electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
CGS 67 Active Real Ring Modulator
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [22 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
Tasmanian Alkaloid



Joined: Jun 29, 2008
Posts: 116
Location: Isle De Mort

PostPosted: Mon Jan 04, 2010 12:46 am    Post subject: CGS 67 Active Real Ring Modulator
Subject description: Anyone built one yet? I'm having problems..
Reply with quote  Mark this post and the followings unread

Hey everyone,
has anyone built the CGS67 Active Real Ring Mod yet?
I have recently built one, & upon powering it up, when i put a jack into the input, the output from my mixer (a seperate module) cut out altogether. Knowing something was wrong, i turned the power off & went over the pcb with a magnifying glass. I couldn't find any shorts, & the wiring is correct as per the diagram on Ken's webpage. I replaced a couple of SMT caps, thinking i might've overheated them when i originally stuffed the pcb.

I powered up a 2nd time, & the same thing happened with the output of the mixer. I went over the pcb again & couln't find any mistakes, all IC's, caps & diodes were correctly in place.

Upon powering up a 3rd time, smoke now came out of the NE5532, & i turned off the power again. The NE5532 had disintegrated, so I rebuilt the pcb with new polarized components, transformers & IC's.

I triple checked my wiring, polarity of the .156 header & all soldering, & powered up a fourth time, only to have the same thing happen again!
It's almost as if the power is reversed, but i'm 100% positive the .156 is oriented correctly as per the pcb artwork.

I'm now pretty much dumbfounded at this point scratch but still really keen to get this circuit operating! Has anyone had a similar problem with theirs? I found no mention of an error in the pcb artwork on the CGS yahoo group, so i doubt very much it's that.

I'm a bit suspicous of the transformers i used- i bought then from Jaycar, an Australian supermarket-type electronics store- i was told they are 3k-3k audio transformers, & they're the same size & shape as the pcb artwork denotes. They have 5 legs. But they have a yellow wrapping & are a different colour from the ones Ken uses & ones i see in online catalogues (they are always shown as blue or red).

I wonder if there are some kinds of 3k-3k audio transormers that are unsuitable for this circuit, if there actually are different types of 3k-3k transformers, at all? Unfortunately the only markings on them (a serial number) lead nowhere in Google searches. I wasn't able to find much information that would suggest there are differences in, or types of 3k-3k audio transformers.
I am going to order some that i know to be the right ones, to be sure.

zthee, if you read this, how did yours go?

Actually, i didn't have mine behind a panel or racked, i just tested the pcb on the bench. I wonder if it might be a grounding problem?

Any ideas would be most appreciated, thanks!
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1174
Location: australia
Audio files: 4

PostPosted: Mon Jan 04, 2010 7:00 pm    Post subject: Reply with quote  Mark this post and the followings unread

well i admire your patience

the transformers look okay on the jaycar catalogue.
even if they are a dodgy batch they shouldn't cause the opamp to blow.
if it is a mislabelled part and actually a power transformer, that could be interesting.......imagine 5V in and 240V out!
Unlikely, but we can dream Surprised

haven't built mine yet, maybe in the next few weeks
Back to top
View user's profile Send private message Visit poster's website
Tasmanian Alkaloid



Joined: Jun 29, 2008
Posts: 116
Location: Isle De Mort

PostPosted: Tue Jan 05, 2010 9:48 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Andrew,
thanks for the reply!
I got them at the shop in Hobart- the other values were the same colours as those on their website, just the 3k ones were yellow.
I've decided to get some new ones from somewhere else & start from scratch with a spare pcb i have, & with a bit of luck it will work as it should.
If it does, i'll know if the problem was the transformers, or if it was something else i missed.







[/i]
Back to top
View user's profile Send private message
fluxmonkey



Joined: Jun 24, 2005
Posts: 696
Location: cleve

PostPosted: Tue Jan 05, 2010 12:59 pm    Post subject: Reply with quote  Mark this post and the followings unread

Tasmanian Alkaloid wrote:
Hi Andrew,
thanks for the reply!
I got them at the shop in Hobart- the other values were the same colours as those on their website, just the 3k ones were yellow.
I've decided to get some new ones from somewhere else & start from scratch with a spare pcb i have, & with a bit of luck it will work as it should.
If it does, i'll know if the problem was the transformers, or if it was something else i missed.[/i]


sorry to ask the obvious, but did you measure the transformers w/a VOM?

also, which 5532 blew?

_________________
www.fluxmonkey.com
Back to top
View user's profile Send private message
lanxe



Joined: Feb 24, 2005
Posts: 102
Location: Columbus, OH - Now Carson City NV

PostPosted: Tue Jan 05, 2010 5:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

I built one recently using the transformers/diodes from bridechamber. Got the rest of the parts from mouser.

Works fine for me, so i am sure it isnt a pcb layout issue.
Back to top
View user's profile Send private message
Tasmanian Alkaloid



Joined: Jun 29, 2008
Posts: 116
Location: Isle De Mort

PostPosted: Thu Jan 07, 2010 4:38 am    Post subject: Reply with quote  Mark this post and the followings unread

bbob wrote:


sorry to ask the obvious, but did you measure the transformers w/a VOM?

also, which 5532 blew?



I hadn't because i'd wrongly assumed they'd need to be measured while the circuit was powered & i didn't want to go poking around with things smoking.

Today i did some research & learnt how to measure them, and found the ones i have are reading the right resistance values between pins.

So it must be something else..

There's only one 5532 used in the circuit.
Back to top
View user's profile Send private message
Adam-V



Joined: Jan 29, 2007
Posts: 300
Location: Australia
Audio files: 1

PostPosted: Thu Jan 07, 2010 3:53 pm    Post subject: Reply with quote  Mark this post and the followings unread

Pull all of the ICs out - you don't want to fry any more of them!
Power the module up - make sure it is on a non-conductive surface.
Measure the voltage at pins 4 and 8 of the socket for the 5532.
Pin 8 should be +15V (or +12 if you are using a 12V supply)
Pin 4 should be -15V (or -12V if using a 12V supply)

Now measure Pins 3 and 5 - they should both be 0V.

Now measure Pin 2 - it should vary between 0 and +ve as you turn the Unbalance control.

Let us know how you go.

Sometimes it's possible to miss obvious things on your own work no matter how hard you try - are you able to post pictures of your board and wiring so we can have a look?

Cheers,
Adam-V

_________________
Digitalis Effect | Fractured Symmetry (www.spiralsect.com)
Back to top
View user's profile Send private message Visit poster's website
Tasmanian Alkaloid



Joined: Jun 29, 2008
Posts: 116
Location: Isle De Mort

PostPosted: Sat Jan 09, 2010 7:26 pm    Post subject: Reply with quote  Mark this post and the followings unread

Adam-V wrote:
Pull all of the ICs out - you don't want to fry any more of them!
Power the module up - make sure it is on a non-conductive surface.
Measure the voltage at pins 4 and 8 of the socket for the 5532.
Pin 8 should be +15V (or +12 if you are using a 12V supply)
Pin 4 should be -15V (or -12V if using a 12V supply)

Now measure Pins 3 and 5 - they should both be 0V.

Now measure Pin 2 - it should vary between 0 and +ve as you turn the Unbalance control.

Let us know how you go.

Sometimes it's possible to miss obvious things on your own work no matter how hard you try - are you able to post pictures of your board and wiring so we can have a look?

Cheers,
Adam-V



Thanks for the advice Adam Smile

I don't have a good enough camera for close-ups of the pcb, but in the next few days i'll do some measurements & let you know.
Back to top
View user's profile Send private message
otherunicorn



Joined: May 11, 2008
Posts: 136
Location: Australia

PostPosted: Thu Apr 08, 2010 12:31 am    Post subject: Reply with quote  Mark this post and the followings unread

I think I've found your problem, though why no one has ever notice before is beyond me.

The pad labelled "0V" on the REV0.0 and VER1.0 versions of the CGS67 is actually connected to the -VE rail. You will need to connect to 0V elsewhere on the board. The pad in question was previously shown as the common 0V connection in the wiring diagram.

Sorry for any inconvenience.

_________________
http://www.cgs.synth.net/
Back to top
View user's profile Send private message Visit poster's website
Tasmanian Alkaloid



Joined: Jun 29, 2008
Posts: 116
Location: Isle De Mort

PostPosted: Sun Apr 11, 2010 4:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

otherunicorn wrote:
I think I've found your problem, though why no one has ever notice before is beyond me.

The pad labelled "0V" on the REV0.0 and VER1.0 versions of the CGS67 is actually connected to the -VE rail. You will need to connect to 0V elsewhere on the board. The pad in question was previously shown as the common 0V connection in the wiring diagram.

Sorry for any inconvenience.


Thanks Ken, that sounds like it would be the cause of the problem i had.

If i had followed Adam's advice above & checked the voltages we probably would have found it earlier on & let you know, i apologise. I was busy & never got back to it.

It hasn't been an inconvenience, rather a good learning experience.
I had convinced myself it was either the transformers or diodes (recycled).

Thanks again for letting us know. Now i'm again keen to hear it!
Back to top
View user's profile Send private message
macumbista



Joined: Sep 12, 2007
Posts: 360
Location: berlin
Audio files: 3

PostPosted: Sun Jul 25, 2010 9:31 am    Post subject: signal nulling Reply with quote  Mark this post and the followings unread

I've got a dual version of this built, I used the following transformers:

http://www.banzaimusic.com/TM018-Transformer.html

and hand-matched Germanium diodes.

I'm not getting very good signal nulling, however. I understand that it's not the same as a multiplier, but I'd like to get better tremolo out of it, and that means the signal should get a lot quieter than it does right now with a slow LFO as DC carrier. I calibrated it as described on the CGS website, is there anything else I can do???

_________________
Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
macumbista.net
Back to top
View user's profile Send private message
otherunicorn



Joined: May 11, 2008
Posts: 136
Location: Australia

PostPosted: Sun Jul 25, 2010 5:31 pm    Post subject: Reply with quote  Mark this post and the followings unread

Check that you don't have one of your diodes in backwards.
_________________
http://www.cgs.synth.net/
Back to top
View user's profile Send private message Visit poster's website
macumbista



Joined: Sep 12, 2007
Posts: 360
Location: berlin
Audio files: 3

PostPosted: Mon Jul 26, 2010 5:59 am    Post subject: Reply with quote  Mark this post and the followings unread

Hey Ken, nope that's not it... diodes look correct to me. The painted band on the diode glass matches the line marked on the PCB for polarity. I get the same amount of signal nulling on both boards so whatever it is, I did it twice!

In mounting the transformers, I noticed that one end was marked "P" for primary. I kept that end oriented towards the signal input in both instances on each PCB. Does one of them need to be reversed? Does this even matter on a 1:1 transformer?

_________________
Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
macumbista.net
Back to top
View user's profile Send private message
otherunicorn



Joined: May 11, 2008
Posts: 136
Location: Australia

PostPosted: Mon Jul 26, 2010 6:31 am    Post subject: Reply with quote  Mark this post and the followings unread

It would be best to keep the same type of coil around the diodes, so use primary as input and output, and secondaries both to the diodes.

Ken

_________________
http://www.cgs.synth.net/
Back to top
View user's profile Send private message Visit poster's website
macumbista



Joined: Sep 12, 2007
Posts: 360
Location: berlin
Audio files: 3

PostPosted: Mon Jul 26, 2010 6:42 am    Post subject: Reply with quote  Mark this post and the followings unread

OK, I'll try it with one and see. Thanks!!!!
_________________
Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
macumbista.net
Back to top
View user's profile Send private message
macumbista



Joined: Sep 12, 2007
Posts: 360
Location: berlin
Audio files: 3

PostPosted: Thu Jul 29, 2010 4:16 am    Post subject: Reply with quote  Mark this post and the followings unread

I flipped the output transformers around and it didn't seem to change much. It's fine, I realize it's the limitation of this kind of circuit I guess. I'll build a couple multipliers for the slower modulation stuff. The ringmod sound of this one is super sci-fi great!
_________________
Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
macumbista.net
Back to top
View user's profile Send private message
Dhamaryder



Joined: Jan 21, 2011
Posts: 14
Location: Cincinnati

PostPosted: Fri Jan 21, 2011 9:57 am    Post subject: Active Ring modulator
Subject description: strange behaviour
Reply with quote  Mark this post and the followings unread

I wasn't sure if i should post a new topic or just add it to this one. Here goes:
i built the Active Ring modulator and it seemed to be working great for awhile. I was using it heavily about a month ago and just got back to it now. It's doing odd things. First, it seems to take about 5 minutes to "warm up". I get a very weak and intermitent sound until it warms up. The it works ok, although I don't seem to be able to duplicate some of the awesome things i was doing a month ago, (I use patch diagrams and recordings to help me remember). It seems to be rather weak in the lower frequencies now as compared to before. Then occaisionally when i change the frequency of one of the inputs it sounds like the module kind of shuts down and then slowly comes back on. This happens too when i have one of the inputs going through a filter first, before going into the RM, then I change either the frequency of the filter or the resonance. It sounds overloaded and shuts down for a couple of minutes and slowly comes back. Anyone have any idea what's going on?
thanks a lot,
steve
Back to top
View user's profile Send private message
kkissinger



Joined: Mar 28, 2006
Posts: 1216
Location: Kansas City, Mo USA
Audio files: 29

PostPosted: Fri Jan 21, 2011 10:24 am    Post subject: Re: Active Ring modulator
Subject description: strange behaviour
Reply with quote  Mark this post and the followings unread

Dhamaryder wrote:
...It sounds overloaded and shuts down for a couple of minutes and slowly comes back. Anyone have any idea what's going on?
thanks a lot,
steve


Suggest that you start out by checking the power supply on the circuit board (past the beads and bypass caps). Make sure that the power supply on all the busses is correct and constant.

If the power supply varies, then you may have a short or a chip that is shorted.

I had a similar problem with the CGS modulo magic -- turns out that I had sourced a chip that is designed for 5 volts rather than 15. The chip was shorting out the power supply and the up and down response was the main bypass caps discharging and charging repeatedly.

From Ken's site:

Quote:
It is probably a 74HCT4015, or some other 74xxx variant designed to run on 5 volts. It is possible that these chips may not have the "74" in their part number, so avoid any that start with "HC".


Anyway, I'm just tossing out ideas. Generally when there is a systemic problem -- that is, when nothing seems to work correctly -- the first place to start is the power supply.

_________________
-- Kevin
http://kevinkissinger.com
Back to top
View user's profile Send private message Visit poster's website
rosch



Joined: Oct 03, 2009
Posts: 162
Location: germany

PostPosted: Sat Jul 16, 2011 12:52 am    Post subject: Reply with quote  Mark this post and the followings unread

hey guys, i hope it's ok tu use this thread again... as the title is quite general, as is my question.
i just got my CGS67 board.
for what should i look to match my germanium diodes? is it just the voltage drop or will i have to compare curves on the scope?
i bought about 25 pcs, but i already expect that might not be enough Smile

i'm using as it seems the same transformers from http://www.musikding.de/product_info.php/info/p406_Trafo-TM018-1-1.html

Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message
iopop3



Joined: May 28, 2010
Posts: 95
Location: Malmö, Sweden

PostPosted: Sat Jul 16, 2011 7:15 am    Post subject: Reply with quote  Mark this post and the followings unread

I have yet to power on my ring mod - so I could be wrong. But I matched the diodes for voltage drop with my DMM and I just had 10 diodes. Also used the same transformer.
Back to top
View user's profile Send private message
rosch



Joined: Oct 03, 2009
Posts: 162
Location: germany

PostPosted: Sun Jul 17, 2011 6:42 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks!
i've matched them with the diode tester on my multimeter and took the 4 closest diodes.
i guess the P on the transformers means primary so i put the P to the outsides. since they had 3 wires coming out on each side i cut the center taps of the P sides.
i still have to power it up though...
Back to top
View user's profile Send private message
defex



Joined: Jun 27, 2008
Posts: 36
Location: Toronto, canada

PostPosted: Fri Dec 09, 2011 2:31 pm    Post subject: unbalance control. Reply with quote  Mark this post and the followings unread

I wired my unbalance control pin one (anticlockwise) to -v instead of ground, which i like because it gives more range. is this going to cause any harm? I cant really see any reason why.

Also i did not have a NE5532 handy, so i used a "hi fi" LM4562 (free sample!) i had instead, it seems to be quite happy for now. (they are sometimes used for headphone amps, so i figured it should be OK driving the transformer)

If i kill it, ill report back.

edit: because of the nice smooth "distortion" on this, and because it doesnt use many pots, i might add a 4th pot for DC offset of the input as well as the carrier. it should just take another 100k resistor next to the "input" one and a pot sharing the voltage on the 1 and 3 pins of the "unbalance" pot with teh wiper going to that resistor.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [22 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use