MC cartridge loading

[mikeyb]

I'm sure I told you but you didn't write it down

Worthy of some detention I think

Oh wait a minute he’s in that already

[Bigman80]

Worthy of some detention I think

Oh wait a minute he’s in that already

Lol yup, that's me.

[Hoffer]

It's easy if you have a calculator;

Loading resistor value = Desired value/(1 - (desired value/1000)).

Thus in David's case, for example, if the desired value is 250 Ohms, the loading resistor placed in parallel with the head amp is

250/(1 - 250/1000) = 250/0.75 = 333 Ohm. (The nearest preferred value is 330Ohm)

Is there a reason why I wouldn't just reset the phono preamp's load to 47k and use a resistor without worrying about the above calculation?

[NRG]

Your loading resistor would still be in parallel with the 47k of the phono stage so Barry’s calculation still applies. However, in reality with 47k and a 100R loading resistor the calculation comes out as near to 100 as makes no difference.

https://www.allaboutcircuits.com/too...ce-calculator/

[Hoffer]

Your loading resistor would still be in parallel with the 47k of the phono stage so Barry’s calculation still applies. However, in reality with 47k and a 100R loading resistor the calculation comes out as near to 100 as makes no difference.

https://www.allaboutcircuits.com/too...ce-calculator/

Thanks. I understand the calculation still works. In other words, regardless of the resistor value, if I use the 47k setting the calculation shows I'm within a fraction of the original. So I was just wondering whether there was some other reason why I would keep the phono setting at 1000 instead of moving it to 47k and using a resistor at it's full value.

[DiveDeepDog]

I missed the 47k setting, it makes life easier, so thats the way to go

[montesquieu]

AirTight PC7 needs a step-up transformer. That's how AirTight themselves handle them.

It's pretty high gain so something between 1:6 and 1:10 would be ideal, and run it into the MM setting.

Seriously get yourself a decent step-up and forget all this faffing with resistors.

At least try it out what have you got to lose? Frankly I've never heard a straight MC phono stage sound as good as a decent MM setting +quality SUT and that includes top-end stuff such as the Aurorasound Vida, one of the best out there. Or the Thoress Phono Equalizer which is mega-cool looking but doesn't have the magic straight to MC.

[Hoffer]

I missed the 47k setting, it makes life easier, so thats the way to go

Excellent. Thanks.

AirTight PC7 needs a step-up transformer. That's how AirTight themselves handle them.

It's pretty high gain so something between 1:6 and 1:10 would be ideal, and run it into the MM setting.

Seriously get yourself a decent step-up and forget all this faffing with resistors.

At least try it out what have you got to lose? Frankly I've never heard a straight MC phono stage sound as good as a decent MM setting +quality SUT and that includes top-end stuff such as the Aurorasound Vida, one of the best out there. Or the Thoress Phono Equalizer which is mega-cool looking but doesn't have the magic straight to MC.

I’ve considered it, but I like to run my turntable balanced (my VPI has balanced outs, and the Ayre has balanced inputs). I’ve yet to find a SUT that provides for fully balanced connections.

[Floyddroid]

I'm sure this has been asked and answered before, but I'm struggling to figure out what is the proper load setting for my AirTight PC-7. Mated with an Ayre p5xe phono pre, I have the options of 100, 1000 or 47k. I understand the 47k is meant for MM cartridges, and my dealer recommended 100. AirTight suggested something more in-between 100 and 800. I currently have it set to 1000 as I found the 100 setting to be a tad shrill on the top end (although the cartridge only has a few hours on it, so additional break-in might relax it a bit?).

The web, of course, is a wonderful but confusing place. I've read with a low output MC such as mine, the setting doesn't matter. I've read others suggest the 1000 setting will exhibit no difference between it and the 47k (I haven't compared this yet). Still others say your cables and gear can have an equal impact on your load settings, and therefore the 1000 setting may be the best/safest course.

I know many of you will say "go with what sounds best" but I'm curious as to whether I might be missing something given my settings are limited to 100 and 1000. I like my Ayre, but I wouldn't be against trading it in for something that offers more flexibility if additional load settings can truly offer an improvement in the sound quality.

Tread carefully, The Ayre is flippin good.

[montesquieu]

Excellent. Thanks.



I’ve considered it, but I like to run my turntable balanced (my VPI has balanced outs, and the Ayre has balanced inputs). I’ve yet to find a SUT that provides for fully balanced connections.

No harm in giving it a go. I've found no advantage in balanced myself though I must admit unlike for digital and pre-power I've never bothered to try it with vinyl.