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4-way Source Selector

A

andyr

Registered User
I want to change the 3-way source selector on my old Naim 12s preamp ... to allow for 4 sources.

(This will involve me re-housing it in a different case, to allow for the extra pair of RCA sockets.)

Does anyone know of a good 4-way source selector switch? (5-way would also be acceptable.)
 
Just be aware that of the two Elma switches referenced above (01-1263 and 01-1264) you would probably want the 1264 variant as it is non shorting (break before make).
 
Grayhill make excellent switches, you won't be disappointed. I used their PN 71B30-02-4-03S for a three-position switcher box with switched grounds.
 
It's a best practice I picked up in doing test & measurement work... switch contacts are cheap whereas time spent looking for ground loops can add up quickly. Incidentally you can get away with a single deck switch to do this with the PN I listed, IIRC that was all that Mouser had in stock when I went to build mine. You could double up the switch contacts if you really wanted to.

I ended up building mine into a C style MicroPak box from Lansing Instruments that I picked up at a local electronics junk shop. I added lots of shielding internally plus a simple mono sum network on the phono channel since my current phono pre lacks one, and managed to match the knob on my external attenuator as well, for the vibes. You can get pretty fancy for not a ton of cash, and switch your grounds by rolling your own (I still haven't seen a pre-made switcher with this functionality).

bXfMQSI.jpg
 
You might want to consider this - see thread:
https://pinkfishmedia.net/forum/threads/possible-gb-bloor-edwards-switches.287258/
I could add it to the GB
I'm getting one for myself for my premp rebuild - a good friend has used them and they seem to be good quality without breaking the bank - compact too

or this from HFC - half the price of RS for the same item (I think):

Elma 2 pole 6 way switch, 01-1264 (15mm shaft length) | HIFICollective

Elma 2 pole 6 way switch, 01-1264 (15mm shaft length)
www.hificollective.co.uk www.hificollective.co.uk
 
I have finally completed the re-build of my NAC12s-5 (ie. having 2x 24v DC supplies) with a 4-way Grayhill source selector. (It was much smaller than I had anticipated ... which made connecting up the wires rather fiddly! :( )

If anyone is interested in seeing the end result - and knows how to post pics on PFM - if they PM me their email address, I will send them a few pics which they can then post.
 
Would love to see it, you can host your photos on a site like imgur for free and with no sign-up, then post the link here.
 
ruckerfoad said:
Would love to see it, you can host your photos on a site like imgur for free and with no sign-up, then post the link here.
Click to expand...

Unfortunately, that doesn't seem possible. :(

When I tried to register on Imgur, I got the following error msg:

"Email sign-up is not possible in your region. Register using a third-party service".
 
Make before break is usually best for audio. Temporarily having you input floating has a habit of causing speaker destroying bangs. HiFi sources are normally immune to output shorts.
 
davidsrsb said:
Make before break is usually best for audio. Temporarily having you input floating has a habit of causing speaker destroying bangs. HiFi sources are normally immune to output shorts.
Click to expand...

Aah - interesting to know, David. Thanks. 👍

I have tested that the switch is correctly wired up (ie. input #1 then #2 then #3 and then #4 get correctly transferred to the output sockets) but I will have to wait until it is installed in the system it belongs to, before I can test for 'bangs'. 😮
 
Avoiding switching thumps is why it is common to have high value resistors eg 470k to signal return on all inputs and to signal ground on the selector switch output
 
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