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 » Thomas Henry designs
TH 101 calibration
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [24 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Wed Jan 06, 2010 6:22 am    Post subject:  TH 101 calibration
Subject description: Could it be the magic smoke in it?
Reply with quote  Mark this post and the followings unread

Hi!
after ordering, loosing, reordering and reloosing a few missing parts for my Magsmoke TH101 I finally put it all together.

Seems to work apart from a heavy Hum problem as you can infer from the soundbite posted

Hum is present on all outputs (sine, square, triangle and even noise).

Things that I've checked:
-power supply
- grounding of the outputs with a tester
- all that I could check by sight (shortsight i should say)

I haven't done any calibration yet

Any suggestion to point me to where things have gone wrong?

Many thanks!

Wink

aero


DSCN3173.JPG
 Description:
the board
 Filesize:  655.15 KB
 Viewed:  158 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

DSCN3173.JPG



566 vco seq 3.mp3
 Description:
the sound

Download
 Filename:  566 vco seq 3.mp3
 Filesize:  359.49 KB
 Downloaded:  231 Time(s)


Last edited by aerogramma on Thu Jan 07, 2010 12:56 pm; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Thu Jan 07, 2010 5:38 am    Post subject:
Subject description: the spirit of tim servo?
Reply with quote  Mark this post and the followings unread

Update!
So I fired up my TH 101 today for a second round of troubleshooting... and.. the Hum issue was gone.

same set up, same cables, same everything... but gone! Ghost in the machine indeed or perhaps the spirit of tim servo visited my oscillator last night

anyway.. the vco sound is very promising!
Now I'm puzzled by the difference on output volume of sine and saw (sine is much higher)... I thought it ought to be the opposite..

However the sine doesn't sound too much like a sine to me yet, perhaps I should really get on with the calibration

I'm posting a couple of samples here

Maybe I have to connect to a VCA first ... or just wait another night Shocked


566 sine seq out.mp3
 Description:
TH 101 sine out

Download
 Filename:  566 sine seq out.mp3
 Filesize:  74.19 KB
 Downloaded:  246 Time(s)


566 sq seq out.mp3
 Description:
TH 101 square out

Download
 Filename:  566 sq seq out.mp3
 Filesize:  70.99 KB
 Downloaded:  254 Time(s)

Back to top
View user's profile Send private message Visit poster's website
Sound



Joined: Jun 06, 2006
Posts: 842

Audio files: 1

PostPosted: Thu Jan 07, 2010 8:14 am    Post subject: Reply with quote  Mark this post and the followings unread

Hello Aerograma, you need calibrate the sinewave. Its completely needed for achieve an accurate sine.
Back to top
View user's profile Send private message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Thu Jan 07, 2010 8:59 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks sound, you're absolutely right

I have only a software oscilloscope at hand so I calibrated mainly by hear and it's a bit more like a sine now.

However reading the building notes and the schematics looks like the sine and the square are actually derived from the triangle wave.

So I have to properly calibrate the triangle first, possibly with a real oscilloscope .. so far not much luck!

aero
Back to top
View user's profile Send private message Visit poster's website
Sound



Joined: Jun 06, 2006
Posts: 842

Audio files: 1

PostPosted: Thu Jan 07, 2010 10:54 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Aerograma, you can use the software oscilloscope. Maybe it can not reproduce the waves under 20hz depending on your soundcard, but you can calibrate it higher frequencies, actually in built notes says that around 1Khz it will be OK.
Back to top
View user's profile Send private message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Thu Jan 07, 2010 1:01 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hello sound, thanks again for the tip

I did try to calibrate using the software oscilloscope and a frequency spectrum analizer.

in particular I used a reference 1k triangle wave to match against.

I'm adding a picture of my findings, as much as I tried couldn't get a triangle wave, more like a square!

perhaps there's something wrong in my build?


TH 101 triangle.png
 Description:
Th 101 triangle
 Filesize:  252.38 KB
 Viewed:  149 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

TH 101 triangle.png



refrence 1k triangle.png
 Description:
reference 1k triangle
 Filesize:  220.48 KB
 Viewed:  151 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

refrence 1k  triangle.png



Th 101 sine .png
 Description:
th 101 sine
 Filesize:  227 KB
 Viewed:  147 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Th 101 sine .png


Back to top
View user's profile Send private message Visit poster's website
Sound



Joined: Jun 06, 2006
Posts: 842

Audio files: 1

PostPosted: Thu Jan 07, 2010 1:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

Well, Seems that the triangle output is completely distorted...

Check the values of R18 and R19. Are they correct?
R18=36KΩ and R19=120KΩ.

Also you should calibrate the triangle offset. If no real oscilloscope available, just put the multimeter to measure DC, tap the triangle output and adjust it to 0V
Back to top
View user's profile Send private message
Sound



Joined: Jun 06, 2006
Posts: 842

Audio files: 1

PostPosted: Thu Jan 07, 2010 1:46 pm    Post subject: Reply with quote  Mark this post and the followings unread

Wait a moment.

Using the software oscilloscope, we are not measuring directly the triangle output of the oscillator. Be careful in no distort the signal in the soundcard input.
Back to top
View user's profile Send private message
Tim Servo



Joined: Jul 16, 2006
Posts: 924
Location: Silicon Valley
Audio files: 11

PostPosted: Thu Jan 07, 2010 10:48 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hey Aero,

I think you're getting pretty close. Couple of suggestions:

1) To properly view a VCO output on most soundcard based viewers, you're going to have to attenuate the signal quite a bit. The VCO output is about +5 to -5V (10V peak to peak), while soundcards are setup for a line level (about 1.7V peak to peak). This is going to be necessary with most any synth level signal.

2) Almost all sound cards have AC coupled inputs. This means that there is a capacitor in the soundcard input that removes any DC bias or offset from the signal. Because of this, you won't be able to see any DC bias that is present in the TH-101 output. Sound has the right method though - if you don't have an oscilloscope, use a multimeter and set it to DC. You should be able to see the DC level and adjust it to 0.

3) Get the Triangle DC bias adjusted first. The Sine and Saw are based on the Triangle, so that is important. You'll be able to see the Sine shape adjustments on your soundcard o-scope, although you'll need to resort to the multimeter again to get the symmetry adjustment right.

Like I say, sounds like you're slowly getting everything nailed down, but you do need to follow all those wave adjustments through. Hope this helps!

Tim (could use a few adjustments) Servo
Back to top
View user's profile Send private message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Wed Jan 13, 2010 1:07 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks to sound and tim for the great advice

I did try the 0V trick with a tester and got a much better triangular wave,

the sine is still eluding me... hopefully I'll get reunited my my analog oscilloscope soon

Wink

aero


Th 101 triangle 0v.png
 Description:
Triangle at 0V
 Filesize:  205.96 KB
 Viewed:  151 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Th 101 triangle 0v.png


Back to top
View user's profile Send private message Visit poster's website
Sound



Joined: Jun 06, 2006
Posts: 842

Audio files: 1

PostPosted: Wed Jan 13, 2010 9:49 am    Post subject: Reply with quote  Mark this post and the followings unread

Good!
But if achieved the triangle you could achieve the sine in this way. without wait for the analogue oscilloscope.
What are u getting at the sine output?
Back to top
View user's profile Send private message
Tim Servo



Joined: Jul 16, 2006
Posts: 924
Location: Silicon Valley
Audio files: 11

PostPosted: Wed Jan 13, 2010 1:08 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Aero,

Okay, you're getting closer! Remember that the sine adjustments interact with each other. You'll have to go back and forth between them a few times to really get a proper looking (and sounding) sine wave. Another thing you might try for the sine adjustments is to put the TH-101 in LFO mode, and apply the sine output to another VCO. You can adjust for the smoothest sounding vibrato for the shape, and listen for equal positive and negative modulation to get the offset. Agreed, you'll be SO much happier with an analog o-scope Wink

Tim (proper looking, but not sounding) Servo
Back to top
View user's profile Send private message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Fri Jan 22, 2010 8:44 am    Post subject: Reply with quote  Mark this post and the followings unread

wow thanks guys! it feels a bit like those movies where a member of the public suddenly has to take control over an airplane cockpit and the good guys in flight control guide him through the rescue process Very Happy

I finally managed to get my hands on my analog oscilloscope again.

I can confirm that the triangle wave is calibrated properly, however no joy from the sine still (sorry for the bad pict)

One thing to notice is that adjusting the waveshape trimmer doesn't bring much change and the saw output is basically mute

any advice to where to look for issues?

thanks again

aero


P1010003.jpg
 Description:
sine wave out
 Filesize:  418.92 KB
 Viewed:  138 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

P1010003.jpg


Back to top
View user's profile Send private message Visit poster's website
Sound



Joined: Jun 06, 2006
Posts: 842

Audio files: 1

PostPosted: Sat Jan 23, 2010 11:36 am    Post subject: Reply with quote  Mark this post and the followings unread

Aerograma, did you follow the build notes? remember that there, is indicated how to place some components

aerogramma wrote:
however no joy from the sine still


R41 should flat the sine, and R50 place its offset to 0.
Check all the values of the resistors involved, and check if Q4 and Q5 are 2N3904 and are correct placed.

Quote:
the saw output is basically mute

Check in the build notes if Q6 is corrected placed.

Regards.
Back to top
View user's profile Send private message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Sat Jan 23, 2010 11:53 am    Post subject: Reply with quote  Mark this post and the followings unread

Hello Sound,
thanks for pointing it out.
I have followed the build notes but looking at Q6 now, I might have mistaken pin2 with pin3 on the MPF 102... will investigate further

thanks!



aero
Back to top
View user's profile Send private message Visit poster's website
Tim Servo



Joined: Jul 16, 2006
Posts: 924
Location: Silicon Valley
Audio files: 11

PostPosted: Sat Jan 23, 2010 2:11 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hey Aero,

Yes, double check that Q6 as that is critical to get the Saw working.

It looks like both the offset and shape trims are off, so I would probably return the Sine trimmers to their mid points and start over. If they're 10-turn, rotate them until they 'click' at the end stop and then rotate then back 5 full turns. Double check the part number and see whether they're 10, 15 or 25-turn. The 'click' is very quiet, so you'll need to be listening carefully (you can also usually feel the click in the screwdriver adjusting the trimmer). I've attached a copy of the TH-101 Build Notes, so anyone out there can look them over.

Also, don't forget that you need to jumper a wave into the PWM comparator. There's no built in connection, so you can choose either the tri, sine, or saw as the PWM input. Hang in there, you're making progress!

Tim (I also click when I rotate) Servo


TH-101-01 Build Notes.pdf
 Description:
TH-101 "Sheboygan" Build Notes

Download
 Filename:  TH-101-01 Build Notes.pdf
 Filesize:  243.83 KB
 Downloaded:  343 Time(s)

Back to top
View user's profile Send private message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Wed Jan 27, 2010 3:31 am    Post subject: gettiing there... Reply with quote  Mark this post and the followings unread

First of all thanks again to Sound and Tim for the invaluable assistance Very Happy

the MPF was mounted correctly, however I found a large problem on the resistor front all the 2.2K were infact 2.2M!
A mouser a glitch in the order? Or my fault (also likely)... but nevertheless I proceed desoldering and substituting (giving my eyesight out to science and synth DIY in the process).

So now I have a Sinewave that looks ok, but to my ears it sounds like there are still a few armonics that perhaps shouldn't be there (see attached mp3), what do you think?

The same extra stuff goes on the other waves too (Saw is also back!)... I might have done some damage to a couple of the resistor seating and might have to do a bit of point to point soldering.

Right now I'm looking suspiciously at R23, R32 and at R69 that goes to P1, but I haven't figured out where P1 is on the board yet.

Anyway it has been a bit of a struggle but I learnt a lot !

thanks!

aero


Picture 5.png
 Description:
 Filesize:  348.38 KB
 Viewed:  137 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Picture 5.png



th 101 sine.mp3
 Description:

Download
 Filename:  th 101 sine.mp3
 Filesize:  121.27 KB
 Downloaded:  235 Time(s)

Back to top
View user's profile Send private message Visit poster's website
Sound



Joined: Jun 06, 2006
Posts: 842

Audio files: 1

PostPosted: Wed Jan 27, 2010 7:08 am    Post subject: Re: gettiing there... Reply with quote  Mark this post and the followings unread

aerogramma wrote:
So now I have a Sinewave that looks ok, but to my ears it sounds like there are still a few armonics that perhaps shouldn't be there (see attached mp3), what do you think?

Try to adjust the sine wave in a lower frequency, say 60hz, then adjust there by ear to more clean sound. if you have acceptable clean sound there you will have more clean sine in upper frequencies.
Remember that the offset shold be =0
I ll check this afternoon mine.

Quote:
The same extra stuff goes on the other waves too (Saw is also back!)...

Glad to hear this.

Quote:
Right now I'm looking suspiciously at R23, R32 and at R69 that goes to P1, but I haven't figured out where P1 is on the board yet.

I dont understand. There is something not working properly?

Quote:
Anyway it has been a bit of a struggle but I learnt a lot !

In my opinion this is the process where you can learn more.
Anyway if you want to learn more about this circuit, I recommend read the book "Making Music with the 566" by Thomas Henry, work on which Tim based this oscillator design.
Back to top
View user's profile Send private message
Thomas_Henry



Joined: Jul 24, 2009
Posts: 129
Location: N. Mankato, MN

PostPosted: Wed Jan 27, 2010 4:11 pm    Post subject: Reply with quote  Mark this post and the followings unread

Trust your ears before your eyes.

In other words, most people think they know what a sine wave should look like, but in fact your ears do a better job of finding the best approximation. I usually just adjust the trimmers until I hear something relatively free of harmonics. That'll usually get you down to 3% distortion or less.

Thomas Henry
Back to top
View user's profile Send private message
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Sun Jan 31, 2010 1:20 am    Post subject: Reply with quote  Mark this post and the followings unread

Thomas_Henry wrote:
Trust your ears before your eyes.

In other words, most people think they know what a sine wave should look like, but in fact your ears do a better job of finding the best approximation. I usually just adjust the trimmers until I hear something relatively free of harmonics. That'll usually get you down to 3% distortion or less.

Thomas Henry


thanks for the advice Thomas, I will do that.

My understanding of synth electronics is poor to say the least, my ears however have received much more training and the usually work quite all right.

By the way even with the extra harmonics your/tim design on the TH101 sounds fantastic, already thinking of building another one

Wink

aero
Back to top
View user's profile Send private message Visit poster's website
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Sun Jan 31, 2010 1:26 am    Post subject: Re: gettiing there... Reply with quote  Mark this post and the followings unread

[quote="Sound"]
aerogramma wrote:

Quote:
Right now I'm looking suspiciously at R23, R32 and at R69 that goes to P1, but I haven't figured out where P1 is on the board yet.

I dont understand. There is something not working properly?
.


Thanks for the precious advice Sound will try to get my head around TH cookbook soon.

The resistors I quoted might have a damaged soldering pad (my fault) , so I'll have to double check with a tester to see if they're actually properly connected
Back to top
View user's profile Send private message Visit poster's website
aerogramma



Joined: Feb 27, 2008
Posts: 150
Location: Roma, Italy - London, UK
Audio files: 13

PostPosted: Tue Feb 16, 2010 2:30 am    Post subject: Reply with quote  Mark this post and the followings unread

Hello again everyone,
after a final round of debugging I got to a result that sounds so good and unique that decided to stop there.

It's possibly still not the purest sinewave I could get out from this VCO but the sample I've attached here is a testament to how good and full of character this design sounds.

It's recorded with no efx of sort - passed through my neve solid state self built clone, piloted by Expert Sleepers' Silent Way in Logic and recorded on a RME Fireface 400

thanks again to all of you that helped me out completing this project

Wink

aero


TH 101 sine out seq.mp3
 Description:

Download
 Filename:  TH 101 sine out seq.mp3
 Filesize:  461.09 KB
 Downloaded:  231 Time(s)

Back to top
View user's profile Send private message Visit poster's website
Tim Servo



Joined: Jul 16, 2006
Posts: 924
Location: Silicon Valley
Audio files: 11

PostPosted: Tue Feb 16, 2010 1:09 pm    Post subject: TH 101 calibration Reply with quote  Mark this post and the followings unread

Hey Aero,

Congrats on getting your TH-101 up and running. Even if the sine isn't perfect, if you like the sound then that's what really matters. I like mine too, and think they have a very nice character to them. Have fun with it.

Tim (up and running) Servo
Back to top
View user's profile Send private message
23isgood



Joined: Nov 18, 2006
Posts: 236
Location: San Francisco, CA bay area
Audio files: 13

PostPosted: Sat Feb 20, 2010 10:51 am    Post subject: Reply with quote  Mark this post and the followings unread

I would like to get some of these pcb's, and I have sent Tim an email, but I haven't head from him. I'm wondering if he is not receiving my emails? Tim could you contact me please?

thanks
pete

_________________
Check out my music
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [24 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 » Thomas Henry designs
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