thoughts and opinions on this unique la2a mod?

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

pucho812

Well-known member
Joined
Oct 4, 2004
Messages
14,832
Location
third stone from the sun
read this online somewhere


One of the complaints on the LA2a is a lack of control of the compression ratio. All you have is a switch for compression or limit. I thought of this this morning. What if one were to substitute a pot for the switch and R7 ? You would have a variable compression ratio. You could also extend the ratio with a higher value pot. It would be a super easy mod. Just throw a pot into the switch hole, hook up the two wiers to the pot , and clip out R7. What do you think?

Get a 2.5 k pot. Unplug the unit. Take out the compress limit switch. Install the pot in the switch hole. You might need some washers if the pot is smaller than the switch hole. Solder the two wires that use to go to the switch to pins 2 and 3 of the pot. (or 1 and 2, it dosent matter) Lift up one leg of the 2.7 k resitor (R7 on the formal schematic, I believe). The resistor can be found by following the switch wires. Color code: red Purple red. You are done. Easy to reverse if you don't like it. If you like it, throw a knob on the pot and label. Maybe put a 470 or 1 k resistor in series with one of the switch wires to have more range.
 
Nope.

It's really NOT a ratio switch. It's an attempt to exaggerate the effect of the feedback circuit, which -TO A POINT- simulates a higher ratio.

Measure what it really does. -Firstly, it's VERY subtle, which is why the switch was always on the BACK of the unit... until UA optimistically moved it to the front, to try and give more optoins from the front panel...

But -beyond measuring, LISTEN to what it does. -The vast majority of people report difficulty in being able to identify a difference. -the difference is bloody tiny to MEASURE, let alone hear.

Forget it. You want to change the ratio of an optical limiter, you need to do more than change one resistor at the sidechain pickup node.
 
Back
Top