This is what I asked myself too. Why is the "better" version cheaper? I have used LT4320-1 but noticed no difference.Interesting that ‘faster’ version is 1.50€ cheaper.Until recently, it was get what version is available at all.
I don’t see any reason why not to order LT4320-1. Performance is likely exactly the same at 50/60 Hz. For a meaningful answer, we would need to compare weather there is any difference in level of harmonics after rectification. Not very likely but I l would like to know as well.
For the next supply, I will order LT4320-1 version and check (not soon).
Also: why produce 2 versions when 1 of them covers all?
Well, I always learn from destruction.
Finally turned my first board on and no LEDs light.
I see I installed Q6 backwards on this one board. What a dumbass. I had made sure all of the diodes were oriented correctly but did not bother to look at that MOSFET.
I replaced it but that did not do any good.
Did this take out all of the MOSFETS? I did replace Q9 at the same time.
Would a reversed Q6 have taken all of the MOSFETs to the rubbish pile?
Would it be better to just build up another board?
Your counsel would be greatly appreciated.
I will try again with another board tomorrow.
Thanks, Tombo
Finally turned my first board on and no LEDs light.
I see I installed Q6 backwards on this one board. What a dumbass. I had made sure all of the diodes were oriented correctly but did not bother to look at that MOSFET.
I replaced it but that did not do any good.
Did this take out all of the MOSFETS? I did replace Q9 at the same time.
Would a reversed Q6 have taken all of the MOSFETs to the rubbish pile?
Would it be better to just build up another board?
Your counsel would be greatly appreciated.
I will try again with another board tomorrow.
Thanks, Tombo
Reversed Q6 should do no damage at all. Only voltage reference and opamp would be left without required supply.
Even with Q6 reversed, green LED should be lit. It may be that LEDs are reversed? When placing, shorter LED pin (marking cathode) should go through square pad.
Next check point is opamp orientation. Lines on the opamp and silkscreen should be on the same side.
Before assembling the next board, it would be better to check if there are assembling mistakes on the first one, not to repeat them. Several pictures of both PCB sides would help.
This project is not well suited as "my first PSU" is it? 🙂 I wish you luck and skills, rickmcinnis. In case of failure I offer to build one for you but shipping costs will make you sleep bad.
Hah, there is a checklist at R21 thread that still applies. 🙂
https://www.diyaudio.com/community/...ower-supply-r21-ps-module.376003/post-6759494
But, anyone willing to learn from its mistakes will succeed.
My path is littered with burned components.
https://www.diyaudio.com/community/...ower-supply-r21-ps-module.376003/post-6759494
But, anyone willing to learn from its mistakes will succeed.
My path is littered with burned components.
Thanks for the help. This is not my first project. I admit my mistake and then ... Oh, well.
Everything but the one transistor was in correctly.
I was careful with the LED placement. Certainly thought I was but anything is possible.
I get voltage at the output that is obviously not regulated.
31.6 volts from the transformer - at the output of the regulator into a 100 Ohms load is around 45 volts. Would reversed LEDs alone do this? I would have figured a lower number. Turning the trimpot made no difference in voltage output.
I will replace the LEDs and see if that is the problem.
Everything but the one transistor was in correctly.
I was careful with the LED placement. Certainly thought I was but anything is possible.
I get voltage at the output that is obviously not regulated.
31.6 volts from the transformer - at the output of the regulator into a 100 Ohms load is around 45 volts. Would reversed LEDs alone do this? I would have figured a lower number. Turning the trimpot made no difference in voltage output.
I will replace the LEDs and see if that is the problem.
If everything is in the right place, green LED must be lit. Reversed LED prevents current to flow and it would disable proper operation. After desoldering green LED, check with multi meter if it is OK, but put a new one.
The LEDs I received have no flat edge so the only way to be sure is to replace them which is what I did.
Opamp is oriented correctly.
Success - I obviously inserted them incorrectly. I replaced them both - not sure if I installed both of them incorrectly or not, which is moot.
Sorry for the stupid drama. Sometimes one can be too careful. I swear I went through the insertion process diligently. Makes me think of high school chemistry lab when the students who were obsessed with doing the experiment perfectly usually got it wrong by overthinking themselves into missing the obvious.
I have a pair of wires to connect to the 40 mF cap bank which I did not connect for the initial turn on. I presume this is a good place to check for before and after regulator voltage?
Now to connect to the THF-51.
Thanks, Tombo
PS - the soft start is very fine!
Opamp is oriented correctly.
Success - I obviously inserted them incorrectly. I replaced them both - not sure if I installed both of them incorrectly or not, which is moot.
Sorry for the stupid drama. Sometimes one can be too careful. I swear I went through the insertion process diligently. Makes me think of high school chemistry lab when the students who were obsessed with doing the experiment perfectly usually got it wrong by overthinking themselves into missing the obvious.
I have a pair of wires to connect to the 40 mF cap bank which I did not connect for the initial turn on. I presume this is a good place to check for before and after regulator voltage?
Now to connect to the THF-51.
Thanks, Tombo
PS - the soft start is very fine!
Great to hear it was that easy to solve.
Input voltage can be measured at first capacitor, or external capacitors bank in your case. Or just put probes between first capacitor and supply output, to measure voltage drop.
Input voltage can be measured at first capacitor, or external capacitors bank in your case. Or just put probes between first capacitor and supply output, to measure voltage drop.
Well, R21 has actually a hard start, with full voltage at output in milliseconds after power on.
R25 has slowly ramping output voltage, which can be considered as a soft start. Obviously only for the output part, not for the inrush current into first capacitor.
OK I thought the full output of R21 after delay counts as softstart. Mine not has milliseconds delay but a noticable time hence my assumption. Haven’t looked at waveform at power on. Board was for testing and curiosity and is an ugly mix of modules and separate parts. Has been a while that I used it.
Yeah the R25 boards are there but the parts were brought when I was away so not delivered.
Yeah the R25 boards are there but the parts were brought when I was away so not delivered.
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Yes, with R21 it takes about 3 s for regulation to kick in. Why is that is explained in the circuit description. I rather call that result a hard start, as full unregulated voltage is immediately at the output for the first 3 s.
Good to see you're powered up successfully now, Rick. 🙂
Are you connecting your external cap bank parallel to C2?
Are you connecting your external cap bank parallel to C2?
The amp is making music.
I get the feeling the regulator wants more voltage drop than I expected - but I am not quite sure where to measure the before and after difference.
As it is it is at a lower voltage at the entrance to the choke (ra7's version of the MOFO with THF51) than it was with the clc filter - 100 mH/0.6 choke in the power supply.
I had initially some glitches that led me to believe I had the voltage set too high even thought the red LED was not lit. I will go up as the evening progresses.
No heating to speak of but the pass mosfet is connected to a whole lotta sink sink.
Three more to go. With only a tweeter amp converted and an half hour of listening I cannot say talk about the sound. It certainly does not sound worse.
Thanks, Vunce and most importantly thanks to Tombo for his help, encouragement and this very interesting device!
With the packaging out of the way I hope to get the other three done before New Years Day. Unfortunately I figure I had best replace the zeners in the other three boards before doing anything else.
Happy New Year!
I get the feeling the regulator wants more voltage drop than I expected - but I am not quite sure where to measure the before and after difference.
As it is it is at a lower voltage at the entrance to the choke (ra7's version of the MOFO with THF51) than it was with the clc filter - 100 mH/0.6 choke in the power supply.
I had initially some glitches that led me to believe I had the voltage set too high even thought the red LED was not lit. I will go up as the evening progresses.
No heating to speak of but the pass mosfet is connected to a whole lotta sink sink.
Three more to go. With only a tweeter amp converted and an half hour of listening I cannot say talk about the sound. It certainly does not sound worse.
Thanks, Vunce and most importantly thanks to Tombo for his help, encouragement and this very interesting device!
With the packaging out of the way I hope to get the other three done before New Years Day. Unfortunately I figure I had best replace the zeners in the other three boards before doing anything else.
Happy New Year!