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I' m too cheap [message #25217] Tue, 13 December 2005 05:33 Go to next message
Leland Crooks is currently offline  Leland Crooks
Messages: 212
Registered: May 2009
Master
to buy a clipcop or a rane gain, I'm going to use my PC for a 440 sine wave into the PA. If you're not familiar with them, they generate a 440hz tone and you plug a pizeo into the output. Turn up gain until it distorts, voila, max gain. They put out at 0dbu, which I understand is 1.23v pro level. Through the di box I don't think my pc will give that much gain. I do now have a meter with a db scale. What's the formula say, if I can give -10db signal, that I can use to mathematically find the 0db level. Then I can adjust my trim knobs and turn down accordingly

I figure I'll only need to do this once, which is why I don't really want to buy one.



Re: I' m too cheap [message #25218 is a reply to message #25217] Tue, 13 December 2005 08:50 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

I've heard of folks doing that. You might want to get a scope sometime too, 'cause they aren't that expensive anymore.


Re: I' m too cheap [message #25219 is a reply to message #25218] Thu, 15 December 2005 12:31 Go to previous messageGo to next message
Leland Crooks is currently offline  Leland Crooks
Messages: 212
Registered: May 2009
Master
This worked great. All my meters on board, comps, xover and amps all clip at the same time. I figure I gained about 8-10db of headroom. It made big changes to my guess derived settings.

Now on to the rta function.

Re: I' m too cheap [message #25225 is a reply to message #25217] Mon, 07 August 2006 09:40 Go to previous messageGo to next message
telegraph.hill is currently offline  telegraph.hill
Messages: 75
Registered: May 2009
Viscount
By pizeo do you mean a piezoelectric crystal?

Re: I' m too cheap [message #25226 is a reply to message #25225] Mon, 21 August 2006 17:02 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Leland is talking about using piezoelectric tweeters. The way he's using them is to listen for HF created by the leading and trailing edge of a clipped signal. If you put a low frequency sine wave into an amplifier, the output signal will also be a low frequency sine wave that can't be heard from a piezo tweeter. But once the amp starts to clip, the sharp edges generated are high frequency so they can be heard with a piezo. That's how Leland plans to use piezos to tell when his amps begin to clip.


Re: I' m too cheap [message #25227 is a reply to message #25226] Fri, 08 September 2006 13:35 Go to previous messageGo to next message
telegraph.hill is currently offline  telegraph.hill
Messages: 75
Registered: May 2009
Viscount
Thanks for explaining that. But what does "clip" mean in this context?

Re: I' m too cheap [message #25228 is a reply to message #25227] Fri, 08 September 2006 23:26 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

It's when an amplifier is pushed hard enough that the output signal rises to the maximum. It canot go any further, so the output is "clipped".


Re: I' m too cheap [message #25229 is a reply to message #25228] Mon, 18 September 2006 04:10 Go to previous message
telegraph.hill is currently offline  telegraph.hill
Messages: 75
Registered: May 2009
Viscount
OK, thanks for explaining.

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