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Thermionic 3 question [message #91396]

Fri, 31 January 2020 04:34

ecc82
Messages: 8
Registered: January 2020

Esquire

I have an old Thermionic 3 speaker with the PSD2002 compression driver and
would like to change this driver to an DE250 B&C .
My question is, which crossover parts I have to change.

Thank you very much

Frank

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Re: Thermionic 3 question [message #91398 is a reply to message #91396]

Fri, 31 January 2020 09:23

Wayne Parham
Messages: 18792
Registered: January 2001

Illuminati (33rd Degree)

It'll swap right over. But change the R1/R2 parts to reduce the tweeter 2dB. See the following chart for values:

R1/R2 Values

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Re: Thermionic 3 question [message #91400 is a reply to message #91398]

Fri, 31 January 2020 15:13

ecc82
Messages: 8
Registered: January 2020

Esquire

Hello Wayne,
Thank you very much for the resistor chart.
What is about the capacitor?
Is it required for the DE250?

Frank

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Re: Thermionic 3 question [message #91401 is a reply to message #91400]

Fri, 31 January 2020 15:55

Wayne Parham
Messages: 18792
Registered: January 2001

Illuminati (33rd Degree)

You won't need to change the capacitor unless you upgrade the radial horn to our H290C waveguide. If you do that, you'll remove the 0.47uF capacitor R1 and install a 16Ω resistor Rs.

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