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Subsonic Filter

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GrahamD View Drop Down
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Joined: 13 Feb 2015
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GrahamD Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2016 at 10:22pm
Thanks for the input guys.
I must admit I never considered the lack of damping provided by valve amp transformers.
What value resistor do you suggest Graham to bring the turn over closer to 20Hz ?
The records in question are not warped, in fact my Oracle Delphi has a record clamp, it seems to be recorded into the 'groove'. One of the culprits is a brand new pressing of Dave Gilmours Rattle That Lock. The first track on side one really gets the cones flapping.
Cheers
Graham
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GrahamD Quote  Post ReplyReply Direct Link To This Post Posted: 25 Aug 2016 at 2:06am
Well, in the absence of further advice I went ahead and changed the resistor value to bring the turnover closer to 20Hz.
I had a couple of 270k resistors available and according to the advice given these in parallel with the amps 100k should result in 73k which with the 0.1uF capacitors results in 21.8Hz with a 6db/octave slope.
It certainly sounds fine to my old ears as I can't detect any difference in the sound switching it on or off but a noticeable reduction in cone movement at these low frequencies.
I am very pleased with outcome as I only wanted a very simple and non-intrusive filter that I could activate when required with little or no impact on the music.
Cheers
Graham

Edited by GrahamD - 25 Aug 2016 at 2:08am
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Joined: 11 Jan 2008
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 25 Aug 2016 at 3:38am
Well done!
Not simple enough for Google-Bot to understand...
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