Does anyone knows where to get a 12V DC regulated power supply that will have no AC hum? It is to be used on an headamp...
and how much does it costs? anyone has it here?
Thanks...
Regulated Power Supply, Adapter., 12V DC, no hum
Regulated Power Supply, Adapter., 12V DC, no hum
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Oct 20 2010, 01:50 PM, updated 14y ago
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#1
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Junior Member
410 posts Joined: May 2010 |
Does anyone knows where to get a 12V DC regulated power supply that will have no AC hum? It is to be used on an headamp...
and how much does it costs? anyone has it here? Thanks... |
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Oct 20 2010, 01:56 PM
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#2
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Senior Member
8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
There are of course commercial units, the better ones going to cost a lot of $$$ on your part. Other than Jalan Pasar, KL, I can't think of anywhere else.
If you are good, there are power supply kits available. With a good transformer and casing, it can be built cheaper with better parts, equal or better performance with equivalent commercial units. |
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Oct 20 2010, 03:55 PM
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#3
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4,234 posts Joined: Nov 2004 |
Hum is usually EMI induced. Make sure transformer is well shielded.
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Oct 20 2010, 11:41 PM
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#4
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410 posts Joined: May 2010 |
but does anyone sells it here?
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Oct 21 2010, 12:27 AM
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#5
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4,234 posts Joined: Nov 2004 |
just go to a shop
and ask for a linear regulated 12VDC adaptor. Teletron Malaysia makes decent wallwarts, been using them for my designs since long ago. |
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Oct 21 2010, 10:06 AM
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#6
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
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Oct 21 2010, 10:25 AM
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#7
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8,046 posts Joined: Jan 2003 |
Seen Teletron stuff for so long, which I feel this company really need to revamp their quality and looks. Its not really cheap but they should at least improve to a more upmarket look. It still feels like some backyard cottage industry product. Sad!.
A good PSU would be based on low noise LM317/LM337 DC regulation and neccessary AC filtering on the primary side. I think I saw some DIY kits on this on Ebay. I was thinking of building one for my phono stage. |
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Oct 21 2010, 10:55 AM
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#8
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Now that you've mentioned it, yeah their products certainly looks the same since I frequent Jalan Pasar when I was still a school boy!
Yes good power supply starts with a good AC filtering.. any hint/clue with regards to ebay kits? Something like this? http://cgi.ebay.com/DIY-LM317-Variable-DC-...=item27b273616c http://cgi.ebay.com/DC-Power-Supply-0-30V-...=item4aa55c2a82 This post has been edited by jazzy939: Oct 21 2010, 11:01 AM |
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Oct 21 2010, 10:30 PM
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#9
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410 posts Joined: May 2010 |
ok, you guys suggest to get a AC-DC Teletron, Linear Regulator...
so, how is it? good enough? got hum? price range? wanna get around 12V-12.5V 1A-1.5A... |
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Oct 22 2010, 06:54 AM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
You go and survey lah what they have on the shelves.. Little Ghost use them, so I guess they're 'good enough'. I don't as I build all my PSUs.
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Oct 22 2010, 09:08 AM
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4,234 posts Joined: Nov 2004 |
QUOTE(santik @ Oct 21 2010, 10:30 PM) ok, you guys suggest to get a AC-DC Teletron, Linear Regulator... as i've previously said, HUM is usually caused by unshielded transformer. It has very little to do with the next stage regulation.so, how is it? good enough? got hum? price range? wanna get around 12V-12.5V 1A-1.5A... |
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Oct 22 2010, 09:49 PM
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410 posts Joined: May 2010 |
so, it's about the transformer... ok... so, what can I do about it?
how to shield it? I got myself EKK brand regulated 12V AC-DC adapter... it has some faint hum... what can I go around it? |
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Oct 22 2010, 09:50 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Little Ghost, its your call!
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Oct 22 2010, 10:38 PM
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4,234 posts Joined: Nov 2004 |
QUOTE(santik @ Oct 22 2010, 09:49 PM) so, it's about the transformer... ok... so, what can I do about it? try separating both the devices as far as possible, see if the problem goes away.how to shield it? I got myself EKK brand regulated 12V AC-DC adapter... it has some faint hum... what can I go around it? What is the headamp used? |
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Oct 22 2010, 10:47 PM
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410 posts Joined: May 2010 |
it's Audio Technica M35.
separate both devices? you mean the amp and the headphones? I got it from Maplin. Normally i get my stuff from nixie but they can't find it... I went to the shop beside Nixie... they don't have it and don't really understand what is it... they showed me a 12VDC switching power supply... Added on October 22, 2010, 11:04 pmoh yeah, there is not ground on the adapter... only a plastic ground pin for ease of plugging in... live and neutral is metal only... Added on October 22, 2010, 11:20 pmis not really a hum... but somewhat hissing... 'ssssssss' very faintly... This post has been edited by santik: Oct 22 2010, 11:20 PM |
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Oct 22 2010, 11:27 PM
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4,234 posts Joined: Nov 2004 |
If it's not a hum, then it's not a transformer induced noise.
You mentioned "SWITCHING" PSU. These type of PSUs only do well in terms of efficiency and they are not meant for low noise applications. They are noisy. You need a "LINEAR" regulated PSU. You also need to double check which type of PSU you're using, I suspect the one you're having is either NON-regulated or SWITCHING PSU. |
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Oct 23 2010, 01:01 AM
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410 posts Joined: May 2010 |
the one I am using is regulated PSU.
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Oct 23 2010, 02:25 AM
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1,293 posts Joined: Mar 2005 From: Ladang |
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Oct 23 2010, 04:07 AM
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ok, but cable tying method can be done now... cables too short... but anyway... I have done tying on signal cable...
I have connected a 680uf 16V capacitor to the power. + to +, - to - ... but I wonder is that good enough... capacity enough? hissing gone... but there is still very very faint hissing... so, now I think using capacitors to smooth it out... higher capacitance? put in series? how? |
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Oct 23 2010, 08:58 AM
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Oct 23 2010, 09:48 AM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Show us some pix of the said regulator.
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Oct 23 2010, 09:44 PM
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410 posts Joined: May 2010 |
from what I see and remember now... it is using isolated transformer...
pics will come later... |
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Oct 23 2010, 09:49 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Isolated transformer? Oh really?
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Oct 23 2010, 09:59 PM
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410 posts Joined: May 2010 |
from the symbols la...
but anyway... I put capacitor at the power and it cleaned most of it... but there is still a little bit more, hissing... but very very faint... you need to listen to it carefully... so I believe capacitors does help... is not hum ah... is hissing... |
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Oct 23 2010, 10:05 PM
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Senior Member
8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
I'd say hissing normally does not come from PSU, its more related to your head amp circuits.. could be related to your impedance mismatched..
This post has been edited by jazzy939: Oct 23 2010, 10:08 PM |
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Oct 23 2010, 10:08 PM
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410 posts Joined: May 2010 |
headamp?
previously... I was using lantern batteries... 6+6... it is so clean... that there is no hissing at all. I wanted to use adapter cos battery died in 2 days of 4-5 hours listening per day... =P |
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Oct 23 2010, 10:11 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Here's a good read I picked up:
Some headphones have limited frequency which can limit the amount of hiss you can hear. Few common causes of the hiss/pops are 1) Unregulatered/unfiltered/noisy power to CD player/DAC/amp, 2) unmatched impedance of headphone and inadequate amp (amp can't handle low impedance cans), 3) picking up interference/noise from unshielded or inadequately shiedded interconnect/power cable/headphone cable, just to name a few. |
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Oct 23 2010, 10:34 PM
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410 posts Joined: May 2010 |
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Oct 23 2010, 10:45 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
It certainly says 'regulated'!
Thanks for the pics. |
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Oct 23 2010, 10:49 PM
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410 posts Joined: May 2010 |
yeah loh... don't know why got that hiss also... maybe my house have bad grounding... or there's short around...
will try at other places and see... |
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Oct 23 2010, 11:25 PM
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Senior Member
8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
IF you tried with batteries and there were no hiss, I guess it must be the EKK PSU then..
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Oct 24 2010, 05:14 AM
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1,058 posts Joined: Apr 2006 From: Penang , Malaysia |
get a better power supply will sure help
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Oct 24 2010, 12:06 PM
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410 posts Joined: May 2010 |
any brand or type to recommend?
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Oct 24 2010, 12:15 PM
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941 posts Joined: Nov 2005 |
hack the adaptor , mod the circuit inside for a real regulated supply
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Oct 24 2010, 12:25 PM
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410 posts Joined: May 2010 |
real regulated power supply?
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Oct 24 2010, 12:27 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
The ABS plastic will be hard to hack open..
You need a hacksaw and cut around it.. put it in a good metal casing for proper grounding and 'improve' the regulating circuit.. Not that I have not done it before.. |
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Oct 24 2010, 12:38 PM
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941 posts Joined: Nov 2005 |
QUOTE(jazzy939 @ Oct 24 2010, 12:27 PM) The ABS plastic will be hard to hack open.. Exactly the same thing i did but i didn't use hacksaw, use even crude (stupid) way to hack up.You need a hacksaw and cut around it.. put it in a good metal casing for proper grounding and 'improve' the regulating circuit.. Not that I have not done it before.. These adaptor if can get dirt cheap at junk store, it serves good as cheap transformer, everyone know how expensive it is now |
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Oct 24 2010, 12:44 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
How true..
But I am curious on the EKK's regulator part of the circuit.. |
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Oct 24 2010, 12:50 PM
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941 posts Joined: Nov 2005 |
My guess is 78xx the most they can give.
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Oct 24 2010, 01:04 PM
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410 posts Joined: May 2010 |
if I open it... what can I do to it?
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Oct 24 2010, 01:08 PM
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Senior Member
8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
See if there is a possibility to improve the regulating circuit?
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Oct 24 2010, 01:26 PM
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410 posts Joined: May 2010 |
well, I don't think I need a saw or anything... after many hours of usage... its casing is loose dy... the glue is not heat resistant...
see how... |
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Oct 24 2010, 01:42 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Lets see it!
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Oct 24 2010, 01:47 PM
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410 posts Joined: May 2010 |
well, the hissing will be gone totally after 3 hours of usage... probably absorbed by the power capacitor...
for now... It is just one 680uf 16V... I might add it in parallel to 680ufx2, 1360uf and see how... I hope it will be better... we see how... => ____ I also noticed the mica in the tube has moved... probably due to vibration in my bag while I moving... haiz... |
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Oct 24 2010, 01:48 PM
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941 posts Joined: Nov 2005 |
maybe changed to high voltage caps. nowadays those caps get at jln pasar mostly under rating.
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Oct 24 2010, 01:49 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Thats good to know!
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Oct 24 2010, 01:54 PM
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410 posts Joined: May 2010 |
the amp is using Panasonic FM caps...
the power cap is using a Nicichon cap. will try... |
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Oct 24 2010, 02:03 PM
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941 posts Joined: Nov 2005 |
the brand is good. just that whether the caps is genuine or not.
report ur result here |
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Oct 25 2010, 04:15 PM
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410 posts Joined: May 2010 |
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Oct 25 2010, 04:37 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
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Oct 25 2010, 08:15 PM
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4,234 posts Joined: Nov 2004 |
What's the headphone amp?
I'm more inclined to believe that it's the amp circuit's problem rather than the PSU's problem at this point. |
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Oct 26 2010, 11:59 AM
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410 posts Joined: May 2010 |
I have made the amp myself, with battery it's clean!
with PSU some hissing... but added a 680uf 16V as power cap and it's clean dy... just some more very minor hissing which is not a big problem... I am wondering on how to remove that remaining hissing.. add another one in parallel? |
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Oct 26 2010, 01:03 PM
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8,183 posts Joined: May 2005 From: Beaumont, Baile Ath Cliath, EIRE. |
Yup. See if that would helps.
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Oct 26 2010, 01:34 PM
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410 posts Joined: May 2010 |
ok. will try add it =>
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