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Dr. Bob
Moderator
Australia
6593 Posts |
 Posted - 04/27/2007 : 09:47:04
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quote:
Originally posted by cyberpunk409
thanks for your lengthy response dr.bob.
i bought a $35 regulated power supply (9v 1100ma) today from a music store. However, it doesnt actually say "Regulated" anywhere on the adapter! I find that the more pedals i add (up to 5), the louder the amp humming gets. So problem NOT FIXED. It was a cheap pedal and like i said, i have no proof that it's regulated.
Some professional regulated power supplies that ive seen online go for $250, so obviously there has to be SOME difference in quality from a $35 to $250 adapter.
SHould i take the adapter back and get a better quality one (i.e. more expensive) ???
Hi cyberpunk409
While I can't say for sure, but it sounds like you have an unregulated power supply.
Which would be made up of just a 4 diodes or a bridge rectifier & a filter capacitor of about 1000uf.maybe 16 to 25V
if you are able to open the adapter, some have four screws, others are welded together, you could try adding another large value capacitor, in parallel with the other one, values of about 2200uf would be a good start.
Then the filter cap value woul be 1000uf + 2200uf = around 3200uf.
If the hum is reduced, that you will know that it's not a regulated supply.
Actually you could just put the 2200uf 25V cap across the positive & negative connections on the adapters output lead.
This should immediately, reduce the hum by quite a bit.
Even simpler, if you get it open, send me a ic of the insides, I will probably be able to tell you strait away, if it's regulated.
I Have found that, most plug packs, even from reputable music stores,
are not regulated.
I saw one in a Dick Smith catalog or maybe it was Jaycar, that state, that the plug pack is fully regulated.
You should get no hum.... from a fully regulated plug pack,
other than if you have faulty earth connections on your guitar leads.
Tyr out your pedals with a different adapter from the store.
See if you can get technical info in it.
Write down & send me the name-s on the adapter, I know quite a few local & imported brands.
What part of Oz are you in?
Good Luck. 
Regards Dr. Bob 
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Edited by - Dr. Bob on 04/27/2007 09:47:41 |
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sp-1
Platinum Member
Germany
1454 Posts |
Posted - 04/27/2007 : 10:08:12
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Dr. Bob
Is there anything I can do about the high v output of the acb apapter ? Is this a common problem ?
thanx |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 04/27/2007 : 10:26:03
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quote:
Originally posted by sp-1
Dr. Bob
Is there anything I can do about the high v output of the acb apapter ? Is this a common problem ?
thanx
Hi SP-1
can it be unscrewed I opened up?
You didn't send a pic of the bottom of the pedal.
You could build a small external regulator circuit, with a LM317T or a 7809
You sould even do it with a 7805 5V regulator, and a resistor in series with the earth lead, that would jack up the 5Volts to about 9V.
Are you any good with a soldering iron?
I could draw up a small circuit-s for you.
It's only a few components & a small heatsink.
If you could open the ACB, it might even all fit inside if you are careful.
But to me, it sounds like the ACB is an unregulated adapter.
Tell me what your thinking of doing?
Regards Dr. Bob
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sp-1
Platinum Member
Germany
1454 Posts |
Posted - 04/27/2007 : 11:04:30
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Dr.Bob
At least I can try to make it work propely. I send some pics to your personal mail.
Do you have any idea why it puts out 14,6V instead of 9V ?
Thanx |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 04/27/2007 : 11:36:01
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quote:
Originally posted by sp-1
Dr.Bob
At least I can try to make it work propely. I send some pics to your personal mail.
Do you have any idea why it puts out 14,6V instead of 9V ?
Thanx
Hi SP-1
Thanks for the Pic in my PM
It is an unregulated power supply.
That's why it's giving out about 14V DC
It just has the usual 4 diodes in a bridge circuit & a large filter cap.
Are you any good with a soldering iron, and can you get some electronic parts
as I said I can draw up a regulator & send a pic of it to you.
Looks like you could put the regulator into the ACB.
I Think the MT32 had an internal regulator.
Regards Dr. Bob
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sp-1
Platinum Member
Germany
1454 Posts |
Posted - 04/27/2007 : 12:06:09
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quote:
Originally posted by Dr. Bob
quote:
Originally posted by sp-1
Dr.Bob
At least I can try to make it work propely. I send some pics to your personal mail.
Do you have any idea why it puts out 14,6V instead of 9V ?
Thanx
Hi SP-1
Thanks for the Pic in my PM
It is an unregulated power supply.
That's why it's giving out about 14V DC
It just has the usual 4 diodes in a bridge circuit & a large filter cap.
Are you any good with a soldering iron, and can you get some electronic parts
as I said I can draw up a regulator & send a pic of it to you.
Looks like you could put the regulator into the ACB.
I Think the MT32 had an internal regulator.
Regards Dr. Bob
Thanx Dr.Bob
I never "really" handled a soldering iron but I can try I guess 
Can't I rip out the regulator out of the mt32? Got two and never use 'm.
I would like a drawing of a regulator but take your time cause I'm busy with other things at the moment. Thanks so far.  |
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midibuddy
Silver Member
Ecuador
285 Posts |
Posted - 04/27/2007 : 21:33:01
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hi there Franzoni!
it's good to hear you're back with the band, we haven't played since march 5th I think... I want to play!
not playing is making my GAS worse, I got new strings and a ZOOM MRT-3 drum machine (discount price, it was old stock), this week I almost bought a modded DS-1, and today I'm getting one to mod it myself... GAS has been awful this month!
So bad to hear the ZOOM will make hums in my chains, I think I'll try it later to see what happens... |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 04/27/2007 : 22:46:29
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Midibuddy....all i can say bro,is to try your zoom adapter and see what happens...make sure the polarity is the same as the pedals so you don't fry them..... i thought (and this is my personal opinion,no basis in science)that the aca pedals worked great with the zoom,the lights looked a lot brighter and the ds1 and the od2 sounded to me a bit louder and crisper but the hum was a bit too much for me especially at gigging levels....sort of like uncontrollable feedback at low levels in the background... the zoom adapter was off a old 505 unit/like i said before i still use it on the wah with no problems...i'm probably running too many boss pedals off the boss adapter at the moment..but i haven't seen the one spot or any of the fancy power supplies in the shops here...i should buy another boss adapter to run the bottom row of pedals on my board......
P.S......G.A.S is dangerous,can get you into a lot of trouble with she who must be obeyed....having said that i'm looking at a walden 12 string acoustic for 170 euro at the moment.... when i get some verbal next week if i buy it...i'll just say it was the doctors advice..........Dr bob's advice......... |
Edited by - FRANZONI on 04/27/2007 22:53:19 |
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midibuddy
Silver Member
Ecuador
285 Posts |
Posted - 04/28/2007 : 00:17:40
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"with she who must be obeyed"
That's funny! LOL
I thought I would keep my GAS away by buying only strings when needing them... I was so wrong... best way is to just... don't buy anything! |
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cyberpunk409
Bronze Member
Australia
56 Posts |
Posted - 04/28/2007 : 05:55:12
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my GAS has been the worst ever! i've bought 4 pedals in the last month, that's about 3 more than I should've given i'm broke as hell at the moment. i'm even contemplating buying a 5th pedal!!! an NS-2 going for $80 AUD, cosmetic condition about 7/10...
oh what to do?!?
as far as my adapter problems go, still no luck! i took the cheap $35 "regulated" one back and am back to using my unregulated adapter. I've been looking into the DUNLOP BRICK, anyone had any experiences with this? will it solve my humming problem? |
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DeFrag
Moderator
USA
3409 Posts |
Posted - 04/28/2007 : 23:20:36
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| What's GAS? |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 04/29/2007 : 01:37:07
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quote:
Originally posted by DeFrag
What's GAS?
Hi DeFrag
G.A.S = Gear Acquisition Syndrome
or
G.A.S = Guitar Acquisition Syndrome
It's what we all seem to suffer from time to time. 
For some of us it gets real bad at times.
Regards Dr. Bob
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DeFrag
Moderator
USA
3409 Posts |
Posted - 04/29/2007 : 02:57:55
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Ahh.. heh tks. I have a bad case myself then. It seems I've spent about $7k in the last 8 months. Sometimes, I'll just page through the bible.. er.. that is Sweetwater catalog.
back to the thread!  |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 04/29/2007 : 08:50:02
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Hi SP-1 & Guys
Bossarea, maybe this should have been posted into "Modifications and Technical Issues"
Here are some pics of a simple Regulator that you might be able to build into the ACB.
It's basically the same circuit for all the 78xx family of regulators.
And in this case, you will substitute a 7809 for the 7805, shown on the circuit.
You cold put a small 10uf to 22uf 16V cap, on the output of the regulator, in parallel with the 0.1uf cap.
Maybe get a friend with some electronics experience to help you,
You will probably have to fit-bolt a small heat sink onto the 7809 reg.
Disconnect the output lead wires, from the board that you sent me pics of,
Connect the input of the reg to the place that you disconnected the output lead.
Connect the output lead, to the output of the regulator circuit.
The 14V no goes, into the reg, & the reg will give out about 9V DC.
The reg will be dissipating 14V - 9V = about 5V as heat,
5 volts at about 300mA is ---- 5 x 0.3= 1.5W and at 600ma is 5x0.6= about 3 Watts of heat.
Not much but it's better safe than sorry.
The formula I'm using to calculate the wattage, is P=VxI
P = watts
V = Volts
I = Current in Amps
That is why you will probably have to fit a small heatsink to the reg.
Just a piece of aluminum Cut & shape it to fit inside the ACB box,
You will have to make sure that nothing is touching or shorting out inside the ACB, when you put it all together.
See the attached pics.
Good luck & have fun building it.
Regards Dr. Bob
PS so I don't get my Butt sued off, I found some of the pics on a web site, on the net.
Download Attachment:  RegComposit.jpg
92.76 KB |
Edited by - Dr. Bob on 04/29/2007 09:10:12 |
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sp-1
Platinum Member
Germany
1454 Posts |
Posted - 04/29/2007 : 10:30:43
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Hi Dr.Bob
Thanx alot
I write down the list of components I need and when I'm near a electronic parts store I'll get 'm.
I'll keep you informed
Thanx again and have a beer on me
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Topic |
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Regulated vs Unregulated Power Adapters
