AMZ FX ANALOG ALCHEMY GEOFX MEF ROG MEF DIY WIKI

Multi Space Filter

Started by StephenGiles, October 05, 2005, 04:44:36 PM

Previous topic - Next topic
Print
Go Down Pages 1 2 3 4 5
User actions

liquids

#20
February 27, 2009, 06:04:48 AM
As much as I'd like to, I'm too much of a newbie to understand all that...but I'll get around to it eventually...once I understand all of this more and have my workspace back, for starts.   :-[   
Breadboard it!

StephenGiles

#21
February 27, 2009, 07:35:02 AM
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#22
February 27, 2009, 08:06:16 AM Last Edit: February 27, 2009, 08:09:24 AM by StephenGiles
http://www.4shared.com/file/89784300/b7d68e64/Space_Filter_S__H.html


This is easier to read now, I may have a go at this over the weekend.
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#23
February 27, 2009, 05:39:35 PM
 :icon_idea: But will the sweep generator stay low after the end of each sweep or will it need some more circuitry to nudge it low?
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#24
February 28, 2009, 05:09:31 AM
Come on, lets see some spark!
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

MarcoMike

#25
February 28, 2009, 05:59:54 AM
How is that sample&hold supposed to work?I'm scratching my head here... ???
as far as I understand.... the envelope generator (is it that?) triggers the 2n3819... which opens and let the cap be charged...
but after that U2 is fed with the voltage stored in the cap... so U2 delivers a constant voltage which depends on your pick.... then?  ::)
Only those who attempt the absurd will achieve the impossible.

StephenGiles

#26
February 28, 2009, 06:30:32 AM Last Edit: February 28, 2009, 08:15:10 AM by StephenGiles
At this stage these are just ideas for discussion.
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#27
February 28, 2009, 08:16:04 AM Last Edit: February 28, 2009, 10:11:37 AM by StephenGiles
Some further explanation of this circuit idea:
http://www.4shared.com/file/89784300/b7d68e64/Space_Filter_S__H.html

With the system at rest, no current flows through the 10k resistor from IC1b output into IC2  pin 1. This results in the transconductance amplifier portion of IC2  being effectively disconnected from it's darlington emitter follower output stage, hence the voltage at IC2 pin 7 follows pin 3, which is at the voltage set by the Stop Frequency control, buffered by IC1c.

When a note is played, IC2 is energised by the current into it's pin 1 and becomes a voltage follower, forcing pin 8 to equal the pin 3 voltage, set by the Start Frequency control (see below). The pin 1 current soon ceases to flow, however, and the voltage at pin 7 decays through the RC network to the Stop Frequency voltage at a rate set by the Sweep Rate contol.

Now, we want the Start Frequency control to set a voltage proportional to the strength of the note played, in other words an Adaptive Start Frequency. The basic Space Drum sweep generator used in the circuit has a fixed Start Frequency however, which is determined by the setting of the control pot.

A possible way of achieving this is to pass part of the voltage output of buffer/amplifier IC1b to the pulse generator consisting of U2, U3 (1/2 13600??) and associated components. (I am a little mystified about R9 hanging from U3!!) The output of IC1b is also passed to FET Q1. With the system at rest, Q1 is off. A pulse generated each time a note is played will momentarily turn on Q1, allowing the instantaneous peak voltage voltage taken from IC1b to be sampled by the other half of U2 and put on the tag of the Start Frequency control which was formerly connected to the positive supply.

So each note played both energises the sweep generator and controls it's Start Frequency according to the strength of the note. The resulting voltage can be used to control a suitable VCF, so once again, we get a Start Frequency following the strength of the note played, but a Sweep determined by a separately controlled CR network.
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#28
February 28, 2009, 10:15:51 AM
Now then, we're off to see 'Slum Dog Millionaire'. When we get back...........I want answers :icon_biggrin:
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

frequencycentral

#29
February 28, 2009, 10:18:57 AM
Quote from: StephenGiles on February 28, 2009, 10:15:51 AM
Now then, we're off to see 'Slum Dog Millionaire'. When we get back...........I want answers :icon_biggrin:

Sorry - can't help, I just build variations on FF's.
http://www.frequencycentral.co.uk/

Questo è il fiore del partigiano morto per la libertà!

StephenGiles

#30
February 28, 2009, 10:51:09 AM
FF????
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

frequencycentral

#31
February 28, 2009, 11:03:10 AM
http://www.frequencycentral.co.uk/

Questo è il fiore del partigiano morto per la libertà!

puretube

#32
February 28, 2009, 01:29:03 PM
Quote from: StephenGiles on February 28, 2009, 10:15:51 AM
Now then, we're off to see 'Slum Dog Millionaire'. When we get back...........I want answers :icon_biggrin:

There are two "U2"-s in the schemo (circuit diagramme...)  :icon_question:  [2 youtoose  :icon_lol:]

FF = Fuzz-Face...



chicago_mike

#33
February 28, 2009, 03:15:35 PM
Shouldnt datasheets for the LM13600 / LM13700 and CA3280 have some of these ideas, or even a cmos cookbook?

I have datasheets of the 3280 I think,, its just a more expensive 13700 with a different pinout I think.. :icon_confused:

StephenGiles

#34
February 28, 2009, 04:39:37 PM
Quote from: puretube on February 28, 2009, 01:29:03 PM
Quote from: StephenGiles on February 28, 2009, 10:15:51 AM
Now then, we're off to see 'Slum Dog Millionaire'. When we get back...........I want answers :icon_biggrin:

There are two "U2"-s in the schemo (circuit diagramme...)  :icon_question:  [2 youtoose  :icon_lol:]

FF = Fuzz-Face...


Updated re U2!

With the system at rest, no current flows through the 10k resistor from IC1b output into IC2  pin 1. This results in the transconductance amplifier portion of IC2  being effectively disconnected from it's darlington emitter follower output stage, hence the voltage at IC2 pin 7 follows pin 3, which is at the voltage set by the Stop Frequency control, buffered by IC1c.

When a note is played, IC2 is energised by the current into it's pin 1 and becomes a voltage follower, forcing pin 8 to equal the pin 3 voltage, set by the Start Frequency control (see below). The pin 1 current soon ceases to flow, however, and the voltage at pin 7 decays through the RC network to the Stop Frequency voltage at a rate set by the Sweep Rate contol.

Now, we want the Start Frequency control to set a voltage proportional to the strength of the note played, in other words an Adaptive Start Frequency. The basic Space Drum sweep generator used in the circuit has a fixed Start Frequency however, which is determined by the setting of the control pot.

A possible way of achieving this is to pass part of the voltage output of buffer/amplifier IC1b to the pulse generator consisting of U2b, U3a (1/2 13600??) and associated components. (I am a little mystified about R9 hanging from U3!!) The output of IC1b is also passed to FET Q1. With the system at rest, Q1 is off. A pulse generated each time a note is played will momentarily turn on Q1, allowing the instantaneous peak voltage voltage taken from IC1b to be sampled by the other half of U2 and put on the tag of the Start Frequency control which was formerly connected to the positive supply.

So each note played both energises the sweep generator and controls it's Start Frequency according to the strength of the note. The resulting voltage can be used to control a suitable VCF, so once again, we get a Start Frequency following the strength of the note played, but a Sweep determined by a separately controlled CR network.

Quote from: chicago_mike on February 28, 2009, 03:15:35 PM
Shouldnt datasheets for the LM13600 / LM13700 and CA3280 have some of these ideas, or even a cmos cookbook?

I have datasheets of the 3280 I think,, its just a more expensive 13700 with a different pinout I think.. :icon_confused:

No chance, the sweep generator using a CA3094 was from a clever EH designer I knew in 1980!!
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#35
March 01, 2009, 05:36:14 AM
 ::) ::) ::)
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#36
March 02, 2009, 10:25:22 AM Last Edit: March 02, 2009, 10:29:55 AM by StephenGiles
So each note played both energises the sweep generator and controls it's Start Frequency according to the strength of the note. The resulting voltage can be used to control a suitable VCF, so once again, we get a Start Frequency following the strength of the note played, but a Sweep determined by a separately controlled CR network.

Think about it, the sweep generator will only be energised when the voltage at IC1b exceeds the level set by the Sensitivity control - rather like the Microsynth, which  will always sweep up (or down) to the same point set by the start frequency control however, but my circuit will provide an adaptive sweep initially according to the strength of the note played.

So perhaps Adaptive Space Filter might be a better name. :icon_biggrin:
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

StephenGiles

#37
March 02, 2009, 02:23:03 PM
Show me another Adaptive Autofilter if you can. ???
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

orangetones

#38
March 02, 2009, 02:31:10 PM
Are you still just doing this all in theory? or have you breadboarded any of this? 

I am always interested in these funky filters...

StephenGiles

#39
March 02, 2009, 04:07:45 PM
Quote from: orangetones on March 02, 2009, 02:31:10 PM
Are you still just doing this all in theory? or have you breadboarded any of this? 

I am always interested in these funky filters...

The sweep generator was breadboarded many years ago having converted the Space Drum circuit from a CA3094. The rest is all in theory for which I have this evening sorted out some of the parts. It will be on breadboard before too long, but judging by the overwhelming enthusiasm I have seen - perhaps fear even that it won't fuzz for this I am not too hopeful that it will find it's way to anyone else's breadboard!!
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".
Print
Go Up Pages 1 2 3 4 5
User actions