Vinyl foibles

I wanat to see what anyone knows about the capacitance setting on the phono preamp. On my previous tubed ARC PH-7 the capacitance was set at 200, so I didn't worry about it. I set the cartridge loading at 200 and was very happy with the sound. Although I knew it lacked detail, it was musical to my ears.

Enter the world of solid state with expensive Pass Labs preamp XP-30 and phono preamp XP-25. When my granddaughter, who's ear I've been training since she was six, listened for the first time, she said, "It's so c walear." 

The problems was that it was too clear, and it resulted in a shrill treble. The Sonus Faber Olympicas were voiced by a different person than the older Sonus Fabers which were known for polite treble. The Olympicas have "transparent" treble.

So, how to fix that? My new Pas Labs phono preamp has a capacitance setting, pretty much on the fly. There's a knob on the front panel. As far as I could see, standard wisdom said that MC cartridges are not much affected by capacitance. Set it to 100 and work with other adjustments. And that's not at all what I"m finding.

When I raise the capacitance knob to 320, the treble is tamed and the bass seems stronger. That's not what's supposed to happen. I am leaving the capacitance set to 320, the cartridge loading to 160, and I've raised the rake of the tonearm to enhance the treble just a bit.

Can anybody explain what capacitance is all about and why my system is behaving opposite of how it's supposed to? Reminder, I have the VPI Shyla caartridge on my VPI prime signature 21 turntable.

@audio-b-dog 

"So, how to fix that? My new Pas Labs phono preamp has a capacitance setting, pretty much on the fly. There’s a knob on the front panel. As far as I could see, standard wisdom said that MC cartridges are not much affected by capacitance. Set it to 100 and work with other adjustments. And that’s not at all what I"m finding.

When I raise the capacitance knob to 320, the treble is tamed and the bass seems stronger. That’s not what’s supposed to happen. I am leaving the capacitance set to 320, the cartridge loading to 160, and I’ve raised the rake of the tonearm to enhance the treble just a bit."

Are you sure you’re not confusing capacitance with impedance? Capacitance shouldn’t have any effect on the sound signature of an MC cartridge, though there are some manufacturers that provide settings in the thousands of picofarads to tame the high frequency ringing that MCs produce but the jury is out as to whether that has any audible effect.

Increasing impedance can brighten the treble noticeably when raised to too high a value. The impedance load as a rule should be ten times the value of the cartridge’s internal impedance. The Shyla’s being 12 ohms thus VPI recommends a 100-ohm load.

@faustuss 

No, I'm not confusing them. That's why it's so strange. The impedance is set to 160. I had it set to 200 on my ARC PH-7. 160 sounds good on the Pass Labs. But there is a treble edge. I don't think the capacitance has as much affect as the impedance, but it defintely has an affect. And I know it's not supposed to on a MC. 

With the capacitance at 320 the sound is a bit more weighty. Treble is audibly less shrill. But that weightiness at 320 takes away a light, quickness at 200. So I've put it back there. I had a long chatgbt session about this. It suggests I turn the capacitance to 320 on certain shrill albums. Otherwise leave it at 200.

I know this sounds counter-intuitive, and that's why I'm reaching out to see if anybody can make sense of all this.

@faustuss

Isn't capacitance part of the impedance?  The other two components of impedance being resistance and inductance....

@mylogic 2?

@richardbrand 

@audio-b-dog 

"Isn't capacitance part of the impedance?  The other two components of impedance being resistance and inductance...."

Good morning, Richard,

I just looked at the manual for audio-b-dog's AR phono stage and he should look at it as well. This phono stage has a fixed gain of 57.5dB for MM and MC and a fixed capacitance as well. Since I can't find a spec for it, I would assume AR chose 150pf for MM and MC as I believe most manufacturers would for the bulk of the cartridges a-b-dog would be using. The phono stage does have 5 impedance settings however, one of 47K for MMs and four more for MCs. He should be using the 100-ohm setting that VPI recommends for their Shyla cartridge, sit tight and let his ears settle into the sound AR and VPI intended or maybe the Sonus Faber's are just too sweet in tonal balance for his preferences.