Good idea! But be aware that, depending on the output voltage range, other changes may be required.
For instance, with a 6.9V ref, the Vout can never be below 6.9V (and that is when one of the resistors is zero).
So for a 5V Vout you should change to a lower ref. Ideally, the ref should be around half Vout, so an LM4040-2.5 would be good for 5V.
Also the zener in series with the output of the opamp which is required to get that output at around half Vout might also be needed to be adapted.
Finally, make sure the opamp can run from the Vout - not all opamps work on 5V for instance.
Jan
For instance, with a 6.9V ref, the Vout can never be below 6.9V (and that is when one of the resistors is zero).
So for a 5V Vout you should change to a lower ref. Ideally, the ref should be around half Vout, so an LM4040-2.5 would be good for 5V.
Also the zener in series with the output of the opamp which is required to get that output at around half Vout might also be needed to be adapted.
Finally, make sure the opamp can run from the Vout - not all opamps work on 5V for instance.
Jan
The excel formula also includes the ref voltage, but it does not check if the desired output voltage is the same or higher as the ref voltage. This can easily be added to the formula of course. I will post the Excel file (BOM) when I get home, so it can be used by anyone who thinks that it's useful.
Ah, missed that in my 24 Volt 'BA3 as a pre build'. Should I replace the zeners and references for around 12 Volt ? It is working properly now.
Quick question about an issue i am having. When i power the regulator on the LEd lights up, but then turns off. I get the full supplied voltage on the output of the reg. The other channel appears to be working perfectly. I haev used the original version of the circuit with the LM317 as a prereg. It would appear that the LED is fine and the with power off, the pass transistor measures the same when checked against the good channel. I would assume the opamp, but both were fired up at the same time and evrything has been triple checked in terms of soldering.
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11V on the input. 51V on the output.
LM329 cooked?
While the other channel is providing the proper output voltage, I suspect it is oscillating, as the led flickers rapidly as the power is turned off. got a scope, but was hoping it would be a trouble free build. Oh well. Know how that goes.
LM329 cooked?
While the other channel is providing the proper output voltage, I suspect it is oscillating, as the led flickers rapidly as the power is turned off. got a scope, but was hoping it would be a trouble free build. Oh well. Know how that goes.
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Which input? You really have to get some info on what's going on, just speculation is very slow and often turning around in circles.
Is the reference input (+input) at 11V? Then check the reference, see if there a resistor feeding it. How much voltage across that resistor, what is the current into the ref.
What is the difference between the + and - input, what's at the minus input? Is the opamp output consistent with the levels at its inputs?
With a simple DMM you can characterize this simple reg in a couple of minutes and home in on the problem, but you need to measure stuff.
Jan
Is the reference input (+input) at 11V? Then check the reference, see if there a resistor feeding it. How much voltage across that resistor, what is the current into the ref.
What is the difference between the + and - input, what's at the minus input? Is the opamp output consistent with the levels at its inputs?
With a simple DMM you can characterize this simple reg in a couple of minutes and home in on the problem, but you need to measure stuff.
Jan
OK, one obvious problem is the ref in the bad channel. Check the LM329, whether the anode is really at ground, measure between the anode and the ground. 14.81 V across it is wrong, should be less than half. I think that should be your first focus.
Check in general whether you are measuring correctly; even in the good channel there's something fishy.
If the good ref is 10.68 how can the + input be 8.15 since they are directly connected through a non-current carrying resistor?
Also the good ref is also too high should not be more than 7V.
Unless you have oscillations. What is your cap at the output?
Have you connected the sense ground to the reg ground?
All the above questions are relevant.
Jan
I apologize, I think we may be talking about different "super regs" I have tried to attach a pic with this reply. It says super teddy on it.
I was thinking of adopting one of these to put in a box with a PD gainclone.
At the moment they are in line with a phono stage rated at 15v
Perhaps better to build a new one from scratch?
I was thinking of adopting one of these to put in a box with a PD gainclone.
At the moment they are in line with a phono stage rated at 15v
Perhaps better to build a new one from scratch?
Attachments
Cap on ouput is 50V 120uF.
r4 2.2K
r5 22K
I changed the ratio of r6/7 to get 36V. DOnt remember the value without lookin it up, but i am pretty confident in the math. Both LM still measure as posted.
My ears are bleeding -- the SuperTed scores very poorly on the FFT test:
An externally hosted image should be here but it was not working when we last tested it.
Solved it, by trying 
I wanted my BA3 as a preamp to run at + and - 32V to get maximum voltage swing. I replaced the LM329 by LM4040DZ-10 a 10 volt reference. ( apparently you can't get them higher then 10.0V). And the zenerdiode for a 16V type. The LM817 was replaced by OPA604 because of the + and - 24 volt they can handle.
And voila, around 45V input and 32 V output, stable it seems. Got to test it some more, but first impressions are OK
I wanted my BA3 as a preamp to run at + and - 32V to get maximum voltage swing. I replaced the LM329 by LM4040DZ-10 a 10 volt reference. ( apparently you can't get them higher then 10.0V). And the zenerdiode for a 16V type. The LM817 was replaced by OPA604 because of the + and - 24 volt they can handle.
And voila, around 45V input and 32 V output, stable it seems. Got to test it some more, but first impressions are OK