DIY stepped pots w/rotary switches & resistors

[Mr. Moscode]

It would be worth it to get a make before break switch so that the wiper doesn't get disconnected between settings especially if there is any chance of DC being on the switch. I don't know the rest of the circuit so that may be a mute point.

Could you post the schematic for the whole device?

 

[Matt Syson]

Yes they should be make before break contacts (MBB), to avoid the break, There is a small variatin WHILE switching but this is usually preferable to a break.

 

[djmiggymigz]

Okay yeah cool. Make before Break corresponds to Non-Shorting correct? That is what I was planning. From what I've gathered, with this circuit if the switch is shorting there can be +6 dB jumps while switching.

I don't have a schematic as the company I bought the PCB's from turned out to be mega scheisty. However, there's a far better circuit in the Nite 3D "Air" EQ thread.

 

[Mr. Moscode]

Okay yeah cool. Make before Break corresponds to Non-Shorting correct? That is what I was planning. From what I've gathered, with this circuit if the switch is shorting there can be +6 dB jumps while switching.

No-other way around. It shorts adjacent contacts as you turn it. I don't think the Lorlin switches have a MBB style. You would need a more expensive style.

The Lorlins lubricant also tend to dry out and tarnish inside after a few years as they are not sealed. You can clean and lube them but they are tricky with a spring loaded ball detent, easy to lose.

I don't have a schematic as the company I bought the PCB's from turned out to be mega scheisty. However, there's a far better circuit in the Nite 3D "Air" EQ thread.

Can you get a schematic of that?

 

[TwentyTrees]

I don't think the Lorlin switches have a MBB style.

Lorlin offers its entire CK range of rotary switches in both MBB (shorting) and BBM (non-shorting) variations. Datasheet screenshot below.

Of course, whether you can find the specific model you're looking for at your preferred supplier may be a different question.

 

[djmiggymigz]

yupp I found some on Mouser. Cant find the exact model on that screenshot but I bought the CK 1458. 12 pos, 1 pole, non-shorting. I dont think stops are included but that's okay I think. Mainly myself using this when it's done so I'll just keep that in mind (if I can't add a stop pin myself)

 

[Mr. Moscode]

Lorlin offers its entire CK range of rotary switches in both MBB (shorting) and BBM (non-shorting) variations. Datasheet screenshot below.

Of course, whether you can find the specific model you're looking for at your preferred supplier may be a different question.

View attachment 131075

I stand corrected! Excellent.

 

[Brian Roth]

yupp I found some on Mouser. Cant find the exact model on that screenshot but I bought the CK 1458. 12 pos, 1 pole, non-shorting. I dont think stops are included but that's okay I think. Mainly myself using this when it's done so I'll just keep that in mind (if I can't add a stop pin myself)

Which one did you buy? 1458 isn't on the list....

Bri

 

[djmiggymigz]

Which one did you buy? 1458 isn't on the list....

Bri

Yeah I know, I scanned the whole doc and didn't see it. Here's the mouser link tho.

https://www.mouser.com/ProductDetail/105-14571

 

[Brian Roth]

Yeah I know, I scanned the whole doc and didn't see it. Here's the mouser link tho.

https://www.mouser.com/ProductDetail/105-14571

Hmmmm....the Mouser link says it's non shorting....

Bri

 

[djmiggymigz]

Hmmm yupp your right. Lemme see. I made that decision based on some info that Harpo posted in the original thread. In an excel sheet he very specifically says that the switches should be non-shorting.

You've also just pointed out to me that I was thinking about the Make before break/shorting relationship backwards.

 

[Brian Roth]

Hmmm yupp your right. Lemme see. I made that decision based on some info that Harpo posted in the original thread. In an excel sheet he very specifically says that the switches should be non-shorting.

You've also just pointed out to me that I was thinking about the Make before break/shorting relationship backwards.

Link to Harpo's post? I'm just on the sidelines here watching the world go by! <G>

Bri

 

[djmiggymigz]

I won't be able to find it right now. If I have some time later on I'll dig and link it. Only saying that because the thread is now 69 pages long and I read thru every bit of it lol... not sure at what point that conversation was had.

I do have said excel sheet with the calculations tho. Just delete the .zip off the file name.

 

[user 138639]

If there's room for suggestions left... may I suggest to choose a good quality-switch? (I know it's probably a budget-thing)... I made something like this myself and was a bit disappointed with the feel of the switch (a chinese 2 channel 24 pos. one), it is quite rough to turn. And as was cautioned before, a switch that is prone to ageing may become a little problematic? Would be a pity for the effort…

 

[inkster]

Spend the money on a quality switch or you will eventually regret not doing it, grayhill's are acceptable, elma is preferred as far as mass produced non custom switches are concerned.
I see alpha switches in lots of gear...and eventually I have the pleasure of replacing them for clients, I love high quality gold wafers but those are not easily obtained and the Blore Edwards switches can be problematic after a couple of years.

 

[djmiggymigz]

((((( ugghhhh I know you guys are entirely right on this. I wish there was some sort of middle ground! Jumping up to the grayhill @ about $17-20 per piece is crazy when I need 12 of them total! Do you guys have any reccomendations of maybe some sort of middle ground switch? I just spent about $90 on the lorlins I bought. I could probably (painfully) muster up $200 total for all 12.

Super bummer. I was reading through the original Nite EQ thread and back in like 2005 someone mentioned buying grayhills for this purpose for like $6-8 per switch. Wish I could time travel!!

 

[djmiggymigz]

maybe something like this? Not sure how the 2 pole would work but I'm sure it's something I could figure out. Wouldn't be mad at more steps either!

https://www.don-audio.com/Rotary-Switch-2024-2-Pole-24-Position

 

[user 138639]

Make a mix if possible, use good switches for the most used positions…

 

[djmiggymigz]

Ouuuuu okay what about these??

https://www.newark.com/grayhill/56s...5v/dp/14M6793?MER=BR-MER-MA-RECO-PDP-STM72306

Thats a good idea! I could probably get away with the cheaper lorlins here and there.

 

[user 138639]

I'n not sure if this is the one you need.
56SDP30-01-1-AJN means

56SDP is the series (these switches ) with adjustable stopstyle
30 = single deck 30° angle
-01 = one channel
-AJN= "Use the letters AJ in this location if adjustable
stop switch is to be ordered.", and N means NON-shorting.

[EDIT: Wasn't sure anymore wether you need a shorting or nonshorting variant. As I presumed attenuation-things should be shorting, I went with the rest of my comment... sorry for any confusion!|

You'd need a switch that ends with S, like these

( https://www.mouser.ch/c/electromechanical/switches/rotary-switches/?contact style=Shorting&index angle=30 deg&m=Grayhill&mounting type=Panel Mount&number of decks=1 Deck&number of poles per deck=1 Pole&number of positions=12 Position )