PCB Mounted Rotary switch for Bridged T attenuator.

[iampoor1]

Hi

I might be looking in the wrong place, but I have been having a hard time finding some suitable PCB mounted rotary switches for a Bridged T attenuator. I want to build some into a couple Preamps Im designing so you can drive the output transformer for some coloration.

Anyways, this is my first foray searching for rotary switches....and it has proven quite frustrating! I am looking for rotary switches that are PCB mounted, so they can be installed on the PCB without interconnects or any additional wiring.

I would prefer a 2 pole with 5-12 positions. All I can find so far:
http://www.mouser.com/ProductDetail/Alpha-Taiwan/SR10010F-0205-20F0B-C7-N/?qs=sGAEpiMZZMsqIr59i2oRcoDcQJQh3%2fc%252bqugkKwyq%2fvw%3d

Contact rating seems low and cutting it too close however....

AM I crazy and wanting a part that doesnt exist? I feel like Im missing something, please fill me in!

Thank you in advance!

-Nathan

 

[Winetree]

I don't know if this is what your looking for but Classicapi.com has some t-pad attenuators.

 

[Harpo]

a 2x6 Lorlin type (shorting - MBB) switch ?

 

[iampoor1]

I don't know if this is what your looking for but Classicapi.com has some t-pad attenuators.

If it really comes down to it Ill consider them. Still I would like to find something cheaper in quantity. Im probablly going to stick with no more then 6 steps....

a 2x6 Lorlin type (shorting - MBB) switch ?

All of the Lorlin switches I have found mount this way
http://www.dadaelectronics.eu/shop/components/switches/lorlin-ck1036-rotary-switch-3-pole-4-positions-mbb

While, what I am looking for one that mounts on a 90 degree angle (shaft relative to the PCB).

Like this
http://img127.imagevenue.com/img.php?image=702306150_IMG_0038_122_230lo.JPG

Is there a Lorlin series like this that I have completely missed? Or is this a lost cause?

If it really comes down to it, I might design a T-pad attenuator board around a Lorlin switch and mount it seperatly with only in/out connections for the Pad. That would be much easier then wiring separate wires to each contact.

 

[ruffrecords]

Good quality PCB mounting 2pole 12pos switches are not likely to be cheap. The obvious choice is Grayhill 71 series.

http://www.digikey.co.uk/product-detail/en/71BDF30-02PAJN/GH7107-ND/98682

Cheers

Ian

 

[Harpo]

While, what I am looking for one that mounts on a 90 degree angle (shaft relative to the PCB).

So use a small sub pcb for the 2x6 shorting Lorlin switch, the 2x5+2=12 resistors and a 3-pin molex type connector.
Look up the connectors datasheet to get the mechanical dimensions for the amount of offset correct and/or use 0.1" displaced solder lugs to make various types fit. Get this right to not stress/flex this connection with the Lorlin fixed to frontpanel and the sub pcb plugged into the corresponding molex socket on main pcb.

Like this
http://img127.imagevenue.com/img.php?image=702306150_IMG_0038_122_230lo.JPG

Pic shows Grayhill series 71. A 2pole/12throw Elma series 04 with 15° indexing for the needed MBB would be another option. Both are not cheap.

 

[shabtek]

how to you do a bridged tee with only 2 poles?

I think you need at least 4 poles for bridged.

edit: I was thinking balanced tee

 

[ruffrecords]

how to you do a bridged tee with only 2 poles?

I think you need at least 4 poles for bridged.

For a fully balanced one you do but most bridged T attenuators are not fully balanced and don't need to be so long as they are floating working from and into 600 ohm sources.

Cheers

Ian

 

[Harpo]

how to you do a bridged tee with only 2 poles?

I think you need at least 4 poles for bridged.

2 poles for stepped bridged tee, 3 poles for balanced bridged tee required.
Something like this, if you like playing with numbers.

 

[emrr]

A 2x6 Lorlin will rotate freely, having no stop pin, correct?  2x5 you can get away with.  I don't know of a cheap right angle PCB mount that's really suitable. 

 

[Harpo]

A 2x6 Lorlin will rotate freely, having no stop pin, correct?  2x5 you can get away with.  I don't know of a cheap right angle PCB mount that's really suitable.

Depends on what you order. You can get them with or without endstop, switching BBM or MBB, with solder lugs or solder pins, ...
A 2x6 Lorlin rotary switch with solder pins, shorting MBB, with end-stop is art-no. 'CK-1060'.
For a right angle PCB mount you need exact mechanical data, else I'd agree this might be unreliable. To come by with using 3 wires for input, output and reference voltage. Lesser cost and pcb real estate, but the OP wanted no wires at all.

 

[emrr]

CK-1060 says it comes with a stop pin, but I have yet to see one where the stop pin didn't lock you out of the last position, making it effectively a 2x5 with the stop pin in place, or a 2x6 with free rotation, stop pin removed. 

 

[Harpo]

CK-1060 says it comes with a stop pin, but I have yet to see one where the stop pin didn't lock you out of the last position, making it effectively a 2x5 with the stop pin in place, or a 2x6 with free rotation, stop pin removed.

The end stop is fixed built into the switch between pos.12 and 1 to prevent dial thru. You still have to displace the endstop washer below the fixing nut to pos.6 after you removed this washer and turned the switch full CCW to get the wanted 2x6 positions. Maybe you refer to a different type/brand of switch.

 

[emrr]

Could be another "Lorlin style' available over here. 

 

[abbey road d enfer]

Lorlin PT series are available in up tp 19P 12T !
http://www.farnell.com/datasheets/54353.pdf

 

[kato]

Bourns 600Ω T-Pad Attenuator for a mere $30.  [Hairball Audio]

 

[My3gger]

Palazzo had this kind of switches, don't know if new owner is still making them. I really like some of their switches, much better than Lorlin. They are also making custom pots in many configurations.

 

[iampoor1]

CK-1060 says it comes with a stop pin, but I have yet to see one where the stop pin didn't lock you out of the last position, making it effectively a 2x5 with the stop pin in place, or a 2x6 with free rotation, stop pin removed.

The switches I ordered are 2x6 free rotating. Wish I could answer the stop pin question!

Thanks for all the helpful replies guys. I like the lorlins, decent enough quality, fair price. Cheap in quantity too.

I would go with the hairball audio solution but Im planning on making atleast 100 of them, and not really looking to take out a small loan for T-pads

 

[Gustav]

So use a small sub pcb for the 2x6 shorting Lorlin switch

Something like this attached image with connector like...

...this - http://www.toby.co.uk/content/catalogue/products.aspx?series=THD-xx-R-RA ?

I used random pin connections and the auto-router for this example, but putting a little more thought into it could probably improve it a lot.

If this would do the job, I can try do it single sided and share a self etch file...Seems like a fun challenge .

IF its possible to turn the pins upwards into the solder side of the board it connects to and successfully solder it (pins going in at solder side), it wouldn't even take up a lot of space - that would require an experiment, and may be a little "greedy" though (and might not make sense the way I explained it!?)

We rarely need more than 2x5 for stuff like this, right?

1,4 inches high.

Gustav

 

[iampoor1]

So use a small sub pcb for the 2x6 shorting Lorlin switch

Something like this attached image with connector like...

...this - http://www.toby.co.uk/content/catalogue/products.aspx?series=THD-xx-R-RA ?

I used random pin connections and the auto-router for this example, but putting a little more thought into it could probably improve it a lot.

If this would do the job, I can try do it single sided and share a self etch file...Seems like a fun challenge .

IF its possible to turn the pins upwards into the solder side of the board it connects to and successfully solder it (pins going in at solder side), it wouldn't even take up a lot of space - that would require an experiment, and may be a little "greedy" though (and might not make sense the way I explained it!?)

We rarely need more than 2x5 for stuff like this, right?

1,4 inches high.

Gustav

Hey Gustav, thats a great idea! Another option would be to have all the resistors loaded up on the sub board and then just have 3-4 pins coming out. Might make it more forgiving to mount and reduce soldering time (Less connections), however it would limit the use of the board considerablly....

Where did you get the Eagle part for the Lorlin 2x6?