3145 Biamp/Triamp Biased Network

[Uncle Paul]

I took the Biamp section of the 3145 Biased network that Giskard graciously created and split it into three sections and modified by adding some protection caps for the compression driver.

For use as a Biamp network BIAMP OUT connects to BIAMP IN and s1 is set to bypass the 47 uF caps. UHF IN is connected to MF IN.

For use as a Triamp network TRIAMP IN and UHF IN are connected and s1 is set to place the 47 uF caps in the signal path. The purpose of these caps is to protect the compression driver. Fc is low enough (< 600 Hz) that it should not be audible, but I can always bypass them with s1 if desired.

I'm considering copper foil inductors, but the closest I can get to exact values for the 0.10 mH and 0.6 mH are 0.11 mH and 0.62 mH respectively.

My question here is if the copper foils are worth the extra expense?

Is it worth the effort to unwind and re heat shrink copper foils to get exact values or are the stock values close enough?

[Guido]

My question here is if the copper foils are worth the extra expense?

I would better spend the money on new diaphragms or whatever.

I'm considering copper foil inductors, but the closest I can get to exact values for the 0.10 mH and 0.6 mH are 0.11 mH and 0.62 mH respectively.
Is it worth the effort to unwind and re heat shrink copper foils to get exact values or are the stock values close enough?

IMHO it is close enough.

[Uncle Paul]

Hi Guido,
Thanks for your input. I am planning to go through all my drivers as part of my project. The copper foils would add less than $30 to my project, so the cost difference is negligible. If it adds to the sonic quality then it's a good value. I'm really interested in whether the advantages of copper foil over air core perfect lay are real or hype.

Thanks again and kindest regards,
Paul

[Ian Mackenzie]

The actual DCR values of those inductors in that particular design are relatively critcal to the correct voltage drives.

[Uncle Paul]

Ian,
Thanks, settles it. I'll go with air core inducrtors that match the DCR's Giskard indicated in the original design.

Paul