2. amps-preamps
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Bryston 2WSB switch box to choose amp that drives speakers

I really want to be able to choose between a low power amp for tv/background music and my good amp for serious music sessions. I'm tired of amp rolling, have posted recently about this and got good advice not to use two sets of speakers cables but only one live amp. So I'm thinking of a device like the Bryston, but have the speaker outputs be the amp inputs and the amp input be the speaker output. As long as only one speaker is selected at a time...electrically that should work. My only concern looking at the schematics is that the red positive leads are wired together and the black negative leads are switched. Could this still cause voltage to be applied to the unpowered amp? If so would swapping polarity work? There's a schematic on this page. 
https://reverb.com/item/10151350-bryston-2-way-speaker-switch-box-model-2wsb-sc1
Any help on this would be greatly appreciated.
treynolds155
treynolds155 OP
185 posts
 
Thanks again Al for really digging in there to help out!! I think there's two versions of Bryston's switch so that may be the difference between common + or - rails. Regardless...probably not safe either way. I looked at Nile's site and their DPS-1 specifically states two amps switched to one pair of speakers but nothing specific about both +/- being switched and it sounds like their binding posts are anemic so probably not the quality I'm looking for.  

I'm starting to think a custom one is the way to go. I found this four pole/double throw on/off/on switch:
https://www.grainger.com/product/HONEYWELL-Toggle-Switch-24D454

All I'd need is a project box and some Cardas binding posts and wire. As long as the switch wasn't noisy it should work great. Thoughts?

Thanks 
Tim
almarg's avatar
almarg
9,670 posts
 
Looks perfect. Nice find!

Also, Digikey sells it for a somewhat lower price:

https://www.digikey.com/product-detail/en/honeywell-sensing-and-productivity-solutions/4NT1-1/480-21...

Best regards,
-- Al

P.S: Keep in mind that if the lower powered amp happens to be a tube amp that has output transformers, it should not be operated without a load connected to its outputs, especially if it is being provided with an input signal.
imhififan's avatar
imhififan
2,227 posts
 
I can confirm that the Niles SPK-1 switching both +/- terminals by using two 12V DPDT relay rated 8A @ 250V internally. The 12v trigger can simply use a 12V DC adapter.
https://www.amazon.com/Gxilee-100-240V-Converter-Household-Electronics/dp/B01FXF6AEQ
treynolds155 OP
185 posts
 
That's a great price Al. I like that it has an off position in the middle, no way for the two amps to be mixed. This whole thing may seem crazy to some but I'm really looking forward to being able to just flick a switch for what amp I want to use. 

I'll post pics when this is built, I've updated my system pics for my recent updates. Pales in comparison to a lot of the systems here but she's mine and it does sound real good...especially when the Threshold is in play. 

Thanks for all the links and help guys!!
Tim
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