mercury switched input selector

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blu_glo

blu_glo

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Joined 2005
I have to admit I thought it sounded like a feasible idea to try at the time, but was put off by lots of people poking problems at it...... one for when I get my lab setup again! With respect to "matching", how does channel balance sound at lower levels? Do you use old fashioned LDR/lamp in a potted box/enclosure or the LDR optocouplers like
http://uk.farnell.com/webapp/wcs/st...electedCategoryId=&gs=true&st=ldr optocoupler
 
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anjump123

Member
Joined 2010
D

DF96

R.I.P.
Joined 2007
myweb.tiscali.co.uk/g8hqp/
blu_glo said:
Has LDR attenutation become acceptable nowadays? It seemed to be a topic of very heated debate not so long ago........
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LDRs are slightly non-linear, hence they will add a little distortion to your audio. This fact is not in dispute, as some people selling LDR volume controls have admitted it on this forum. The issue is whether there is sufficient distortion to be a problem. Some say no; others prefer to have less distortion by using ordinary resistive material for volume controls, either as pots or switched networks. In any case, it is simply wrong to say that LDR controls are more transparent or have better resolution, as that is factually untrue. It is fine for someone to say that he prefers the LDR sound, as that is a matter of taste and personal opinion.

anjump123 said:
I think the argument was between those who have tried it and those that just theorised about it.
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No, it was between those who presented facts and those who at first denied facts and then later said that the facts don't really matter that much. LDR nonlinearity is not a theory but a fact. Some, but not all, LDR volume control fans seem to try to avoid the isue by conflating two completely different issues:
1. signal linearity (or lack of it) due to LDR resistance non-linearity
2. control law linearity due to LDR matching and careful design of driving circuitry
People new to LDR volume controls may not always realise what is meant when an LDR fan (or seller) mentions "linearity".

Some people, having tried LDR controls find that they like them. This is not evidence that the facts are untrue.
 
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anjump123

Member
Joined 2010
I really don't know or care about that. I just know that the LDR pre-amp is better sounding than any I've tried before. End of story as far as I'm concerned. I'm just trying to help a fellow DIYAudioer out, he can make his own mind up.

The only exception may be the Overkill system I heard at a HiFi show a while back in London but that's a whole other ball game, active crossover, room correction,etc. which I will try later when I can.
 
R

ric-paul

Member
Joined 2005
AndrewT said:
Is this why many of is can't think? or why I can't remember much I did 5minutes ago?

I remeber a friend in class coated his ring in mercury and turned it a nice silvery colour. Then wore it on his finger !
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[offtopic]
I took photo's of mercury droplets while lighting it with a 1kW oldschool 8mm movie lighting lamp.
It only dawned on me how stupid I was being when I saw a gradual (hopefully perceived instead of actual) schrinking of a droplet...:eek:
[/offtopic]

[even more offtopic]
This was about the same time I took actionphoto's of pepples falling into burning petrol and had water in a bucket in case something went wrong. When the petrol spilled, I poored water 'over' it only to find that the burning petrol floats ON the water and the water just greatly enlarges the burning surface...
[/even more offtopic]
 
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