If you have a prereg you must have 4 volt more as input voltage as the set output voltage.
What is the voltage at pin 2, 3 and 6 of the opamp?
What is the voltage at pin 2, 3 and 6 of the opamp?
Hi,
I have built several of the SR's also ,a guess here is you have fried the opamp,You could remove it and place a dip socket and a adapter in it's place or a dip 741 will work to test the circuit out,smd don't like alot of heat.
If your soldering Iron has a screw in tip and you can remove it ,a large sewing needle will work in the soldering tips place to solder small traces,and of course there always a chance the pins are shorted by solder that didn't get remove by the wick.
Happy new year!
NS
I have built several of the SR's also ,a guess here is you have fried the opamp,You could remove it and place a dip socket and a adapter in it's place or a dip 741 will work to test the circuit out,smd don't like alot of heat.
If your soldering Iron has a screw in tip and you can remove it ,a large sewing needle will work in the soldering tips place to solder small traces,and of course there always a chance the pins are shorted by solder that didn't get remove by the wick.
Happy new year!
NS
And the question was how does the super reg compare to the LT1085.
With the smart hat answer "check the datasheet".
I know where to find the LT one. Now let's see the super reg one for comparison purposes.
Besides in Walt Jung's/Jan Didden's articles you can find recent measurements made by jackinnj in the Bookzine Linear Audio vol. 4.
http://linearaudio.net/volumes/785
http://linearaudio.net/volumes/785
Attachments
It is also worth noticing that the jackinnj tests show very clearly how important the opamp is besides the pcb layout. The AD825 is lower open-loop gain than the AD797 which gives less feedback in lower frequencies. The AD825 has also a bit high noise.
What this test doesn't show is the EMC immunity. I'll suspect that my 4-layer board has a rather good chance here.
What this test doesn't show is the EMC immunity. I'll suspect that my 4-layer board has a rather good chance here.
I was fortunate to have picked up a number of the original boards which Jan designed, were sold via the Old Colony (ed dell's) website -- the layout is larger, but i think the grounding scheme better than the current variety.
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An externally hosted image should be here but it was not working when we last tested it.
just my 2 pfennigs.
Got similar results in my attempts to simulate a variant of the circuit.
The design is quite optimistic regarding the RF performance of electrolytic capacitors. Be prepared to solder some SMD ceramics across their terminals 😉
So for DC input it still requires 4V? I thought in the other implementation 2.5V was used.
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So after years of the article being published, have we got better opamps now than the original recommendations of AD825 and AD797? Which are the most suitable opamps?
The LM317 is set for 2 or in my case 2.5V and the super regulator itself requires 1.5 V depending a little of other things.
The '797 wasn't recommended really. Both Walt and myself acknowledged that the '797 is often difficult to stabilize in this particular application.
Jan
To be very frank, in my last build about a couple of months ago, I bought all AD825 for the SRs. I am very happy with the sound.
But if something is better, of course I will use it.
I will be using 4 SRs to drive 4 way active crossovers, with each SR drives each branch of circuit. I am yet to replace two AD825s (assumed overheated during soldering) to make the 2 SRs work. I was worried about overheating so I set the soldering iron temperature too low (250 degree?) which actually overheated it because the soldering iron needed to contact the tracks for long. I have now learnt that I should stick with 360 degree and leave it quickly. This would be the first time in over a dozen years of learning to do soldering that I burnt some active devices., if that is proven to be the case.
But if something is better, of course I will use it.
I will be using 4 SRs to drive 4 way active crossovers, with each SR drives each branch of circuit. I am yet to replace two AD825s (assumed overheated during soldering) to make the 2 SRs work. I was worried about overheating so I set the soldering iron temperature too low (250 degree?) which actually overheated it because the soldering iron needed to contact the tracks for long. I have now learnt that I should stick with 360 degree and leave it quickly. This would be the first time in over a dozen years of learning to do soldering that I burnt some active devices., if that is proven to be the case.
i built a 3.3V version on prototyping board (looks stable with low pass filter on feedback loop).
the superreg, is pretty good for it's purpose, in my opinion, though i havn't built the "standard" version.
No other reg has it's output impedance as low, to my knowledge.
However, if you want a bit more of a "natural sound", i would build a salas V1 reg.
Actually, i'd use salas reg for 3.3v, but, the design doesn't really allow for that a low output voltage.
If you really want to upgrade the superreg, maybe you can play with the pass bjt...? It can have significant impact on sound.
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I don't think so.
Salas:
An externally hosted image should be here but it was not working when we last tested it.
Jung:
An externally hosted image should be here but it was not working when we last tested it.
According to a different thread, there are gentlemen here that still have to acknowledge it 🙄
There isn't anything magic about it, you would be looking for a low noise opamp with high open loop amplification. Something between the 825 and 797 (as to have chance of improvement, yet not go into full problems with stability).
You can also try a pass transistor with higher beta, to give you a chance at driving higher loads without overtaxing the op amp output current.
Also I was wondering - since a LM317 was introduced in the budget - why not use it instead as a voltage regulator for powering the opamp and voltage regulator. Eliminating startup issues and the need for the transistor-led current source. You might then even be able to use the 797.
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