Fun with vinyl measurements

[Balle Clorin]

First try.
Any corrections or recommendations reg. cartrigde/measurement setup would be appreciated.

View attachment 431021

Hard to comment without any given information…is this the ortofon sweep… it is useless. Only partly correct even if you only look above 2000hz

 

[Danish ear]

Yes it's the sweep from the current Ortofon test record. Stated by Ortofon, the sweep has constant velocity amplitude. The stylus pressure was 1.5g(measured), loading 48K/165pf, 96 KHz sampling frequency.

 

[USER]

Yes it's the sweep from the current Ortofon test record. Stated by Ortofon, the sweep has constant velocity amplitude. The stylus pressure was 1.5g(measured), loading 48K/165pf, 96 KHz sampling frequency.

Unfortunately the Ortofon record can't be used for frequency response. That all said it seems that you have everything else you need to make measurements. Look out for the Clearaudio TRS-1007 and the CBS STR-100 (Issue 3) and hopefully you can find a copy of one of them at a good price. Those are the test records to use, with the Clearaudio being the best option.

 

[Balle Clorin]

Almosts fooled myself today.

I as running test with diffrent mats and noticed the lelev were different,, crazy right? I tracked it down the that the length of a pink noise recording affects the level in REW


When recording and trimmed 15 seconds the levels are the same, can someone explain what is going on please?

But still when I correct and use samE recording length the PLATTER mat used affects the OrTofon OM10 response on Denon 21F, but nothing like that happens on my Sony ps-212 with aAT95E, STRANGE!!!

The whole experiment was triggered off since I notioced that the CA trs-1007 sweeps on the Ortofon OM10 was varied with plater mat used, and was not consistent

 

[Thomas_A]

Is it repeatable? Temperature in room the same?

 

[Balle Clorin]

Did 2 runs showing same high trend to 20k on the SRM -Tech mat, with Sony mat the result vary more …’
Temp same

 

[Balle Clorin]

OK, to check the dip on the response I ran the AnalogMagik V2 (pink noise RIAA eq) test record at 33 and 45 rpm and go this.
The dips at 65 and 180Hz are still there so , so the resonance is probably arm related.
GREEN is reference turntable

The strange thing is that no other test record reveal the 65/180Hz resonances. Why only the AMV2 record? I found that the AM record is 10db? lower in level than the other pink noise records, does that matter?

 

[Thomas_A]

A long shot but could you share the waveforms L+R for the one with resonance and without?

 

[Balle Clorin]

Reference without resonance 4.6seconds

zoom

With resonance, lower recording level but same track

zoom

 

[Thomas_A]

Odd. It seems arm resonance is excited at the same level regardless of pink noise level.

 

[Balle Clorin]

Not sure how you concluded on that?, the arm resonance is only visible on the specific low level Analog Magik pink noise track,

But I see signs of 200 and 400hz resonance in the CA-TRS-1007 crosstalk channel here too, but no 65hz ..?

The analogMagik V2 pink noise track that uusiallay "finds" resonance looks like this

 

[Thomas_A]

Not sure how you concluded on that?, the arm resonance is only visible on the specific low level Analog Magik pink noise track,

But I see signs of 200 and 400hz resonance in the CA-TRS-1007 crosstalk channel here too, but no 65hz ..?
View attachment 434440

The odd thing: if resonance is there it seems to be visible only at low pink noise levels and masked at higher levels.

 

[Balle Clorin]

Another investigation: 100Hz peak and side bands hunted down to likely cause =tranasformer vibration transferred to TT/ARM/PU

Transformer hangs form 2 rubber grommets, I damped side against chassis with some sorbothane that did help, but did not elimnate it

The following investigation showed that 100Hz peak was much lower when motor running , and PU listed up off record , peak at 100hz increase when stylus in groove: makes me think cause is mechanical=Transformer vibration

Denon 21F vs 51F, 21F does NOT have the same vibration

Noise levels

 

[Balle Clorin]

The odd thing: if resonance is there it seems to be visible only at low pink noise levels and masked at higher levels.

Yes, strange, maybe higher levels mask it. Just posted some other noise things on my other TT Denon 51F

 

[JP]

I recall the topic of tracking error coming up recently but I don't recall where, so I'll just drop this here may it be of interest. I've not gone through the math, but at least by the illustrations it looks to be a more thorough treatment than I usually see in that it includes actual signal distortion in consideration of groove radius, amplitude, and frequency.

Tonearm tracking error and distortion

In the last posting, I reviewed the math for calculating the tracking error for a radial tonearm. The question associated with this is “who cares?” In the March, 1945 issue of Electroni…

www.tonmeister.ca

 

[Thomas_A]

How do you handle the results from the tracks 9 & 10 of the CA-TRS1007 record? I have settled with a bit more HF end using the tracks 1 & 2, but it seems to drop off quite a bit on tracks 9 &10 which even is not the inner track of a typical record. Does the JVC record show the type of drop? @JP ?

 

[JP]

Depends on the stylus minor radius. Not either an ML on the JVC. Will check the reference plots after breakfast.

 

[JP]

TRS-1007 has about 0.75dB loss measured with an ML.

 

[Thomas_A]

TRS-1007 has about 0.75dB loss measured with an ML.

At what fr? I see 1 dB @10 kHz. More at 20 kHz

 

[Balle Clorin]