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PSUDii tips [message #8792]

Mon, 31 January 2005 15:56

PakProtector
Messages: 935
Registered: May 2009

Illuminati (2nd Degree)

Hey-Hey!!!,
I just got the output voltage tuning done for the filament supplies on my new linestage design. L-C and L-C-R-C. They matched PSUDii sim predictions to a few percent.

Critical stuff is the input voltage and component DC resistance. The input voltage should be the unloaded voltage measured when line voltage is applied and the winding in question is otherwise unloaded.

DC resistances of just the secondary have been acceptable. With the step-down ratios encountered with filament supplies, the small primary resistance appears even smaller.

The ESR of the capacitors seems to make very little difference. The data is either available from the manufacturer or guess. Tens of mOhms to a tenth of an Ohm seems to be a reasonable bet for a 'lytic. Go for the minimum allowable for good film caps.

regards,
Douglas

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Re: PSUDii tips [message #8793 is a reply to message #8792]

Mon, 31 January 2005 16:28

Manualblock
Messages: 4973
Registered: May 2009

Illuminati (13th Degree)

I am confused again. Reading the Radiotron 3rd ed. It appears to say input voltage rating of power transformers should be made with the secondary fully loaded. What am I doing wrong if I may ask.
Regarding Guenievere; I have printed out three different filament schematics. We are using the filament windings on the power trans; not the radio shack 12v trans is that correct?
And I thought Golf was hard.

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Re: PSUDii tips [message #8795 is a reply to message #8793]

Mon, 31 January 2005 16:55

PakProtector
Messages: 935
Registered: May 2009

Illuminati (2nd Degree)

Hey-Hey!!!,
I suppose it depends on how the model works. I have no details about the numeric methods PSUD uses. The best results come out when I put in the numbers from the measurements I described.

On Guinevere, I had planned on using the RS trans for a seperate DC supply. Not too expensive and keeps things a bit seperate. The charging current spikes from a cap input filter tend to spread around and infect things. Some small resistive/capacitive filtering on the primary side of the filament TX ought to keep the B+ quite clean.

If I try Golf sometime, and after hitting that ball, ever find it again, I'll put it back in my pocket, consider myself lucky and call it a day.
regards,
Douglas

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Link to heater info request [message #8796 is a reply to message #8793]

Mon, 31 January 2005 17:17

colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas

Illuminati (3rd Degree)

Follow thread. I hope this helps.....Colin

http://audioroundtable.com/GroupBuild/messages/252.html

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Re: PSUDii tips [message #8797 is a reply to message #8795]

Mon, 31 January 2005 17:24

Manualblock
Messages: 4973
Registered: May 2009

Illuminati (13th Degree)

I see you have the game of Golf down pretty accurately. Thats what I should have done.
Please; so we are using the RS; LM 317 set-up for the filament supply on the Rec tube, is that correct? I really have three diff. schematics in three diff. styles. I am trying to get this down before the trans arrives. The PSUD response; verrry cryptic. I will try to decipher.
I am stuck on the model and the method. Your posts are really geared towards one who knows. That ain't me. Thats why I am trying to follow in the textbooks but we come to a logjam occasionally.
Still thanks for responding so quickly, that is very kind.

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