Good bilateral switch?

Can anyone recommend a good bilateral (analog) switch? Preferably +/- 18V, low distortion, quad or more...
Something like the old CD4066 that I can use for full voltage audio.

Thanks!

Interested too. Every time I look into this, I end up using throwing in Takamisawa relay in stead. Gets expensive and power consuming in the long run..

/Jakob E.

bluebird said:

Can anyone recommend a good bilateral (analog) switch? Preferably +/- 18V, low distortion, quad or more...
Something like the old CD4066 that I can use for full voltage audio.

Thanks!

Click to expand...

Define good...
I've used DG 308/408/411 with excellent results; it takes a good analysis of specs to operate them in their comfort zone.
Now these are of an old generation. Check MAX 312/313/314.

Why post this in the Brewery? This should be in Drawing Board or maybe Truth Table.

The key specs are on resistance (Ron), on resistance flatness and capacitance. They are all quite high compared to a relay. So the surrounding impedances become important. You can't just drop it into whatever circuit.

But if the surrounding impedances are good, then they work great. Although the last time I actually used one I was just fooling around and it was in the very beginning when a really didn't know what I was doing.

ADG1412 is worth a look.

Of course the really good ones are pretty expensive. But when you consider the size and associated components that go with using 2-4 separate relays, they're really not. And many of them are digital control which can be a huge plus.

If I ever become rich and have unlimited resources and time, I would like to build something that is entirely Audigio™ [1].

[1] First coined by mystery poster "squarewave" on groupdiy.com December 15, 2019, "Audigio" means a 100% digitally controlled analog small signal audio device such as an automated mixer.

abbey road d enfer said:

Define good...
I've used DG 308/408/411 with excellent results; it takes a good analysis of specs to operate them in their comfort zone.
Now these are of an old generation. Check MAX 312/313/314.

Click to expand...

Exactly... Transfer gate technology is mature and has improved a lot over the decades, that said it is not the best choice for many situations.

You can minimize or effectively eliminate the known weaknesses in cmos TG  by good execution. I could not measure the distortion in one console circuit I used back in the 80s (using a soundtechnology distortion analyzer, good for its time.)

Relays are brute force but easier than killing brain cells if cost no object.

JR

PS: Completely digitally controlled analog was pretty well explored last century and not embraced by the market when all digital paths offered superior feature sets with good audio path performance, and low cost.

JohnRoberts said:

PS: Completely digitally controlled analog was pretty well explored last century and not embraced by the market when all digital paths offered superior feature sets with good audio path performance, and low cost.

Click to expand...

I think that could easily go back the other way. If you have any analog gear, do you put it on aux channels of a digital mixer at 5ms round trip each? I've never tried but I would imagine serious recording people have an analog part and a digital part and once you go digital there's no going back. So having devices that can be automated in the analog domain would be nice.

abbey road d enfer said:

Check MAX 312/313/314.

Click to expand...

Perfect! thanks Abbey.

Audigio™

Click to expand...

I would appreciate perusing the code.  ;D

bluebird said:

Something like the old CD4066 that I can use for full voltage audio.

Click to expand...

If you can allow some additional circuitry, this issue is solved by using for instance this virtual ground topology
(but you probably will have considered that already)



( https://groupdiy.com/index.php?topic=50726.0 )

The most important issue is leakage due to capacitance in the OFF position (and also parasitic capacitance). This parasitic leakage must be dumped in a low impedance path. Indeed for a basic ON/OFF switch, it takes two cells to get optimum attenuation in OFF position, but for source-select applications, such as by-pass or X-into-1 selector, the low impedance path is provided by the selected source. That's why signals should be buffered before switching.
Current switching (sources feeding a VE stage via resistors) suffer from inadequate OFF attenuation, unless the leakage is dumped to ground, taking two cells per signal.

clintrubber said:

If you can allow some additional circuitry, this issue is solved by using for instance this virtual ground topology
(but you probably will have considered that already)

( https://groupdiy.com/index.php?topic=50726.0 )

Click to expand...

I've told this story so many times even I'm getting bored, but if you connect the NF resistor around the series TG any TG non-linearities also get reduced by the op amps NF.  A few more parts than that simple schemo but I used it in a console back in the 80s to electronically switch whole banks of channels between monitor and mixdown with one logic signal. The linearity of that switching was below the distortion floor of good circa 80's bench equipment.

For more details search around I have talked about this (too many times) here before over the years.

JR