Introducing the Phono Cartridge Measurement Library

[aaaakkkk]

definitely looks solid peeking inside. my v15rs has a dead channel and it along with the vst III is supposed to be the same generator as the v15vxmr, so i pulled it apart.

The V15 III yellow inscriptions, and also a dead channel

 

[dlaloum]

Very good - that makes the V15III the best Shure body to mate with Jico SAS.... High inductance and laminations.

 

[JP]

I updated the MC-L1000 and XL-88D posts with a better image of each.

 

[essence]

AT-VM95ML

Spoiler: 23.5k load mismatch

• Reloop RP7000MK2 (super oem) turntable
• Cart brand new <1h usage, pre-assembled w/ AT-HS6BK headshell
• CBS STR100 Issue3 is NM and flat however seems like the scuffed version?
• reloop line out > e1da ADC

 

[JP]

Cart straight to APU? That R load would explain why the HF response is so abnormal.

 

[Balle Clorin]

Something is very wrong with the cartridge, the load or RIAA input, I guess JP is correct
It must sound pretty dull.

 

[essence]

Cart straight to APU? That R load would explain why the HF response is so abnormal.

Yeah. Could this explain the missing rise I see other people get at 10k before the fall?

I included another measurement of riaa disabled. So my cart seems seems abnormal? Any chance its test record?

 

[JP]

You're putting a 20k load on the cart. Your plot shows what one would expect from an inappropriate load. The APU is not a suitable MM preamp.

 

[USER]

Yeah. Could this explain the missing rise I see other people get at 10k before the fall?

I included another measurement of riaa disabled. So my cart seems seems abnormal? Any chance its test record?

Only you know the history of the cartridge, but the test record or cartridge being the issue seems unlikely. In fact, everything is screaming the APU being at fault. You need to test it with a real phono preamplifier to find out for sure. I have not read anything here that would make me think that the APU is usable as a standalone phono preamplifier. For that cartridge you need roughly 47k and 100pF for loading.

 

[JP]

ou're putting a 20k load on the cart. Your plot shows what one would expect from an inappropriate load. The APU is not a suitable MM preamp.

What's the input configuration? The specs say input Zi=20/10kohm bal/unbal, and for "as a phono" Zi=47/23.5k bal/unbal. Not sure how they're getting from one to the other. Regardless, your plots look like a 20k or less load.

 

[JP]

Info on these devices is a hot mess. From what I could find it seems the device needs to be modified for the 23.5/47k load, or perhaps it's also an order option. The Ali store is set to vacation so you can't even see it. The standard 10/20k probably works fine for MC.

 

[USER]

Info on these devices is a hot mess. From what I could find it seems the device needs to be modified for the 23.5/47k load, or perhaps it's also an order option. The Ali store is set to vacation so you can't even see it. The standard 10/20k probably works fine for MC.

Hmm. Does it depend on the turntable and cable wiring being fully balanced? The website says the following in the input section: TRRS pinout as +In/-In/GND/GND.

@essence, are you feeding the APU a balanced input with a proper TRRS cable? Note that I use a balanced phono preamp as well and had to modify my turntable wiring for balanced output. However I use that set up as an archival and measurement turntable station only, and with my laptop. For everyday use I use regular phono preamps on a non-modified turntable.

 

[JP]

Depends on how you wire to the APU. If the cart is between +in and -in it'll see 20k, and if between +in or -in and GND it'll see 10k.

 

[USER]

For whatever it is worth, here are old measurements of a modern Denon DP-400 turntable with built-in phono preamp. From what I can tell, the cartridge is the equivalent of the Audio-Technica 3600L. The result is similar in that it shouldn't droop if it is working as it should. Big if at this point. I have been meaning to measure it again using my Flat MM phono preamp with the turntable in bypass mode as well as with the built-in phono preamp connected to my miniDSP SHD. The measurement was taken years ago so set-up is getting hazy. It could have been connected to my E1DA Cosmos. Wish I took better notes.

 

[USER]

@JP Do you recommend any particular headshell wires?

 

[essence]

No its connected unbalanced RCA -> TS, I was waiting on my lcr meter to consider if it was worthwhile bypassing the 100pf output circuitry and to match my cable run. Thanks for all the help, I see where my problem lies. Both my apus are default stock so its most likely seeing a 10k load, now to source a proper phono preamp without riaa eq...

 

[JP]

@JP Do you recommend any particular headshell wires?

Conductive

 

[USER]

No its connected unbalanced RCA -> TS, I was waiting on my lcr meter to consider if it was worthwhile bypassing the 100pf output circuitry and to match my cable run. Thanks for all the help, I see where my problem lies. Both my apus are default stock so its most likely seeing a 10k load, now to source a proper phono preamp without riaa eq...

If you happen to have modest soldering skills and like DIY projects, this is the best that I know of (thanks to JP). The hardest part is finding a good case for it, though I may have a source if they are up for making them again. (I have ideas for a near perfect case modification, though I'd need to come to them with some interest.) I had no experience with such things and I was able to put one together, so anyone can do it as long as they are patient. Works perfectly with the Cosmos and can be set to bal/unbal for universal application, though bal is optimal in a numbers only sort of way. In fact, I believe I read that is has better specs than the APU for these purposes. It's an extraordinary device.

Flat Moving Magnet Phono Preamp With Balanced Input and Balanced Output

Flat Moving Magnet Phono Preamp With Balanced Input and Balanced Output

ka-electronics.com

 

[essence]

I think my load was messed up as my RCA negatives weren't indepedant but tied together. I just ended up using the built in line out and updated the graph in my previous post.

 

[JP]

I think best to leave that and post a new one, as the proceeding conversation wont make much sense if someone wasn’t following along.

As for the new plot, I’d recommend trimming the beginning of your files so that electronic roll-off isn’t there. Aside from plotting something that has nothing to do with the cartridge the scale isn’t very useful.