Klaus
The UK 'Audiophile' supplier that I quoted above recommended the P11 (cermet track) device in preference to any of the conductive plastic types that he had tested.
I have not tried the PA11, but have used the P11 for several years now in various pieces of equipment. In all cases, it has been an improvement over the manufacturer's original pot and any conductive plastic ones I have tried, though I must stress that I have not compared it against the more expensive conductive plastic devices since I refuse to pay the inflated prices asked for these.
Sorry I can't help more. Perhaps someone else has compared (or is willing to compare) the two and can provide more feedback.
Geoff
The UK 'Audiophile' supplier that I quoted above recommended the P11 (cermet track) device in preference to any of the conductive plastic types that he had tested.
I have not tried the PA11, but have used the P11 for several years now in various pieces of equipment. In all cases, it has been an improvement over the manufacturer's original pot and any conductive plastic ones I have tried, though I must stress that I have not compared it against the more expensive conductive plastic devices since I refuse to pay the inflated prices asked for these.
Sorry I can't help more. Perhaps someone else has compared (or is willing to compare) the two and can provide more feedback.
Geoff
Kettch
tvi has indicated in a previous post that Farnell have P11 pots in Australia, at A$16 for log types and A$10 for lin. As you require a 100k it will need to be a linear pot with a law-faking resistor (see http://sound.westhost.com/project01.htm if you don't know how to do this).
RS is another source here in the UK, though I don't know about Australia (it could be the same).
Geoff
tvi has indicated in a previous post that Farnell have P11 pots in Australia, at A$16 for log types and A$10 for lin. As you require a 100k it will need to be a linear pot with a law-faking resistor (see http://sound.westhost.com/project01.htm if you don't know how to do this).
RS is another source here in the UK, though I don't know about Australia (it could be the same).
Geoff
I just read the RS catalog more closely:
The Sfernice P11 pot is only available with 100k in single form, double only in 5k and 10k, all linear.
How can I change a 2 x 10k lin pot to an audio log one ? With a suitable law-faking resistor it's impedance will probably be too low then.
BTW, how do all you Pass-fans construct the necessary 4 x 5k output pots for the preamps, without using expensive switches or relais circuits ?
Is using two different (double) pots the only way to do this ?
This is the main reason I did not start building one of these amps. I personally do not like to have to adjust always TWO pots in an exactly similar way when I just want to change the volume...
greetings
Klaus
The Sfernice P11 pot is only available with 100k in single form, double only in 5k and 10k, all linear.
How can I change a 2 x 10k lin pot to an audio log one ? With a suitable law-faking resistor it's impedance will probably be too low then.
BTW, how do all you Pass-fans construct the necessary 4 x 5k output pots for the preamps, without using expensive switches or relais circuits ?
Is using two different (double) pots the only way to do this ?
This is the main reason I did not start building one of these amps. I personally do not like to have to adjust always TWO pots in an exactly similar way when I just want to change the volume...
greetings
Klaus
Yeh, I see that in the farnell catalog as well, only 5 and 10k for the P11
A guy that helped me make the amplifier said about using an Alps Blue or Black Beauty series pots or a bourns 81 or 82 series. Anyone used these before? And I don't seem to find them on the farnell catalog. Any place that ships internationally with good prices would be good.
Thanks
A guy that helped me make the amplifier said about using an Alps Blue or Black Beauty series pots or a bourns 81 or 82 series. Anyone used these before? And I don't seem to find them on the farnell catalog. Any place that ships internationally with good prices would be good.
Thanks
I have several ALPS big black pots in use (every day actually).
And I can report nothing bad, they seem very reliable (mine are quite old now) and sound good. This is a professional item, designed for high-priced mixing desks and high-end preamps, for a very long lifetime.
But they are really expensive. And beware: They are carbon pots, like all other ALPS pot too (the small "green" ones and the "blue" ones).
The blue Alps pot is long known in many amplifiers, from ROTEL to who knows.
Carbon pots also have significantly less power ability than conductive plastic and cermet types.
C. plasic types are usually designed for many cycles, but cermet pots more for longtime value stability.
Something probably heretical: I personally doubt there is a great difference in sound between all quality made pots. The cheaper ones tend to become noisy, the better ones do not; the audio log characterisic is probably implemented better on some types, and a tight tolerance is often a question of a costly selection.
But the sound ? I have used the very basic ALPS carbon pot several times, I could not say that it was a big difference.
The differences between pots are greater with faders, specially with precision and reliability.
I have two Penny & Giles audio faders here in my studio: Here the difference to usual mixing desk faders is somewhat breathtaking, but it is surely more the very smooth way of using them and the precision of the log curve in the low settings. They move so easy that I can make a complex scratch-like tremolo with them !
greetings
Klaus
And I can report nothing bad, they seem very reliable (mine are quite old now) and sound good. This is a professional item, designed for high-priced mixing desks and high-end preamps, for a very long lifetime.
But they are really expensive. And beware: They are carbon pots, like all other ALPS pot too (the small "green" ones and the "blue" ones).
The blue Alps pot is long known in many amplifiers, from ROTEL to who knows.
Carbon pots also have significantly less power ability than conductive plastic and cermet types.
C. plasic types are usually designed for many cycles, but cermet pots more for longtime value stability.
Something probably heretical: I personally doubt there is a great difference in sound between all quality made pots. The cheaper ones tend to become noisy, the better ones do not; the audio log characterisic is probably implemented better on some types, and a tight tolerance is often a question of a costly selection.
But the sound ? I have used the very basic ALPS carbon pot several times, I could not say that it was a big difference.
The differences between pots are greater with faders, specially with precision and reliability.
I have two Penny & Giles audio faders here in my studio: Here the difference to usual mixing desk faders is somewhat breathtaking, but it is surely more the very smooth way of using them and the precision of the log curve in the low settings. They move so easy that I can make a complex scratch-like tremolo with them !
greetings
Klaus
The Vishay-Sfernice P11 pots stocked by Farnell, RS etc. are not the same as the ones sold by RATA and other 'Audiophile' suppliers (they are about 15% of the price for a start!). The P11s are available in several grades. The Farnell variety is the basic grade with 10% tolerance and standard channel balance. The RATA etc. variety is a higher grade (J119 - available to special order) with 5% tolerance and channel balance/accuracy to 0.42dB (or <0.3dB or <0.8dB, it depends which catalogue you read).
The advantage with the Sfernice over the Alps, Panasonic etc is its size (12.5mm x 12.5mm x 16mm) so it will fit as a replacement in more situations. If close channel matching is not a primary requirement, the P11s from Farnell should be a very good buy.
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Russ Andrews has his followers but the P11 sound s quite distinctive compared to other, better pots. Compared to switched resistor pots they are 'bright' and compared to conductive plastic one they are 'clear'.
Compared to Audio Synthesis Passive, they don't sound good to me. The privce is also ridiculous.
The advantage with the Sfernice over the Alps, Panasonic etc is its size (12.5mm x 12.5mm x 16mm) so it will fit as a replacement in more situations. If close channel matching is not a primary requirement, the P11s from Farnell should be a very good buy.
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Russ Andrews has his followers but the P11 sound s quite distinctive compared to other, better pots. Compared to switched resistor pots they are 'bright' and compared to conductive plastic one they are 'clear'.
Compared to Audio Synthesis Passive, they don't sound good to me. The privce is also ridiculous.
Good quality pots
It may be just lack of experience but I have not been able to hear significant differences in sound between decent quality pots. The differences I have noticed are build quality and feel. I was able to get ahold of some of those Vishay-Sfernice p-11's through Newark Electronics (Farnells sister company here in the U.S.) and although they appear to be made well I was disappointed with how rough they felt when turning. Recently I found some Bourns 82 series , Dual gang 10k linear for $10.00 each from an electronics surplus website. Very nice. Smooth travel and tight tolorances.
It may be just lack of experience but I have not been able to hear significant differences in sound between decent quality pots. The differences I have noticed are build quality and feel. I was able to get ahold of some of those Vishay-Sfernice p-11's through Newark Electronics (Farnells sister company here in the U.S.) and although they appear to be made well I was disappointed with how rough they felt when turning. Recently I found some Bourns 82 series , Dual gang 10k linear for $10.00 each from an electronics surplus website. Very nice. Smooth travel and tight tolorances.
Deunhido, Newark does'nt acually have those p-11's in stock. I had to give them the Farnell part number and Newark in turn ordered them from Farnell and sold them to me. This transaction took about three months. I dont have the part number handy, but you can find it on the Farnell website. As far as Bourns goes, there is a company in Pennsylvania, www. Reliance.com where I found some really nice pots. Go first to the Bourns website and and download the .pdf description of the 81/82 series panel mount pots. This will give you the exact part number breakdown so you can then plug those part numbers into the Reliance search engine. To make things easier just type in the first five charactors of the part number, eg. "82A2A" and Reliance will spit back what ever parts they have in stock. If you find something you're interested in they can e-mail you a quote.
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