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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.
tlscapital
13-02-2019, 16:03
I set my load, capacitance and gain by ear. That since an "exotic" cartridge can require the oddest values and as you implied, the rest of the phono chain will have an impact on the signal al the way up to the speakers. Trust your ears !
Hi David, you can use custom loaded resistors to get different gain settings according to the manual, it can be viewed or downloaded from the Ayre website if you don't have one.
What loading do Airtight recommend?
I set my load, capacitance and gain by ear. That since an "exotic" cartridge can require the oddest values and as you implied, the rest of the phono chain will have an impact on the signal al the way up to the speakers. Trust your ears !
Yeah, I think there's a lot of truth to this. I do enjoy the 1000 setting, but not having more options has me curious as to whether I'm missing something.
What loading do Airtight recommend?
Anywhere between 100 and 800. He wasn't specific, and stated the end of the spectrums would change the sound from forward/cool to dark. I took this to mean the 100 setting would give a more focused sound, and the 800 setting would add more space/openness.
Hi David, you can use custom loaded resistors to get different gain settings according to the manual, it can be viewed or downloaded from the Ayre website if you don't have one.
How did I miss this?!? Thanks for pointing it out. Interesting enough, I called Ayre and they felt the phono worked best when it had the least resistance, which may be why I liked the 1000 setting more than the 100. I only wish I was handy enough to solder my own resistors like the manual suggests. Maybe I can convince my dealer to help me..
Anyways, thanks for all the responses.
DiveDeepDog
14-02-2019, 10:52
I use a phono Y connector
https://www.ebay.co.uk/itm/1-RCA-Phono-male-to-2-female-Audio-Gold-Splitter-Adaptor/264190100064?epid=1837843476&hash=item3d82f50260:g:Qv8AAOSwtglcYFbg:rk:5:pf:0
with this to put a resistor in
https://www.ebay.co.uk/itm/323675235245?ViewItem=&item=323675235245
I've got a Paradise in a compact case and drilling holes was a PITA, this solution with Y cable works, perhaps not the most elegant but I'm forever swapping carts.
There's online calculator to work out resistance values, you can use the 1k setting and add resistance with the plugs.
I knew I came to the right place. Thanks!
Bigman80
14-02-2019, 12:25
"There's online calculator to work out resistance values, you can use the 1k setting and add resistance with the plugs".
Got a link? This would be particularly useful at the minute.
Sent from my VKY-L09 using Tapatalk
DiveDeepDog
14-02-2019, 13:40
https://www.digikey.co.uk/en/resources/conversion-calculators/conversion-calculator-parallel-and-series-resistor
Lots out there.
For the OP, Hifi Collective will sell pairs of resistors and supply in individual bags if like me your colour vision isn't great.
"There's online calculator to work out resistance values, you can use the 1k setting and add resistance with the plugs".
Got a link? This would be particularly useful at the minute.
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)
Bigman80
14-02-2019, 14:36
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)Ah, excellent. Thanks Barry.
Ah, excellent. Thanks Barry.
That equation was specific to David's case of his head amp presenting a load of 1000 Ohm.
In general the formula for two resistors, R1 and R2 in parallel is:
R1*R2/(R1 + R2)
So if R1 is the impedance of the head amp (call it Rh) and Rc is the value you want the cartridge to 'see', then the value of the additional loading resistor (RL), wired in parallel with the head amp (or SUT) is
RL = Rc/(1 - Rc/Rh).
Maths lesson over for today! :)
Bigman80
14-02-2019, 14:51
That equation was specific to David's case of his head amp presenting a load of 1000 Ohm.
In general the formula for two resistors, R1 and R2 in parallel is:
R1*R2/(R1 + R2)
So if R1 is the impedance of the head amp (call it Rh) and Rc is the value you want the cartridge to 'see', then the value of the additional loading resistor (RL), wired in parallel with the head amp (or SUT) is
RL = Rc/(1 - Rc/Rh).
Maths lesson over for today! :) [emoji23][emoji23] Thanks mate. I'll try it out.
Bigman80
14-02-2019, 15:08
Ok, so using your equation, my phonostage presents 1k so for the desired 470R loading I like I'd need 626R
Have I done that right?
Ok, so using your equation, my phonostage presents 1k so for the desired 470R loading I like I'd need 626R
Have I done that right?
No, the value should be 887 Ohm:
470/(1 - 470/1000) = 470/0.53 = 886.8 Ohm.
Bigman80
14-02-2019, 15:24
No, the value should be 887 Ohm:
470/(1 - 470/1000) = 470/0.53 = 886.8 Ohm.[emoji23][emoji23] I know if got it wrong. I'm am awful at math. Seriously bad.
Bigman80
14-02-2019, 15:32
[emoji1787] honestly, I have that numerical dyslexia I think. I should get checked out.
try 2000 amp and 300 desired
just to confuse matters i was told for my paradise that the rough loading is about the value of the resistor minus 10%
Bigman80
14-02-2019, 17:06
just to confuse matters i was told for my paradise that the rough loading is about the value of the resistor minus 10%
TBH, this formula, now i have worked out how to use it, does match the values i already have. I'll trust it.
The Bigbottle is 1K so if i have it right:
Loading: 470R - Requires 887R - Nearest value is 820R
Loading: 250R - Requires 333R - Nearest value is 330R
Loading: 200R - Requires 250R - Nearest value is 240R
Loading: 100R - Requires 111R - Nearest value is 110R
Loading: 75R - Requires 81R - Nearest value is 82R
At last 5/5 - well done! :)
Bigman80
14-02-2019, 18:14
At last 5/5 - well done! :)I didn't get the formula. Had to get the wife to break it down!!
Once I understood it, I was ok. Cheers Barry.
for what its worth i have mine loaded with a 270r so what does that get me,using my 10% formula i make that 243,what is it using yours?
for what its worth i have mine loaded with a 270r so what does that get me,using my 10% formula i make that 243,what is it using yours?
That implies the intrinsic input impedance of your Paradise phono stage is 2.43k. I have no idea if that is correct, but it fits the "-10%" rule, as well as the formula I quoted.
Firebottle
14-02-2019, 20:21
TBH, this formula, now i have worked out how to use it, does match the values i already have. I'll trust it.
The Bigbottle is 1K so if i have it right:
Loading: 470R - Requires 887R - Nearest value is 820R
Loading: 250R - Requires 333R - Nearest value is 330R
Loading: 200R - Requires 250R - Nearest value is 240R
Loading: 100R - Requires 111R - Nearest value is 110R
Loading: 75R - Requires 81R - Nearest value is 82R
I've told you all this before :doh:
Bigman80
14-02-2019, 20:23
I've told you all this before :doh:You did and you didn't. We talked about it but I never got the formula to work it out.
One of those convos that got derailed by an idea I think.
Firebottle
14-02-2019, 20:27
I'm sure I told you but you didn't write it down :ner:
Bigman80
14-02-2019, 20:31
I'm sure I told you but you didn't write it down :ner:Yup. That's the one. It is now written down in a way I understand it.
I'm sure I told you but you didn't write it down :ner:
Worthy of some detention I think [emoji6]
Oh wait a minute he’s in that already [emoji23]
Bigman80
14-02-2019, 22:44
Worthy of some detention I think [emoji6]
Oh wait a minute he’s in that already [emoji23]Lol yup, that's me.
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?
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/tools/parallel-resistance-calculator/
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/tools/parallel-resistance-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
15-02-2019, 18:55
I missed the 47k setting, it makes life easier, so thats the way to go :)
montesquieu
15-02-2019, 19:21
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 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
15-02-2019, 22:39
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
15-02-2019, 23:04
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.
cool,thats for clearing that up,just knocking off 10% is maths i can understand lol
Because Paradise input impedance is around 2k8 ohm and in parallel with loading resistor 300R which gives 270.97 ohm
Back calculating, with a 270R loading resistor, karma67 said he gets an effective value of 243R, so the intrinsic input impedance of the Paradise works out to be 2k43.
If it is 2k8 as quoted, with a loading resistor of 270R, the apparent load, as seen by the cartridge, will be 246R. That is, "about the value of the resistor minus 10%".
The exact value of loading resistors is not really that important (anything greater than 10x the cartridge coil impedance will do, allowing the transmission loss to be less than 1dB). The important thing is that the loading resistors for each channel ought to be with 5% of one another, so the channel balance is within 0.1dB.
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.
You can use a transformer with an amplifier having balanced inputs if the transformer has a centre tap. If not, use a pair of 100k resistors wired between the secondary leads and take the junction of the two resistors to ground (pin 1 of the XLR input).
Just to say I can clearly hear a difference between using a 270 loading resistor and a 249 but that may be down to the quality of the resistor
Somehow I thought he said is getting 270R with 300R resistor , but Paradise has impedance around 2k8 so 246R value with 270R resistor would be correct
Well whatever the paradise is I’m using a 270 and a 249 and doing it by ear,I reckon im around 200-250 loading in reality.
Just to say I can clearly hear a difference between using a 270 loading resistor and a 249 but that may be down to the quality of the resistor
Are the two resistors of the same type and made by the same manufacturer? If not, then I can believe there could be a perceived audible difference.
the 270 is a charcroft naked foil,the other is a vishay so yes it could be down to resistor spec rather than loading.
its not perceived either by the way :ner:
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