1272 loud pops when changing gain

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

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

Jonkan

Well-known member
Joined
Jun 7, 2004
Messages
733
Location
Sweden
I have a problem with my 1272 clone thats wired pretty much as the JLM audio hotrod method. For schematics, check the jlm audio website:
http://www.jlmaudio.com/Schematic.htm

(The difference is that im using a 3 deck switch and im alternating boosting the output and the input gain after the pad isnt engaged anymore. When the pad is engaged, my output gain is set with an 1k5 resistor)

Problem:

When changing the gain from the lowest setting to the next lowest setting the micpre makes a loud pop!

This only happens at the first to the second gain setting, otherwise the preamp works great. No pops whatsoever from the second gainsetting and up.

What could cause this, and how do i fix it?

Any ideas would be greatly appreciated!
/Jonas
 
"Its make before break". But since it only happens at the first to second gain setting, something must be strange, right?

/J
 
Yes exactly, between -10 and -15!!

What could it be?


Up to -40 my wiring is exactly the same as JLM hotrod, after that im trying out something different to see if i like it. Alternating boosting the output and input gain, to level the workload some. But that shouldnt make any difference in this case im guessing.
/J
 
this is the switch: http://monacor.no/2003/?id=5&sub1=5&sub2=4&prod=RS-3312

I'll go look for strange shorts then.

I have one more channel that i havent wired with the switch yet. Ill mount it soon and see if the same thing happens on that channel.

The first channel is my "test" channel...It looks pretty bad, Some lifted solderpads and gerilla fixes with resistor legs etc. ´Since im new to all of this, and a bit clumsy, these things seems hard to avoid for me.

Everytime i try to desolder something on a double sided pcb, something gets broken. But as long as the components are properly connected to each other, i guess it doesnt matter, right?

I hope looks arent as important as sound. :green:

But hey, atleast it works/passes audio fine!
/J
 

Latest posts

Back
Top