Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Foreplay III => Topic started by: bernieclub on January 27, 2010, 06:25:07 AM

Title: T-pads for FP111...
Post by: bernieclub on January 27, 2010, 06:25:07 AM

I want to experiment with T-pads on my FP111 in lieu of very large padding resistors.    Online calculators ask for input and output impedances.    Is the 15K of the S.Whispers the number to plug in, or do I need to add the 33K standard padding resistor?
T.I.A.
Bernie     

Title: Re: T-pads for FP111...
Post by: Paul Joppa on January 27, 2010, 09:30:46 AM

The Sweetest Whispers is normally set up as a shunt mode control fro the FP-III. The normal setup provides about 10dB attenuation at the maximum setting. With the 33K padding resistor, input impedance is 33K to 48K depending on the setting. You can use a constant-resistance T pad at around 40K with pretty good results.

Title: Re: T-pads for FP111...
Post by: bernieclub on January 27, 2010, 09:56:48 AM

Thank you Paul

>---R1------R2---->S.W.    with Rshunt between R1 & R2.....the original padding resistor removed, with R1 & R2=40K