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Old 29th May 2003, 08:38 AM   #1
Doug is offline Doug  Canada
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Default Potentiometers log vs linear

This sounds like a dumb question, but are the volume controls on audio amplifiers linear taper or log taper.

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Old 29th May 2003, 08:42 AM   #2
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Volume controls are in 99.9 % of the cases logarythmic types because human ears are not too linear.

In the case of an inverted Gainclone you'll see that ( because of that particular topology ) a linear type is used. The way it is used in that schematic causes "log-like" behaviour.
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Old 29th May 2003, 08:51 AM   #3
Doug is offline Doug  Canada
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Default Linear vs log

Thanks Jean-Paul;

Do I understand this right? A linear taper increases the volume in a linear fashion ie: 1/4 turn = 25% increase in volume, 1/2 turn = 50% increase in volume etc etc.

A log taper will increase the volume level a lot more during the first 50% of travel, then during the next 50% of travel the volume level becomes less and less ( more compressed ) or is the other way around. What am I missing??

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Old 29th May 2003, 09:55 AM   #4
dhaen is offline dhaen  Europe
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Default Log pot

The progression of signal level is very slow at the start. Rate of change increases with clockwise rotation.
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Old 29th May 2003, 10:01 AM   #5
Doug is offline Doug  Canada
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Default Log pot

Thanks John;

Hey, I was close, just had it backwards

So, what do most amps have, log or linear? Build lots of speakers, but not amplifiers LOL

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Old 29th May 2003, 10:02 AM   #6
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Quote:
Volume controls are in 99.9 % of the cases logarythmic types because human ears are not too linear.
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Old 29th May 2003, 10:13 AM   #7
Bricolo is offline Bricolo  France
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Quote:
Originally posted by jean-paul
Volume controls are in 99.9 % of the cases logarythmic types because human ears are not too linear.

In the case of an inverted Gainclone you'll see that ( because of that particular topology ) a linear type is used. The way it is used in that schematic causes "log-like" behaviour.

shouldn't this apply to every amp that has negative feedback?
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Old 29th May 2003, 10:17 AM   #8
Doug is offline Doug  Canada
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Default log vs linear

Thanks once again Jean-Paul

I am aware that the ear is a very non linear device ie: it dosent hear all frequencies equally well, especially at low volumes levels. The ears response flattens out as the overall volume level is increased. This is based on the equal loudness curves developed by Fletcher Munson. Attached is a link for those who are interrested.

http://hyperphysics.phy-astr.gsu.edu...nd/eqloud.html

Doug
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Old 29th May 2003, 07:09 PM   #9
Doug is offline Doug  Canada
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Default Gainclone

Quote:
Originally posted by jean-paul

In the case of an inverted Gainclone you'll see that ( because of that particular topology ) a linear type is used. The way it is used in that schematic causes "log-like" behaviour.
I'm not familiar with the " gainclone " design, although I've seen the name before, could you fill me in?

My son was in Toronto recently and has just discovered tube amps. He listens to headphones a lot and I have been thinking about getting him a kit amp for next Christmas for his first experience. It wont be the highest end amp, but wont be the lowest end either. Do any of you guys have any suggestions?

Doug
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Old 29th May 2003, 10:56 PM   #10
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Quote:
I'm not familiar with the " gainclone " design, although I've seen the name before, could you fill me in?
http://www.diyaudio.com/forums/searc...der=descending
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