Building a Pearl 2

[Steve Luck]

Quick question - does the Pearl two work with moving magnet and moving Iron cartridges.

I have a Cartridge Man Music Maker three moving Iron Cartridge:

Specifications

- Output voltage: 4mV
- Frequency response: 10Hz - 50KHz
- Stereo separation: >25dB across 10Hz to 30KHz range
- Loading requirement: 47K Ohm (standard moving magnet)

Thanks

Steve

 

[Eric]

4mV cart is fine! I'm using an Audio Technica cartridge that has 5mV of output. Depending on the specifics of your gear, you may need to reduce the output of the Pearl 2 a bit by adjusting R14 a bit. Mark has a nice explanation of this here.

 

[6L6]

Yes, will work wonderfully!!

 

[Steve Luck]

Thanks guys that’s great news. I thought I read something about moving coils and the Pearl and would have to look else where. Asking questions on different parts of the forum because it’s a major effort moving from a fully integrated amp (much loved Audio Innovations 500) to a pre and power set up. Two ACA and a Korg built Pearl 2 and power supply/s to follow.

 

[jackinnj]

It's a very nice sounding phono-pre with MC cartridge.

But with MM Cartridge output @1kHz is only part of the story. The second stage, in the stock version, runs out of "overhead margin" with a high output cartridge. The gain should be run back.

 

[metalman]

I'm running an Ortofon VMS20 mkii moving iron cartridge that has a 5.0mV output. My Pearl II worked fine with it built as the original schematic. The output was a little high but not in any way distorting, just not optimal. I put sockets in the R15 and C15 spots to allow me to adjust gain, and for the VMS20 I settled on shorting R15 and a 46.4k resistor in C15 to adjust gain at 1kHz to 45dB. I've left R14 at 1k. Works great!

Terry

 

[McQuaide]

Hi all, here's an update on my Pearl 2. I finally acquired the third arm for my DDX-1000 and it's now sporting:

SME3009 Series II Improved / Ortofon MC25FL
VPI JMW9 Memorial Signature / ZYX RS-30-02
Jelco SA-370H / AT33PTG

I was getting tired of switching cables, so I added extra inputs and a 3-way selector switch to the Pearl:

I put the switch on the back to keep it closer to the inputs. You can also see the switches for adjustable gain and loading. I think this one is done!

 

[Steve Luck]

Have I got this right? It looks like if I buy the power supply board set from the store I'll need a centre tapped transformer 2x25 volt to produce -35 and +35volt supply lines and one ground wire? Hence the need for three pin connectors from power supply unit to pre amp boards with one being -V and on +V Or will any decent transformer with four ouput cables chucking out 25volts each pair do?

Been looking at the Toroidy web site but not seen centre tapped transformers there.

Thanks

Steve

 

[Dennis Hui]

Just use a dual secondary one.

 

[Eric]

Yep, dual secondaries will do, just tie the middle two secondary wires together to form your center tap. I used this one from Antek for my Pearl 2.

 

[Steve Luck]

OK Pearl two ordered from PASSDIY with the FETS - Is there a full BOM in this thread? The PASS DIY site just lists the capacitors looks like the resistor values are all on the boards themselves. Does the full list of parts come with the boards?

 

[Dennis Hui]

There was no parts list with the boards when I ordered it a few years ago.

The resistor values are listed at the end of the project article pdf:

https://www.passdiy.com/pdf/PEARL 2.pdf

Hope this helps.

 

[6L6]

Nice BOM was just a handful of posts ago - Pearl-2 BOM.xlsx - Microsoft Excel Online

Order extra ZVP3310, more than 1/2 the builders have destroyed one or two (very static sensitive) during construction, it's nice to have extras on hand.

There are lots of PCB on eBay that would be perfect for the raw PSU, example - Dual Polarity Symmetrical Power Supply PCB Only DIY For Audio Amp | eBay

Remember to build the PSU in an enclosure that doesn't match the box with the Pearl PCBs so you are not tempted to stack them and negate the entire point of the separate PSU. Pearl 2 is only truly quiet when it's 1M away from any transformer.

 

[Steve Luck]

Thanks guys the link to the PDF seems to have gone from the Passdiy site all you can see is a list of capacitors and mouser and digikey refs . I’m ordering parts now for ACA power supplies so that I can stack them on the ACA. i’ll Then put those on the floor on suitable plinths off the main rack. I tidied my temporary system arrangement over the weekend and have gone from silent to low level hum as a result! Too many wall warts and bricks from different MFRs all different voltages too. Look forward to choosing parts for the pearl and building it slowly. I’ve splurged big time moving from integrated amp to seperates and phono stage is the last piece.

 

[6L6]

The link goes straight to the PDF that it’s supposed to. The article never had a BOM with all the part numbers, and anyway if it did, many if not all would be obsolete numbers because the article is almost 10yr old.

The schematic has all the values on it.

 

[Steve Luck]

Link above in the thread works fine but that link has gone from the Passdiy website that i’m Looking at just a link to the “shop” ��

 

[McQuaide]

I used a proto-board and built the power supply in the Pearl 2 PDF. Very simples and provides all that the Pearl needs.

 

[metalman]

I used a proto-board and built the power supply in the Pearl 2 PDF. Very simples and provides all that the Pearl needs.

X2 for using proto-board. I went a step further to a CLC supply. With porto-board for a supply you have a lot of flexibility to build it to your own tastes.'

Terry

 

[Alypius]

I know the P2 is sensitive to PSU noise, but does a steel case (such as those from Antek) provide sufficient shielding?I'm planning out my chassis purchase for this and my BA-3 preamp.

 

[laverda]

I know the P2 is sensitive to PSU noise, but does a steel case (such as those from Antek) provide sufficient shielding?I'm planning out my chassis purchase for this and my BA-3 preamp.

I've recently had a issue with a Pearl II I built for a family member, it started buzzing/crackling (after well over a year of perfect operation) I had it back in the workshop to fault find and rectify. PSU checked at the same time obviously. I could not find anything wrong with it and in my system worked and sounded superb as it should.

It was returned and all was well for a few weeks the once again it started buzzing/crackling intermittently ...errr. Back to mine, all as good as gold. eeerrrrr.

Back to his fine for a month or so..then it started again, New leads installed along with chassis phonos, etc etc ...

Today I returned again to 'just check' as he said it was still buzzing intermittently I arrived Fluke in hand. But on inspection, the pearl is on a mid shelf on a racked system, I notice a blue glow from the rear of the shelf the pearl was sat on. What's that I asked, that's the WIFI router he said.

Ahh. I nearly hit him...We relocated the router 2mtrs away from the pearl and a instant fix. This pearl is built into an old Naim audio shoe box case (Ali). Steel would be better.