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Projects => Tech Help - Projects Page => Topic started by: angrykoko on February 21, 2014, 02:37:02 PM

Title: Wall wart (PSU) for tube amp use
Post by: angrykoko on February 21, 2014, 02:37:02 PM
I"m wondering if the wall wart I bought has short detection?

I've been working on a sub mini tube amp, just got it done but wont power up... heaters are not glowing even.
Noticed that the wall wart has a little led on it that goes out when I turn the amp power on....

Long story short, the heaters are directly connected to the power and run to ground.  I'm wondering if this PSU has a short detection safety switch and cant use it  to power a tube amp.   Is a built in safety feature like this a thing?  could it possibly be what's plaguing me?

It's a qsee QS12500MA (it's for cameras, cheep only 9.00)

Anyone?
Title: Re: Wall wart (PSU) for tube amp use
Post by: angrykoko on February 21, 2014, 05:01:10 PM
Yep, it was the power supply.
Found another around, and it worked for a min but now I have some.real debugging to do.
Title: Re: Wall wart (PSU) for tube amp use
Post by: jubal81 on February 21, 2014, 08:13:36 PM
Sounds like an interesting project. Which design did you use?
Title: Re: Wall wart (PSU) for tube amp use
Post by: angrykoko on February 22, 2014, 04:24:12 AM
Superfly  http://www.diystompboxes.com/smfforum/index.php?topic=78302.0 (http://www.diystompboxes.com/smfforum/index.php?topic=78302.0)

Need to debug it, tone pot not working and the mosfet in the power section got crazy hot (hopefully not dead).
I'll post pics when I get it going the next couple of days.
Title: Re: Wall wart (PSU) for tube amp use
Post by: angrykoko on February 23, 2014, 02:39:17 PM
Grr.. boiled my inductors innards.
Time to play the waiting game for a mouser shipment.
Title: Re: Wall wart (PSU) for tube amp use
Post by: jubal81 on February 23, 2014, 03:07:03 PM
Ugh. Bummer. I've been reading up on that 555 SMPS and it seems at least a 2A inductor is recommended.
Title: Re: Wall wart (PSU) for tube amp use
Post by: angrykoko on February 23, 2014, 04:54:53 PM
really?  damn, talk about "should have posted before I ordered".
The one I"m using is max 670ma (the same as what Frequency Central used on his).

I have other issues in my build though;  I swear I was not drinking when I put this one together but.. wow.. I have no excuse for some of it (looking at it again).
Title: Re: Wall wart (PSU) for tube amp use
Post by: angrykoko on March 05, 2014, 04:19:05 PM
IT'S ALIVE!!
I'll do a build report once I finish.  Very cool little amp, not very loud but loads of fun so far noodling around with it.
Have it pushing a single Vin 12.

(https://lh4.googleusercontent.com/-qcIrxB6QUDg/Uxe8iDmesbI/AAAAAAAAA2E/Gq7gdbVgx7o/w951-h536-no/2014-03-05)
Title: Re: Wall wart (PSU) for tube amp use
Post by: jubal81 on March 05, 2014, 07:42:19 PM
Wow. Very, very cool. Are you going to be able to give us some sounds?
Title: Re: Wall wart (PSU) for tube amp use
Post by: angrykoko on March 06, 2014, 04:00:59 AM
Quote from: jubal81 on March 05, 2014, 07:42:19 PM
Wow. Very, very cool. Are you going to be able to give us some sounds?

Sure...  except in my head I"m jimmy page.. but to the rest of the world I sound like henry kaiser and his wang bar.
But at least I have my electrons in a crystal lattice - all Dumble style  :P

It'll be sometime late next week till I get back to this.. Boyscouts "Space Camp" weekend (boo ya!!) this weekend.

Cheers!
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