Pearls

oliverniekamp · 26th June 2002, 04:56 PM

I have finished my pearl boards today.

oliverniekamp · 26th June 2002, 05:03 PM

The last one says: I like symetry

oliverniekamp · 26th June 2002, 05:08 PM

ptp is fun

peranders · 26th June 2002, 05:13 PM

Symmetry is a good thing in hifi and in order to get the two (or more) channels identical (more or less). My thing is to make the channels as two duplicates, not mirrored (much work). It's just to press CTRL-D (but I press CMD-D since i use Macintosh) and move the duplicated piece. If I make a design with mixed parts, matched transistors, regulators, IC's it's virtually impossible to make the PCB 2 x the design. Connectors, skrewholes makes a small asymmetry if you have limitations of the board size.

oliverniekamp · 26th June 2002, 05:17 PM

Just for fun and to do something different between pearlwork i made a small analog filter and output circuit referring to the pass DA converter manual. Its size is 1x2 inches

oliverniekamp · 26th June 2002, 05:39 PM

In the pearls i made some changes, as you may see there are more toshibas to make the pearl fit for low output MCs and i tried to make them as small as possible, the circuits are 2x3 inches for one channel and i cant make them smaller. There was no reason using the 2sk389 as i use for jfet in the output for minimum. The output coppling capacitor is a black gate bn unpolarized cap, they sound amazing, unbelievebal for a electrolytical capacitor.
I matchet 100 jfets for the pearls.
I soldered 96 transistors 78 capacitors and maybe 200 resistors just to test my patience.
As you see, i put in some dip switches to make it possible, to find the right resistance for every MC between 30 ohm and 2K, that should work for every low output MC.
All the voltages are allmost perfekt, the matching still had some tolerance, below 5 percent in the worst case but i think that will be no problem. I didnt want to buy more of them.

carpenter · 26th June 2002, 06:20 PM

Tell us more about the sound of these beautiful looking phono preamps. I'm just now rediscovering vinyl audio and will, eventually, construct the pearls. Your efforts are an inspiration to me.

And while I'm gushing: Nelson is such a treasure to our DIY community. What would we do without him?

John Inlow

Nelson Pass · 26th June 2002, 07:46 PM

The Pearl is the work of Wayne Colburn, so you can
gush for him if you like

carpenter · 26th June 2002, 09:27 PM

I saw your name (Wayne Colburn) at the head of the Pearls article and thought you were the author of that article. Since you're also the designer, it seems most appropriate to thank you and give credit where credit is due.

Thanks Wayne,

John Inlow

joe · 27th June 2002, 11:43 AM

Hi Oliver, some questions as i'm ordering parts for the pearl at the moment.
What did you use instead of the sk389, paralleled sk170? Did you buy the jfets from "Schuro"? Do you think that a BlackGate sounds better than a film-cap?

arndt

p.s.: Any experience yet from the DAC-Filter? What DAC-Chip is connected?

26th June 2002, 05:13 PM	#4
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Symmetry is a good thing in hifi and in order to get the two (or more) channels identical (more or less). My thing is to make the channels as two duplicates, not mirrored (much work). It's just to press CTRL-D (but I press CMD-D since i use Macintosh) and move the duplicated piece. If I make a design with mixed parts, matched transistors, regulators, IC's it's virtually impossible to make the PCB 2 x the design. Connectors, skrewholes makes a small asymmetry if you have limitations of the board size. __________________ /Per-Anders (my first name) or P-A as my friends call me

26th June 2002, 06:20 PM	#7
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	beautiful job! Tell us more about the sound of these beautiful looking phono preamps. I'm just now rediscovering vinyl audio and will, eventually, construct the pearls. Your efforts are an inspiration to me. And while I'm gushing: Nelson is such a treasure to our DIY community. What would we do without him? John Inlow

26th June 2002, 09:27 PM	#9
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	Thanks Wayne I saw your name (Wayne Colburn) at the head of the Pearls article and thought you were the author of that article. Since you're also the designer, it seems most appropriate to thank you and give credit where credit is due. Thanks Wayne, John Inlow

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26th June 2002, 05:39 PM	#6
oliverniekamp diyAudio Member Join Date: Sep 2001 Location: Düsseldorf Germany	In the pearls i made some changes, as you may see there are more toshibas to make the pearl fit for low output MCs and i tried to make them as small as possible, the circuits are 2x3 inches for one channel and i cant make them smaller. There was no reason using the 2sk389 as i use for jfet in the output for minimum. The output coppling capacitor is a black gate bn unpolarized cap, they sound amazing, unbelievebal for a electrolytical capacitor. I matchet 100 jfets for the pearls. I soldered 96 transistors 78 capacitors and maybe 200 resistors just to test my patience. As you see, i put in some dip switches to make it possible, to find the right resistance for every MC between 30 ohm and 2K, that should work for every low output MC. All the voltages are allmost perfekt, the matching still had some tolerance, below 5 percent in the worst case but i think that will be no problem. I didnt want to buy more of them.

26th June 2002, 07:46 PM	#8
Nelson Pass The one and only Join Date: Mar 2001	The Pearl is the work of Wayne Colburn, so you can gush for him if you like

27th June 2002, 11:43 AM	#10
joe diyAudio Member Join Date: Oct 2001 Location: Hamburg	Hi Oliver, some questions as i'm ordering parts for the pearl at the moment. What did you use instead of the sk389, paralleled sk170? Did you buy the jfets from "Schuro"? Do you think that a BlackGate sounds better than a film-cap? arndt p.s.: Any experience yet from the DAC-Filter? What DAC-Chip is connected?

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