About 11 years ago a friend on my old forum offered to build a shunt attenuator for me using a Seiden switch and Welwyn RC55Y resistors.
Not long after the idea of 'shunting the pot' was put forward by the mod on that forum. various resistors were tried - Tants/Riken/Kiwames and cheap metal films from Maplins, I decided to try Vishay Z foils.
Everyone who tried this mod agreed that there was no comparison between a straight pot and shunting it - simply because whatever pot was used it got shunted out of the way.
It controlled the volume to a class A valve amp. I now use a Bada PH32 integrated hybrid amp which with only a couple of cap changes sounds way better than the class A valve amp.
Of course I shunted the 50K Alps Blue that came with the Bada using 47K Z foils. This amp supplies class A for the first few watts then class AB, I want the amp to use only class A as I intend to build very efficient OB speakers in the future.
My problem is that I have to wind up the volume due to the -5/6dB that happens shunting the pot and I felt that I was losing some dynamics.
So I removed the Z foils. I hav'nt listened to an amp using just a pot for about 11 years now and the sound is awful, I doubt if it would be much better using another pot regardless of price.
Question - the 'received wisdom' is to use a resistor about 90% of the pots value - why can I not use a 50K resistor and what effect if any will this have?
Or - if I use a lower value pot shunted of course will that give me that little bit fuller natural oomph that I miss?
My phono stage is a Talk Audio MC3 with easily adjustable load and gain settings (it's also a cracker). I don't want to use too much gain if I can help it. I also use an old 63KI CDP but in the future intend to digitize my music so it will have input from a DAC only.
I don't mind if I cannot use as much of the pot as normal. I like to listen to music which fills the room and I don't now and will not in the future have to mind about upsetting neighbours as we will have none really close.
If you have a powerful amp that can handle the 6dB drop you really should try shunting the pot with Z foils or Caddocks if you have experience of them - it really is a no brainer. The volume control has such an influence on the sound of your whole system one wonders why more manufacturers don't use this in the design and build of their amps. A couple of Z foils are around $12 a piece + a simple pot of course I'm sure that a Penny & Giles may well be even better but by how much and at what a price and size disadvantage.
I really welcome responses but only from those who have practical empirical experience.
Not long after the idea of 'shunting the pot' was put forward by the mod on that forum. various resistors were tried - Tants/Riken/Kiwames and cheap metal films from Maplins, I decided to try Vishay Z foils.
Everyone who tried this mod agreed that there was no comparison between a straight pot and shunting it - simply because whatever pot was used it got shunted out of the way.
It controlled the volume to a class A valve amp. I now use a Bada PH32 integrated hybrid amp which with only a couple of cap changes sounds way better than the class A valve amp.
Of course I shunted the 50K Alps Blue that came with the Bada using 47K Z foils. This amp supplies class A for the first few watts then class AB, I want the amp to use only class A as I intend to build very efficient OB speakers in the future.
My problem is that I have to wind up the volume due to the -5/6dB that happens shunting the pot and I felt that I was losing some dynamics.
So I removed the Z foils. I hav'nt listened to an amp using just a pot for about 11 years now and the sound is awful, I doubt if it would be much better using another pot regardless of price.
Question - the 'received wisdom' is to use a resistor about 90% of the pots value - why can I not use a 50K resistor and what effect if any will this have?
Or - if I use a lower value pot shunted of course will that give me that little bit fuller natural oomph that I miss?
My phono stage is a Talk Audio MC3 with easily adjustable load and gain settings (it's also a cracker). I don't want to use too much gain if I can help it. I also use an old 63KI CDP but in the future intend to digitize my music so it will have input from a DAC only.
I don't mind if I cannot use as much of the pot as normal. I like to listen to music which fills the room and I don't now and will not in the future have to mind about upsetting neighbours as we will have none really close.
If you have a powerful amp that can handle the 6dB drop you really should try shunting the pot with Z foils or Caddocks if you have experience of them - it really is a no brainer. The volume control has such an influence on the sound of your whole system one wonders why more manufacturers don't use this in the design and build of their amps. A couple of Z foils are around $12 a piece + a simple pot of course I'm sure that a Penny & Giles may well be even better but by how much and at what a price and size disadvantage.
I really welcome responses but only from those who have practical empirical experience.
I listen to the system at the same level all the time. Therefore, I just soldered in a voltage divider in place of the pot using resistors of choice. If you require more than one setting, use a good quality 2-6 position switch with your choice of stepping attenuator (series,shunt, etc). You may get even better results by getting rid of the pot completely and cheaper than a Penny & Giles!
optimationman,
thanks for the reply, I could'nt reply earlier as I was in hospital - out and feeling fine now.
A good suggestion and I'm sure it works for you but is anathema to those who think they need a zillion positions. Because music is recorded at different levels I feel there is a need for at least 3 settings.
Shunting the pot means literally that - it shunted out of the way.
Thanks to a Canadian on another thread I now know about mil. spec pots produced in Ontario that (a) will fit in the same restricted space as an Alps Blue and have a wide range of specs. to choose from.
As the Alps and most available pots go from 10K to 50K they are a no-no. These mil. spec pots are available from Digikey but not with all the options I would like so I shall phone them this Monday to see if I can buy a 35K pot directly - vamos a ver.
thanks for the reply, I could'nt reply earlier as I was in hospital - out and feeling fine now.
A good suggestion and I'm sure it works for you but is anathema to those who think they need a zillion positions. Because music is recorded at different levels I feel there is a need for at least 3 settings.
Shunting the pot means literally that - it shunted out of the way.
Thanks to a Canadian on another thread I now know about mil. spec pots produced in Ontario that (a) will fit in the same restricted space as an Alps Blue and have a wide range of specs. to choose from.
As the Alps and most available pots go from 10K to 50K they are a no-no. These mil. spec pots are available from Digikey but not with all the options I would like so I shall phone them this Monday to see if I can buy a 35K pot directly - vamos a ver.
optimationman,
the more I think about your reply, the more I like it - definately thinking out of the box.
Since no other replies are forthcoming I tried using a different value of shunt but of course it did'nt work because the pot is still 50K. So before I can put your idea into practice I need to establish exactly what resistor values float my boat.
So I shall buy a cheap Alps blue of 20-25K and experiment with resistor values from around 38K or less. When I am satisfied I will then purchase a quality 6 position switch (probably Seiden) and use 0.01% Vishay Z foils.
Last night I played a few diverse LPs - Jan Gaberak - Making Music/ Jackon Browne - Late For The Sky and Jacintha - Tribute to Ben Webster. The last is a direct cut from the analogue tape and was not only sonically superb but played much louder even than the ECM recording - so yes 3 maybe 4 resistor pairs, thanks again for the positive idea - it's what the forum should always be about.
the more I think about your reply, the more I like it - definately thinking out of the box.
Since no other replies are forthcoming I tried using a different value of shunt but of course it did'nt work because the pot is still 50K. So before I can put your idea into practice I need to establish exactly what resistor values float my boat.
So I shall buy a cheap Alps blue of 20-25K and experiment with resistor values from around 38K or less. When I am satisfied I will then purchase a quality 6 position switch (probably Seiden) and use 0.01% Vishay Z foils.
Last night I played a few diverse LPs - Jan Gaberak - Making Music/ Jackon Browne - Late For The Sky and Jacintha - Tribute to Ben Webster. The last is a direct cut from the analogue tape and was not only sonically superb but played much louder even than the ECM recording - so yes 3 maybe 4 resistor pairs, thanks again for the positive idea - it's what the forum should always be about.
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