mono cartridge vs stereo

Actually, I was wrong in my post above this one. The two Y-adapters would feed the 2-channel output of the stereo cartridge to the phono stage in parallel. This would alter the impedance relationship between the cartridge and the phono stage that may or may not have negative consequences. When you use the mono switch on your preamplifier, you are combining the channels AFTER RIAA correction and phono stage amplification, which has got to be less harmful. Sorry if I misled anyone.

If you have separate phono and linestages, you could install the Y-adapters between the two components, which would work exactly like a mono switch, more or less.

Lew, thanks. Yes, I'm going to put it b/t my phono preamp and my linestage. I think I'll have BlueJeans Cable make one up for me to try it out. I'm assuming all it takes is making a normal set of cables, opening them up in the middle, soldering the hot wires together and soldering the ground wires together. Pretty simple. Someone should make a high quality adaptor that plugs right into your linestage to offer you a mono input. I guess the other way to do it, if you have a spare RCA input on your linestage, is just to solder a jumper across the two hot contacts on the RCA jacks. I'm wondering if that is all one would need to do. That is, given the ground configuration, if the grounds are all joined together anyhow. I might call VAC and ask them about that. It would be so easy to do with a small piece of wire, and I have the extra input...

Am I getting it right? Thanks, Peter

I should understand this subject better than I do, but here goes. The problem with using a stereo cartridge on a mono record is that the stereo cartridge has both vertical and horizontal compliance, which on a mono record having music only in the horizontal plane opens up the possibility for picking up a significant amount of surface noise. On new reissues of mono LPs this is really not a problem, or at least it shouldn't be. For old and well used mono LPs, though, the noise difference is frequently quite pronounced. If the wiring in the cartridge is set up to ignore the vertical information, the net effect is identical to using the mono button on preamps so equipped, and is also identical to using Y cables as already discussed. I have a mono cartridge and can attest that it sounds significantly better on old mono records than using a stereo cartridge, but on new re-issues, the advantage is less pronounced. One of my stereo cartridges is an Ortofon 2M Black, which has a shibata stylus. The shibata shape is not easy to set up for quiet tracking with the vertical tracking angle being particularly critical. For that reason, I prefer the much more forgiving conical stylus geometry for mono. I hope that helps.

Thanks Bill. I don't have the flexibility to set up a mono cartridge on my turntable. Too much effort readjusting the VTA every time I would change. So I guess I'm stuck with using Y adapters, or on advice from VAC, I could strap together the positive pins of one of my inputs on the preamp to essentially create a mono input. I'm considering that approach, because I have extra RCA inputs.

Peter_s.
Yes, the difference between a stereo and true mono cart is if there is output from vertical cantilever motion. Noise with old mono records is dramatically reduced with a true mono cart, but virtually all records since the around 1950 are V cut microgroove, invented in '48.
http://ortofon.com/hifi/products/mono-series

"If you play a mono record with a stereo cartridge you will not achieve the same signal in the two channels due to imperfections such as crosstalk, noise, phase errors, tracking error, antiskating and distortion. This difference between the channels will result in an unstable and partially fuzzy image. A mono switch, to some extent, can improve this."

If you combine channels in your line stage it should have the same impedance implications as combining cart output - cut it in half. There's source impedance and input impedance. If channels are combined wouldn't both be halved?
Regards,