I just saw this article over at Audio Asylum. The idea is certainly novel, but the article doesn't go into any details on how its implimented besides saying that a second, identical cartridge (to the one being used as the input) is installed in the feedback loop of the opamp in the circuit. I'm very intrigued, but I don't really know much about electronics. Anyone have any ideas on how this could be implimented? I'd love to try it.
Hi,
seems like the first flat stage gain block is replaced with this complex feedback gain block. Then the really flat signal is sent on for RIAA processing and out comes another flat signal. More majic or are all my flats getting jumbled?
seems like the first flat stage gain block is replaced with this complex feedback gain block. Then the really flat signal is sent on for RIAA processing and out comes another flat signal. More majic or are all my flats getting jumbled?
Very interesting. Besides a handful of functional Grados i have even more without stylus. Who wants to do the experiment?
My one viist to Paul & Stan's Santa Maria facility was VERY interesting....
dave
My one viist to Paul & Stan's Santa Maria facility was VERY interesting....
dave
Mr.Radar said:
Hey, that was my post at AA (and my blogger page) 😉 .
So far, not much response at AA.
My engineering knowledge is limited to ones and zeros, so I am not sure how to implement it, that's why I asked the question at AA, to see if anybody over there would pick it up.
Too bad I can't get a hold of Stan on the phone anymore, he would be able to tell me how to implement it.
Randy
Re: Re: Interesting idea to make MM carts sound better...
When I saw the thread at AA I immediately thought of this forum (if there's anyone out there who could figure this circuit out, they're probably here). Like you, I know hardly anything about analog electronics (my favorite form of DIY'ing is writing computer programs (if you consider that DIY'ing...), and recently PICs have piqued my interest (no pun intended), but I haven't gotten around to actually doing anything with them yet).
randytsuch said:
When I saw the thread at AA I immediately thought of this forum (if there's anyone out there who could figure this circuit out, they're probably here). Like you, I know hardly anything about analog electronics (my favorite form of DIY'ing is writing computer programs (if you consider that DIY'ing...), and recently PICs have piqued my interest (no pun intended), but I haven't gotten around to actually doing anything with them yet).
AndrewT said:
Or, (possible stupid question) does the second cartridge do the RIAA correction for you?
Max
maxro said:
No. The cartridge doesn't know anything about the RIAA -- it is embedded on the record.
dave
inverted model
A very intriguing article. I should not have dumped my 30 year old multivariable control theory textbooks.
My first hunch was that you need an inverted model (system) to nill the anomalies.
Inverting not meaning that it is laying on its back??.
I would not have a clue anymore whether putting the (original) (model) in the feedbackloop would have the same effect. This will give some restless sleep.
E&E
A very intriguing article. I should not have dumped my 30 year old multivariable control theory textbooks.
My first hunch was that you need an inverted model (system) to nill the anomalies.
Inverting not meaning that it is laying on its back??.
I would not have a clue anymore whether putting the (original) (model) in the feedbackloop would have the same effect. This will give some restless sleep.
E&E
inverted signal for "grado/PS Audio" tweal
2 thinks strike me about this...
how easy it would be to implement for any cartridge.... and how easy it could ocur if your phono stage has a pair of inverted inputs..
As the owner of a wonderful sounding PS Audio lll phono stage, I'm gonna pop the hood and have a peak inside.. oir hunt down the owners manual/schematic if I still have it🙂
2 thinks strike me about this...
how easy it would be to implement for any cartridge.... and how easy it could ocur if your phono stage has a pair of inverted inputs..
As the owner of a wonderful sounding PS Audio lll phono stage, I'm gonna pop the hood and have a peak inside.. oir hunt down the owners manual/schematic if I still have it🙂
There was an audio company in existence once that
sold preamps based on this idea - namely that a "replica"
of the nonlinear component was inserted in the feedback
loop of the gain stage to cancel out nonlinearities of the
device. The name of the company escapes me at the
moment. Eventually they had power amps and other
devices using this "principle".
sold preamps based on this idea - namely that a "replica"
of the nonlinear component was inserted in the feedback
loop of the gain stage to cancel out nonlinearities of the
device. The name of the company escapes me at the
moment. Eventually they had power amps and other
devices using this "principle".
I suppose that if you had a spare cartridge of the same type, you could try it out to see if it worked. Howver, cynical me thinks that it sounds like the kind of thing that a cartridge manufacturer, or a hi-fi dealer, would suggest, in order to sell you two cartridges rather than one!
cynical U...
Well PS Audio was/is in the business of selling components as a manufacturer.
I believe Kinergetics (stated in the link to the blog in this thread) was the "manufacturer" of the device in question (or rather they became Kinergetics) and did not make any cartridges.
The idea is "sound", amplifier manufacturers have been using ideas like this for a while (feedback that is). Why wouldn't this work? Hmm, seems like anybody wishing to drop out noise, etc (Noise cancelling headphones anyone?), or undo what a component may add to the signal would use this simple technique.
It may be difficult to implement, and the use of cheap cartridges to prove the point should be pretty astounding..
If a couple of $60 Grados ($120 for the pair) could outperform much more expensive cartridges ($120 + for one), then why not. I'd love to hunt down the Kinergetics guys if still around, or anyone who heard this first hand for their impressions.
Well PS Audio was/is in the business of selling components as a manufacturer.
I believe Kinergetics (stated in the link to the blog in this thread) was the "manufacturer" of the device in question (or rather they became Kinergetics) and did not make any cartridges.
The idea is "sound", amplifier manufacturers have been using ideas like this for a while (feedback that is). Why wouldn't this work? Hmm, seems like anybody wishing to drop out noise, etc (Noise cancelling headphones anyone?), or undo what a component may add to the signal would use this simple technique.
It may be difficult to implement, and the use of cheap cartridges to prove the point should be pretty astounding..
If a couple of $60 Grados ($120 for the pair) could outperform much more expensive cartridges ($120 + for one), then why not. I'd love to hunt down the Kinergetics guys if still around, or anyone who heard this first hand for their impressions.
I may be just being dense, but surely the only thing that would be cancelled out would be any non-linearities in the coil, which would be fairly minor compared to the other non-linearities in the cartridge/arm system such as mechanical ones.
You are quite right Al. There is no no chance in the world to compensate for things like bad tracking with this method. Actually, according to the article they only claimed to compensate for the frequency dependency of the cartridge impedance. I don't know much about electrhomechanical systems, but won't actually the impedance also depend on the stylus position, so that the impedance actually varies with the stylus movements? This could not be compensated either, but any such effect is probably small on the other hand. They also don't compensate for the cable part of the input impedance, but we probably don't want add long cables to the feedback loop. 🙂
BTW, has anyone figured out how it works? The only solution I have come up with is to start with a unity gain stage with "cartrdige feedback" and then basically use a normal phono amp after that.
BTW, has anyone figured out how it works? The only solution I have come up with is to start with a unity gain stage with "cartrdige feedback" and then basically use a normal phono amp after that.
Hi,
the first stage could be a low noise gain stage (non inverting +12db upto +20db) with the dummy cartridge in the feedback loop. This would then give a good signal to feed into the inverting feedback RIAA stage that inherently has slightly higher noise. That way you have not added any extra stages and that first stage is correcting for coil anomalies.
the first stage could be a low noise gain stage (non inverting +12db upto +20db) with the dummy cartridge in the feedback loop. This would then give a good signal to feed into the inverting feedback RIAA stage that inherently has slightly higher noise. That way you have not added any extra stages and that first stage is correcting for coil anomalies.
But how do design that gain stage so the compensation works? I am not saying it is impossible or even non-obvious, just that I couldn't figure out how to do it. For a gain of 1 it is obvious, on the other hand.
I think that it equalizes the impedence on the inverting and non-inverting inputs of the input op-amp. If they are equal, then common-mode distortions cancel. Using identical cartriges on both inputs will make the impedences equal, and gain variations due to this will be cancelled.
I read somewhere a very long time ago about this; the author described it but left out how it was done, but he implied that it used discrete components rather than another cartridge.🙂
I read somewhere a very long time ago about this; the author described it but left out how it was done, but he implied that it used discrete components rather than another cartridge.🙂
Integral concept
I do like the idea that you should compensate for the cartidge-tonearm-phono pre (pre). There is an other thread running to do a similar thing with LS driver(s).
One should be able to do such a thing with a DEQ2496 type of system. Add the difference between the known and the testsignal output to the pre-power system.
Problem is the known signal, assuming that your CDP is more correct then your vinyl based system, you need a (limited bandwith)pink/white noise on vinyl and CD that are the same.
For what it is worth
earsandeyes
I do like the idea that you should compensate for the cartidge-tonearm-phono pre (pre). There is an other thread running to do a similar thing with LS driver(s).
One should be able to do such a thing with a DEQ2496 type of system. Add the difference between the known and the testsignal output to the pre-power system.
Problem is the known signal, assuming that your CDP is more correct then your vinyl based system, you need a (limited bandwith)pink/white noise on vinyl and CD that are the same.
For what it is worth
earsandeyes
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