[sdiy] discrete/no-OTA VCO

[Dan Snazelle]

I am a bit confused as I have the Linear Applications Handbook VOL one from 1977 and the only triangle VCO is lm3900 based.
Do i have the wrong volume?

I want to get more of these books so any info would be great!

thanks



also...TOny...is there an APP note number for the mentioned circuit?

thanks

--------------------------------------------
check out various dan music at:

http://www.myspace.com/lossnyc  


http://www.soundclick.com/lossnyc.htm


http://www.indie911.com/dan-snazelle
(or for techno) http://www.myspace.com/snazelle 




> Date: Mon, 29 Dec 2008 16:51:59 -0500
> From: tony at makenoisemusic.com
> To: harrybissell at wowway.com
> Subject: Re: [sdiy] discrete/no-OTA VCO
> CC: synth-diy at dropmix.xs4all.nl
> 
> harrybissell at wowway.com wrote:
>> There is a triangle wave VCO that uses two opamps and one
>> transistor. The CV is input to the first opamp (an inverting
>> integrator) through two resistors, one to inverting and one to non-inverting.
>> A transistor shunts the non-inverting side to ground. Unequal
>> resistors make the ramps equal in time. The other opamp is a schmitt
>> trigger.
>>
>> Classic circuit suffers from relatively small tuning range (maybe 10-20:1)
>> because eventually the control voltage must get really large to get the
>> current in.  Current controlled oscillators have much wider range.
>>
>> I think this is in the National Semiconductor Linear Apps databook...
>> but I can't find it right now.
>>
>>   
> 
> It is in that databook. I designed a variation of this circuit into a 
> small noise instrument I built for somebody. They work great for sound 
> design and noise, but definitely are not able to be tuned to 1V/oct or 
> any standard that I recognized.
> 
> TOny
> 
>> H^) harry
>>
>>
>>
>> On Mon, 29 Dec 2008 08:45:02 -0500, DAF wrote
>>   
>>> thanks for all of the suggestions thus far - I am particularly 
>>> intrigued by the UJT voltage-controlled relaxation osc. especially 
>>> because of the low parts count, but I am wondering if the UJT is 
>>> also going the way of the dodo bird, and also is the control of 
>>> frequency linear over a wide enough range (I see it used in synths 
>>> that use octave divider schemes)?
>>>
>>> In that Ray Wilson schematic, he says for a VCLFO, leave out the 
>>> parts in RED; are you to join the resulting gaps together on the 
>>> wires shown remaining?
>>>
>>> Dave
>>>
>>> ----- Original Message ----- 
>>> From: "Simon Brouwer" 
>>> To: "sdiy" 
>>> Sent: Monday, December 29, 2008 3:13 AM
>>> Subject: Re: [sdiy] discrete/no-OTA VCO
>>>
>>>     
>>>> Here is one:
>>>>
>>>> http://www.elby-designs.com/asm-2/lfo/lfo1-asm2-cct.pdf
>>>>
>>>>
>>>> DAF schreef:
>>>>       
>>>>> Hello - can someone point me to a circuit for a  voltage-controlled
>>>>> lfo that uses discrete or other easy to source parts.  I have used an
>>>>> OTA-based design in the past, but I want to design around more generic
>>>>> parts.  I seem to remember a vco that used a discrete JFET?  I don't
>>>>> neet expo response or temp compensation.  I am looking for about a 2
>>>>> to 10 Hz response range.  I don't want to use any specialty chips or
>>>>> OTA's, just discrete transistors and op-amps.   Any help greatly
>>>>> appreciated.
>>>>>
>>>>> thanks,
>>>>> Dave
>>>>>         
>>>> -- 
>>>> Vriendelijke groet,
>>>> Simon Brouwer.
>>>>
>>>> | http://nl.openoffice.org | http://www.opentaal.org |
>>>>
>>>> _______________________________________________
>>>> Synth-diy mailing list
>>>> Synth-diy at dropmix.xs4all.nl
>>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>>>
>>>>       
>>> --------------------------------------------------------------------------------
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG - http://www.avg.com
>>> Version: 8.0.176 / Virus Database: 270.10.1/1867 - Release Date: 
>>> 12/28/2008 
>>> 2:23 PM
>>>
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at dropmix.xs4all.nl
>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>>     
>>
>>
>> Harry Bissell & Nora Abdullah 4eva
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>   
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy