School me about interlock switches versus latching switches

[JAY X]

Hi!

I was thinking to build a 1176 compressor, when i read that the Ratio push switches are not "normal dpdt or 4pdt latching" switches (like the ALPS SPUJ /SPUN series) but "interlock switches"

What is the difference?

Besides, these switches are not available at the usual distributors, (Mouser, Farnell, RS), only Aliexpress...


Jay x

 

[radardoug]

You push one, it releases the last button pushed. So push 1, it releases 4(last pushed). Push 2, it releases 1.

 

[JohnRoberts]

ganged Push-push switches with mechanical interlocks work like Radardoug described.

I used a 4 section ganged interlock switch on the Loft delay line/flanger back in the late 70s for delay settings.

JR

 

[JAY X]

Hi!,
Ok... So, if i understand right, the advantage of this type of switches over normal latching switches, is that you don't need to press again the last switch to turn it OFF. Correct?.

 

[Brian Roth]

Hi!,
Ok... So, if i understand right, the advantage of this type of switches over normal latching switches, is that you don't need to press again the last switch to turn it OFF. Correct?.

Correct....when you press a different switch the last one selected automatically pops back up.

Keep in mind there are two styles of interlocking switches:

1. Interlocking/not locked out. If you press individual switches, the previous switch pops back up. BUT if you press two or more at the same time, all selected switches will remain "on". That's what was on a 1176. There is a mode some folks use with all four ratio switches pressed at once; it has a slang name like "OMG" <g>.

2. Interlocked/locked out. Only one switch can be activated at a time.

Bri

 

[JAY X]

Ok!. Very claryfying!!
But, say I use normal latching push switches like the alps SPUN series. In that case, I could push easyly all switches at once for the ratio. Right?. Of course, I would loose the interlocking behaviour, and to switch off, I will have to push again the switch.

 

[JAY X]

I saw a YouTube video about an interlocking switch bar of 4 switches. The metal bar holds a spring that helps releasing one switch when you push another... A key feature of this type of switches.

 

[JAY X]

Hi!

I'm thinking to build a 1178. I was looking at the urei 1178 schematics (in the user manual), and also some pictures around the internet, they used 1/2 watt resistors 5% tolerance. Maybe because back in the day metal film resistors were much expensive than today and often it is said that using higher wattage resistors, helps reducing johnson noise...¿Is that right?

Another question. C31/R31, form a HPF. Maybe changing the cap value with a rotary switch, it would be possible to make a variable passive HPF?

Jay x

 

[Hubbub]

One of the issues with changing C31 is that it doesn't work against R31, but sometimes R31 in parallel with a much lower resistor depending on the Ratio switch (S3) selection. So the C31-Rx corner frequency already moves upward depending on compression ratio. (I'll leave it to you to calculate the four different -3dB points.) If there was a unity gain buffer inserted between C31 and the R31-S3 combination you could add a resistance to ground between C31 and the buffer, making that resistor variable would allow changing the corner frequency above which the compressor responds, now independent of Ratio selection. It would be a single pole, so not a steep rolloff to the low end, but it could permit a less compressed (boomy?) bass response with compressed highs, if that is your goal.

 

[JAY X]

Hi Hubbub!

Ok, Now I see clear!!.

Thank you very much!

jay x

 

[JAY X]

Hi!

Attached is a schematic of a HPF. I think it is correct, but better to check with more eyes...
The resistor values is what worries me the most, as they are so low...

This HPF is placed in between C31 (100uf) and R31 (6k2), and the ratio switch.

Jay x

 

[Hubbub]

Your schematic is not an HPF add-on, it is an attenuator/distortion generator. It will overload the driving op-amp and give unpleasant results. If you want a switched HPF just add a series cap (or caps) to C31 such that the coupling capacitance can be varied downward from the 100uF of C31. Or replace C31 with a switch selectable parallel combination of 47uF, 33uF, 22uF, and 15uF.

 

[JAY X]

Hi!

Ok, so it should be an arrangement simmiliar to the GSSL HPF..

 

[Hubbub]

I didn't check your RC corner values, but the circuit looks like it would work good, with reasonable gains in place. Worth giving a try.

 

[JAY X]

Hi!,

Another option is a hpf buffer with a switch to select a single frequency, or bypass...keeping the original CR filter 100uf/6200R.
I attached a schematic...

NOTE: I forgot to place the + sign at the 100uf electrolytic..