand years ago. Nice cartridge.

The Dyna 20xl works great on all JMW arms and represents good value for the performance.
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Re: Compliance and Arms and Carts, Oh My!

Postby bhjazz » Tue Feb 28, 2017 12:57 am

So see, that's part of my questions. Why is the Stanton not the best match with any JMW tonearms?

It seems as if the Dyna would work better with with the JMW 10 better than it would with the 3D arm, since the 3D arm is a gram lighter in mass. And conversely, then, the 3D arm might be fine for a high compliance cart like the Stanton.

:?
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Re: Compliance and Arms and Carts, Oh My!

Postby Brf » Tue Feb 28, 2017 10:39 am

bhjazz wrote:So see, that's part of my questions. Why is the Stanton not the best match with any JMW tonearms?

It seems as if the Dyna would work better with with the JMW 10 better than it would with the 3D arm, since the 3D arm is a gram lighter in mass. And conversely, then, the 3D arm might be fine for a high compliance cart like the Stanton.

:?


Both the metal and 3D JMW tonearm are considered medium mass tonearms which are not the best match for a high compliance cartridges. Typically, when a high compliance cartridge is mated with a medium mass tonearm, resonances in the sub 20hz range may occur in addition to some unwanted high frequency damping.

Do you know the mass of your cartridge?
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Re: Compliance and Arms and Carts, Oh My!

Postby bhjazz » Tue Feb 28, 2017 11:37 pm

Typically. I know! Yeah. Not trying to be irritating, but I am actually fascinated by all of this analog alchemy. I think I'm just going to have to dig in further and do some actual calculations...and read some more.

I ran across this as well, but I think we are currently in the ballpark of his thoughts anyway: https://www.gcaudio.com/tips-tricks/ton ... atability/

I may be able to use this: http://www.resfreq.com/resonancecalculator.html
...but will need to convert dyn to cu somehow. Anyway, an interesting journey for me.

Here are the specs for the two cartridges I mentioned. Thanks for your thoughts. I appreciate it.

Stanton 681EE:
Moving Iron
Output voltage: 4mV
Stylus: D-6800EE
Channel Balance 2dB
Freq Resp: 10Hz - 20kHz
Load Imp: 47k ohms
Tip: elliptical 0.2 x 0.7 mil
Tracking force: 0.75 - 1.5g
output imp: 1300 ohm
Dynamic compliance: 25 x 10-6cm/Dyne
mass: 5.5g

Dynavector DV20X2L:
low output MC
output voltage: 0.3mV
Channel balance: 1.0dB
Freq resp: 20-20
Load imp: > 30 ohm
tip: micro ridge elliptical nude diamond
tracking force: 1.8 - 2.2g
output imp: ?
compliance: 12 x 10-6cm/dyne
weight: 9.2g

(In one calculation I read, the Dyna 17D3 was a better match for the 3D arm at 5.8g and 15 x 10-6 cm/dyn. Interesting.)

VPI JMW 10 3D
Pivot to spindle: 258mm
Effective length: 273.4mm
Effective mass: 9g
Overhang: 15.4mm
Offset angle: 19.98 degrees
Average RMS distortion: 0.311%

VPI JMW 10
Pivot to spindle distance: 258mm
Effective length: 273.42mm
Effective mass: 11g
Overhang: 15.42mm
Offset angle: 19.98 degrees
Average RMS distortion: .311%

VPI JMW 9 (In the case of the Scout)
Pivot to spindle: 223mm
Effective length: 240.7mm
Effective Mass: 10.2g
Overhang: 17.7mm
Offset angle: 22.85 degrees
Average RMS distortion: .36%
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Re: Compliance and Arms and Carts, Oh My!

Postby Wax » Tue Feb 28, 2017 11:56 pm

I run a high compliance Denon 301 mk 2 on an older aluminum(?) JMW 9t with no issues. The 9t has an effective mass of approx 9 (I've seen it referenced/spec'ed as low as 7.7 on vinyl engine). Anything under 10g can be considered a low mass arm. With the Denon's compliance of approx 20 I calculate a resonance frequency of about 9Hz. The cart sounds phenomenal.
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Re: Compliance and Arms and Carts, Oh My!

Postby bhjazz » Wed Mar 01, 2017 1:14 pm

Hi Wax,

I ran across the excellent resources at VinylEngine last night when I was reading. I'll post what I found tonight at home, but most of the resonance calculations were outsize of the trouble zones. I was surprised to see these numbers (for borth carts) as I had actually prepared myself for the possibility that my scheme might not work.

More tonight. Thanks for the info. Much appreciated!
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Re: Compliance and Arms and Carts, Oh My!

Postby mmai » Wed Mar 01, 2017 1:30 pm

Wax wrote:I run a high compliance Denon 301 mk 2 on an older aluminum(?) JMW 9t with no issues. The 9t has an effective mass of approx 9 (I've seen it referenced/spec'ed as low as 7.7 on vinyl engine). Anything under 10g can be considered a low mass arm. With the Denon's compliance of approx 20 I calculate a resonance frequency of about 9Hz. The cart sounds phenomenal.


Sometimes, this compliance thing really escapes me.

I have an Audio Technica ART9 with a compliance of 27 and the resonance frequency, when mated with a 10.5iSE arm, is about 7Hz. Yet, it sounds good to these tin ears. I guess this is why VinylEngine regards this as a guideline only: https://www.vinylengine.com/cartridge_r ... luator.php
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Re: Compliance and Arms and Carts, Oh My!

Postby bhjazz » Wed Mar 01, 2017 4:46 pm

Guideline for sure. But in some cases you can get a gain in the output, as I understand. Additionally, it can induce mistracking.
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Re: Compliance and Arms and Carts, Oh My!

Postby bhjazz » Thu Mar 02, 2017 1:17 am

So here are the numbers from the vinylengine calculator. Depending on whether you believe the combination of cartridge and arm should be in the range of 10 - 14Hz, or even 9 - 11Hz, here are the results.

Stanton 681EE 8Hz on 3D arm, and 8Hz on JMW 10 arm
Stanton 681EE 8Hz on scout JMW9 arm
Dyna DV20X2L 11Hz on 3D arm, and 10Hz on JMW 10 arm
Dyna DV20X2L 11Hz on scout JMW9 arm

Clearly, the Dyna is a no brainer. Cool! But the Stanton actually doesn't look that bad. I was expecting worse. Seems to be worth a try.
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