Could someone with a flat cartridge please...

[cgallery]

Well the pink noise is known to be pretty awful, which doesn't say much for the sweep but I'll perform a capture nonetheless.

BUT, I should also note that I'm using a DIY phono stage. A single op amp based on the OPA164X data sheet. I am using 1% caps in the RIAA network, though, and the RIAA simulations show about +/- 0.1dB or better.

Anyways when I get a break, I'll gran the sweep(s) from the album and post them.

 

[DVDdoug]

It seems like the real problem is that you need (or want) a better test record...

Well the pink noise is known to be pretty awful, which doesn't say much for the sweep but I'll perform a capture nonetheless.

Noise is random, by definition, and if you watch a VU meter you'll see the needle wiggle (or an unstable digital display). Over a long time the average should be stable but it's hard to get precise measurements.

The difficult of a sweep from a record is probably knowing the exact frequency at any moment in time.

BUT, I should also note that I'm using a DIY phono stage. A single op amp based on the OPA164X data sheet. I am using 1% caps in the RIAA network, though, and the RIAA simulations show about +/- 0.1dB or better.

It's probably fine and if you made a big mistake it will sound terrible!

But as you may know, the load capacitance (from the preamp and cables) will affect the high frequencies. For that reason, you'd probably have to average the measurements from multiple people who have the same test record and Shure cartridge...

 

[JP]

Matrices HFN 002-A and 002-B?

 

[cgallery]

But as you may know, the load capacitance (from the preamp and cables) will affect the high frequencies. For that reason, you'd probably have to average the measurements from multiple people who have the same test record and Shure cartridge...

I figure someone with a known-good test record (JVC or whatever), and a copy of the script discussed here, would know they have a flat setup with whatever vintage Shure or AT cartridge, and use that combination to capture the HFN track.

Their capture of the HFN track will tell me how far off that track is, such that I can generate a calibration file to correct the anomalies.

Does that make more sense?

 

[cgallery]

Matrices HFN 002-A and 002-B?

Indeed, exactly what I have.

 

[JP]

Ok. I have it.

 

[cgallery]

Ok. I have it.

Awesome.

 

[JP]

Tracks A3-A5 flat. If you want RIAA applied, then in Audacity Nyquist prompt, paste and run:

(setf *track* (biquad-m *track* 1.2549796389053600E-01 4.5878679703151200E-02 1.8820452752400900E-03 1.0000000000000000E+00 -6.6168391000000000E-01 -1.8158841000000000E-01))
(biquad-m *track* 9.08612614639649000E-01 -5.22931473883012000E-01 -3.44913691685509000E-01 1.00000000000000000E+00 -6.04500910000000000E-01 -3.90945930000000000E-01)

Dropbox

www.dropbox.com

 

[dlaloum]

The problem with any of the excellent MM's for recording a "flat" track, is that their "flatness" is extremely sensitive to load variation - so unless you have the C & R load just right (and how do you calibrate that without a reference point?) - you are basically back in a circle of confusion.

Possibly the ultimate readily available "flat" cartridge is the Dynavector Karat MC....

That should provide a flat F/R with relative load independence, making it a very useful calibration tool

 

[JP]

Measure it? Kinda what we do here, and what he asked for.

 

[cgallery]

Tracks A3-A5 flat. If you want RIAA applied, then in Audacity Nyquist prompt, paste and run:

(setf *track* (biquad-m *track* 1.2549796389053600E-01 4.5878679703151200E-02 1.8820452752400900E-03 1.0000000000000000E+00 -6.6168391000000000E-01 -1.8158841000000000E-01))
(biquad-m *track* 9.08612614639649000E-01 -5.22931473883012000E-01 -3.44913691685509000E-01 1.00000000000000000E+00 -6.04500910000000000E-01 -3.90945930000000000E-01)

Dropbox

www.dropbox.com

View attachment 400881

Well, the good news is that I think it worked great.

The bad news is, I think my DIY phono stage RIAA or something else is off somewhere.

If you look at the REW window I captured below, you'll see a capture (ORANGE) made about a year ago using my previous turntable/DIY arm + Signet AM10 cartridge body + VMN40ML stylus. This was imported while using the calibration file I just created from the WAV file you made for me (THANK YOU! btw). It is pretty darn similar to what you guys are getting for 200-pf, the capacitance of my rig at the time.

The green line, however, was captured recently via my DIY phono stage with an SL-N15 (vintage Panasonic linear turntable) + AT152LP cartridge + VMN40ML stylus. My total capacitance should still be approx. 200-pf.

Oh oh.

It was extremely generous of you to create that file for me. I now have some confirmation that something is amiss and I can start drilling down on it.

The SL-N15 has a built-in phono stage which I will enable and take some more measurements and compare, then figure out my next step.

 

[cgallery]

Oh and BTW, @JP here are two imports of the same older file I used above. Orange is with the benefit of the calibration file I was able to generate, red is without.

I'm not arguing that this works as well as the script + a known good test record, but it pretty clearly has paid some dividends.

 

[Balle Clorin]

I imported @JP HFN file in Rew and Get this,
The vinyl track (blue) seem to be RIAA equalised ( JP recorded with no RIAA) so I used I used a reverse RIAA calibration file in REW to linearise the file. Then I get a typical pink noise slope( red). I do not know how to combine the RIAA + Pink noise calibration to make the red curve horisontal, so I used a digotal pink Noise file and subtracted thet form the RIAA response= Yellow response curve. Knowin that the cartridge if very flat this tells me that the PN track on the record is "flat" too.

Tips on how to combine reverse RIAA and PN to horisontal into a single calibration file is welcome, @cgallery how do you get your plots horizontal?

Tracks in CooleditPro

 

[cgallery]

Well the first thing I did was to use Audacity to take thirty seconds of the first track, my archive of captures averages about thirty seconds each.

Then I applied RIAA via the Nyquist prompt (per JP's instructions in his post), and exported the result to a new WAV file.

I imported this into REW, then I did File/Export/Export measurement as text. I opened this file with my spreadsheet app, and subtracted the value @ 1000-Hz from every other frequency's value, and then saved this with a new name ("hifinews_jp_calibration.txt").

Back in REW, I went into Preferences/Cal files and selected this file under "Mic." You can also use "Soundcard cal file" section but I've found it can be a little more difficult to clear this if needed, so I place it under "Mic" and it works just fine.

I hope that makes sense.

I've attached the cal file I created below, just in case you want to give it a try.

 

[JP]

Oh and BTW, @JP here are two imports of the same older file I used above. Orange is with the benefit of the calibration file I was able to generate, red is without.

I'm not arguing that this works as well as the script + a known good test record, but it pretty clearly has paid some dividends.

View attachment 400910

As you're measuring electronics, I'm going to point you back to Wyn's post. Use his RIAApreemp calibration file in REW for the output device, use a resistive divider off your sound card to knock the level down to not overload your phono stage, and then run a sweep measurement in REW.

 

[cgallery]

As you're measuring electronics, I'm going to point you back to Wyn's post. Use his RIAApreemp calibration file in REW for the output device, use a resistive divider off your sound card to knock the level down to not overload your phono stage, and then run a sweep measurement in REW.

Yes, I'm going to have to do this now. Davey @ the stevehoffman.tv site also provided instructions.

I also found last night that at some point in the past, I dropped the loading to 36k without making any notes.

Next-up I have to follow the instructions from Wyn and Davey on measuring the phono stage.

BUT, I'm sort of thrilled to have the ability to look at my old captures in a new light.

 

[Balle Clorin]

I should probably update my REW RIAA calibbration file o be sure, but her is my compariosn of JP file for Shure V15 V-MR and my Shure V15 IV-SASB with Puffin eq at AIR=1.

The version 1 of the Hifi news pinenouse RIAA equalised is not bad at all..

 

[cgallery]

I just swapped the input resistors to 47k (from 36k) and made another capture (below). Green is 47k, red is 36k.

It occurs to me that I have an unadulterated Hagerman Bugle 2 that I can use for a quick sanity check and even switch to using until I have a chance to test my DIY model with REW.

 

[cgallery]

Was just horsing around with the calibration file I created from JP's needle drop.

This is an ADC T4P cartridge with a Rivertone ADC XLM MKII Improved stylus (these styli are assembled from new-old-stock components from the original ADC factory).

The green line is my measurement with the calibration file applied, red is without the calibration file applied. One of these days someone here is going to measure these ADC styli using "the script," I was just curious about relative flatness. Also, you can really see the difference in the level of resonance control (JP's arm and/or cartridge doing much better).

I haven't measured my DIY phono stage yet, need to source a better ADC. I'd prefer something very portable (fits in my pocket) and have selected a model, just need to order one now.