Re: EML500 filter resonance
2011-11-02 by bill bigrig
Howdy,
i've had an EML 500 for many years, ($20 cost), the filter will not resonate enough to go into oscillation. Is this normal?
Rig
Thread
Re: EML500 filter resonance
RE: [emlsynth] Re: EML500 filter resonance
2011-11-02 by George Mattson
Typically, yes. They used a 2-pole, 12dB/oct filter. You could
get them to resonate by reducing the resistance in the feedback
path.
From: emlsynth@yahoogroups.com [mailto:emlsynth@yahoogroups.com] On Behalf Of bill bigrig
Sent: Wednesday, November 02, 2011 6:15 AM
To: emlsynth@yahoogroups.com
Subject: [emlsynth] Re: EML500 filter resonance
Howdy,i've had an EML 500 for many years, ($20 cost), the filter will not resonate enough to go into oscillation. Is this normal?Rig
RE: [emlsynth] Re: EML500 filter resonance
2011-11-02 by bill bigrig
Ressistance in the feed back path eh? Any hints what components that resistor would be between?
rig
RE: [emlsynth] Re: EML500 filter resonance
2011-11-02 by George Mattson
Not a clue. I don't have a 500. But, the 400 filter uses that
board.
Look for a 15K resistor connected to the top of the Q
slider.
That 15K resistor connects to the input of a 748 quad op amp,
two 100K resistors and a 3.3pF cap.
The 100K resistor in parallel with the 3.3pF cap is the
feedback limiting resistor from the LP output back to the network
input.
Reduce the 100K.
From: emlsynth@yahoogroups.com [mailto:emlsynth@yahoogroups.com] On Behalf Of bill bigrig
Sent: Wednesday, November 02, 2011 10:10 AM
To: emlsynth@yahoogroups.com
Subject: RE: [emlsynth] Re: EML500 filter resonance
Ressistance in the feed back path eh? Any hints what components that resistor would be between?rig
Re: [emlsynth] Re: EML500 filter resonance
2011-11-02 by bill bigrig
Thank you!
rrig
From: George Mattson <axisair@...>
To: emlsynth@yahoogroups.com
Sent: Wednesday, November 2, 2011 10:55 AM
Subject: RE: [emlsynth] Re: EML500 filter resonance
To: emlsynth@yahoogroups.com
Sent: Wednesday, November 2, 2011 10:55 AM
Subject: RE: [emlsynth] Re: EML500 filter resonance
Not a clue. I don't have a 500. But, the 400 filter uses that board.
Look for a 15K resistor connected to the top of the Q slider.
That 15K resistor connects to the input of a 748 quad op amp, two 100K resistors and a 3.3pF cap.
The 100K resistor in parallel with the 3.3pF cap is the feedback limiting resistor from the LP output back to the network input.
Reduce the 100K.
From: emlsynth@yahoogroups.com [mailto:emlsynth@yahoogroups.com] On Behalf Of bill bigrig
Sent: Wednesday, November 02, 2011 10:10 AM
To: emlsynth@yahoogroups.com
Subject: RE: [emlsynth] Re: EML500 filter resonanceRessistance in the feed back path eh? Any hints what components that resistor would be between?rig