I'm happy to go through my test records to see if I've any that are exceptionally low noise. Scott it'd help to get your code so I can see what plays well with it. If I've one that works happy to send it on tour.
Last count I've around 50 test records - 3-4 copies of the Denon XG-7002 and 4-5 BK QR2010. QR2010 is CV above 1kHz but goes to 45kHz rather than the 50kHz the Denon does. These obviously won't go on tour but I've a lab setup that's super easy to do needle drops from comprised of an SP-10R or MK3, EPA-500, flat balanced instrumentation amp, RME ADI-2 PRO ADC, and Tascam DA-3000 for quick captures. Anything I have that's interesting I can record and post.
I also have a large collection of high-bandwidth carts with some examples that seem as healthy as one could hope for - P100CMK4 with ~5 good OEM styli, P205CMK4 with ~4 styli, P205CMK3 with one good styli, Sony XL-88D. The last still sealed so no idea on that one.
I also think I've a BK 8307 accelerometer on the way to use as a vibrator per their tech article. That one may be a bit above my brains and time capacity, so if someone like Scott is interested in trying that method I could loan it out. I'd like it back at some point with a repeatable method so I can use it on my above carts.
Last count I've around 50 test records - 3-4 copies of the Denon XG-7002 and 4-5 BK QR2010. QR2010 is CV above 1kHz but goes to 45kHz rather than the 50kHz the Denon does. These obviously won't go on tour but I've a lab setup that's super easy to do needle drops from comprised of an SP-10R or MK3, EPA-500, flat balanced instrumentation amp, RME ADI-2 PRO ADC, and Tascam DA-3000 for quick captures. Anything I have that's interesting I can record and post.
I also have a large collection of high-bandwidth carts with some examples that seem as healthy as one could hope for - P100CMK4 with ~5 good OEM styli, P205CMK4 with ~4 styli, P205CMK3 with one good styli, Sony XL-88D. The last still sealed so no idea on that one.
I also think I've a BK 8307 accelerometer on the way to use as a vibrator per their tech article. That one may be a bit above my brains and time capacity, so if someone like Scott is interested in trying that method I could loan it out. I'd like it back at some point with a repeatable method so I can use it on my above carts.
It would certainly be interesting to see how your collection works with the test records and the more data off records we have the better in terms of working out what we should be scouring for. If we can end up with 3 or 4 people with the same record that is great, but we need to pick the right record(s).
I'm trying to catch up on discussions over last week but starting to think we are looking at several different things at once which is confusing those of us who are bears of little brain. I think i am slowly working it out though 😀
I'm trying to catch up on discussions over last week but starting to think we are looking at several different things at once which is confusing those of us who are bears of little brain. I think i am slowly working it out though 😀
Yup if you mean their current one in production. I shared one file with you regarding measuring crosstalk with the 1 kHz tones on that record.
If I have time I may switch to my OM40 and record the results. Or I’ll do some test with my Shure MR beryllium. The JICOs I use don’t extend well above 20 kHz.
And whilst I can but dream of the 205CMK4 I do have its grandad the 205CII-L. I got it because I wanted to experiment with the low inductance generator, but I am not convinced that there is anything MM in current production that is more advanced.
(No George this is not a new purchase 😀 )
Edit: JP Those are the sort of plots we've been expecting! Is that the Denon record again?
(No George this is not a new purchase 😀 )
Edit: JP Those are the sort of plots we've been expecting! Is that the Denon record again?
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I ordered the boron, ruby, and sapphire for the V15V as well. One of the few carts with such a broad range of cantilever materials to easily play with.
I had the ruby, but it broke due to a bad fit in the shank. I had time to listen and measure it and still the boron is the best of the bunch.
I will try order the Vivid line stylus as well, when time allows.
I am not sure what determines what material you can get for cantilevers. I was surprised about the zirconia variant. Heavier material, but made hollow. A hollow boron would be nice, but that would probably be just a dream.
I think there's also good opportunity in Scott's software that uses a single frequency sine tone played by hand at various speeds, and builds instantaneous f and level into a composite response.
This also would allow f response to be plotted at various levels, assuming one can find enough sine tones at different levels on test records.
LD
This also would allow f response to be plotted at various levels, assuming one can find enough sine tones at different levels on test records.
LD
Scott,
I think I just solved the discrepancy problem.
You probably assumed a constant amplitude of the sweep.
Well, it is not.
Below you see level in dB versus frequency.
The 2-3dB dip at 5kHz that you thought to have, turns out to be caused by the decrease in sweep level, and not by a velocity error.
We are back at the point that out PN traces are identical from 1k to 6kHz,
I have no velocity error at 5kHz, and neither do you.
Hans
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Wow, just what I was thinking the other night. I'm glad you are willing to entertain such an unorthodox hack. 🙂
Hans I have no idea what you are showing here, my cart has the mid-range dip on all sweep LP's I have looked at. It's real and it's there, the problem is else where. The sweep on the Adjust + is not constant amplitude it has RIAA pre-emphasis applied.
Why not take the Adjust + sweep and record it through your RIAA pre-amp and don't process anything and post the picture that's what I did. What reference did you use to show that it is off?
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And also; good if you can report back on those. I can't say whether my ruby version was bad from start. I saw this link below and their measurements looks better than what I found:
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Of course I played the adjust+ through the Riaa preamp.
The level vs frequency curve I showed was thus after the Riaa correction.
Posting a time/level picture as you did is utmost unprecise and only suited for very coarse measuring.
But from an exact same picture made with my set from the same track, I have measured the rms level of 30 sinusses, after having zoomed in with LT Spice, from successive time spots. This was followed by measuring the time of ten sinusses. Frequency= 10* 1/time. That’s way more accurate in getting results.
Whatever you have done with other sweeps, I don’t know, but this picture you have posted as a prove for a dip, has no dip at all after correction for the sweep level decrease vs frequency, and is completely in line with the CV plot that you posted that also has no dip when corrected for the 10dB/dec roll off, etc, etc.
Hans
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