Building a Pearl 2

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jackinnj

jackinnj

Member
Joined 2002
tech-diy.com
Wellerman said:
Personally I preferred the ever so slightly fuller sound of the original.
Click to expand...

A recent stereophile letter comments that we went through a period of ascetic neutrality for listening components with disdain for bass and treble controls, no "loudness" button etc. at least from the late 1970's until just recently. Now room equalization software is all the rage.

I listen to a lot of vocal, piano...not a whole lot of guitar.
 

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Berkbear

Berkbear

Member
Joined 2020
Desktop power supply

Hello,

This past year I was bitten by the DIY Audio bug. So far, I have built the ACA monoblocks and ACP+. Now I am tackling the Pearl 2 Phono Preamp.
I received the PCBs and JFETs yesterday. I’m beginning to think about the power supply. According to Wayne, you can build a linear power supply, but "this is by no means the only way to do it, so feel free to substitute any reasonable supply that delivers the required voltages (28 to 34 volts at 100 mA). You may also elect to use switching supplies, wall-warts, stacked batteries."

Having used the Meanwell desktop power supplies for the ACA I have a good idea how to use a similar supply to power the Pearl 2.

The supply I am thinking of using is:
https://www.mouser.com/datasheet/2/260/GC30U_SPEC-1109941.pdf

And the DC power jack is:
https://www.mouser.com/datasheet/2/393/712AFMS_721AFMS_CD-1391745.pdf

Will this meet the requirements of the power supply for the Pearl 2? Would this PSU severely impact the ripple and noise characteristics?

Any help is much appreciated,
BerkBear
 
codyt

codyt

Member
Joined 2019
Paid Member
Berkbear said:
Hello,
Having used the Meanwell desktop power supplies for the ACA I have a good idea how to use a similar supply to power the Pearl 2.
Click to expand...
You could use desktop switching supplies, but you’d need two of them to get a bipolar supply. If you go that route, you’d need to use insulated jacks to keep the ground floating until it gets to the boards. You’d also have to decide if you’d buy 24v supplies and skip the regulation and filtering that happens on the board, or go with a bit higher voltage and run it through the board as-is.

All that said, I’d follow McQuaide’s advice and build something like the PSU Wayne included in the documentation. You could even use the store’s universal PSU board.
 
WBS

WBS

Member
Joined 2007
If I can do it just about anyone can!

I built a point to point power supply using Wayne's schematic and the correction made by 6L6. I posted pics of it somewhere in this thread if you want to see it. Voltages were dead on once I got it ironed out, and it is as quiet as Grant's tomb. Go for it! :)

Hmmm. As a matter of fact, I think I might have a new AnTek for this build laying around somewhere. PM me if you're interested.
 
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6L6

6L6

Moderator
Joined 2010
Paid Member
Aljordan- the 7800/7900 regulators need 2.5v more input than output voltage to work properly. Anything more will be wasted as heat in the regulator itself. A volt or two extra is no big deal, but many is a bit of a waste.

Berkbear- this is a bipolar supply, you can’t use one of those bricks, you need two. (As mentioned by Codyt) Also make sure they are connected to the same power strip and you switch the pearl on/off at that strip.
 
Berkbear

Berkbear

Member
Joined 2020
codyt said:
You could use desktop switching supplies, but you’d need two of them to get a bipolar supply. If you go that route, you’d need to use insulated jacks to keep the ground floating until it gets to the boards. You’d also have to decide if you’d buy 24v supplies and skip the regulation and filtering that happens on the board, or go with a bit higher voltage and run it through the board as-is.

All that said, I’d follow McQuaide’s advice and build something like the PSU Wayne included in the documentation. You could even use the store’s universal PSU board.
Click to expand...

McQuaide-Thank you for the clarification. Having two power supplies for each of the two PCBs makes sense, as does building Wayne's power supply.
 
Berkbear

Berkbear

Member
Joined 2020
codyt said:
You could use desktop switching supplies, but you’d need two of them to get a bipolar supply. If you go that route, you’d need to use insulated jacks to keep the ground floating until it gets to the boards. You’d also have to decide if you’d buy 24v supplies and skip the regulation and filtering that happens on the board, or go with a bit higher voltage and run it through the board as-is.

All that said, I’d follow McQuaide’s advice and build something like the PSU Wayne included in the documentation. You could even use the store’s universal PSU board.
Click to expand...

CodyT-Great advice insulating the jacks, thanks. In the ACA build, the ground buss of the barrel connector went to the speaker jacks. The supplies I was looking at both have the min. recommended VDC of 28.
 
Berkbear

Berkbear

Member
Joined 2020
WBS said:
I built a point to point power supply using Wayne's schematic and the correction made by 6L6. I posted pics of it somewhere in this thread if you want to see it. Voltages were dead on once I got it ironed out, and it is as quiet as Grant's tomb. Go for it! :)

Hmmm. As a matter of fact, I think I might have a new AnTek for this build laying around somewhere. PM me if you're interested.
Click to expand...

WBS-Yes, I started digging through the various postings related to 6L6's build and saving links to helpful ones. If I go that route, I will follow up regarding the toroid from AnTek. Thank you for the help.
 
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