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Can someone please do a check run on psud2 for me?

173.185.144.238
Posted on January 3, 2017 at 15:37:58
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 I am getting what looks like a weird ripple for the power supply the way it is loaded with the 813's. Wondering if I am doing something wrong. Data is

full wave tube 5ar4 rectifier

power transformer has a half no load output of 432.8 vac per Hammond (278x)

first cap is 2.2uf

first choke is 10 H/65 ohms (Hammond 193M)

second cap is 94 uf

second choke is 5H/55 ohms

third cap is 94 uf

load is 160 mA based on measuring an average of 40 mA plate current across the cathode resistor (355vdc/750 ohm cath resistor)

When I run this I get a low value for the ripple of about 2 or 3 mV, but a very high frequency that make the band quite thick looking. Never have seen this before. Am I doing something incorrectly?

 

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RE: My Take - with a Step Load, posted on January 23, 2017 at 16:13:24
Mike C
Audiophile

Posts: 1074
Location: Essex
Joined: November 23, 2000
 My personal view here, which has given me good results in several units.
I was pointed in this direction by Jeff and it's based on John Swenson's work. I suggest you look up his posts about PSUD.
Note: I have not gone as far as John and Jeff in terms of LSES but I may try that sometime. What I have used is their methods of step load analysis, and for me it really works well.

The method is to edit the current load and specify a step load, with the step about 10% or so more. I make it come in after 15.1 seconds. Then observe the change of output voltage after the step (specify 'after a reporting delay' of 15 seconds).
If there is oscillation, it's a *poor* PSU which is likely to sound harsh.
If the drop is steady without oscillation but slow, the sound may be somewhat slow and verging towards boring, probably with poor leading edges.

The ideal (I am told, and believe) is a fast clean drop without oscillation, with a very slight overshoot. Ideally it stops dropping after about 0.06 seconds.

This cannot be achieved with large capacitors, so to get reasonably low ripple requires a 2 stage PSU.
My best SET amp uses a cLCLC supply tuned to give this response and it sounds *very* good, with fast clean leading edges and rhythm and dynamics enough to satisfy a diehard Naim fan friend.

Now to your PSU.
It is accepted practice to increase the C and/or L values as you go along a multi stage PSU. Your use of 10H and 5H in that order contravenes this and is most likely the reason for the oscillation on startup.

I modelled it with a step load 160mA to 180mA after 15.1 sec and this clearly shows 5 oscillations after the step.

Swapping the chokes over (5H then 10H) gives an improvement, 3 oscillations, but taking 0.3 seconds to get close to final value.

Changing C2 to 30uF ... now it gets interesting!
Smooth drop, no oscillation, no overshoot, getting there in just under 0.2 seconds; not too bad a PSU. About 19mV of ripple (analyse for say 900mS after delay of 14 seconds to get the ripple).

If you can tolerate more ripple, you can go further.
Change C3 to 50uF and now there is slight overshoot, no oscillation, and a response of 0.1 seconds; reasonable.

Change C3 to 40uF and it's ugly! Definite oscillation. Now you have to play with various values to try to get what you want.

With just a bit of playing I found good results with:
4uF; 5H 55 ohm; 20uF; 10H 65 ohm; 40uF
Smooth drop, no oscillation, just detectable overshoot, and response
under 0.1 sec (looks like about 0.75 sec). A very good PSU IMHO though I expect a few comments on this ...

I suggest you try these models and see if you can do better; also check the ripple and see if it's low enough for your needs.

I hope this helps; I repeat, it has really worked for me.

Regards
Mike
(in the freezing UK)

 

stop monkeying with psud2 hoooey, its never right, posted on January 3, 2017 at 18:48:02
elblanco
Audiophile

Posts: 3486
Joined: August 20, 2004
 and do it the

 

The right way, posted on January 12, 2017 at 07:57:31
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
 WOW !!! Imagine !! A graduate EE adding a 200 Ohm resistor in series as the filter to the Finals, and then, using an additional 108 Ohms of DC resistance to the two chokes !! 308 Ohms of UGLY series resistances.

And look, a 'C" input filter !! Oh well.

I liked the graphs and such, but the UNconcious EE author's suggested design will work and sound like doggie - doo.


Jeff Medwin ...... a Business Major...... Penn State.... 1966

 

RE: stop monkeying with psud2 hoooey, its never right, posted on January 4, 2017 at 03:02:42
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 You go right ahead on it sport, that's not for me. psdu2 has always worked fine for me until I switched to windows 10. It is not yet set up for that apparently. Good thing I did not sell my windows 98 laptop.

 

RE: stop monkeying with psud2 hoooey, its never right, posted on January 4, 2017 at 06:43:06
Triode_Kingdom
Audiophile

Posts: 10044
Location: Central Texas
Joined: September 24, 2006
 PSUD has significant limitations when it comes to designing a supply for audiophile use. It's nice for quickly predicting ripple content and loaded/unloaded output voltage, but not much else. Many "old-school" designs perform well in those two areas, but will color the sound. If you want to design power supplies that really perform, you'll need to learn SPICE.



 

RE: stop monkeying with psud2 hoooey, its never right, posted on January 4, 2017 at 06:44:37
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 I get a headache just looking at that link! I can live with psud2, at least for now.

 

RE: stop monkeying with psud2 hoooey, its never right, posted on January 4, 2017 at 07:02:40
Triode_Kingdom
Audiophile

Posts: 10044
Location: Central Texas
Joined: September 24, 2006
 I wasn't referring to the link, but to SPICE, which is a means of modelling circuitry using a computer in order to make theoretical measurements and performance predictions. SPICE was very expensive software not generally available to hobbyists until Linear Technology began to offer a version for free, named LTspice.

PSUD is almost certainly using some version of SPICE internally, but with a simpler and more limited user interface. Just as one example of its limitations, PSUD can't tell you the output impedance of a power supply over frequency. I consider this a critical characteristic, and I won't build a supply now without analyzing it in SPICE.


 

RE: stop monkeying with psud2 hoooey, its never right, posted on January 4, 2017 at 14:48:00
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 I'll try to take a look at it, but I have a feeling most of it is going to be more complicated than I like to get.

 

RE: stop monkeying with psud2 hoooey, its never right, posted on January 4, 2017 at 18:55:54
Triode_Kingdom
Audiophile

Posts: 10044
Location: Central Texas
Joined: September 24, 2006
 Start with something simple. Stick a voltage source on the page and ground the bottom. Then wire two series resistors across it. Tell the software to RUN. When it's done, look at the voltage and current around the circuit. It's a small step from there to viewing RC time constants, LC filters, power supplies, tube amplifiers etc. Not for everyone, I know, but it's an extremely useful tool.







 

RE: stop monkeying with psud2 hoooey, its never right, posted on January 5, 2017 at 02:57:22
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 I might be able to handle that.... : 0 ). Thanks for the info.

 

Nice Link!, posted on January 3, 2017 at 18:54:12
Triode_Kingdom
Audiophile

Posts: 10044
Location: Central Texas
Joined: September 24, 2006
 Almost everything you need in one place! That plus a copy of LTspice will get it done.

 

Can this software be used on Windows 10....., posted on January 3, 2017 at 18:10:51
Cougar
Audiophile

Posts: 4574
Location: SoCal
Joined: June 25, 2001
 Without any issues?

 

RE: Can this software be used on Windows 10....., posted on January 5, 2017 at 09:09:16
tweakydee
Audiophile

Posts: 432
Location: VA
Joined: February 27, 2004
 Yes, I recently downloaded the latest version and it works with no issue on Windows 10.

 

RE: Can this software be used on Windows 10....., posted on January 5, 2017 at 15:41:30
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 Maybe for you, but not for everyone. I had issues using it on my brand new laptop with windows 10. Gave different results than other folks were getting with older OS. When I switched to my old laptop with NT, it was ok again. If you look at the website, windows 10 is not among the OS's listed as working with it.

 

RE: I've had no issues n/t, posted on January 3, 2017 at 18:39:03
bean
 z

 

RE: I've had no issues n/t, posted on January 4, 2017 at 03:12:14
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 You may not have hit the right combo yet. This is the first time this has happened to me.

 

RE: where I HAVE had issues - before and after W10, posted on January 4, 2017 at 14:26:14
bean
 it seems like sometimes a well-worn model (where I have made multiple changes) has a "memory", and changes don't do what I expect.

If I close such a model down and re-enter the same data a fresh new model, I get different, expected results.

I just figure that it is par for the course with hobby freeware.

 

maybe not, posted on January 3, 2017 at 18:34:47
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 Just went to the website and windows 10 is not one of the operating systems listed. Ah #$%&*, now what do I do? May have to dust of my old laptop and load it on there.

 

RE: Can this software be used on Windows 10....., posted on January 3, 2017 at 18:19:48
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 Maybe not. See my reply to TK below. This is a question I really need an answer to.

 

RE: Can someone please do a check run on psud2 for me?, posted on January 3, 2017 at 18:04:11
Triode_Kingdom
Audiophile

Posts: 10044
Location: Central Texas
Joined: September 24, 2006
Is this it?






 

RE: Can someone please do a check run on psud2 for me?, posted on January 3, 2017 at 18:18:00
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 Opps. I forgot to say the resistance of the power trans is 95 ohms. Everything else is the same though. I got a much different chart, with a rounded corner at 411.8 vac. I tried changing my values to yours and I still don't get the same peak at the start that you do. How is that possible?

 

OS: Windows 95, Windows 98, Windows 2000 or Windows NT.e?, posted on January 3, 2017 at 18:40:58
Triode_Kingdom
Audiophile

Posts: 10044
Location: Central Texas
Joined: September 24, 2006
 Are you using one of those? This is an old program Vinnie, and I guess it's not worth the author's time to recompile it for newer systems. I use PSUD2 (2.0.2) with Win XP and consider myself lucky that it runs.








 

RE: OS: Windows 95, Windows 98, Windows 2000 or Windows NT.e?, posted on January 4, 2017 at 15:52:42
Cougar
Audiophile

Posts: 4574
Location: SoCal
Joined: June 25, 2001
 TK, Thank You for that bit of info. I still have my older computer with Windows XP, so this should work on that with my other audio softwares.

 

might, posted on January 4, 2017 at 14:44:22
elblanco
Audiophile

Posts: 3486
Joined: August 20, 2004
 give

 

RE: OS: Windows 95, Windows 98, Windows 2000 or Windows NT.e?, posted on January 4, 2017 at 04:45:09
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 Loaded it up on an old thinkpad I got with windows nt to run SE CAD and it seems to be doing ok there. That's two programs I have to run on ancient software now or not at all. Oh well, at least I can use it. It is a very handy program for quickly doing what ifs, and it also has been fairly accurate for me in the past. I would hate to lose it.

 

RE: OS: Windows 95, Windows 98, Windows 2000 or Windows NT.e?, posted on January 4, 2017 at 03:06:23
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 I have an old lap top with windows 98, guess I will have to try that. Blah!

 

RE: Can someone please do a check run on psud2 for me?, posted on January 3, 2017 at 16:24:25
used-hifi
Audiophile

Posts: 1100
Location: Surprise AZ
Joined: March 18, 2003
 Don't use the CC use just a resistor for the load try that.


Lawrence

 

RE: Can someone please do a check run on psud2 for me?, posted on January 3, 2017 at 18:21:01
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 How do I determine the value of a resistor that is equivalent to the four 813 tube currents?

 

OOOOOOOOOOHHHHHHHHHHMMMMMMMMMMSSSSSSS LAW --NT-, posted on January 3, 2017 at 18:46:16
elblanco
Audiophile

Posts: 3486
Joined: August 20, 2004
 .

 

give the drama queen role a rest already huh? nt, posted on January 4, 2017 at 03:13:55
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 nt

 

RE: Can someone please do a check run on psud2 for me?, posted on January 3, 2017 at 16:08:56
sony6060
Audiophile

Posts: 1465
Location: USA
Joined: August 8, 2014
 Looks good to me. Tried to save image as a picture, but did not save.

 

RE: Can someone please do a check run on psud2 for me?, posted on January 3, 2017 at 18:24:49
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
did you get a really heavy saw tooth ripple?

 

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