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Power Supply Schematic - STEPS or TREAD

post #1 of 24
2/20/12 at 1:15pm
Thread Starter 

Hey all, I searched and couldn't seem to find it. I know Tangent removed the schematics for the STEPS and TREAD from his site, but does anyone still have the schematic? I'm trying to build an original Millet and need a power supply. Is there any other that you would recommend over the STEPS or TREAD?

Thanks a ton!

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post #2 of 24
2/20/12 at 2:57pm

Amb sigma11...

 

use the wayback machine to find it... (tread)

 

http://www.archive.org/web/web.php

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post #3 of 24
2/20/12 at 5:19pm

σ 25 seems nice if you cant get/dont want to build a STEPS/TREAD.

I dont think that lack of adjust ability will matter for a millet hybrid

 

http://www.amb.org/audio/sigma25/

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post #4 of 24
2/20/12 at 8:09pm
Thread Starter 

I've built a σ 25 before. I don't know why I didn't think of it before. For some reason, I was thinking the σ 25 was 12V only. Great! Thanks, guys.

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post #5 of 24
2/20/12 at 8:18pm
Thread Starter 

Anyone have any experience with Pete Millett's new(ish) regulator?

http://www.pmillett.com/DC_filament_supply.htm

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post #6 of 24
2/20/12 at 9:02pm

I would assume that the Millet Filament supply will work with some resistor tweaks outlined on that page. 

 

An all millet millet hybrid could be kind of neat!

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post #7 of 24
2/20/12 at 9:35pm
Thread Starter 

How very meta...

I was thinking the same thing.

Though, the overwhelming simplicity of the TREAD (or the similar σ 25) is appealing.

I was considering, that since I have no board and would be building this on protoboard, I might just increase the wattage of those resistors, instead of necessarily increasing their resistance.

 

Also, the TREAD is very appealing given Tangent's testing of the ripple.

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post #8 of 24
2/20/12 at 9:40pm

You can find the TREAD schematic in the lm317 datasheet, more or less. 

 

I don't think that the millet hybrid is really dependent on a super high quality power supply, so, just build an lm317 regulator on perfboard with a good, fast capacitor (oscon or similar solid polymer) on the output and the additional capacitor across the reference leg. 

 

Like i said, it's in the datasheet. or was it the application notes. At any rate, it's no secret. 

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post #9 of 24
2/20/12 at 9:42pm
Thread Starter 

I already found the TREAD schematic. I probably should have said that earlier! Thanks!

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post #10 of 24
2/22/12 at 12:25am
Thread Starter 

Almost done with my BOM over at Mouser. Last problem, Mouser won't sell the 1N521, which is the current regulator for the tubes, in quantities under 2500. Is there another part anyone knows of that works as well? I've seen some people using resistors, with mixed results. Others use a transistor/resistor. Anyone have any experience?

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post #11 of 24
2/22/12 at 5:58am

Here is a LED CCS to replace the CRD:

 

CCS.png

 

I hope that is enough information

A suitable LED would be 630-HLMP-D101 on mouser

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post #12 of 24
2/22/12 at 8:11am
Thread Starter 

That would work! I should match transistors, right?

 

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post #13 of 24
2/22/12 at 8:32am

Yes, you should match the transistors for best performance.

You can use a common LED between both channels.

If you use two LEDs, they will need to be matched as well.

 

Optionally, you can make R2 adjustable.

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post #14 of 24
2/22/12 at 8:35am
Thread Starter 

Couldn't I eliminate everything and just make R2 a varisistor?

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post #15 of 24
2/22/12 at 8:54am

No

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