Speaker Selector Switch - Distortion & Noise?

[SteveAndBell]

Hi.

Now that my main vintage listening system is growing with more & more repaired/restored gear I'd like to be able to switch between speakers to make easy & instant A-B comparisons from my listening position. I've only found a couple of devices that will do this and they seem fine... all except for the fact that I just saw a THD+N value listed in the specs of one of them (see Page 8 of this manual: http://www.wharfedalepro.com/Portals/0/PDF_Data/WPR-26MKII_User_Manual.pdf)

Surely a multi-speaker selector box like this would just be a bank of relays controlled by a logic circuit right? Just like the home-made very manual switcher I built a few years back using boring 4PDT switches yeah? If this is the case how could a simple switching device like this introduce its own noise or could it be from the active electronics of the logic circuitry perhaps?

I know enough to be dangerous but when it comes to things like this I need to learn so any help is appreciated. I'm just concerned that adding a device like this to my system will dirty up my nice squeaky clean & relatively expensive 'Natural Sound'

 

[Odysseous]

Check this out. I bought it and don't see any sound quality degradation or distortion. It can handle up to 100 watts. It's pretty light so I'm sure it's just relays and the logic control, as opposed to the other ones i tried that offer impedance matching via heavy and distorting elections. I don't need impedance meeting since I only use one pair of speakers at a time for A/B testing.

http://www.outdoorspeakerdepot.com/7-pair-speaker-selector-with-remote-control.html

Amazon has it for $150

Best of luck!

 

[ConradH]

I can't imagine the Wharfedale unit would even have a measurable THD. Maybe the +N adds something, but according to the manual, it's just relays. Maybe they couldn't confirm a lower value with the equipment at hand. My guess is somebody in marketing just had to stick a number on it.

 

[SteveAndBell]

Check this out.http://www.outdoorspeakerdepot.com/7-pair-speaker-selector-with-remote-control.html

Thanks Odysseous. I have seen that one before and like the look of it however it isn't easy to get down here in Oz. Due to the crazy region-ist attitude of Amazon I can't buy it through them so the only place I can semi-easily get one is via a Canadian reseller (www.avgearshop.com) but postage boosts the total cost to around $250! I'm still fine to pay that as it seems to be the best available device however on top of the high cost it will also apparently take 6-9 weeks to arrive :sigh: so I'm treating it as my reliable backup plan if nothing else comes along.

There's another comparative switcher I can very easily source locally that I really really like, has been designed by a very reputable local Aussie audio/PA company (Redback) and is quite a good price ($345) and even has a nice little programmable 2 line LCD on the front panel so you can have it display the names/models of the speakers it's currently switched to (http://www.ebay.com.au/itm/310611664995?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649). It can handle 10 pairs of speakers however problem is that it's only a single source input plus the connections are fiddly little screw-down strips which kinda kill it for me. It also only has a 200W maximum and although most of my listening would only be down under the 50W mark I'd like to know that I could take it a lot higher if need be without melting anything and I have a few Amps in the repair pipeline that easily exceed that rating.

I have been thinking about making a nice sleek add-on box for that one though... a slave switcher box of sorts. Use the original box just for its logic controls and simply get it to switch a 12VDC signal out to the slave box via a low current multicore cable. The slave box would contain a bank of fat & juicy 4-pole relays easily capable of handling a lot more than 200W and would terminate via large banana sockets instead of the fiddly screw terminals on the original. This would be close to the ultimate for me and relatively easy to make however it would end up costing a lot more plus even after all that expense and hassle it still can't do dual inputs anyway

So yeah, that's where I'm at. I'm not even sure if I'll need dual inputs and I could probably live without them however I can also see me regretting it later on too. I've also had thoughts about buying TWO of the 10-way switchers, building each of them a slave box and using one as an input selector and feed that into the other as an output selector but I dunno. Seems like a lot of money when a $150 unit would do the trick.

Hmmm....

 

[SteveAndBell]

Maybe they couldn't confirm a lower value with the equipment at hand. My guess is somebody in marketing just had to stick a number on it.

Yeah, my thoughts too. The '0.1%' figure seems a little too convenient to be accurate BUT they are an audio company so you'd assume they'd have the proper measuring tools. Then again if they are just relays there shouldn't be any added distortion or noise once switched.

All very strange.