Voltage mode vs current mode phono stages


Can someone explain the differences in layman's terms and why is one better than the other? 

rsf507

Clearthinker, that’s an impressive list of cartridges. Your colibri with 36 ohm internal resistance probably has a healthy voltage output. Do you run it into the Grail in current mode or voltage mode or does the Grail even offer that choice via separate pairs of inputs? Thx.

@lewm 

I am curious about what happens when you mate a Sussuro, for example, with a current driven phono stage.

This post from a recent Little Loco thread may shed some light:

I ended up with a Soundsmith Sussurro cartridge, but the Low Z (Low impedance) version. I would suggest if you were to buy one make sure Peter Lederman knows it's for a transimpedance stage.

The long version is that I contacted Peter and he contacted Ron Sutherland and compared notes. Peter built a low impedance version of the Sussurro and sent to me. I didn't like it, thought it was rolled off up top a bit. Peter offered to refund my money but I told him I would prefer he try to resolve and asked him if he would be willing to put in the time to do that. He agreed and I ended up sending the cartridge and the Little Loco to him to work with. The results are as you would expect if one of the most knowledgeable and talented guys in the cartridge/phono industry had your gear on his bench...an excellent match, I'm loving what I am hearing. 

My comparison is the Audiotechnica ART-9 which sounds pretty darn good but not nearly as good as the Low Z Sussurro, and my digital: Innuos Zen MKIII and Bricasti M1 SE MDX (who names these things?!) DAC. 

I actually picked the cartridge and Little Loco up at his shop because I was in the area visiting family. Peter took me on a tour, we listened to music, talked about dogs...he's a great guy, I'm really thankful for the entire experience (and for sure I'm glad he was willing to take the time to make the cartridge sound so good).

Hi Ralph, You wrote, "This suggests that as the impedance of the cartridge goes up, the gain of the circuit goes down, which is probably good since the output of the cartridge will be higher."  The linear relationship between voltage output and stylus velocity (higher at higher frequencies) is accounted for by the RIAA correction.  Would you want the cartridge to alter that relationship by virtue of an upgoing internal impedance?

@lewm I don't think I would employ any EQ on the transimpedance input (meaning the opamp). I would leave that for later in the circuit, such as a passive EQ network at the output of the opamp. In this case the constant velocity aspect of the cartridge really has nothing to do with it.

@lewm , IMHO the Grails are horrendously over priced. Looking at the internals the construction quality is not up to modern standards. As an example the boards are through hole not surface mount which is considered to be better. 

The Seta L Plus has significantly better construction, a better power supply and comes in at $10K. It's only down sides are it is not very versatile having only one input and switching between current and voltage mode requires going into the unit and removing or replacing a jumper. You would have no problem with that and I greatly prefer the simplicity.

Without ever having heard or even seen any current drive phono stage, my current favorite just based on tech and reviews and cost, plus balanced operation, would be BMC MCCI.

I suppose some aspects of SMD construction are beneficial, especially in a device centered around an op amp, but not all, and not when repair is needed.