pucho812

Passive audio compressor..
« on: May 23, 2020, 05:38:26 PM »
You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is.


EmRR

Re: Passive audio compressor..
« Reply #1 on: May 23, 2020, 06:23:05 PM »
Everyone should wire various lightbulbs in series with a guitar amp cabinet at least once. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde


moamps

Re: Passive audio compressor..
« Reply #3 on: May 23, 2020, 08:03:32 PM »
Everyone should wire various lightbulbs in series with a guitar amp cabinet at least once.

Some of as replaced burned "passive audio compressors" on abused JBL CTRL 1.

jensenmann

Re: Passive audio compressor..
« Reply #4 on: May 24, 2020, 05:45:54 AM »
That´s an old trick that has been used since the early days of PA systems to protect HF drivers. There´s even a 500 product out which uses a bulb: https://www.anamodaudio.com/tlcompressorbr.html
Jens
Quote from: PRR
The tubes of course don't care what frequency they distort

JohnRoberts

Re: Passive audio compressor..
« Reply #5 on: May 24, 2020, 09:56:56 AM »
I had to watch the video before posting.  :-\

I am not sure that lamps are completely passive, but they have long been used for level control (inside sine wave oscillators like that classic old HP) but more widely as protection for loudspeakers (tweeters).

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

clintrubber

Re: Passive audio compressor..
« Reply #6 on: May 27, 2020, 08:12:11 PM »
That´s an old trick that has been used since the early days of PA systems to protect HF drivers.

I learned that SWR 4*10" bass cabs use this method for horn-protection as well,
when band members alerted me on 4 illuminated circles per cab behind me: the cone edges of the 10" speakers  :o :D

A simple auto-lightbulb, effective.

Re: Passive audio compressor..
« Reply #7 on: May 27, 2020, 08:40:06 PM »
I had to watch the video before posting.  :-\

I am not sure that lamps are completely passive, but they have long been used for level control (inside sine wave oscillators like that classic old HP) but more widely as protection for loudspeakers (tweeters).

JR

I wonder about the linearity of the bulbs when not compressing.

JohnRoberts

Re: Passive audio compressor..
« Reply #8 on: May 27, 2020, 11:37:37 PM »
I wonder about the linearity of the bulbs when not compressing.
Not very linear...  Peavey designed an improved version where a PTC fuse shorted across the lamp when cold, so clean when not limiting. After it heats up and starts limiting distortion is relative....

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

Re: Passive audio compressor..
« Reply #9 on: May 28, 2020, 12:24:17 AM »
Not very linear...  Peavey designed an improved version where a PTC fuse shorted across the lamp when cold, so clean when not limiting. After it heats up and starts limiting distortion is relative....

JR

Nice idea!


JohnRoberts

Re: Passive audio compressor..
« Reply #10 on: May 28, 2020, 11:47:36 AM »
Nice idea!
Not my idea, one of the lads working in transducer engineering came up with it.

I used some PTC fuses in my 1980s boosted rail power amp (PMA70+) to limit the recharge rate for the boost capacitors.  60W rms when cold, falling back to 35W continuous when slammed. Playing typical music it didn't fold back. It put out more than 60W for transient peaks.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.


 

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