Groove damage from spherical styli

The only things required to be identified are the input impedance and capacitance.
You need to know the latter before recommending the former as they form a filter.
I agree that simply suggesting the application of X impedance without accounting for the capacitance is of little use.

The same input condition on any phono stage will produce the same response from any given cartridge. There are no other variables at play.

The comments here refer to a specific AT MM. Change the cartridge and its back to square 1 for the calculations.

 

Sorry this just shows lack of understanding, headroom and power supply impedance has direct effect on this sonically and there are other parameter that I wont go into. This is just old think that the public are palmed off with, simple specs that are largely meaningless.

Why do you think exact matching is important with a SUT, because it has no headroom, or I should say it diminishes the headroom available in the following stage because it robs from it. And I am not talking about voltage clipping as such, it is the rails being pulled down.

Think of it as a door, if there is only the possibilty of light contact and push, then equal air pressure etc is required for the door to open easily (matched impedance), if you have a strong push capabilty (or in this case push / pull) then it matters bugger all how well matched the two side of the door are you just barge through

Capacitance cannot be seen in isolation to resistance it is just an intinsic part of the load. Even a resistor, a plug, or a bit of wire has *a* capacitance.

 

I don't see where the disagreement is?

You can argue about sonic merit but a tuned circuit is a tuned circuit - the effect on the cartridge frequency response is entirely predictable. If you know all of the required parameters you get a known result.
You can argue that you get a better *musical* result with a super stiff PSU but it will make sod-all difference to a frequency reponse peak caused by incorrect matching. So a cartridge that sounds 'toppy' because of inband resonance will still sound that way.

We are discussing a MM cartidge here in the AT440, not a MC so talk of SUTs is of no use.

I'm not seeing capacitance in isolation - the calculation for these purposes takes the lumped capacitance on the input, wiring, tags etc as the total figure.

 

Well I am sorry but you are still being too simplistic, simple impedance (which includes capacitance as that is the major diference between impedance and resistance) does not help. It helps when the circuit as a whole is struggling to do the job (as when using valves and SUT) but when it isn't and there is lots of muscle available then it matters bugger all. I can run my SPU into 470 ohms or 10k (with 470pf to comp out RF) or even into 47k ohms and I defy any of you to hear the difference. With most other phono stages you will hear differences of varying degrees, and with some like a badly designed solid state or valve with or without SUT you will hear differences down to a few K changes. This does not make it better at the job it makes it worse, which is the whole point of my argument.

A good phono stage does not need this faffing around.

 

I know - and we still aren't disagreeing!
You haven't read the query

We are not discussing a MC here - we are discussing a standard Audio Technica MM cartridge that *is* sensitive to loading conditions. It would sound very different into 30k ohms, and varying capacitance from say the practical minimum of 100 puff to the likely max for a phono input of 400 puff has a large effect on the HF response.

Your argument relates to a different topic entirely, though any phono stage needs 'faffing' if you run a typical MM into it. There is no one size fits all with MMs.

 

I was just using the SPU as an example it would be the same on the AT, we are talking about circuit design.

OK if you wish - I could load your AT with 10k or 47k and you would not hear the difference. There is no need for input capacitance with a MM as the input level is high enough to avoid RF on a good circuit. Of course 400pf will comp out HF, it is not necessary.

So your AT is only load (in terms of resistance) sensitive to the extent you indicate if a badly designed phono stage is used.

 

No, load the AT as you describe and it will sound severely broken, for well understood reasons.

Input capacitance is critical with a MM.

I'll demonstrate if you wish by recording a MM into 10k ohms, and then varying the capacitance.

AT specify 47k and 200pf for a reason - it performs to specifation at that loading.

The fact that the AT has high output is neither here nor there. It has high self inductance, much higher than MC, and will react strongly to the load conditions presented.

I'm afraid that is the real world and however much you may want cartridges and phono stages to match under some universal law, they dont.

 

I am sorry you are wrong, I can prove it to anyone who wishes to bring that cartridge to my place.

This is the silliness that started my contribution to this thread. It *may* sound broken on what you use it on because what you use it on *requires* the matching, it does not mean that is the situation always, this is a presumption that is at the root of this problem. I explained the reason and I don't need to repeat it.

If AT promote and continue this in their literature then that shows them up as to the circuits they have used the cart with.

 

AT recommend 47KOhm they don't specifically advise or suggest on using 30Kohm
this has come from recommendations by users who find it toppy & it does calm the performance down a bit. You can say all you want but I'll advise using 30Kohm for this cart if someone is finding it a bit extreme on 47kohm.

My criticsm of this cart is despite it having the microline stylus & having an excellent spec & overall it does everything supremely well, I still find piano is not as rounded as it should be & it lacks a certain atmospheric. It is the most detailed & cleanest sounding cart I've ever had, conversely I am more inclined to get up a dance with other carts.

 

The cartridge requires a specific load in order operate correctly (as specified).

It either gets that loading or it doesn't.
What goes on inside your phono stage has no bearing on matters. All that matters is the load presented to the cartidge at the input terminals.

Every MM cartridge manufacturer since the invention of the things many decades ago specifies loading conditions.

If you have a link to the explanation of how your load rejecting circuit works I'd like to read it - I've not seen it.

 

You read it at PF, it is all about circuit design, headroom and power supply back up.

I can prove it very easily to anyone who wishes to listen as I have proved to *every* owner of that phono stage design.

I am sorry Rob but your knowledge is too simplistic and based on written spec and what your test gear says, it is not that simple and if you haven't the experience of designing phono circuits for as long as I have, you wont get it, and I am not sure I am willing to give it away apart from on a simplistic level, but as I say again you are welcome to bring it around and prove me wrong.

 

All I can say is a little knowledge is a dangerous thing. You make presumptions that don't exist in reality. Your phono stage just *requires* you to do this in *conjunction* with the cartridge i.e. *interface*.

 

I do recall it but not in detail. I'll revisit it.

But power supply design and headroon will not alter the fact that a cartidge has a demonstrably different response into different loads. Nothing more than simplistic understanding is actually required here, since the issue is a simple one.
You can argue that making the supply stiff and improving headroom makes for a more enjoyable musical experience if you wish, but these things won't change the fundamental response.

Test gear is king here - sorry you cannot escape it.

If I alter the cartridge loading, the response changes and you can both hear it and display it visually. This happens with all phono circuits and there aren't any exceptions unless you've discovered a whole new set of rules that have passed the rest of science by.

What input conditions does your MM & MC phono stage present to the cartridge?

 

Reading this thread, I am so effing glad that I no longer have to worry about stylus profiles, RIAA curves, VTA, tracking weights, azimuth, bias, and all the other sundry arcana associated with dragging a rock along a boulder strewn plastic canyon!

Chris

 

I avoid it where possible but still want to play the 3500+ albums I have.
So needs must I'm afraid.

 

Per usual test gear just lies to you, it tell you it (what ever) is working to design spec, no more than that, it cannot tell you how circuits interface while playing music.

I repeat I can prove it and have done so many many times.

MC is set to 470 ohms 470pf - MM is set to 47k ohms and no capacitor.

 

view this site, www.at-oc9ml.co.uk.

 

also, www.moving-coil-cartridges.com/ audio technica http.

 

Ok, play the AT440 into your MM stage at those setting.
It should sound very good at it doesn't like capacitance - the arm cable usually has enough for the 440 in most cases.

Then try it with 300pf on the input

The HF response of the cartridge will change very markedly and more importantly, very audibly.

The test gear will tell me exactly what will happen to the frequency response of the cartridge - no mystery.

You can prove that changing load (avoiding the plain daft extremes) has very little audible effect on a SPU. Same would go for a Dynavector or any other low output, low inductance MC. I can do it with my AT33 MC. I've built a phono stage on which you can alter loading on the fly. The biggest change is decreasing level as you progressively slug the cartridge.

Things are very different in MM land where the tonal balance goes all over the place and that will be the case on all stages.

 

I am not nor have I questioned the effect of capacitance. It is far more pronounced obviously in conjunction with a high value load resistor and with MM cart. With MC it is different with lower load resistor like 470 ohm then 470pf is innaudible, even 1000pf is virtually innaudible.

My bone of contention in this thread is *resistance* load, and all this nonsense going on at the forums about needing to match, design a phono stage correctly, as some are, and it is not important. It is basic lack of understanding, load is interface, interface is between two things, so *they* have to match and if the one you are going into load rejects then there is no problem to solve QED.

So to go back to my original point unless everyone forgets it. We were being told that 32k ohms sounded better than 47k ohms, well if it does then you have a pretty duff phono stage if it is so messed up by so little input loading resistor difference. So you should *qualify* the statement by saying what the phono stage is so people only relate the statement for that cart used with that phono stage, as that is the interface in question.