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In Reply to: RE: High compliance, low output MC? posted by John Elison on February 28, 2017 at 02:04:07
Hi John
I have a pair of SL1200s and the LF resonance of the DL304 is ~7Hz. I will take it on faith that the arm mass as 12g (I confess I have never bothered to verify the ACTUAL effective mass). The DL304 is mounted in an original Technics headshell (m=7.5g) and the DL304 is ~7g. I estimate the compliance to be ~23*10-6 cm/dyne.
Yes that price is quite high, but was not too different to what I paid 2Juki a couple of years ago and still represents a cost saving relative to an S1 if they were still in production.
Apart from the wire, I'm not sure that the S1 is that different to the 304. The tip mass is likely identical (0.07mm square shank Special Elliptical, not the rectangular shank that several websites quote) and the frequency response of the 304 is even quoted to be slightly wider suggesting that the tip resonance is at least similar.
Regards Anthony
"Beauty is Truth, Truth Beauty.." Keats
Follow Ups:
Hi Anthony,
> I will take it on faith that the arm mass as 12g
Me, too! I read that somewhere and I've been taking it on faith. Of course, that number includes the Technics headshell. Therefore, when adding 1-gram for mounting bolts, I calculate the arm/cartridge resonance frequency to be approximately 7.4-Hz if your cartridge's compliance is 23*10 -6 cm/dyne.
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> Yes that price is quite high, but was not too different to what I paid 2Juki a couple of
> years ago and still represents a cost saving relative to an S1 if they were still in production.
The price is not too high for me but TubeDriver mentioned he didn't want to spend a lot of money because the cartridge was for a backup turntable.
Additionally, you're probably right about the similarities between the DL-304 and the DL-S1. I'm sure the DL-304 is nearly as good as the DL-S1 and possibly better in some areas. I bought my two DL-S1 cartridges some time ago when they were selling for $509 through Comet Supply. I think I paid $535 each with shipping and handling.
Best regards,
john Elison
Hi John
Thanks for posting up the formula! I confess I got lazy and just quickly scanned the graph on the HFNRR test disc sheet.... Cheat sheet!
While we're on the subject of effective mass specs...Have you seen JoshT's q on the SL1301 arm? They quote 22g including cartridge mass of 6g. Headshell is 9.5g. I thought at a glance that it was really 12g, but checked the instruction manual for the 1301 and also the EPA-100 out of curiousity and that quoted 22g as well. Is the effective arm mass really about 16g? I've never seen it specified the way Technics have done in this case. Also really surprised to see the strange geometery with the offset at 21.5degrees. They look to have applied Lofgren B to a very narrow envelope so they end up with ~3 deg error at 146mm! Crazy stuff...
Regards Anthony
"Beauty is Truth, Truth Beauty.." Keats
Hi Anthony,
> They quote 22g including cartridge mass of 6g. Headshell is 9.5g.
That's interesting and very commendable on Technics part. They also state the VTF of 1.75-grams. This represents a very precise way of presenting effective mass because effective mass actually varies slightly depending on the position of the tonearm counterweight. Therefore, knowing cartridge weight and VTF pins down the position of the counterweight precisely.
The effective mass of the tonearm without the 6-gram cartridge might be slightly greater than 16-grams since the center-of-mass of the cartridge is probably not concentrated at the stylus but is slightly behind the stylus. For example, suppose the center-of-mass of the cartridge were 7-mm behind the stylus. The cartridge's effective mass would be calculated as follows:
Cartridge Effective Mass = 6*223 2 / 230 2 = 5.64-grams
Now, if you removed the cartridge without changing the position of the counterweight, the tonearm effective mass would be 22 - 5.64 = 16.36-grams. However, we normally don't go into this kind of detail so we simply approximate tonearm effective mass as 22 - 6 = 16-grams.
With respect to tonearm geometry, the Technics SL-1301 reminds me of the geometry of the early SME III. Compare the two graphs below:
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Hi John
Thanks for the information! It's interesting how one gets a sense of the quality of engineer involved in designing a product based on how the specifications are presented - particularly when comparing to other similar products. I'm always suspicious of products (in the audio field especially) where the technology or specifications are concealed. For example Power Conditioners or cables where they claim no active components, but then try and cloak the details in some mystical explanation!
I thought your curiousity would be piqued by the tonearm geometry for the 1301 when I first plotted it out. This MUST have been a conscious design choice by the designers and not a mistake...surely!
Regards Anthony
"Beauty is Truth, Truth Beauty.." Keats
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