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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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7th Jan 2020, 10:36 am | #1 |
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Log potentiometers with taps
As you probaby know, log pots with taps are no longer available.
Even Blore Edwards cant make them. I was therefore thinking of simulating one using either a dual pot for mono or 4 ganged for stereo (assuming there is room to fit it. Can anyone think of a way this could be done? |
7th Jan 2020, 10:49 am | #2 |
Hexode
Join Date: Jun 2018
Location: Buckinghamshire, UK.
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Re: Log potentiometers with taps
If you search for "potentiometer loudness" on eBay you'll find lots of pcb mounting ones in the 'Alps' style, and some ready made boards with 'round' 100k ones.
https://www.ebay.co.uk/sch/i.html?_n...sPageName=GSTL Cheers |
7th Jan 2020, 12:15 pm | #3 |
Heptode
Join Date: Jan 2008
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Re: Log potentiometers with taps
There are several type of tapped log pots available for jukeboxes from https://www.jukebox-world.de/index.p...=potentiometer . They are not cheap, but may be of help.
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Martin BVWS member GQRP Club |
7th Jan 2020, 2:27 pm | #4 |
Nonode
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Re: Log potentiometers with taps
Post #5 in this thread has an alternative suggestion for a tapped pot.
https://www.vintage-radio.net/forum/...d.php?t=126515 Al
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I won't tell you how I discovered that. |
7th Jan 2020, 7:01 pm | #5 |
Octode
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Re: Log potentiometers with taps
Hi, how important is it that you have a tapped pot? The main use for one as I understand is the original baxandall tone control design.
Anyway I had a think and if its really important you can adapt/alter a switched resistive attenuator of which several types are available and not too expensively on the Auction site. I have one here that I've had for years, 100k log 23 position switch that switches in individual pairs of resistors in a potential divider rather than a shunt or simple ladder configuration. Each switch tag is easily accessible so you could place a tap wherever you want it along the 23 positions. With effort it could easily be converted to a linear control by replacing the individual resistors. If you'd like to have a play with it then drop me a PM, I won't want anything for it if it's going to be useful to you. Andy. |
7th Jan 2020, 11:12 pm | #6 |
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Re: Log potentiometers with taps
One thing I didn't mention is that in the machine that i'm repairing, the volume control with a tap also has a mains switch on it!
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9th Jan 2020, 12:33 am | #7 | |
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Re: Log potentiometers with taps
Quote:
The tap is needed for the shape/loudness/contour switch. The Pye BB circuit is fixed, this is switched. |
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10th Jan 2020, 12:23 am | #8 |
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Re: Log potentiometers with taps
Here is a circuit of the pot in question.
How could one incorporate the shape switch into a dual or quad log pot. Thats what I'm having difficulty with. Remember this is also got the mains on/off switch, so I cannot use any of the alps type pots. |
13th Jan 2020, 4:22 pm | #9 |
Hexode
Join Date: Apr 2007
Location: W Yorks, UK.
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Re: Log potentiometers with taps
Some people add their own custom taps using conductive paint.
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13th Jan 2020, 5:32 pm | #10 | |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
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Re: Log potentiometers with taps
Quote:
What is wrong with the old one? |
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13th Jan 2020, 6:32 pm | #11 |
Dekatron
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Re: Log potentiometers with taps
As referred to by Al in post #4 above, you might wish to consider the option at the forum link he gave.
To save going to the other link, the circuit is attached below. Blore Edwards can supply a dual gang log pot with mains switch (Type 2AR-45) here: https://www.blore-ed.com/series45potentiometers
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David. BVWS Member. G-QRP Club member 1339. |
14th Jan 2020, 12:58 pm | #12 |
Hexode
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Re: Log potentiometers with taps
I have such a pot, ganged 22k tapped at 9k with a double pole switch.A short plastic shaft,D'ed 1 inch long. NOS(not a solder onto PCB type) if you are interested I'll send you a pic via PM,Les
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