Cartridge Thread for Transimpedance/Current Mode Phono Stages

[qik_shift]

Transimpedance phono stages have been sold by a few companies over time (BMC, Channel D, Meitner, AQVOX, Sutherland, CH Precision etc.), but in comparison to voltage mode phono stages, there's not a ton of data on which cartridges work and which ones don't.

 

Rather than read the theory on what works and what doesn't, can people please pass on their experiences in this thread for reference?

 

Is it actually true that low internal cartridge impedance is the golden rule?

 

For example I'm running a Kiseki Purple Heart which runs a (not low) internal impedance of 42 ohms, and report that it sounds great on a Sutherland Big Loco and sounded great on the Sutherland Little Loco too.

 

I wonder if it works well for a Sutherland whether it would sound good on another brand transimpedance unit?

 

Apparently some carts don't sound so good and would love to hear this feedback too to help save others from making costly mistakes.

[Gryffles]

I think it will differ on different brands but still worthwhile. I use an Air Tight ATE-2005 which is trans impedance

 

One that works very well indeed is the Benz Ebony L 0.26mV and 3.5ohm. 

[Gryffles]

@qik_shift

 

Below is copied and pasted from a different forum. This will answer your question about low imp carts with trans imp phono stages. 

 

J Carr:

 

Resistance is one of those things that is easy to mis-construe unless everyone discussing the topic is very clear (even verbose) with the terminology. Higher capacitance values should be paired with lower resistance values, and vice versa.

The loading resistor value is placed across the phono cartridge's output terminals, which means that any output voltage produced by the cartridge will be forced to flow through the load resistor in the form of current. The higher the load resistor value is, and the farther the net impedance is from the cartridge's internal resistance, the less current will be produced. Conversely, the lower the load resistor value is, and the closer the net impedance is to the cartridge's internal resistance, the more current will be produced.

Forcing the cartridge to produce more current works it harder, and in so doing, stiffens the compliance (the cantilever moves less readily). Making the net impedance closer to the cartridge's internal impedance (by using lower-value load resistors) will also attenuate the voltage output from the cartridge, which makes the job of the phono stage (the vast majority of which are voltage amplification devices) harder.

IMHO, the only time that forcing the cartridge to produce more output current could be justified is when using it into an IV phono stage. Since this kind of phono stage converts input current into output voltage (and is more or less oblivious to input signal voltage per se), it would make sense to feed an IV phono stage with as much input current as possible. An IV phono stage, however, possesses de facto a low impedance input node that receives the output current from the cartridge as a series element (without needing a separate load resistor). This is not how a normal loading resistor works with a typical voltage amplification stage, since there the separate load resistor bleeds the current from the cartridge into ground (thereby wasting that energy). Also, IV phono stages sound qualitatively different to voltage amplification phono stages., and part the reason is that undoubtedly the cartridge is forced to operate into a zero-ohm load (or some other values that is quite close to the cartridge's internal resistance).

[Steever]

Dynavector like to espouse the virtues of what they call Phono Enhancer in their phono stage, the P-75 mk4. https://www.dynavector.com.au/index-4-P75.html

They suggest their low impedance carts function well in PE mode. I had one of these phono stages and was going to grab one of their low output carts to match. I picked up a Rega Ania Pro instead and this worked very nicely into PE mode with its low impedance.

[Demondes]

A Sutherland Little Loco Mk2 transimpedance phonostage user here brilliant with ZYX 4D cartridge with internal impedance of 4ohm and output voltage 0.24mV.

 

[artaudio]

Currently using the Dynavector P-75 with the Dynavector XX2 MkII till my DV-XV1s returns from warranty repair. been playing with PE Mode and Standard loading and have found the sound better using the standard loading at 5x in this case the XX2 MkII is 6 ohms and loading with 30 ohms is much better than PE mode (Current Mode).

 

Dr Rod Crawford from Legend Acoustic also tried with his ZYX cartridge with the DV P-75 and found that PE mode sounded better. 

[andyr]

2 hours ago, artaudio said:

 

Currently using the Dynavector P-75 with the Dynavector XX2 MkII till my DV-XV1s returns from warranty repair. been playing with PE Mode and Standard loading and have found the sound better using the standard loading at 5x in this case the XX2 MkII is 6 ohms and loading with 30 ohms is much better than PE mode (Current Mode).

 

 

Did you try any higher loading options the P-75 has?  I believe it offers 220 ohms and 470 ohms?

 

Andy

 

[Gryffles]

Another cartridge that works well is the Transfiguration Axia. Out of production unfortunately but can be found cheap and then get it rebuilt or re-tipped. 

 

0.4mV and 4ohms

[qik_shift]

My Sonic Labs Signature Platinum - oh hell yes this works.

 

Internal impedance 1.4 ohms.  0.5mV @ 1 kHz output.

[qik_shift]

Should have mentioned I was so happy with demoing a Koetsu Coralstone that I brought one. Works very well.
 

internal impedance 5 ohms, output 0.3mV.