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 Forum index » DIY Hardware and Software » Developers' Corner
Moog type ladder filter with FETs?
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Grumble



Joined: Nov 23, 2015
Posts: 698
Location: Netherlands
Audio files: 20

PostPosted: 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?

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mrand



Joined: Mar 30, 2014
Posts: 56
Location: Yukon and London Ontario

PostPosted: Mon Jan 22, 2018 8:11 am    Post subject: Reply with quote  Mark this post and the followings unread

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
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PostPosted: Tue Jan 23, 2018 3:54 am    Post subject: Reply with quote  Mark this post and the followings unread

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?

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mrand



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Location: Yukon and London Ontario

PostPosted: Tue Jan 23, 2018 5:49 am    Post subject: Reply with quote  Mark this post and the followings unread

ah, you see I told you i was no expert Wink
I'm interested to hear if you develop this further.
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