Need Dan Alexander Class A Dual Channel Mic Preamp Schematic
- fnps90
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Need Dan Alexander Class A Dual Channel Mic Preamp Schematic
Hi,
I just bought a Dan Alexander Class A Dual Channel Mic Preamp and the Phantom Power is not working on the unit. I need a Schematic for it to get it fixed. Here is a Picture of the unit. If anyone has one, I would really appreciate it.
Thanks!
Steve
I just bought a Dan Alexander Class A Dual Channel Mic Preamp and the Phantom Power is not working on the unit. I need a Schematic for it to get it fixed. Here is a Picture of the unit. If anyone has one, I would really appreciate it.
Thanks!
Steve
- digitaldrummer
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not sure what the power supply looks like on that unit, but here's a picture on the DAA site showing an external power supply that might help...
http://www.danalexanderaudio.com/pastprojects.html
I would suspect it's probably sending +24 and +48 separately. Bad cable or connector? fuse blown? actually in this photo it looks like they have a separate board/transformer stepping up the +24 to +48 for the phantom. so I'd make sure you are getting +48 out of there first.
Mike
http://www.danalexanderaudio.com/pastprojects.html
I would suspect it's probably sending +24 and +48 separately. Bad cable or connector? fuse blown? actually in this photo it looks like they have a separate board/transformer stepping up the +24 to +48 for the phantom. so I'd make sure you are getting +48 out of there first.
Mike
- fnps90
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The Power is Supply IS Correct, Straight from Dan!
Straight from Dan Alexander himself. The Early ones had a Black Power Supply "Box" say like a Brent Averill.The Later Units had a "Harman Kardon" power supply. I thought the same as you, but Dan said 1/2 of these preamps that they made indeed has a wall wart. Also, the Cord to the earlier ones are Multi-Pin like most External Power Supplys. On the back of this Unit is the from the factory input jack for a Wall Wart. I got a screamin' price on this unit and it's because the whole "that's the wrong power supply deal" scared alot of bidders off, thinking they would have to spend $250 or more. I talked to Dan and was no longer worried, so I bid and here we are.
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Re: The Power is Supply IS Correct, Straight from Dan!
I stand corrected. Great score!
fnps90 wrote:Straight from Dan Alexander himself. The Early ones had a Black Power Supply "Box" say like a Brent Averill.The Later Units had a "Harman Kardon" power supply. I thought the same as you, but Dan said 1/2 of these preamps that they made indeed has a wall wart. Also, the Cord to the earlier ones are Multi-Pin like most External Power Supplys. On the back of this Unit is the from the factory input jack for a Wall Wart. I got a screamin' price on this unit and it's because the whole "that's the wrong power supply deal" scared alot of bidders off, thinking they would have to spend $250 or more. I talked to Dan and was no longer worried, so I bid and here we are.
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Can you post a close up of that boart at the top right? Preferably wih angles that let us read the markings on the caps and the two to220 dudes.
I'd guess 24VAC transformer, using a diode-cap doubler circuit. But a close up that would let us see what's a resistor and what's a diode on that board would help.
Nice of them to use color coded wire that would allow us to trace the hookup.
I'd guess 24VAC transformer, using a diode-cap doubler circuit. But a close up that would let us see what's a resistor and what's a diode on that board would help.
Nice of them to use color coded wire that would allow us to trace the hookup.
"What fer?"
"Cat fur, to make kitten britches."
"Cat fur, to make kitten britches."
- digitaldrummer
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I would remove the tie-wraps, then follow the wires from that small board. It should go to both of the preamp boards. either at the small board or at the other end, see if you are getting +24 and +48. if no +48, then it's likely the smaller power board and then (like The Scum said) you gotta start looking at those components close up... this would at least start to narrow it down.
MIke
MIke
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