Building a Pearl 2

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Dennis Hui

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Now that you mentioned it, I do have some spare speaker binding posts left over from my misguided speaker building venture. The cardas post is surprisingly inexpensive so I'll just give that a try.

I'm hoping that chassis is big enough for me since I always have trouble working
in confined spaces. :)

Dennis
 
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Russellc

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Joined 2003
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Eric said:
I've always experienced these offset adjustments to be a bit finicky. Both channels are very sensitive to adjustment - small adjustments move offset by relatively large amounts. One channel adjusts smoothly and predictably while the other channel is a bit twitchy. On the twitchy channel, a slight adjustment leads to more significant swings in offset, from positive to negative and back again until it settles. I'm wondering if I have a cold solder joint on the pot. I'll have to reflow it.

Do your LEDs blink at all as the boards start up? The nature of my PSU (added resistance following the rectifier) makes it somewhat softstart in nature. So, the LEDs are initially off for the first second or two after receiving power, then they start to glow, blink off for a fraction of a second, then come back on and slowly get brighter as the power supply hits full power.
Click to expand...

Ok, I watched mine fire up. I did not notice any sort of flicker, LEDs just came on upon power up.

Russellc
 
Eric

Eric

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sites.google.com/bucknell.edu/ericshometheater/erics-home-theater
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Thanks for the details, Russell! I suspect the blink is related to the soft start nature of my PSU and when the onboard rectifiers start to kick in. The first power resistor directly after the rectifier gets most hot during the first 20s or so while the caps charge up and then cools off a bit. I'm waiting for one more delivery (power umbilical cord) before the Pearl is completed.
 
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Russellc

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Eric said:
Thanks for the details, Russell! I suspect the blink is related to the soft start nature of my PSU and when the onboard rectifiers start to kick in. The first power resistor directly after the rectifier gets most hot during the first 20s or so while the caps charge up and then cools off a bit. I'm waiting for one more delivery (power umbilical cord) before the Pearl is completed.
Click to expand...

What are you using for umbilical? I used 4 conductor mic cable, neglex star quad or something like that...and microphone cable connector jacks to hook it up on both ends. I believe I stole that idea from 6L6...

Russellc
 
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bkdog

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Joined 2005
I like Tuchel connectors on umbilicals, like this C091 31H008 100 2 Amphenol Tuchel | Mouser

Since I use balanced lines all the time I don't want an XLR connector on anything outputting DC!

Tuchel connectors were used for mic's several decades ago, but it's unusual enough now that it's unlikely to ever be plugged into anything sensitive. They are also screw-locked so they are difficult to remove and a little more dust-tight than XLR connectors.

A Speakon connector might also be a viable alternative and more suited to the function NL4FX Neutrik | Mouser
 
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Russellc

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bkdog

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Joined 2005
Star-quad cable is designed to be wired with the same colour connectors joined at each end. Thus the colour scheme in the Canare cable. For a mic lead this allows a more even distribution of RFI across the conductors and therefore better rejection at the mic preamp.
 
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Russellc

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bkdog said:
Star-quad cable is designed to be wired with the same colour connectors joined at each end. Thus the colour scheme in the Canare cable. For a mic lead this allows a more even distribution of RFI across the conductors and therefore better rejection at the mic preamp.
Click to expand...

Well, there are 3 wires used in this particular Pearl 2 application, (4th isnt used) but I can see why in an actual microphone cable application it would matter. His wire, with 4 different color codes makes it easier to keep each individual wire's job consistent on each end.

The wire I used, for this particular application required a lot of double checking of continuity, as it only had the two colors....which is perfect for its intended application, which obviously this project deviates from. Its basically just what came to hand.

Russellc
 
Eric

Eric

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I thought about putting the Pearl boards in the same chassis as my preamp, but my preamp chassis is getting a bit crowded with a transformer, a DCB1 as a regulator for the BA-3 boards as well as for input switching and volume control, a separate regulator board for the Light-Dependent-Resistor volume control, remote control for input switching and volume control. Thus, I've decided to keep the pre-amp separate from my phono stage. Another week or two and both should be operational.
 
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Russellc

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Joined 2003
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Eric said:
I thought about putting the Pearl boards in the same chassis as my preamp, but my preamp chassis is getting a bit crowded with a transformer, a DCB1 as a regulator for the BA-3 boards as well as for input switching and volume control, a separate regulator board for the Light-Dependent-Resistor volume control, remote control for input switching and volume control. Thus, I've decided to keep the pre-amp separate from my phono stage. Another week or two and both should be operational.
Click to expand...

That transformer in the same box with Pearl would have never worked. I had my BA-3 pre right next to the Pearl 2 when I first fired it up...it hummed so loud I was sure I left a ground totally off. Moving the pre solved this completely. You would have needed a remote box for pre power supply transformer...I guess it could be in same box as Pearl power supply....

Russellc
 
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Dennis Hui

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Joined 2002
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Umbilical

Hi,

I was just wondering if anyone has built the Pearl 2 with a 4 conductor
umbilical cord, with the 4th connecting the power supply chassis to the
preamp chassis? Does that make any sense?

In other news, I ended up ordering the Hammond cases and cardas
post from Partsconnexion so I should be able to pick them up next week.
I found out that I forgot to order the zvp3310 from Digkey last week. :(
Must remember to add that to Mouser order...

Dennis
 
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Russellc

Member
Joined 2003
Paid Member
Dennis Hui said:
Hi,

I was just wondering if anyone has built the Pearl 2 with a 4 conductor
umbilical cord, with the 4th connecting the power supply chassis to the
preamp chassis? Does that make any sense?

In other news, I ended up ordering the Hammond cases and cardas
post from Partsconnexion so I should be able to pick them up next week.
I found out that I forgot to order the zvp3310 from Digkey last week. :(
Must remember to add that to Mouser order...

Dennis
Click to expand...


wait for 6L6 or someone else to verify, but my understanding is the grounds are where they are and everything else floats. I assume that is for a reason, but dont know for certain if it would hurt or not. I ignored the 4th wire and mine is stone quiet.

Russellc
 
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