Power Supply for Pearl

dkimble · 12th March 2004, 06:14 PM

I am finally building a Pearl. (Got the parts almost 2 years ago. I am using the power supply schematic in the instructions. Transformers are Digikey TE70053, each with two 15VAC .5A secondaries in series. The trouble is that the supplies put out about 53 VDC unloaded, and exactly 50 VDC with a 1K ohm load (50 ma). Will this be too high for the regulators on the Pearl pcbs? Or will the load of the Pearls drag down the voltage further? Should I drop the voltage down further before the Pearl boards?

I will post pictures when this is finished.

Thanks in advance for any help!

Dave Kimble
dave.kimble@gte.net

Nelson Pass · 12th March 2004, 07:20 PM

Wayne says no.

dkimble · 12th March 2004, 09:13 PM

Thanks!

I am super cautious when it comes to the initial powering up of a project. I've failed numerous "smoke tests" in my life!

Dave Kimble

Nelson Pass · 13th March 2004, 05:26 AM

Amplifier builders and vampire hunters have two traits in
common: Patience and Fearlessness .

Panelhead · 15th March 2004, 09:03 PM

Quote:

Originally posted by dkimble
I am finally building a Pearl. (Got the parts almost 2 years ago. I am using the power supply schematic in the instructions. Transformers are Digikey TE70053, each with two 15VAC .5A secondaries in series. The trouble is that the supplies put out about 53 VDC unloaded, and exactly 50 VDC with a 1K ohm load (50 ma). Will this be too high for the regulators on the Pearl pcbs? Or will the load of the Pearls drag down the voltage further? Should I drop the voltage down further before the Pearl boards?

I will post pictures when this is finished.

Thanks in advance for any help!

Dave Kimble
dave.kimble@gte.net

No sweat on this! I used a 50 watt dual thirty volt transformer. Under operating conditions it runs right at 50volts into the circuit board. Running those 10,000K caps at 50 volts places a lot of stored energy on the regulator.
The series regulator can handle a bunch more disapation than this. Mine barely heats up the sink.
I think the sonics are improved when running the input voltage up on a regulator like the one in the Pearl. The stored energy increases with the square of the voltage differential. A cap at 20 volts above the regulator stores 4 times the energy of one running at 10 volts above.

George

moe29 · 16th March 2004, 12:22 AM

just be sure to use silver solder too

dkimble · 16th March 2004, 05:57 PM

Yep! Silver solder was my first choice!

I am also using Arctic Silver II thermal compound on the regulator heatsinks, although it sounds like they don't really need it. I have used it on CPU heatsinks, noticeably increasing the heat conductance, but I have never heard of it used in audio. I imagine it would work well in power amps.

Dave Kimble

12th March 2004, 06:14 PM	#1
dkimble diyAudio Member Join Date: Jul 2002 Location: Santa Maria CA	Power Supply for Pearl I am finally building a Pearl. (Got the parts almost 2 years ago. I am using the power supply schematic in the instructions. Transformers are Digikey TE70053, each with two 15VAC .5A secondaries in series. The trouble is that the supplies put out about 53 VDC unloaded, and exactly 50 VDC with a 1K ohm load (50 ma). Will this be too high for the regulators on the Pearl pcbs? Or will the load of the Pearls drag down the voltage further? Should I drop the voltage down further before the Pearl boards? I will post pictures when this is finished. Thanks in advance for any help! Dave Kimble dave.kimble@gte.net

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12th March 2004, 07:20 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	Wayne says no.

12th March 2004, 09:13 PM	#3
dkimble diyAudio Member Join Date: Jul 2002 Location: Santa Maria CA	Thanks! I am super cautious when it comes to the initial powering up of a project. I've failed numerous "smoke tests" in my life! Dave Kimble

13th March 2004, 05:26 AM	#4
Nelson Pass The one and only Join Date: Mar 2001	Amplifier builders and vampire hunters have two traits in common: Patience and Fearlessness .

16th March 2004, 12:22 AM	#6
moe29 diyAudio Member Join Date: Dec 2002 Location: Florida	just be sure to use silver solder too

16th March 2004, 05:57 PM	#7
dkimble diyAudio Member Join Date: Jul 2002 Location: Santa Maria CA	Yep! Silver solder was my first choice! I am also using Arctic Silver II thermal compound on the regulator heatsinks, although it sounds like they don't really need it. I have used it on CPU heatsinks, noticeably increasing the heat conductance, but I have never heard of it used in audio. I imagine it would work well in power amps. Dave Kimble

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