Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Paramount => Topic started by: Gerry E. on April 05, 2021, 10:31:31 AM
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Hi:
I'm currently using my Paramounts as mid-range/tweeter amps. Can I modify the circuit to cut the low frequencies? I'm looking at a cutoff frequency in the 80 - 160Hz range. I assume some combination of capacitor and/or resistor changes would do the trick. Thanks!
Gerry
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You could decrease the size of the coupling cap to induce a gentle rolloff. The same could be done for the parallel feed capacitor, though that's a bit more tricky.
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It's best to put the filter as early in the chain as possible, such as adding a capacitor in series with the RCA input. The filter reduces the strain on what's downstream of it, so a small interstage coupling cap won't protect the driver stage, and a small parafeed cap protects only the output transformer.
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I made a simple filter box and insert between ForeplayIII and Paramount/Stereomour/MonAmour to drive the mid/treble
It use 0.01uF Jupiter cap and also build in shunt attenuator and bypass switch. Crossed over around 150Hz (depend on attenuator position and input impedance of amp).
Hope this helps
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Think I'll try one of these, for my Kaiju (only without the attenuator) thanks for the idea!!!
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Think I'll try one of these, for my Kaiju (only without the attenuator) thanks for the idea!!!
I imagine you thought of this, but it would be easier to solder in the HPF/LPF cap at the input of the Kaiju vs. building a separate box.
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Yep! I'm looking to do a multi switch box to test for the correct value by measure but mostly by ear. Good weekend project.
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It's best to put the filter as early in the chain as possible...
I took this quite literally by putting Harrison Labs FMOD 150Hz high pass filters on the Paramount input jacks (see photo below). I had excellent success using a Harrison Labs attenuator on the right channel input to my preamp to correct for a channel imbalance, so I thought I would give the FMODs a try.
It worked out great and really cleaned things up. I'm reluctant as the next guy person to put any additional devices into the signal path that can muck things up but these passive Harrison Labs devices work really well! Thanks for the replies.
Gerry