saves you finding it, Cheers Laurie >From: "Laurie Biddulph" <elby_designs@...> >Reply-To: ElektorFormant@yahoogroups.com >To: <ElektorFormant@yahoogroups.com> >Subject: Re: [ElektorFormant] problem with formant pro vco (new design) >Date: Mon, 10 Apr 2006 17:48:50 +1000 > >Read the attached which is an extract from the original Formant VCO and >explains the operation of this circuit. >You will NOT see any voltage at points C or E, that is how this circuit >works. You WILL see a voltage at F but it will be VERY small. As the text >says about -27mV per volt of input > >Best Regards > >(Mr) Laurie Biddulph >Mobile: 0400 257 645 > >Elby Designs >ABN: 70 022 727 605 >http://www.elby-designs.com > >This e-mail and any files transmitted with it are confidential and intended >for the addressee only. >If you are not the addressee you may not copy, forward, disclose or >otherwise use it, or any part >of it, in any form whatsoever. If you have received this e-mail in error >please notify the sender >and ensure that all copies of this e-mail and any files transmitted with it >are deleted. Any views >or opinions represented in this e-mail are solely those of the author and >do not necessarily >represent those of Elby Designs. Although this e-mail and its attachments >have been scanned for the >presence of computer viruses, Elby Designs will not be liable for any >losses as a result of any >viruses being passed on. > > ----- Original Message ----- > From: ganesha > To: ElektorFormant@yahoogroups.com ; harrybissell@... > Sent: Monday, April 10, 2006 6:12 AM > Subject: Re: [ElektorFormant] problem with formant pro vco (new design) > > > Hi Harry, > Thanks for you reply. > IC 6 is a CA3086 transistor array. > You can take a look at the schematic here: > http://www.krinkel.be/formant/schematic.jpg > I've written in red the points where I measure and the > results I read on my DVM. > I think the problem is my cv and rangevoltage become > 0V after the resitors so nothing is going into theIC1 > opamp, but I have no idea why this is happening. > > regards, Kris > > --- harrybissell <harrybissell@...> wrote: > > > --------------------------------- > I'm not looking at the schematic... but I guess that > IC6-p2 is the inverting input of an opamp with > negative > feedback and used as a summing or inverting amp. > > Voltages in this circuit are actually converted to > currents in the resistors. A positive current in the > input > is cancelled out by a negative current in the > feedback... > so the net voltage at IC6-p2 sould be whatever the > non-inverting > input (IC6-p3 ?) is. If that is zero volts, so should > pin 2 be. > > an educated guess... > > H^) harry > > ganesha wrote: > > > > Hello Kris > > I just did some measurements and have no voltage at > > pin2 of ic6. I'm pretty sure, the problem is caused > by > > the resistors R5, R6 and R3. > > For example: I feed A 3V cv source. If I measure it > > right before R3 it is 3v, but right after R3 it is > 0V > > so it looks to me the R3 is blocking the whole > thing. > > The same with R6 For the range. I turn the > > rangepotmeter open so I put 12V in. But right after > R6 > > I measure 0V. > > Can you please measure what voltage you have right > > after R3 if you feed it a cv of 3V? (When you have > the > > time ofcourse) > > > > regards, Kris > > > > --- Kris Bishop <bishopkris40@...> wrote: > > > > --------------------------------- > > I live in Scotland and have the strangest name, > > everyone asks where it is > > from. Can you imagine how strange this is lol > > > > Kris, First how good is your english > > second how good is your understanding of the > > electronics in this synth? > > > > I'm not that good and I managed this so here we go: > > > > First, > > > > Do not under any circumstances change any components > > unless you have read on > > the internet to do so. This is important as the VCO > is > > based on a lot of > > electronic and electrical values that are dependant > on > > each other. > > > > you were correct about r1 I have marked this as > wrong > > in the book (cannot > > remember why??) but I am sure if you put the > original > > value back in then we > > can work from here. (Next week I will open my synth > > and check my value, but > > moving house so please be patient) > > > > What you want with nothing other than a CV is for > the > > current out of IC6 pin > > 5 to double for every 1v change. This is the key to > > controlliing the synth. > > > > This said we can remove this device and insert a > > current, First you need to > > check what you are getting at pin 2 of IC 6. this is > a > > voltage so is easy to > > test. make sure that you are getting something here, > > 1v, 5v whatever. now if > > you can monitor the current from pin 5 of IC 6. what > > do you get and if you > > increase CV by 1V what do you get. (This section is > > only used to scale the > > input CV) > > > > ok so you get the correct operation from IC6 > (CA3086) > > You must be using > > this. there is other methods but no for this > circuit. > > > > no matter what happens if you get a current in to P7 > > or input to IC2 then > > you should see Oscillations. I hope at this point > like > > me everything is ok > > until now as this is where I had a problem. IC5 is a > > comparitor of sorts. we > > need the voltages to be different to get this > circuit > > to work. > > > > Sorry but I'll come back to help in the next few > days. > > But please did you > > get any sound at the start. also are you trying to > > build 1 or 2 VCO's?? > > Where did you get your CA3086's from? I had 5 of > these > > and only 3 > > worked..... > > > > I did not carry out any tests from the book as I do > > not speak German but I > > did get good results after checking all components > and > > soldering. Your > > circuit looks good but what does the other side look > > like? Mine is messy but > > works so don't worry. Where do you get your CV from. > > Sorry I need more info > > for the next step. > > > > If you want when I am at work I can talk to you on > > Skype if you'd prefer but > > I hope you speak english. We can even just use the > > chat by text option if > > you want but we can arrange a time. Probably > Thursday > > or Friday night is > > best, I work night shifts then. > > > > Bishop (Kris) > > > > >From: ganesha <goaqihai@...> > > >Reply-To: ElektorFormant@yahoogroups.com > > >To: ElektorFormant@yahoogroups.com > > >CC: bishopkris40@... > > >Subject: RE: [ElektorFormant] problem with formant > > pro vco (new design) > > >Date: Sat, 8 Apr 2006 09:43:02 +0100 (BST) > > > > > >Hi Kris, ;-) feels like I'm writing something to > > >myself. > > > > > > > > >Thanks for your reply. I'll try to descibe the > > >different steps I did. > > > > > >In the beginning everything went fine, I've build > the > > >eingangsspannungaddierers, exponentiators and > > heizung. > > >I plugged it in and after 20 minutes I have set the > > >voltage at kollektor tr 4 to 1.6V with trimmer > > >p8. So far no problem,I then continued building the > > >Sawtoothoscillator without soldering Tr3 so I could > > >meassure the current between kollektor tr3 and pin3 > > of > > >ic2. I also made the abgleichskeyboard (I had to > > >replace R1 with 47K because otherwise my maximum > for > > >switch 5 was 2.86 V instead of 4 V) and soldered > the > > >pots for range and tune to the VCO pcb. I then > tried > > >to messure the current that is supposed to be > 0.002mA > > >but > > >nomather what switch I used on the > abgleichskeyboard, > > >or to what position I turned the range and > fine-tune > > >pots, I'm allways measuring 0,000mA. I thought > > >maybe I did not solder enough components on the pcb > > >because of the difference between the book and the > > new > > >design so I continued the entire pcb except for > tr3. > > >But still no result. At the end as a last resort, I > > >also soldered tr3 in position but still no current. > > >Can you tell me what measurement I can do to track > > the > > >fault? On strange thing I allready noticed is that > if > > >I meassure betweent the mass and before R5 (range) > I > > >have 11.84V because I set the range pot fully open. > > >But after R5 (100K) I measure 0V. I suppose this is > > >not normal and that is the cause why turning the > > range > > >pot has no influence? So is the 100K to big? > > >Also would it be a problem that after the 7812 > (ic7) > > >there is only 11.84V instead of 12V? > > > > > >I've uploaded a pic of the vco to > > >http://www.krinkel.be/formant/formantVCO.JPG > > > > > >best regards, > > >Kris > > > > > > > > > > > >--------------------------------- > > >I'll reply here and on personal, as the group is > here > > >so that people like us > > >can search problems first then ask. > > > > > >I'll help, but moving house so I can only promise > you > > >an answer by Tuesday, > > >when I go back to work. What is the problem mate? > > > > > >Regards > > >Kris > > > > > > > > > >From: ganesha <goaqihai@...> > > > >Reply-To: ElektorFormant@yahoogroups.com > > > >To: ElektorFormant@yahoogroups.com > > > >CC: synth-diy@... > > > >Subject: [ElektorFormant] problem with formant > pro > > >vco (new design) > > > >Date: Fri, 7 Apr 2006 23:25:54 +0100 (BST) > > > > > > > >Hi, > > > > > > > >I'm building the formant pro vco from the book of > > > >Hans-Joachim Helmstedt. But I'm having a problem > > that > > > >I cannot solve myself. Is there anyone who has > > >already > > > >built it and who would like to assist me? > > > >Please contact me off-list so I can send you a > mail > > > >where I describe the problem. > > > > > > > >Thanks in advance! > > > >regards, Kris > > > > > > > > > > > > > > > > > > >___________________________________________________________ > > > >To help you stay safe and secure online, we've > > >developed the all new Yahoo! > > > >Security Centre. http://uk.security.yahoo.com > > > > > > > > > > > > > > >--------------------------------- > > > YAHOO! GROUPS LINKS > > > > > > > > > Visit your group "ElektorFormant" on the web. > > > > > > To unsubscribe from this group, send an email > > to: > > > ElektorFormant-unsubscribe@yahoogroups.com > > > > > > Your use of Yahoo! Groups is subject to the > > Yahoo! > > >Terms of Service. > > > > > > > > >--------------------------------- > > > > > > > > > > > > > > > > > > > > > >___________________________________________________________ > > >How much mail storage do you get for free? Yahoo! > > Mail > > >gives you 1GB! > > >Get Yahoo! Mail http://uk.mail.yahoo.com > > > > > > > > SPONSORED LINKS > > > > Sampler > Electronic > > instrument > > Synthesizer > > Music synthesizers > > Synthesizer music > > Electronic music > > > > > > --------------------------------- > > YAHOO! GROUPS LINKS > > > > > > Visit your group "ElektorFormant" on the web. > > > > To unsubscribe from this group, send an email > to: > > ElektorFormant-unsubscribe@yahoogroups.com > > > > Your use of Yahoo! Groups is subject to the > Yahoo! > > Terms of Service. > > > > > > --------------------------------- > > > > > > > ___________________________________________________________ > > Win a BlackBerry device from O2 with Yahoo!. Enter > now. http://www.yahoo.co.uk/blackberry > > > > > > Yahoo! Groups Links > > > > > > > > > > > --------------------------------- > YAHOO! GROUPS LINKS > > > Visit your group "ElektorFormant" on the web. > > To unsubscribe from this group, send an email to: > ElektorFormant-unsubscribe@yahoogroups.com > > Your use of Yahoo! Groups is subject to the Yahoo! > Terms of Service. > > > --------------------------------- > > > > > > > > > ___________________________________________________________ > Yahoo! Messenger - NEW crystal clear PC to PC calling worldwide with >voicemail http://uk.messenger.yahoo.com > > > > Yahoo! Groups Links > > > > > > ><< Pagesfromchap3-5.pdf >>
Message
Re: [ElektorFormant] problem with formant pro vco (new design)
2006-04-10 by Kris Bishop