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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Mon Jan 15, 2018 2:26 am Post subject:
Moog type ladder filter with FETs? Subject description: is this possible? |
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While cleaning out old component boxes I have found 8pcs dual FET's K146GR.
Very little info on the net, only THIS where it says : Quote: | the K146 is a silicon N - FET dual transistor, Uds=40V, Idss=5 - 30mA, applications: audio frequency stage, low noise, if OEM from japan see 2SK146 |
I wonder if these can be used in a Moog type ladder filter since my guess is that they are well matched? _________________ my synth |
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mrand
Joined: Mar 30, 2014 Posts: 56 Location: Yukon and London Ontario
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Posted: Mon Jan 22, 2018 8:11 am Post subject:
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Do you mean in place of the BJTs in the transistor ladder itself? I think that is not really possible, but I'm not an expert. But perhaps you could use them as buffers in an OTA type filter? Look at the roland system100 vcf, for example, which works best with 4 matched FETs. |
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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Tue Jan 23, 2018 3:54 am Post subject:
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Yes I was hoping to build the Moog ladder filter with these FET's, because they are very nicely matched because they are with 2 in one housing.
I was under the impression that the Moog ladder filter was just a number of current mirrors with a capacitance in between them.
And making current mirrors with FET's isn't that hard, is it? _________________ my synth |
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mrand
Joined: Mar 30, 2014 Posts: 56 Location: Yukon and London Ontario
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Posted: Tue Jan 23, 2018 5:49 am Post subject:
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ah, you see I told you i was no expert
I'm interested to hear if you develop this further. |
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Parkchemiker
Joined: Mar 20, 2012 Posts: 12 Location: Berlin
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Posted: Wed May 23, 2018 1:32 pm Post subject:
Moog ladder filter with FETs instead of BJTs |
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Hello Grumble
FETS don't have the same I (collector) - U (base) behaviour as the transistor. But one should test this FET-ladder-filter with LTspice.
Parkchemiker _________________ Thomas Strauß · 10407 Berlin · diodenfilter@gmx.de |
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varice
Joined: Dec 29, 2004 Posts: 961 Location: Northeastern shore of Toledo Bend
Audio files: 29
G2 patch files: 54
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Posted: Wed May 23, 2018 6:43 pm Post subject:
Re: Moog type ladder filter with FETs? Subject description: is this possible? |
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Grumble wrote: | While cleaning out old component boxes I have found 8pcs dual FET's K146GR.
Very little info on the net, only THIS where it says : Quote: | the K146 is a silicon N - FET dual transistor, Uds=40V, Idss=5 - 30mA, applications: audio frequency stage, low noise, if OEM from japan see 2SK146 |
I wonder if these can be used in a Moog type ladder filter since my guess is that they are well matched? |
Hmmm… a very intriguing idea.
But, I think that it is worth noting that the good Dr Bob Moog only used silicon trannys in the multiple ladder designs that I have seen, such as even his more recent design of the moogerfooger MF-101.
BTW, it is Bob's birthday today
Still, I would be interested if anyone comes up with any Moog ladder alternative designs. _________________ varice |
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cslammy
Joined: Apr 27, 2018 Posts: 206 Location: USA
Audio files: 1
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Posted: Tue Dec 11, 2018 1:29 pm Post subject:
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I have seen plenty of ladders with diodes and not trannies. Roland SH2 for instance (right?)
have never seen it with FETS. _________________ Visit my AUDIODIWHY blog and website |
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