I suppose, those days design consideration was quality and long lasting product as their product was new/ one of its kind, unlike today where products are desined with lifespan for recurring revenue source.OMG, thanks for that. Some of the older equipment has quality beyond our memory.
Syllabus changedFunny that 80 years ago they knew how to make attenuators and now they don’t..,,
in post #39+40 under
https://www.diyaudio.com/community/...od-or-not-for-hi-fi.60548/page-2#post-7375185
I ask for a replacement for a P&G potentiometer by a stepped attenuator (e. g. ELMA type 04)
The actually question is, what resistor type should I prefer ?
https://www.diyaudio.com/community/...od-or-not-for-hi-fi.60548/page-2#post-7375185
I ask for a replacement for a P&G potentiometer by a stepped attenuator (e. g. ELMA type 04)
The actually question is, what resistor type should I prefer ?
Update:
Some time doing research seems to suggest that series resistor should be half of shunt. Also series resistor as low as possible, like 33K or less for input to a valve stage. Ideally much less. Found some comments:
A reasonable load for any normal line driving stage is:
Most can cope with driving 10k to 100k.
Some will cope with driving 2k to 10k.
Very few will be able to drive less than 2k, but some op-amps can.
34k input resistor value is a bit high. I like to do 50~70% pot value for input resistor value so loudness at 12 o'clock is about the same as a normal pot. Also did the Shunt mod today on my 50k pot tested with 25k and 47k, and 33k has a better control of the volume.
91k to 191k for a 100k pot, 47k to 97k for a 50k pot, 18k to 38k for a 20k pot. I'd recommend going Vishay Z foil VAR (thru hole), VSM (surface mount). It will be well worth the extra.
Some time doing research seems to suggest that series resistor should be half of shunt. Also series resistor as low as possible, like 33K or less for input to a valve stage. Ideally much less. Found some comments:
A reasonable load for any normal line driving stage is:
Most can cope with driving 10k to 100k.
Some will cope with driving 2k to 10k.
Very few will be able to drive less than 2k, but some op-amps can.
34k input resistor value is a bit high. I like to do 50~70% pot value for input resistor value so loudness at 12 o'clock is about the same as a normal pot. Also did the Shunt mod today on my 50k pot tested with 25k and 47k, and 33k has a better control of the volume.
91k to 191k for a 100k pot, 47k to 97k for a 50k pot, 18k to 38k for a 20k pot. I'd recommend going Vishay Z foil VAR (thru hole), VSM (surface mount). It will be well worth the extra.
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