Hagerman Piccolo Zero: New transimpedance head amp

I think the input resistance of the current driven phono stage is in parallel (not in series as per your equation) with the internal impedance of the cartridge, but I am open to discussion about that.  Anyway, my net experience with two very different current driven stages and three different LOMC cartridges is that the input impedance of the stage, which must be some finite but very low value above zero, plays into the resulting sonics.  So, it's not just whether you have enough net gain but also how the cartridge can drive that input impedance. The result is that the SQ is not always predictable.  Every pairing of cartridge with current driven stage is a new experience.  Where data are available, I found the input impedance of various units to vary between 2 ohms and up from there to about 10 ohms.

It should be noted that tonearm wiring DCR should be added to the internal cartridge impedance for your calculations.  This can often be 1-2Ω which becomes substantial in relation to the super low impedance cartridges.

dave

Interesting. Thanks @intactaudio , think I’ll just make a JavaScript calculator where I can plug in different parameters including cable + input resistance. 1-2 ohms seems awful high for 1.2m of cable, even at these small gauges (~ 24 - 26 AWG?). Is a lot of that from the physical contact points?

@lewm

Yeah I suspect you’re right on the matching. It’s not just about gain, though that is an important factor. I ran the Colibri at +12dB level last night (19dB "estimated" head-amp gain) and it was loud enough but still sounded bad lol. I’m not sure why the input resistance of a transconductance phono would be in parallel, though (e.g. loading resistors for voltage mode head amps are in parallel because it makes sense there). Does anyone else have a comment on that?

The thick wire that nets a low DCR also restricts movement so from the cartridge to the din connector is typically 12" of #36 or #37 which puts you at about 1/2Ω per foot.   I have an early Schick and a Schröder and both are in the 1Ω range from pins to RCA so that becomes 2Ω since they are in series.  

dave

@mulveling It is great to see your inquisitiveness has now landed you in Head Amp Territory, in use these have proved to be very impressive to myself and for certain music in my own system, the use of the Head Amp surpasses any SUT experienced on the same music genre to date.

As for the Head Amp in use in other Systems, I have heard it used with Miyajima, Ortofon, Audio Note IO and Sumiko Pearwood, where the H'-Amp has excelled as  comparative device to both In Built MC stages and SUT's.

If like myself, the investigations are taking place around tracks that are well known, I can' help but be very confident that there is to be a music genre discovered that will transcend your experience all ready had to new levels.

One more consideration to ponder if the Head Amp becomes the mainstay. The he TA could become a design to have the Signal Path as a Continuous Wire > Cart' Tags to RCA Phono Connectors ??.

I have recently heard this on a TA I know very well, where PC Triple C has been used as the Signal Path Wire.

  , 

@mulveling So, almost 3 months out, have your initial views changed at all on the Piccolo Zero or how it compares to other step-up alternatives? Has a little time shed any more light on ideal cartridge matching?  It looks like a great product!

Agree, would love an update

"Head amp" usually refers to any outboard device that adds gain but not RIAA correction to the phono signal, ahead of the phono stage.  These days, a head amp can be current driven or voltage driven.   The Piccolo comes either way, I think.

Dear @jobeare ​@tomic601   : " It looks like a great product! "

A cartridge develops voltage not current, then wh use a current design with a voltage audio item. Has no sense.

That to some audiophiles like it to use current phono stage/head amps designs means almost nothing, the real issue is that's a wrong road to go no matters what and again that " any one like it " means only that : thet he like it even if it's wrong but this is more or less usual in the audio world with several eaxamples of wrong audio items ( for whatever reasons ) where audiophiles just touted everywhere like the Dava cartridge or VIV tonearm and ovbiously current design. Obviously too that is way more easy the current phono stage design against a voltage one.

Current design is something very old technology and the first phonolinepreamp and head amp came from Classé Audio from Canada with its NIL ( Natural Load Impedance ) that was in the end of the 70's early 80's and guess what: I owned both with out knowing were current designs, I sold both.

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

A cartridge develops voltage not current, then wh use a current design with a voltage audio item. Has no sense.

100% wrong. One of the most misinformed comments I have ever seen on this forum.

High output moving magnets typically produce higher voltage and lower current relative to most low output moving coils. Conversely low output moving coils produce much lower voltage and therefore much higher current than typical high output moving magnets.

Here is an explanation -

A phono cartridge is essentially an electric motor. It turns the mechanical power that the record puts into moving a stylus into electrical power. It does this by placing a magnet nest to a coil of wire and moving one with relative to the other. This varies the magnetic field in the coil and produces electrical power.

So for the same mechanical input both MM and MC cartridges should produce the same amount of electrical power (and in fact they do) so why are MM cartridges described as “high output” and most MC cartridges “low output”.

The terms high and low refer to the output voltage from the cartridge not the output power.
Output voltage is determined by the number of turns of wire in the coil which equals extra weight so most MC cartridges have only a small number of turns of wire on the coil so produce a proportionally lower voltage (about a 10th) than a MM cartridge.
However electrical power is voltage x current so for the same mechanical input a MC cartridge can deliver 10 times the current of an MM cartridge.

for more info 

@dover 10+ I think the better analogy would be a generator not a motor, but they are the same thing in reverse. 

I have a Channel D Seta L Plus. It can be used in both voltage and transimpedance mode. The Atlas SL has more gain and sounds better in transimpedance mode, but the Hyperion has more gain and sounds better in voltage mode. So, it depends on the cartridge. The best predictor is the cartridges impedance. IME cartridges with an impedance below 5 ohms work best in transimpedance mode, between 5 and 10 ohms is neutral and over 10 ohms works best in voltage mode. 

@mulveling That is way too much math for me. I think @lewm is correct, they are parallel. 

@mijostyn  : My post is rigth: a cartridge develops voltage.

R.

@mulveling - Thank you for the kind words and posting results of your experimentation. I ran the calculations and input impedance of PICCOLO ZERO comes in at about 0.02 ohms at 1kHz. This is purely dependent on the gain/frequency characteristic of opamp in use. 

@rauliruegas - I'm sorry, but that is not how Faraday's Law of Induction works. Yes, a coil moving within a magnetic field generates an EMF (measured in Volts), as a function of velocity. When the coil is open circuited, you get a voltage. This is how most cartridges are operated. When the coil is shorted however, the EMF forces a current to flow, creating a magnetic field equal and opposite. See Lenz. There is no output voltage, as it is a short circuit.

Therefore, a cartridge can develop a voltage, current, or power. The latter when loaded somewhere between zero and infinite ohms. Seriously, are you trying to say our transimpedance stages do not work? 

Dear @hagtech : Of course not, obviously it works.

I know very well your whole explanation that between other gentlemans as atmasphere werein a deep and hot long thread only because that EMF/Lenz.

I think that maybe I can share the link of that thread,is a learning one for sure..

R.

@rauliruegas My apologies. I thought you were saying cartridge is not pumping out current when used with transimpedance stage. 

Curious if anyone has insight into the differences, if there are any, in technology (or sound character) between the Piccolo Zero and the Sutherland SUTZ? They seem like basically the same thing yet the Piccolo Zero is so much more accessible and space-friendly.