Switches: power and bypass

[Guest]

I?m trying to decide between leaving the makeup gain on my GSSL in or out when I bypass the unit. But then something occurred to me: I?m already wiring it on a 3 position rotary switch, so instead of just using the 2 positions (bypass in/bypass out), why don?t I use all three [bypass out, bypass in (with makeup), bypass in (without makeup)]? I couldn?t find anything in the SSL threads about this, except something that suggested using a relay to accomplish this. But it looks to me like I can just wire up the switch pretty much as indicated in Jacob?s diagram, but just change a few things: "on" wire goes to C3, "off" wire goes to C2, and is jumpered to C1. Make up bypass wire goes to A3, and then is jumpered to A2. So that in the second position the comp would be bypassed and the makeup gain would still be engaged, but in the third position, the unit would be bypassed, and the makeup would be defeated. I?m a complete newbie, so I suspect that if this was a good plan, someone else would have already thought of it?.

Also, and I?m totally embarrassed to be asking this, but how do I wire up the On/off switch? I?m assuming it just goes in between the hot pin on the IEC and the transformer, right?

Thanks!

 

[bcarso]

"Also, and I?m totally embarrassed to be asking this, but how do I wire up the On/off switch? I?m assuming it just goes in between the hot pin on the IEC and the transformer, right?"

Yes. But...

Don't feel too bad. Once, a Cornell physics grad and very bright guy asked me how a switch worked--what was inside one, etc. He was a bit embarrassed as well. It took me a while to figure out what he really meant. He knew what it was supposed to do, he just didn't know how it did it. Eventually I explained that there was this arrangement of two or more pieces of metal, that moved mechanically when the lever was moved so as to press the movable piece against one or more of the stationary pieces, etc.

I guess he thought there were some electronics inside or something. But when you think about it it's easy to imagine that this topic might never have come up during a person's education, especially in the absence of any hobbyist activities in the days of one's youth.

 

[Guest]

Thanks. No such thing as a dumb question, right? :grin:

So what do you think about that bypass switch wiring I'm considering? Think it's kosher?

 

[gyraf]

..it should work - but in use, the bypass works best (gives most useable comparisons) when makeup is disabled when bypassed..

Jakob E.

 

[Guest]

Is that something specific to the GSSL? I find that when comparing, I often like to have the makeup gain stay in because if I use the makeup gain to boost the signal beyond it's nominal level, it's difficult to determine what the compression is doing to the sound because the louder-ness of the non-bypasses signal makes it sound better. So in those cases I'd like to at least have the option.

So, yeah, if I'm using the makeup gain to return the level to it's nominal level after compression, it would be silly. But since you included wiring on your drawings to defeat the makeup gain, I'm assuming that you thought it would be a worthwhile feature. And I agree. :grin:

 

[soundguy]

If you are limiting 10dB, you are going to be pulling 10dB of gain from the output amplifier. If you are feeding the unit line level, when you switch the unit into bypass, you are now sending +14dBm to your console. Thats fairly worthless for comparison in any situation Ive been in.

What would be more useful is a level matching circuit (which I think is what you want) where the unit gives you the same perceived level when in bypass. The easiest way to do this is with a fader, when I audition stuff, I'll always have a finger on a fader to match the perceived level of the limiter when I swith it into bypass. Sending all the makeup gain you are applying, if its alot, is often louder than the "perceived" level, so my guess is that with your idea you'll need to pull a fader *down* as opposed to pushing the fader *up* without it.

Its worth a try though, Ive never wired it up to report any first hand experience, but Im guessing thats the situation you'll be in. try it out with an 1176, when you defeat the limiter you get ALL the level from the line amp and turning that switch on and off doesnt do anything for comparison at all.

Hopefully you get what Im saying here, I cant tell if this makes sense or not.

dave

 

[Guest]

Dave,

I am have a hard time following you, but you definitely get what I'm saying. A level matching circuit would be ideal, but a circuit to match perceived level of compressed and uncompressed audio?.if not difficult to design, would probably be prohibitively difficult for me to implement, because I?m new to DIY and because I?ve got the faceplate on it?s way back to me from FrontPanel already. Is there a way to do that, anyway?

I could do it on a fader, yes. But I?ll mostly be using it on the 2 buss of my pro tools mixer, and it would just be nicer to have the capability on the unit instead of using up another stereo pair my digital mixer (I?m usually pushing the track limit/dps as it is).

Well, given all this, I think I?ll just wire it up with the 3 options I mentioned above and be happy. If there IS some way to do what you?re talking about, I?d love to hear about it, and implement it on my next project.

David.

 

[soundguy]

If you are compressing at a 20:1 ratio, if you are compressing say -10dB, that's an awful lot of makeup gain the output amplifier has to provide. If you are sending the limiter a line level signal, a signal that in theory is already registering at 0 VU on your console, to just throw the unit into bypass, you'll get, returning to the console, the 0 VU signal you sent to the limiter PLUS *ALL* the gain from the makeup amplifier of the limiter, which will peg the meters on your console or whatever.

The reason to put a bypass there would be to use the line amplifier as just that, a line amplifier and people do this with 1176 all the time because the circuit sounds so cool. If you throw the unit into bypass AND get all the gain, you'll have to quickly pull down the console fader and hope the console input can accomodate the large amount of level its now about to see. In my mind, this isnt any different than having the circuit in global bypass where you have to then raise the fader to make the track a little louder for comparison. You're either changing the fader position or you'll have to change the output pot on the limiter.

Its useful to try it and have access to the line amp if you ever need it, that would be cool, but I suspect the above scenario is where you are gonna be. Again, I havent tried it, Im going on the assumption that it would function exactly like an 1176 in this regard.

As far as a level matching circuit, I imagine that would be fairly complicated to do just based upon the perceived difference in loudness between 1:2 and 1:20, it seems like it would be pretty difficult to accurately make something like that, moving a fader is so much easier.

dave

 

[Guest]

Ah, gotcha. So it seems I can?t do exactly what I?d like to, but that there is good reason to include the third switch position. Bypass with no makeup gain to compare (assuming I?m not boosting the overall output), or bypass WITH makeup gain to use as a line amp, ala the 1176.

Cool!