ejbasses

how do i build a Pan circuit? like in mixers
« on: December 02, 2004, 09:26:25 AM »
Hi guys,

this is my first post, i wanna ask how do i build a pan circuit like in the mixers? Im planning to build a simple mixer but this is the last hurdle i have to finish

any help would be great

thanks


tmbg

how do i build a Pan circuit? like in mixers
« Reply #1 on: December 02, 2004, 09:37:20 AM »
passive panner would be a pot, mono input connected to the wiper, stereo output is either side of the pot.

active panner can be done with an op-amp.  There's a circuit for it in my H&H book, but that's at home :/

If noone else comes up with one, I'll post it tonight.

NewYorkDave

how do i build a Pan circuit? like in mixers
« Reply #2 on: December 02, 2004, 09:42:39 AM »
Input to wiper, output from ends does not make for a good panpot. It won't follow a constant power law and you won't get complete attenuation at either end.

I'll post some links to panpot resources later....

ejbasses

thanks
« Reply #3 on: December 02, 2004, 09:46:45 AM »
that passive pan pot was my first idea too. looks like it could work.

any more ideas??

ejbasses

how do i build a Pan circuit? like in mixers
« Reply #4 on: December 02, 2004, 09:53:38 AM »
BTW. what kind of pots do i use in the passive pan circuit? is it okay to use Log pots?

Svart

how do i build a Pan circuit? like in mixers
« Reply #5 on: December 02, 2004, 09:57:14 AM »
i believe that there are companies that make pots specifically for panning however this is only based on memory so I don't know who it was.  :sad:
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NewYorkDave

how do i build a Pan circuit? like in mixers
« Reply #6 on: December 02, 2004, 10:16:08 AM »
Panpots can be made using standard single and dual-gang linear pots.

Here's a Neve tech bulletin that shows some details on dual-ganged panpot construction.
Page 1
Page 2

Here's my own version of the dual-ganged panpot. It has a 6dB minimum loss, but it has a more constant input impedance and better adherence to constant-power law than the "standard" type detailed above.
Schematic (GIF)

The "Orban" type uses a single linear pot. It can be designed for very good adherence to constant-power law and a fairly constant input impedance, but "correct" implementations of the circuit have a minimum loss of 12dB or greater. Maximum attenuation may not be as good as the dual-pot type, depending on the grounding arrangement of the console.
Schematic 1
Schematic 2 (PDF)

SSLtech

how do i build a Pan circuit? like in mixers
« Reply #7 on: December 02, 2004, 10:16:23 AM »
Quote from: "ejbasses"
BTW. what kind of pots do i use in the passive pan circuit? is it okay to use Log pots?
NOooooooooooooooo!!!

for a single gang it must be linear. Otherwise 'center' will be at about 9-o'clock!!!

The post from tmbg is wrong. Feed the incoming signal to two equal value reisistors. join the other end of the resistors to two ends of a linear pot. Ground the wiper. Output is from both ends of the pot, and can either go directly into a high-impedance follower circuit, or to two resistors feeding virtual-ground summing amps.

Keith
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Quote from: PRR
Ah, but that was 1999; we don't party like that any more.

how do i build a Pan circuit? like in mixers
« Reply #8 on: December 02, 2004, 07:00:45 PM »
What about a voltage controlled pan?

- Michael nil-x

Laska

how do i build a Pan circuit? like in mixers
« Reply #9 on: December 03, 2004, 05:07:34 AM »


ejbasses

nice
« Reply #10 on: December 03, 2004, 05:18:54 AM »
Thanks guys

I didnt know a pan circuit would be so simple

now I have to find some linear Pots. Where i live, theyre not so easy to find *sob*

AMZ-FX

how do i build a Pan circuit? like in mixers
« Reply #11 on: December 03, 2004, 05:53:11 AM »
Actually, if you are using the single pot circuit, the best response is an s-taper, sometimes listed as G response. They are quite difficult to find.  For the duals, a log-antilog is a bit smoother - also somewhat hard to locate.  

regards, Jack
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Re: how do i build a Pan circuit? like in mixers
« Reply #12 on: January 09, 2017, 05:30:04 AM »
Dear future searchers (and sorry others for the zombie thread), I found this thread while looking for panpot schematics. Since NewYorkDave's links were posted, most of them are dead. Here are the following links to the Wayback Machine archive so you can still find the images:

Neve bulletin pic 1: https://web.archive.org/web/20060209205933/http://www.phoenixaudio.net/tech6_1_1.gif
Neve bulletin pic 2: https://web.archive.org/web/20060209210131/http://www.phoenixaudio.net/tech6_2_1.gif

NewYorkDave's schematic sadly was a noindex, but the broken Orban link is: https://web.archive.org/web/20050213214538/http://wavefront.mcmail.com/orban.gif


ruffrecords

Re: how do i build a Pan circuit? like in mixers
« Reply #13 on: January 09, 2017, 01:23:55 PM »
I think there may be an error in the second page of the Neve Technical Note concerning low cost pan pots. The resistor values given do not seem to work. There is a 3K6 feed resistor, a 10K pot and a 6K8 bus resistor.

With the pot in the centre, the pot plus bus feed resistor is 6K8//5K = 2K88.

The loss is therefore 2K88/(2K88+3K6) = 0.44 = 7dB

With the pot hard panned, the pot plus bus feed resistor is 6K8//10K = 4K04

The loss is therefore 4K04/(4K04+3K6) = 0.52 = 5.53dB

So the difference in loss between centre and hard panned is 7 - 5.53dB = 1.47dB which is not enough

Can someone check my maths please?

Cheers

ian

pucho812

Re: how do i build a Pan circuit? like in mixers
« Reply #14 on: January 09, 2017, 07:58:16 PM »
Dear future searchers (and sorry others for the zombie thread)

NewYorkDave's schematic sadly was a noindex, but the broken Orban link is: https://web.archive.org/web/20050213214538/http://wavefront.mcmail.com/orban.gif

That organ is very reminiscent of how trident does their pants in the 80B....

As for special pots for pan, I can't see any thing special other then taper and perhaps a center detent which some consoles do not use the center detent.
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