1176LN Slam Mode


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gswan
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A circuit analysis of the 1176LN will show that the all button in or 'slam' mode is equivalent to a 10:1 compression ratio.

-Geoff

studio139
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How does that work?

I thought that compression ratio 4:1, 8:1, 12:1, 20:1, so I would have assumed
it would be closer to 40:1. I am not arguing with the conclusion, just curious.

gswan
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The compression ratios are

The compression ratios are not added if you press all the buttons.

The switches are placed across a couple of resistive dividers, one controlling the level of signal entering the gain-reduction rectifier and the other controlling the amount of offset applied to the rectifier output. Pressing the 20:1 and 4:1 together is the same as pressing all 4 buttons, since the two end buttons short out the ones in the middle when pressed together.

I did an analysis of it here if you are interested.
http://www.axtsystems.com/index.php?option=com_content&view=article&id=8...

studio139
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Thank you

Thank you for the information and the link.
I understand that "shorting" is just meant as simplified explanation,
but does using the "all buttons in" actually harm the unit?
Do you know if there was ever an official modification of the
unit to make the "all button in" a "preset" function? i.e.,
was the circuit redesigned in order to accommodate using the unit
in this way. A very interesting area of study.

gswan
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"Shorting" is exactly what a

"Shorting" is exactly what a switch does :)
'All buttons in' does not harm the unit, it simply changes the resistor divider position.
I'm not aware of any official modification to add another button to do this, most people simply use the 'all button in' mode.