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High-pass filter Laurel

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What is the best way to roll of the low frequencies from a Laurel IIx amp? A RC-filter at the input or just decreasing the value of one or both the coupling caps in the amp (see postings below about the effects of the value of the coupling cap on bass response).
I want to build a SS subwoofer for frequencies below 50 Hz to support DIY horns. Maybe the Laurel have more power in reserve when the lowest frequencies (say below 50) are filtered out. Which value is appropiate? I prefer not to use an active cross-over for this purpose of use the filter on the subwoofer amplifier.
Thanks.

Follow Ups:

Re: High-pass filter Laurel Ron W. 21:04:10 01/10/01 (1)
The equation is:
frequency = 1/(2piRC)
Solving for C:
C = 1/(2pifR)
C = capacitance
R = input resistor to next stage
pi = 3.141
You can change the existing coupling cap or add a new one to the input. Obviously adding a new one will increase the degradation.
Ron
- Re: High-pass filter Laurel - Calculating R Chris O 11:01:22 01/19/01 (0)
  Is the resistance R calculated by the total of the "grid stopper" resistor plus the Plate resistance of the next stage? Or is it the shunt resistor resistance?
  To solve this equation for the "normal" 20hz start of rolloff for the typical 0.22uf cap, the R is around 36k ohms.
  C = 0.00000022
  F = 22
  Therefore R = 36,000
  (I love calculations that include Pi)
Re: High-pass filter Laurel John S. 07:42:30 01/05/01 (0)
When I am talking about the coupling caps in the Laurel, I mean the coupling cap between the mu-stage and the 300B (indicated as C4) in the diagram).

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