Impedance matching for DYI RCA attenutators

[Barry]

Hi Barry,

Can you please clarify how you calculated the 99.8 Ohm to be seen by the amp? Isn't it supposed to be 13.2 KOhm = 1/(1/(33000+100) + 1/22000)?

Thanks

Oops - wasn't thinking clearly! Yes Alex you're quite correct, if you include the 47K input impedance of the amplifier the source impedance as seen by the amplifier is 10.3K. So not a good idea after all!

Ignore what I wrote - one shouldn't have 'bright' ideas so late at night! Stick to a series resistance of 10K with a shunt resistance of 5.1K (placed on the amplifier side of the L-pad), and you will be OK!

Apologies for misleading you
Barry