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Old 26th October 2010, 10:55 AM   #561
Salas is offline Salas  Greece
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The Vishay come up on ebay in very small numbers from time to time in no full values order. For about $5 each. At 0.1% tolerance.
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Old 26th October 2010, 12:22 PM   #562
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Originally Posted by Nikon1975 View Post
Could this fit as pot choice ?

Hi-End Volume Control DIY Kit,LED, Remote Control /V-03 - eBay (item 290485343961 end time Nov-07-10 04:10:12 PST)

It says max out impedance 22K.

Thanks,

Davide
the ad, says "impedance varies".
It also says "super stable output impedance".

I think the impedance you quoted is the variable input impedance to achieve a near constant output impedance.
but I could be wrong.
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Old 26th October 2010, 12:42 PM   #563
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Originally Posted by LucasAdamson View Post
I am using PRP Audio grade Metal Film resistors, which cost 30c each. The price/quality ratio for these is unsurpassed, period.

I think it's pretty ridiculous to spend that kind of money on resistors before you've let the circuit settle in - like using $30 silver/gold film caps in a power supply or gold wiring.

For me, such resistors would be a potential tweak for a year or so down the road, if I felt the need. That way you can hear for yourself if you've wasted you're money or not.
I agree with your comments re PRP. However, after listening to Kiwame, PRP, Takman Rex, Caddock MK132 and TX2575, I vote for these in this circuit.
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Old 26th October 2010, 01:25 PM   #564
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and what Is your second choice

has anyone think of new project - quality relay volume control for this
something like shunt pot
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Old 26th October 2010, 02:34 PM   #565
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That's what I am trying to achieve.
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Old 26th October 2010, 04:06 PM   #566
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well at least we (Tea Bag) got the most expensive part - relays
my basic Idea Is to switch shunt pair of resistors conected to 2 NO contacts of one tq2 relay
rotary switch will power only one shunt pair at the time
the only problem Is that for each step will need two tq2 relays - unbalanced and four when go balanced
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Old 26th October 2010, 11:01 PM   #567
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This is the question I was asking before. From what I understand the configuration you propose is good if you need to keep the impedance constant. But if you have the buffer you do not really need, and you can have a shunt configuration, that let you use half of the relays. Am I correct ? Mostly if you use two buffers, one before and one after. The source and the amp will never know what is in the middle.

D.
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Old 27th October 2010, 12:54 AM   #568
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you mean something like this?

Joshua Tree - A Twisted Log Attenuator
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Old 27th October 2010, 06:36 AM   #569
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this Is what am talking The relay-switched attenuator volume control

It Is shunt type - the signal pass at only 2 resistors at the time and relay contacts
and gives constant Impedance
all other volume controls I have seen pass signal through many resistors / relays and are not of Interest to me
the only problem here are count of relays - but In practice we only listen to not more than 16 step of attenuation
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Old 27th October 2010, 10:59 AM   #570
AndrewT is offline AndrewT  Scotland
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Originally Posted by samoloko View Post
the signal pass at only 2 resistors at the time and relay contacts
and gives constant Impedance
impossible.
Either the input impedance will vary with attenuation required or the output impedance will vary with attenuation required.
You cannot get both input and output impedances unvarying with switched twin resistors.
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