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Switch box Rotary Switch help

post #1 of 12
4/17/07 at 2:44pm
Thread Starter 
Hey guys. I've been wanting to make a switchbox for quite some time now, but I have a few questions regarding a rotary switch.

I want a 3 input 1 output switchbox (which I can later add both more inputs and outputs if desired) and I don't think I can use a regular switch. After checking out some rotary switches, what do you guys think is better?

2 Pole X throw/way rotary switch
2 Pole (R/L Signal) would be attacked to the rotary switch while the grounds are connected to the chassis

4 Pole X throw/way rotary switch
4 Pole (R/L Signal and R/L Ground

I think they basically work the same since the ground lug on the RCA jack is connected to the chassis anyway. Would going with the 2 pole perform the same?

Thanks for anyone who reads this. =T
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post #2 of 12
4/17/07 at 3:16pm
Do a search as there are many switchbox threads here. As far as switching the grounds or not, that depends upon your application and how anal you want to be (sorry). I switched the grounds on mine because one of the inputs was from my modest video system (DVD) and I didn't want it mucking up the grounds on my audio system when not switched in. You can use 3 pole for this, as you are correct in assuming that most equipment has the RCA grounds common between both channels. Going for more poles will decrease the number of positions (inputs) available unless they are seperate decks on the switch (some spolit poles on one deck, so you lose switch positions for each additional pole).

For multiple outputs, you will probably have to use a second switch to control which output the first switch is going to.
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post #3 of 12
4/17/07 at 3:24pm
Thread Starter 
Yea, I plan to just use a regular toggle switch for that.

Did you feel therew as any loss in sound quality after implementing the switch box?
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post #4 of 12
4/17/07 at 3:31pm
You might find something useful in my tut
http://www.mb3k.com/socram.html
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post #5 of 12
4/17/07 at 3:46pm
Thread Starter 
Very nice tutorial, but I don't quite understand the Crossfeed. What does it do?

Also, I need a non-shorting switch right?
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post #6 of 12
4/17/07 at 3:55pm
The crossfeed is just an external device. You can connect anything to those "crossfeed" RCA jacks (ie. If you want a preamp before the amp).
In my case I don't have a preamp, instead I chose to put crossfeeds in the "middle" position between the source and the amp. You can see there's also the option to switch it off so it bypasses the "middle" position.
Sorry if it's vague, but hopefully it cleared it up.

EDIT:
You should get "shorting" switches so the signal ground isn't lifted when you switch .
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post #7 of 12
4/17/07 at 4:01pm
Quote:
Originally Posted by laxx View Post
Yea, I plan to just use a regular toggle switch for that.

Did you feel therew as any loss in sound quality after implementing the switch box?
I haven't done any extensive comparisons of direct vs. switchbox, but I would think there are far more effective means of sound improvements than worrying about switch contacts. Then again, some cable advocates seem to indicate they can hear the differences in metal types on connectors, etc. If you do a search here, there is an electroswitch series that rickcr42 recommends (Mouser, ~$25) that is sealed with I believe solid silver contacts. It isn't crazy expensive, doesn't rely on voodoo or BS marketing claims, etc. so I can't see any reason not to use it versus say a $5 Lorlin switch from Mouser. It also has the added benefit of being solid and heavy, which would help keep the switchbox from moving around.
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post #8 of 12
4/17/07 at 4:08pm
great link m3bk, thank you
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post #9 of 12
4/17/07 at 4:40pm
Thread Starter 
Quote:
Originally Posted by mb3k View Post
The crossfeed is just an external device. You can connect anything to those "crossfeed" RCA jacks (ie. If you want a preamp before the amp).
In my case I don't have a preamp, instead I chose to put crossfeeds in the "middle" position between the source and the amp. You can see there's also the option to switch it off so it bypasses the "middle" position.
Sorry if it's vague, but hopefully it cleared it up.

EDIT:
You should get "shorting" switches so the signal ground isn't lifted when you switch .
Oh, I did a search before and someone said not to get a shorting rotary switch. =T

I wasn't so worried about the contacts, as it's more about me not owning multiple pairs of the same branded interconnects. I have Starquad IC's and pure silver IC's, so I just wasn't sure about the outcome of using DAC -> Switchbox with Starquad and Switchbox to Amp with pure silver. If I had the money, I'd switch to identical cables and use the same wires within the switchbox, but that would be way too costly. =T
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post #10 of 12
4/17/07 at 10:12pm
Unless you have active grounds then shorting is better. That way you won't get any loud pops when you're switching.
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post #11 of 12
4/17/07 at 10:48pm
The Elma 01 or 04 type rotary switches are very high quality. DACT and Goldpoint resell them, but you can buy direct from Elma for less.

The 01 (01-1430) would give you 4 poles (you really only need 3) and 3 exactly positions.

The 04 (04-1370) would give you 3 poles and up to 7 positions. But, If you are using less than 7 posistions, you'll have to buy stop screws; those are only $2.64, though.

Including shipping and stop screws for the 04 switch, the 01 type configuration would cost you about $27, and the 04 type configuration would cost you about $43. These are prices direct from Elma and you need to request a price quote. That'll probably take 1 or 2 business days. Also, they may not have the product you want in stock. I bought that very same 04 type switch and I was told I'd get it in 3 weeks, but I got it in about 2. YMMV.

The part numbers I gave are for the switches with gold flash. Gold 3um is slightly more expensive (I'm not sure by how much), but I was told that the gold flash is better as long as you clean it now and then by putting it through a full rotation back and forth. The gold 3um is meant for applications in which the switch may not be turned for a long time.
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post #12 of 12
4/19/07 at 8:02am
Have alook at teh darwin source selector over at www.twistedpearaudio.com. You will need to add a 5V supply which is easily enough done but the kit is only around $50. Gives you 6 inputs, 2 outputs all on a relay based device. I've just built one, support is great and the kit is pretty easy to do. Worth considering.

Fran
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