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You'll probably get some more descriptive answers from the hardcore Mac users, however I can tell you it's a 64 bit app so will work only on the later 64 bit systems. I know that users have had problems running it on older OS (like from about 10 years ago).

If you can let us know what version of MacOS you are using, I'm sure someone will be able to confirm if they have it running on that or not, thanks.

Regards,
Duncan

I downloaded version 77. Haven't installed it yet. What OS versions does this work with? Thanks

If you are using RC filters, you can burn off as many volts as you like in the resistors, so long as all components can stand the off-load voltage. It's much easier to lose volts than add them.

Hi

Is designed a PSU with 290v-0v-290v transformer (Imax = 100mA, 58VA, Rpri=21ohms, Rsec=238ohms) and a 57mA total load. I want to have arround 350Vdc at my B+ (with silicone diode rectifier, and only 2 RC network after the B+)

I have doubts since I saw some many schematics with annotated values that let me understand that the transformer voltage might be to big. And since I am about to order it, i need some help :). I have tried the PSUD 2 method design which gives me 346Vrms


I have tried the Merlin Blencowe way with very close results http://www.valvewizard.co.uk/psu.html I found the following results Rl = 290*sqrt2/0.057 = 7195 Rs=243.2 Rs/Rl=0.0338 f * C * Rl = 50 * 47?F * 7195 = 16.9 ==> Green Curve 120% of transformer RMS Voltage ==> 1.2 * 290 = 348Vdc. Many people on told me that i should get values more close to 380VDC, far to high for a 5W amp...
My conclusion is they use rule of thumb by multiplying by x1.3 the RMS transformer output which should be right with a more powerfull PT arround 200mA, but in the same time, it looks their explainations are based on personal experiences.

So how much reliable is PSUD in my context and should I consider to buy a lower voltage power transformer (10 volt less for exemple) to get 350VDC?

Thanks, I think I get it now, although I believe it is usual to include the winding resistance in the total limiting resistance, rather than adding it, when using capacitor input.

Your plan to include a hybrid bridge option in PSUD3 will make this a lot simpler!

Best regards,

Richard.

There's a little bit more to it. The transformer impedance is, for the most part, caused by the primary winding resistance and the secondary winding resistance - both will affect the impedance feeding the remainder of the PSU.

In addition to this, you may want to add some limiting resistors. The best way I can think to illustrate this, is if you pull up the choke_input.psu file from the examples folder (on my machine it's?C:\Program Files (x86)\PSU Designer II\examples). This shows a source impedance per leg of 130 ohms.

If you want to have a 100 ohm limit resistor, simply change the source impedance to 230 ohms (130 + 100) and so on.

Should you need more info on how to figure out the 130 ohms impedance of the basic transformer in the first place, please shout and I can walk through some examples.

Regards,
Duncan

Thanks very much for the reply.

Just to be clear, if I need 100R in each leg, I just enter the secondary winding resistance as100R and this value will be applied to each leg when calculating?

PSUD shows the source impedance (combination of primary and secondary impedance) for just one leg of the winding.

You can directly add the series resistance to this value to simulate the current limiting resistors specified by the manufacturers.

Regards,
Duncan

Tube rectifiers often specify the minimum resistance required in series with each rectifier to limit peak current. For full-wave rectification, does the source resistance shown in PSUD refer to the whole secondary winding or, as with the voltage, half of it?

On 11/7/2022 2:09 PM, Duncan Munro wrote:

on the log as "needs fixing"

JUST after I saw your reply, I was on The Register.com ' Oops~ column, and saw this comment:

"Bug reports are a Good Thing for software that people find useful: it's a sign that people are using it (and quite probably for things you didn't envisage)!"

article:
comment:

Thanks for looking at this.

'When' is the check?

The checking is done when you try and exit the box containing the value. For example, if you key in -1u then nothing happens until you try and move. Pressing tab or clicking on the OK button will cause the field exit checks to be carried out.?

However... I've found out how it's been happening though as I can now reproduce the problem:

• Exit the box by pressing Tab - Throws an error - CORRECT
• Exit the box by clicking the mouse - Throws an error - CORRECT
• Exit the form by pressing Enter - Accepts any old rubbish - INCORRECT RESPONSE

I'll put it down on the log as "needs fixing", thanks for letting me know.

Regards,
Duncan

a minimum value for a
capacitor which should prevent a negative value being keyed in.

'When' is the check?

I am not sure I can do this on initial setup. I seem to do it at-will by editing an existing setup. Transformer voltage dialog objects to <2V at first setup, but if I enter 2V then click again to edit, it accepts backspace dash (leading minus sign). It may *later* throw floating-point or other error, but a re-edit negative is accepted and often runs. (Often enough that I did not immediately suspect fumble-finger.)

It *may* depend if I OK out of the dialog by mouse-click or by TAB to the OK button and Enter. Not sure of this, and I have to take the car for inspection today....


On 11/7/2022 12:47 PM, Duncan Munro wrote:

Subject:
Re: [duncanampspsud] Negative capacitor?
From:
"Duncan Munro" <duncan@...>
Date:
11/7/2022, 12:47 PM
To:
[email protected]
Hi Paul,
Thanks for sending the screen dump and other info. I've had a look in the file you sent, and the value in there is definitely -1E-6 (-1uF). However, I cannot offer any kind of explanation as to how it got in there.
I've checked the code back as far as I can, there is version control back to 2011, and even back then there was a minimum value for a capacitor which should prevent a negative value being keyed in.
I'm working on Build 78 here which is slightly newer than your version, but there are no heavyweight changes between the two. I'm unable to duplicate the problem or key in a negative value no matter how I try. That's probably not a helpful answer, but I'm out of ideas on what might be wrong.
Regards,
Duncan

Hi Paul,

Thanks for sending the screen dump and other info. I've had a look in the file you sent, and the value in there is definitely -1E-6 (-1uF). However, I cannot offer any kind of explanation as to how it got in there.

I've checked the code back as far as I can, there is version control back to 2011, and even back then there was a minimum value for a capacitor which should prevent a negative value being keyed in.

I'm working on Build 78 here which is slightly newer than your version, but there are no heavyweight changes between the two. I'm unable to duplicate the problem or key in a negative value no matter how I try. That's probably not a helpful answer, but I'm out of ideas on what might be wrong.

Regards,
Duncan

Screen capture showing values and plot, .psu file, About screen, Windows properties screen.

This sounds quite bizarre, I'm fairly sure I would have put some minimum and maximum limits on values to prevent "issues" so it's quite odd that negative values can go in. Could you please let me have the following:

• Reply to the email with a screen dump, or the .psu file so I can have a look
• Details of the build number from Help | Abpout
• Details of the OS you're using

In the interim, I'll have a look at this end to run some checks. Thanks very much.

Regards,
Duncan

I had a sim would not resolve. "Timestamp has fallen..."

On re-entering I realized I had entered C1 as "-0.5u"... negative!

The font used on my installation makes this very hard to see.

While a negative capacitance has some meaning in theory, in context of PSDU users this is almost certainly a finger-fumble.

I dunno if it is worth adding a sanity/censor-check to refuse negative caps. I have been using PSDU for a decade+ and I think this is the first time I made this screw-up.

Hmmm, negative resistor---- ah, it accepts the input then blows-up at 5,102V. Which is probably correct: the neg-resistor is powering the circuit, just as neg-R repeaters power-over telephone line loss.

Thank you Duncan and Paul for the guidance. I now downloaded the latest build 76 from the io Files folder.

Regards
Luis

On 11/3/2022 4:08 PM, Greenpitu@... wrote:

I am getting this error when trying to download the official windows executable from

Isn't that an old version?

The current versions seem to be on groups.io under the 'Files' tab.

/g/duncanampspsud/files/psud2_windows

There appear to be some issues with the server, I've just been on chat to support.?

The files stored at??were just legacy files anyway and are way out of date so I've updated the page to reflect this.

All downloads can now be found at the Files area on this groups.io page which is on the left hand bare if you are accessing this via the web, or at the following link if you are reading this by email:?/g/duncanampspsud/files

Regards,
Duncan

Thanks for the help so much.

So the question I am unsure of is what makes a good transient response compared to another, I sort of felt like the speed (tightness of the curve) to return to the steady state is desirable to be as rapid as possible; within the context of acceptable ripple and the lack of ringing / misshape of the profile curve or the output voltage. Is this correct and should I also look for ringing in other areas of the circuits?

This is the PS circuit I am trying to model, with approximately the design I am moving towards btw. The 6c45 takes voltage from halfway up the doubler of 2 x 5u4GB rectifiers, and I have struggled a bit to have confidence this is modelled correctly.