SimpleSE PSUD II B+

[squiffiness]

Hello to all,

New to the TubeLab Forums. Nice to be here. Have ordered a SimpleSE board and am considering various Edcor power transformers to suit.

I would like to do a standard build but have it flexible enough to support all of the tubes on TubeLab's simulation pages (i.e. EL34, 6L6GC, KT88 and 6V6) as well as possible tube rectifier swaps, so more current from the Transfo is required from the 5V supply (i.e. > 2A)

However, have to start somewhere.

Would the Edcor XPWR002-120 suit? Rating:

720VCT (360-0-360) at 220mA
60V at 800mA
6.3V at 7A and
5V at 4A

And, lastly, does anyone have a PSUD II file for modeling the power supply that they could furnish to get me started. so I could determine the B+ voltage after cap C1?

Merci beaucoup.

Squiff

[squiffiness]

Originally Posted by squiffiness

Hello to all,
And, lastly, does anyone have a PSUD II file for modeling the power supply that they could furnish to get me started. so I could determine the B+ voltage after cap C1?

Really looking to learn on Duncan PSUD II. Does anyone have a PSUD model file I could use as a basis to be sure I am starting correctly?

Ideally, one that uses the 5AR4 and stock values for C1, C2 and the optional power supply choke and auxiliary cap?

If this were gears and pistons, this mech. eng. could figure it out. Electrons puzzle me a bit when my last formal electronics training was 25 years ago in college.

Danke.

[rknize]

Mine is attached. You'll want to tweak L1 and C2.

[squiffiness]

Originally Posted by rknize

Mine is attached. You'll want to tweak L1 and C2.

Thanks for that...will play with it this aft when I get home from work.

Going to try a different Edcor XPWR unit (002-120) which is 720VCT on the secondary side and pumps more current for the 6.3V and 5V heaters.

[squiffiness]

Originally Posted by rknize

Mine is attached. You'll want to tweak L1 and C2.

Russ,

I opened the file and altered the settings for my Transfo as follows using the "Offload Voltage Calculator"

Nominal Output Voltage = 360 (corresponds to 720 VCT for the Edcor I am considering)

@220 mA available from the secondary at 5% regulation (assumed)

The offload voltage calcs to 378 V (RMS) and a Z of 81.8 ohms.

For L1, I put in the Edcor choke values of 5H and 58 ohms (their data).

C1 I left at 47 uF as in the BOM.

C2 I am assuming comes from the values of C2 and the Aux Motor Run Cap in Parallel to ground summing. You have 220 uF but the BOM value is 120 uF and the motor run unit I might get is 40 uF for 160 uF in total.

Does what I have input sound correct?

Can you explain your current draw of 150mA followed 5 seconds later by 3.5mA in your model?

The sim gives me a voltage at I1 (the current draw) of 437V. Sound correct.

Your help is really appreciated.

Squiff

[squiffiness]

Originally Posted by squiffiness

Can you explain your current draw of 150mA followed 5 seconds later by 3.5mA in your model?

Sorry...followed TWO seconds later by 3.25mA draw.

[rknize]

Your input values sound reasonable. The 220uF is because that is what I used on my PCB (there is room for one). Your B+ is coming in a little high because of the lower DCR of your choke. That is OK, just in case you are wondering.

150mA is the nominal current draw. 3.5mA is the "unloaded" current draw before the tubes warm up. I guess I saved it when it was swapped. I test it both ways just to see the transient behavior (checking for ringing at the transition, watching the behavior when the switch is flipped while the tubes are hot, etc).

[squiffiness]

Originally Posted by rknize

Your input values sound reasonable. The 220uF is because that is what I used on my PCB (there is room for one). Your B+ is coming in a little high because of the lower DCR of your choke. That is OK, just in case you are wondering.

150mA is the nominal current draw. 3.5mA is the "unloaded" current draw before the tubes warm up. I guess I saved it when it was swapped. I test it both ways just to see the transient behavior (checking for ringing at the transition, watching the behavior when the switch is flipped while the tubes are hot, etc).

Russ,

Am I approaching C2 correctly then by summing C2 and the Auxiliary Motor Run Cap?

Or, is the CLC filter in PSUD II intended to ONLY be C1, then L1, then C2?

Lastly, just want to confirm that I should take the voltage across the current load "I1" as the B+ voltage.

Thanks for the support.

Brad (i.e. Squiff)

[boywonder]

Originally Posted by squiffiness

Russ,

Am I approaching C2 correctly then by summing C2 and the Auxiliary Motor Run Cap?

Or, is the CLC filter in PSUD II intended to ONLY be C1, then L1, then C2?

Lastly, just want to confirm that I should take the voltage across the current load "I1" as the B+ voltage.

Thanks for the support.

Brad (i.e. Squiff)

If you want to run a motor run cap in parallel with C2 on the PCB, then sum the uf values of the two caps for the value of C2 in the PSUD model.

Yes, the B+ voltage is the voltage across I1 in the model.

[squiffiness]

RKnize/BoyWonder:

OK...so I have a running model here and just a few minor remaining questions before I settle on an operating point with my chosen Power Transformer.

1) For the Power Transformer Primary -- does this need to be input and the default 240V swapped for my 120VAC wall voltage?

2) For the secondary I am modelling the Edcor XPWR002-120: I have a nominal voltage output of 360-0-360 at 220mA -- Do I use the "Offload Voltage Calculator" or the "Source Impedance Calculator" or both/neither?

3) What impact will the Equivalent Series Resistances for the capacitors and the choke have on the simulation?

4) In Russ' model he has a stepped load of 150mA followed 2 seconds later by a 3.25 mA load. Should this be reversed to present a "warm up" load followed by all the tube currents (e.g. 2xEL34 at about 75mA per plus the 12AT7 of about 10mA rated)?

As this exercise with the SimpleSE is as much learning for me as it is listening enjoyment, I am attempting to use PSUD II to help finalize a BOM including a few 5W resistors to allow easier swapping in of tubes just like RKnize did, but not quite as elaborate, say, a 3 position, 2 pole toggle to allow 3 values, one for each tube type as on TubeLab's "Tubes and Transformers" page.

Thanks,

Brad