T attenuator, Ratio, Meter - ALPS rotary non shorting switches for 1176 rev D

I want to make bridged t-attenuator, from NewYorkDave schematic:

http://electronicdave.myhosting.net/miscimages/600bridgedt.gif

Also i want to use this same type alps switches for ratio and meter section on mnats rev D 1176LN.

Can i use not shorting switch? What will be difference when i use not shorting type? More audible pops and clicks or something more?

Second thing are parameters of the switches:
0.15A 12V DC/50µA 3V DC

Are not too low?

Alps SRRN:
http://us.100y.com.tw/pdf_file/SRRN.PDF

I know i didn't do it my homework very well, but rotary switches are not my forte.

Please Guys advise something!

One more time in case of rotary stepped attenuator, still i'm not sure how to connect it. I removed my older post.
My second idea in attachement. On the drawing (master of paint)  first and second pole with numbered pins and dB steps instead resistors.
It's correct connection? Looking on Dave schematic and the different schematics for rotary stepped t-pads, h-pads etc. and i don't get it...
I think now's fine, but any confirmation will be very helpful.
I really had problem to get those values of resistors, so i don't want to screw up  desoldering them again and again.

Alps switch should handle max 1.8W, resistors are 0.6W. I think it's enough. Bourns T-pads are 0.25W. Do i'm thinking correctly?

Anyone?

nice drawing; not sure that the wipers need to be tied to position 1.the switch on the right position 1\off should be tied to 0v or low side of signal input---a labeling such as in+,in-, out+,out- may clarify.
a shorting switch mbb will make less noise when switching but may not matter here.
to determine if a switch mbb or bbm put continuity beeper across 2 adjacent positions, see if there is a momentery beep when switched.

wattage rating is fine for +4 audio signals
read up on different types of pads and attenuators
try to picture each position as it's own distinct pad

I'm trying to figure out the same thing myself now. The drawing has helped me visualise it but it still doesn't make complete sense to me. Shabtek says the wipers don't need to be tied to postition 1 but that's what it looks like in the schematic. Can anyone else confirm that it's correct?

Here's my own attempt at drawing the connections of the top pole.

The original schematic is correct.

Cheers

Ian

Thanks!

trashcanman said:

I'm trying to figure out the same thing myself now. The drawing has helped me visualise it but it still doesn't make complete sense to me. Shabtek says the wipers don't need to be tied to postition 1 but that's what it looks like in the schematic. Can anyone else confirm that it's correct?

Here's my own attempt at drawing the connections of the top pole.

Click to expand...

Both are correct.
If you want to use it for 1176 circuit, then look at it was made by UA/UREI.
http://www.jblproservice.com/pdf/vintage%20jbl-urei%20electronics/urei-1176lnmanual.pdf

For rev A-E there's no need to connect wipers.
For rev F it's.
Of course in both ways it would work, but i would connect it as it was made in original for specific revision.
There are also two 600ohm (620) resistors and the rest are potentiometer sections. Each secection is equivalent of each resistor ladder. Basically it's the same.