The correct internal-inductance of Windfeld cart.?

Axel,

I originally misinterpreted what you were saying about "free" voltage multiplication.

What is interesting about your experience with primary loading of the PW cartridge is that your ideal loading (the reflected load seen by the cartridge) is radically different when using that SUT than the recommended loading when using only an active phonostage or secondary loading.

I was wondering if you have any speculation as to why this is so. I know that some experts maintain that there is a specific "critical" load that effectively dampens the high frequency peak without excessively rolling off the high frequencies. I was wondering why it is not the same load (as presented to the cartridge) regardless of the type of downstream amplifying device.

I am asking this because my phonostage (Viva Fono) utilizes a SUT as the first stage voltage gain device (feeding a tube active stage). I don't even know the gain of the device, but, it is loaded at the primary with a 460 ohm resistor. This resistor is soldered across the back of the RCA input jacks. Because of the difficulty in accessing and changing the resistor value (tight space, a lot of nearby wires), I've limited my experiments to connecting and disconnecting one leg of the resistor. I am now wondering if I should try a MUCH lower value resistor.

Hi Saudio
it is like so many things in this here endeavour a ROT value and used if you want to impedance match your cart to an SUT. It is of NO value if you do not use an SUT.

Greetings,
Axel
PS: As in all things Audio YMMV, but I must say it works spot on for me, else I would not have mentioned it. Look at the minimum impedance cart spec. quoted, and it should be close. Often some specs do not consider SUTs, then in other more user friendly specs they give you both impedances for SUT and 'normal' straight into phono-pre , say 10ohm SUT and 100ohm otherwise.

Axel, To me, the "minimum impedance" spec given by the cartridge maker is not the same as the optimal impedance. Can you name any cartridges where two different impedances are suggested, one for SUT, one for no SUT? In my very limited experience as an owner of high-end LOMCs, I have not seen that. This is not a challenge to your integrity or your perspicacity, just a question.

Larryi, The point you are making is exactly the same one I was trying to make with Axel, when this thread was in its infancy. His finding is interesting, indeed. His response to that question is what got us rolling in the current direction (pun intended).

Hi Lewm
funny, punny as ever, hey.

Now to my: >>> integrity or your perspicacity <<< aka wisdom, uff. So now you want me to go on digging in the web to give you satisfaction…
This info came about by some expert that taught me a LOT about how to set-up a trannie.

Some (at least to me) more obscure makes where mentioned, and you may be right in not having seen such your self, neither have I. Should I then not mention it? I don't think it really matters, unless we want to get religious about this stuff. I’m not in the habit of venting fantasies in a forum neither.
I also do not go through serious cart-loads (pun intended) like e.g. Raul. So he may just be the man to corroborate this information, let’s hope he can!

Now, on a more serious note, let's get to those specs that EVERYONE (including me) has actually seen. Look at any Ortofon MC spec. in the low output range and, lo and behold, it says >10 ohm (they fixed up their mistake(s) by now).
So, go and tell me of someone, who does not use an SUT, that has EVER used 10ohms load with a 0.3mV cart?!
Starts sounding like there's something here, yes?
In fact, I tried it! Actually 13ohm || with 47k phono-pre to be quite exact i.e. > 10 ohm, yes?
IT SOUNDS PATHETIC! Utterly unusable! Rolled off as hell, dull, totally over damped, and very much down in output. Now if that is so, why would Ortofon quote >10 ohm?!

Another one of their mistaken spec. numbers? Not so!
BTW, the same could be said for a Jubilee too, also >10 ohm.

I could go on quoting some more. However I have not tested any of these, lest here comes Lewm, go question my integrity again. So we better leave that to some one else to proof. How about you yourself? Then YOU can do some tellin’ and only questioning.

So, take that same cart (PW) and load that baby, using an SUT, on secondary with 18k [with a 1:31.6 (30dB) trannie] it will give you ~ 13ohm on primary and we have a VERY good impedance match / load! And it sound already better than most phono-pres I heard, hallo!

Now, I say: this could STILL be better, and now go load it on primary, straight with 13ohm, (and brother you better use a Tantalum, Shinkoh or some such) now || with 47ohm reflected, [the natural impedance of a 1:31.6 working into 47k phono-pre] and we have a 10 ohm impedance load!!! AND it works like a charm! Even better than 18k on secondary!

Now, go call me names if it still feels appropriate. That’s REAL not fantasies.

Next, you now get the idea why >10 ohm was quoted? Let’s hope so.
It gets even more clear when you learn, that a PW can work best into 47k! IF YOU DO NOT USE AN SUT. Same would apply to a DV X1-s, which I have heard with 47k loading, it sounded VERY nice. I bet you with a tranny it will be even better, BUT with ~ 10ohm.

So, what was your next question (-:

Greetings,
Axel
PS: Any of you 'interrogators' use any SUT? I'm not sure if you are having me on sometimes...

Lewm,
I'm still tying to get back to the source for 2.5 x cart DCR = lowest loading = ~ best approximation of cart impedance.

There are other 'notions' about that, which I found not to be workable, neither for secondary nor primary loading i.e. 5 x RDC for ~ loading 'start point'
or even more exotic (French...)
4 x loading + 1x RDC.

So in a case of a 4 ohm RDC cart you’d get:
1) my version 2.5 x 4 = 10ohm minimum ~ and assumed cart impedance

2) 5 x 4 = 20ohm minimum ~ start load... it is too high for an SUT impedance match and far to low for 'normal' non-SUT loading in my experience.

3) 4 x 4 + 4 = 20ohm also, the above comment applies.

IF, you go just below 10ohm (SUT imp. matching) say ~ 9 ohm, you will get already a powerful cart output drop, if you go to just 13 ohm (a 15 ohm R with 47ohm SUT reflected) the sound starts to get on the bright side and toward unbalanced.

If, you're brave and try 100ohm (all primary we are talking) you get your ears flossed, big time! Going even higher 230, 500, 1k a steady output roll-of is then the case. If you do not know about impedance matching this can be confusing, because a 13ohm (non SUT) loading produces a similar result in sound than e.g. anything around 250 -500 - 1k ohm WITH an SUT.

IF you take e.g. a DENON 103 with 40ohm RDC 'my' reported 2.5 ROT with say 40ohm x 2.5 = 100ohm minimum cart loading (on primary) and we are not talking the resistor value just to make sure since we are in || with the SUTs impedance -- what ever that is. This, but i have to tried it, sound in may finding just fine for primary SUT loading.

Some SPUs could sound confusing here, as they would give >10ohm minimum for a 6ohm RDC cart, but that might be one of their misprints also...

Greetings,
Axel