cheap 12v linear power supply

gychang · « **Reply #120 on:** 17 Dec 2014, 08:27 pm »

Quote from: Odal3 on 17 Dec 2014, 04:58 pm

Almost forgot, there is a lot if humming from my Astron. Can hear it when no or very soft music. No difference if connected to the amp or not. Added woodblock underneath made it worse, and added some weight to the top took away some of the lower hum but made it more high pitched instead. There is no diff if put on a concrete floor or if removing the top metal cover so I can see the internals. What do you think is causing this and whats the best and easy fix?

similar prob I had with ten-tac 937 PS, initially I connected to my chip amp on the furniture, I thought it was a hum from PS, but finally I moved the setup to my garage with built-in bench and no more noise, it was the furniture vibrating also tightened up the PS cover screws. Now it is dead quiet..., may not be your problem though...

gychang · « **Reply #121 on:** 17 Dec 2014, 08:31 pm »

Quote from: Salis Audio on 17 Dec 2014, 05:54 pm

Speaker wire, gychang

so speaker wires will need to be connected the usual with Red/White plus shield-amp ground?... sorry for the newbie questions.

Folsom · « **Reply #122 on:** 17 Dec 2014, 08:35 pm »

Yes.

Shield is grounded to DC - , the circuit ground. It is not attached to speakers. The two wires inside cable are the + and - connected to output of amp and speakers. If you're using Belden 8412 it's white and black colors, but just use the white as black.

The unwrapped shield is big when you twist it together, which is why I suggested connecting a smaller wire from it to run to DC - .

lacro · « **Reply #123 on:** 17 Dec 2014, 09:44 pm »

Quote from: Odal3 on 17 Dec 2014, 04:58 pm

Almost forgot, there is a lot if humming from my Astron. Can hear it when no or very soft music. No difference if connected to the amp or not. Added woodblock underneath made it worse, and added some weight to the top took away some of the lower hum but made it more high pitched instead. There is no diff if put on a concrete floor or if removing the top metal cover so I can see the internals. What do you think is causing this and whats the best and easy fix?

Couple of questions: Is your case in perfect un-bent condition? Many of these very heavy Astron's have been dropped either by owners or in shipment. The one I got was indeed dropped which had bent the bolts holding the very heavy transformer, causing it to contact the case which caused a hum. I took the transformer out, straightened the bolts, and using a body hammer and dolly brought the case back into correct shape. Re installed everything, and no more hum

You may want to check to see if the bolts holding the transformer are all tight. These big transformers are going to hum, but you shouldn't hear it without laying your ear on the case.

Odal3 · « **Reply #124 on:** 20 Dec 2014, 04:22 am »

You nailed it. Yes, there was some shipping damage. So I tightened all the screws, and slightly pushed some of the cables to the side from the sides. This reduced it a lot, and once I added some electrical tape in the lining where the cover touches the base (can't see it from the outside), it took away most vibration and hum, and I can only hear it when I put the ear up close.

Thank you for the help!!!

gychang · « **Reply #125 on:** 22 Dec 2014, 09:03 pm »

Quote from: rhing on 9 Sep 2014, 11:19 pm

We opened up his Astron RS-12A, and I was shocked to see this little 18,000uF/25V CDE electrolytic cap inside. Granted this cap has similar capacitance to the Kemet (formerly Rifa) PEH200 cap in my Astron RS-12A, the ESR is triple what the Kemet cap is specified at.

If you have a stock Astron power supply and you know how to work safely with AC mains power, you owe it to yourself to upgrade the caps.

I have a stock RS-7A (got from ebay) and wonder if this can be improved as done here, more information will be appreciated.

ljbrandt · « **Reply #126 on:** 31 Mar 2019, 06:40 am »

Resurrecting an old thread, but I recently bought a Astron SL-11a to power two chip amps that I'm intending to use for vertically bi-amping my speakers. Question is, I'm having a hard time finding a "decent" DC power cable with a 2.1x5.5mm barrel (into amps) and lugs/spades/rings (onto Astron). Not looking for small gauge flimsy wire, nor something more than $20/cable. Not really a DIYer either.

- thanks in advance for any suggestions.