I built Jim Williams oscillator, spent many hours making it work. Its a lot more tricky than it looks to be. I wasn't happy with the final outcome and just had to stop.
There is another source for the optocouplers, low distorion ones in fact. http://www.silonex.com/audiohm/index.html I found them after I moved on to other things. If I didn't have the KH 4400 or the Boonton 1120 I would still be looking at this.
The 10 KHz oscillator looks interesting. I don't have time to build one but I could hook it to the CLT1 and measure the 3rd harmonic accurately. It would be interesting.
-Demian
There is another source for the optocouplers, low distorion ones in fact. http://www.silonex.com/audiohm/index.html I found them after I moved on to other things. If I didn't have the KH 4400 or the Boonton 1120 I would still be looking at this.
The 10 KHz oscillator looks interesting. I don't have time to build one but I could hook it to the CLT1 and measure the 3rd harmonic accurately. It would be interesting.
-Demian
SG505
here's the schematic --
this link is to a large GIF which is more clear:
www.tech-diy.com/sg505_a.gif
here's the schematic --
An externally hosted image should be here but it was not working when we last tested it.
this link is to a large GIF which is more clear:
www.tech-diy.com/sg505_a.gif
EchoWars said:Got the power supply (TM501) for the SG505 a few days ago. I'm impressed. Connected the SG505 to the DA4084, and at about 2V RMS output, the reading I get from the DA4084 says 0.0004% THD+N. I'm quite happy.
That's great news! But how do you get a DA4084 and an SG505 into a TM501 -- are you sure it isn't a '503?
The DM4084 is stand-alone (there is another model that is a 500-series plug-in, I can't remember at the moment). Technically, I guess the DM4084 is kind of a plug-in too, as it releases the same way a regular plug in does, but it cannot be used in a 500-type plug in, and 500-type plug-ins cannot be used in the power supply that comes with the DA4084, or at least this is the way I was told and the way I understand it. The SG505 is the only one in the TM501, obviously.
I wish I had bought a TM502, and I could look for a FG501 or a 501A or a FG502, and sold that cheapie CFG253.
If I do decide to buy a FG plugin, which one ought I to look for??
I wish I had bought a TM502, and I could look for a FG501 or a 501A or a FG502, and sold that cheapie CFG253.
If I do decide to buy a FG plugin, which one ought I to look for??
Tek Function generator
This would be the most useful: Tek-FG504 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=25405&item=3851068409&rd=1
40 MHz lin/log sweep etc. But its two slots.
-Demian
This would be the most useful: Tek-FG504 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=25405&item=3851068409&rd=1
40 MHz lin/log sweep etc. But its two slots.
-Demian
EchoWars said:The DM4084 is stand-alone (there is another model that is a 500-series plug-in, I can't remember at the moment). Technically, I guess the DM4084 is kind of a plug-in too, as it releases the same way a regular plug in does, but it cannot be used in a 500-type plug in, and 500-type plug-ins cannot be used in the power supply that comes with the DA4084, or at least this is the way I was told and the way I understand it. The SG505 is the only one in the TM501, obviously.
I wish I had bought a TM502, and I could look for a FG501 or a 501A or a FG502, and sold that cheapie CFG253.
If I do decide to buy a FG plugin, which one ought I to look for??
Just parenthetically, sometimes it's better to donate your unwanted equipment than to sell it (from a tax standpoint) -- figure this, the tax benefit is (1- tax rate) * fair market value = tax benefit. Fair market value is likely to be a lot higher than the scrap value.
Not that we give stuff to 501C-3's just for the tax benefit, but it is something to consider. I've outfitted an entire inner city high school electronics lab just with discarded Tek PS503's and DM501's -- and they are a lot better than the stuff they get from Pascoe or Vernier. If the economic benefit doesn't quite make it, at least some under-equipped high school teacher will think more kindly of you!
Well, I finally cobbled together the Super-Oscillator from Linear Technologies Application Note 67 -- I didn't have all the polystyrene caps I was looking for:
An externally hosted image should be here but it was not working when we last tested it.
Great news Jackinnj, that looks very nice! Offcourse the big question is... can I buy a PCB from you... ... and.. hahaha I'll be happy to check your finished version for you .... but seriously, I been wanting to build the superoscilator for over a year now, but the lack of a pcb has hold be back.. I would be very interested in buying a PCB from you...
Kindest regards,
Thijs
.... but seriously, I been wanting to build the superoscilator for over a year now, but the lack of a pcb has hold be back.. I would be very interested in buying a PCB from you...Kindest regards,
Thijs
Thijs -- there are a couple tweaks to do here -- the 50k amplifier "gain adjust" pot should be 10 or more turns -- this adjustment is a little "nervy". I have used ceramic caps since that was all I had on hand -- will see if i can fit some polystyrene ones (on order) in their place. I used an SMA connector for this board -- I am sure that most folks would like BNC -- and I am further sure that 1kHz would be preferred to 10kHz -- but 10kHz has its own challenges and rewards.
you have seen this site -- http://www.amplifier.cd/Technische_Berichte/Amplifier_reiner_Sinus/amplifier_clean_sine.htm
you have seen this site -- http://www.amplifier.cd/Technische_Berichte/Amplifier_reiner_Sinus/amplifier_clean_sine.htm
some hints -- I have made some measurements -- not in a shielded case yet (and using a noisy TEK PS5010 supply) -- all of the filter circuits should be 1% metal film, all of the filter capacitors should be polystyrene (you could use mica I suppose) -- and the 3 trimmer pots should be 12 turns -- we are getting down into the 0.00X% THD readings which will improve when it is shielded and has a noiseless power supply -- this really does amplify anything nearby !!!
when I simmed the device's circuits in Multisim I get a 11.3 kHz -- crossover -- in reality the device is oscillating at 7.6kHz. -- curious -- that's roughly a factor of 1/sqrt(2)
when I simmed the device's circuits in Multisim I get a 11.3 kHz -- crossover -- in reality the device is oscillating at 7.6kHz. -- curious -- that's roughly a factor of 1/sqrt(2)
Hi Jackinnj,
Sorry,.. haven't been able to post in a while... i'm terrible busy at my work... but I'm reading everything .... I got the last IC for the uber-oscilator last month or so... nothing left to keep me from building one this summer holiday.. keep us posted on your results..
mean while I managed to buy a Krohn-Hite 4400A oscilator from ebay.. low thd, fully adjustable frequency and amplitude.. should be nice....
cheers m8,
Thijs
Sorry,.. haven't been able to post in a while... i'm terrible busy at my work... but I'm reading everything .... I got the last IC for the uber-oscilator last month or so... nothing left to keep me from building one this summer holiday.. keep us posted on your results..
mean while I managed to buy a Krohn-Hite 4400A oscilator from ebay.. low thd, fully adjustable frequency and amplitude.. should be nice....
cheers m8,
Thijs
Here's a pair of comparison pix of the spectrum to 100kHz. The first is the Linear Tech design, the second is from my Boonton 1120 .
Boonton
An externally hosted image should be here but it was not working when we last tested it.
Boonton
An externally hosted image should be here but it was not working when we last tested it.
i briefly got it down to where it should be operating -- actually the Boonton (which is in cal) said 0.00012% -- perhaps for a second or so -- then it reverted to 0.0029% -- it's running on 10 "D" cells now -- i am not happy with the stability -- will run for 30 minutes or so at very low THD and then break out.
Looks like you made more progress that I did on the oscillator. I still don't believe they built it in an afternoon.
I have never been able to get any of my Boontons below .0007%. I believe its a noise limit more than anything else. I have also noticed that its possible for the measurement routine to "lockup" and require a restart (press the local button to reset the system)
I am attaching the distortion residuals from both the internal oscillator in the Boonton and the KH4400. These are FFT's of the output of the Boonton analyzer
Boonton:
I have never been able to get any of my Boontons below .0007%. I believe its a noise limit more than anything else. I have also noticed that its possible for the measurement routine to "lockup" and require a restart (press the local button to reset the system)
I am attaching the distortion residuals from both the internal oscillator in the Boonton and the KH4400. These are FFT's of the output of the Boonton analyzer
Boonton:
Attachments
Here is the KH4400 (I haven't figured out how to attach two images to one post yet.)
Both read .0008% THD w/ 30 KHz low pass filtering, using inverting input and all of the other tricks I have figured out for lowest readings.
The display is 0-25KHz and the marker is at 2 KHz.
Krohn Hite:
Both read .0008% THD w/ 30 KHz low pass filtering, using inverting input and all of the other tricks I have figured out for lowest readings.
The display is 0-25KHz and the marker is at 2 KHz.
Krohn Hite:
