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Re: Valve doubler bug in PSUD2 ?
Hi Tim,
I've duplicated your circuit using the values listed in your message, and I can confirm that something is badly broken. Looking a I(T1) the positive and negative excursions should be the same but are anything but. Will have to take a deep dive on this and start prodding in the software to find out what's going on. Probably won't get a chance to review/resolve until Sunday. Regards, Duncan |
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Valve doubler bug in PSUD2 ?
Duncan, seems you're busy with V3, but perhaps you have time to quickly check an inconsistent response when using a valve based voltage doubler.? I have a setup with 330V 21R secondary supplying a 2x 5U4G per arm rectifier into? 47uF 1R filter caps with simple 7.5kohm load.? It provides about 780V output across 7k5, but the concern is the markedly different diode current waveform asymmetry, and the resultant different voltages across the series connected output caps.
I tried different options settings (accuracy, frequency, leakage) but no change.? There is some variation with different valve diode models, but the asymmetry doesn't show with ss diodes.? I'm using Windows build 76, V2.22. I can't quickly find this topic issue discussed on-line.? My previous use of doublers in PSUD2 have been ss based, but I have a valve based doubler in an amp on the bench now :-) Ciao, Tim Robbins |
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Re: PSUD3 Windows Beta / Preview edition
Hi Duncan,
I'm so glad I found this. I used the original PSUD almost 20 years ago now and it helped so much. After this long I'm building valve amps again, but the computer I had the original software on is long gone. Hope to be able to try out V3 soon! Regards, Ken |
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Re: Thank you!
开云体育
Agreed as well! Thank you Duncan!
"Conan, what is best in life?"
"To crush your code. To see it working before you. And to hear the adorations of your users!" |
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Re: Thank you!
开云体育+1 ? Van: [email protected] <[email protected]> Namens TJTomPhillips
Verzonden: maandag 15 januari 2024 16:51 Aan: [email protected] Onderwerp: Re: [duncanampspsud] Thank you! ? I wholeheartedly agree. The SW program is a wonderful tool and it's especially nice that Duncan continues to improve it. |
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Thank you!
I hope this message isn't a bother to everyone, I just wanted to say thanks to Duncan for making this software available. I have been playing around with it for a bit, and and it's great! Thank you Duncan!
If anybody else feels this way, i suppose this is a good thread to pile in to. Cheers, Tim |
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Re: psu2
Hi, you indicated issues with downloading the software on 21st March, however I did not hear back to be able to assist with the issue. The original thread is here -->?/g/duncanampspsud/topic/97773153#205
Regards, Duncan |
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Re: PSUD3 Windows Beta / Preview edition
Hi Dom,
Thanks for the offer. I've paused the PSUD3 Beta at the moment, there has been some really useful feedback on it which I will incorporate over the Christmas break. There's a message with a bit more detail here ->?/g/duncanampspsud/message/262 Once it gets started up again, I will be sure to include you. Thanks for your continued support. 73, Duncan MM0KGK |
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Re: Where did the current go?
Just a word of thanks, Duncan for making such a useful piece of software available gratis. I've used it as necessary for many years; it beats faffing around finding suitable models for Spice, and for sure beats using Schade's paper and his graphical method. Actually back in the day Schade was how I used to do this stuff before free versions of Spice were available, and long before your software was available. Cheers! Craig (in the UK)
------ Original Message ------
From "Duncan Munro" <duncan@...>
Date 17/11/2023 08:47:40
Subject Re: [duncanampspsud] Where did the current go? Hi John, |
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Re: Where did the current go?
Hi John,
This is a PSUD2 problem rather than a mismatch in setups. Kirchoffs first law is quite clear, the currents going into a node should equal the currents coming out. To speed up and simplify simulations, PSUD2 breaks Kirchoff's laws and, as such, has been broken as designed for over 20 years. Most of the time it's reasonably close, and can get away with it but there are times when something comes up that diverges to a really whacky result. Wasn't really expecting it on such as simple example as the one you've illustrated. For your example above, all three currents should be identical at all times. Therefore, the mean/min/max should all be the same too. The problem stems from the way PSUD2 tries to balance the network of components, so it's not fixable without a total rewrite, which is why I started on PSUD3. This uses a matrix solver which is similar to the SPICE family and will respect both of Mr Kirchoff's pearls of wisdom. Unfortunately PSUD3 has taken a pause right now, I recently put out a beta to a half dozen participants to try it out. It needs more work in the way the user interface operates, and was messing up their installations in some instances which isn't acceptable. I'll get more time to work on it during the Christmas break so should be able to incorporate their feedback and introduce it to a wider audience. Will post on here when it's good to go. Regards, Duncan |
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Where did the current go?
Hi. I've been poking around trying to explain a 10volt difference between PSUD2 and LTSpice results for an EZ81 based power supply. It's not a big deal (the amp's been working for years) - I'm just trying to understand the use of both tools for Power Supply design. I've been assuming that the difference is in the models of the EZ81. I kept trimming the design down until I reached the attached configuration. The Transformer current matches the Diode current, but the Resistor current (Mean) is 7mA less. What am I missing?
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Re: Capacitors in series to increase working voltage question
I would say that the 1mA or so of current through the balancing resistors is insignificant. You could use a 100uF 500v capacitor instead, but it would probably cost more than the two 250v ones.
The 6N1P is very different from the 6922, apart from having the same pinout. It has much higher anode impedance and likes a higher voltage. It looks more like a higher-gain 6CG7 substitute to me, but does not sound anything like as good. I'd stick with the 6922/E88CC. Edit: You will need to check that the 6922 can provide enough voltage swing to drive the EL34 without distorting. |
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Re: Capacitors in series to increase working voltage question
开云体育Hi Paul,I believe you asked about the voltage divider resistors in parallel with the series resistors. While it is a small current going through them it still presents a load on the supply. I would not ignore them On Nov 13, 2023, at 2:46 PM, Duncan Munro <duncan@...> wrote:
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bias57
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