Building a Pearl 2

to AnthonyA #2017

Hello Anthony,


I have transformers between my lowoutput-MC and my Pearl 1. Works beautiful.


Sometimes I use a super simple 'le pacific'-MC-prepre.
You can get this at / check the 'boozehound-labs' webpage:
404 Not Found
Ortofon T-5

Or if you want to spend more or a lot more money:
Check Lundahl - transformers and many more possibilities / manufacturers...

Greets
Dirk
 
Correct shielding technique (from Morrison "Grounding and Shielding Techniques in Instrumentation").
 

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Hi all,

I hope everyone is doing ok with quarantine. I finally had time to work on my Pearl 2. After several failed attempts at making a case, I got one that works for me. I hooked everything up for a rough first run. With the dc voltage, I set it to zero with the trim pots as instructed on the boards. I hooked everything up to my Sony TA-5650, but upon turn-on of the Sony I get a pop. When I select the line that has the pearl connected it seems quiet with no cart installed, only a faint hiss when I turn it way up, but when I select another input I get a crazy oscillating type of noise? Not sure if I am describing it correctly. When I did turn the Pearl for a test when I brought it into the house, it did blow a fuse the first time so that was a sign of something not right. Any ideas?

Thanks goes out to 6L6 for going way beyond the norm to help me with the power supply!!! Thanks so much.

I've attached some pictures

I tried again this morning. The Pearl 2 plays and there is enough gain. I had a few mysteries:

First, after some frustrating confusion, I realized that the right tonearm cable had a torn connection, which I fixed.

Second, another fuse blew but has not blown yet since replacing a couple of hours ago, although I have not turned off and on the Pearl since then.

Third, and most annoying, is the turn-on pop and the weird oscillation thumping sound in the other inputs that are not playing anything. I switch from the Sony TA-5650 to a passive pre and Music Reference RM-10 and it went away, while also being dead silent. So there is something going on with the Sony and Pearl, possible DC flowing through that is not tamed in the Sony?
 
Hello Anthony,


I have transformers between my lowoutput-MC and my Pearl 1. Works beautiful.


Sometimes I use a super simple 'le pacific'-MC-prepre.
You can get this at / check the 'boozehound-labs' webpage:
404 Not Found
Ortofon T-5

Or if you want to spend more or a lot more money:
Check Lundahl - transformers and many more possibilities / manufacturers...

Greets
Dirk
Thanks Dirk. That sounds like a gud idea
 
I tried again this morning. The Pearl 2 plays and there is enough gain. I had a few mysteries:

First, after some frustrating confusion, I realized that the right tonearm cable had a torn connection, which I fixed.

Second, another fuse blew but has not blown yet since replacing a couple of hours ago, although I have not turned off and on the Pearl since then.

Third, and most annoying, is the turn-on pop and the weird oscillation thumping sound in the other inputs that are not playing anything. I switch from the Sony TA-5650 to a passive pre and Music Reference RM-10 and it went away, while also being dead silent. So there is something going on with the Sony and Pearl, possible DC flowing through that is not tamed in the Sony?

Is it possible you are using a high inductance cartridge? If you haven't read the thread linked below, check it out. It sounds somewhat like what you are experiencing:

Strange problem with Pearl 2 and SAE Cartridge
 
Enochrome - what are the noises you are describing? The other inputs when Pearl is attached?

Hey 6L6! Good to hear from ya!

Yeah, it's a strange 1000hz repetitive thump sound in the other inputs when the Pearl is attached; one input is louder than the other. I also get a 200hz pop when I turn the Sony on when the Pearl is already on. When I select the Pearl input, things are normal, albeit with a high noise floor. Now, I am using my passive pre and Music Reference RM-10 and no problems and it's dead silent. I did blow two fuses as well, but since switching over to the passive combo, I have turned it on and off to switch loading resistors and all is good. It sounds great.

The Sony TA-5650 is a really weird integrated, in my opinion.
 
A friend built a Pearl 2 years ago, and I decided to build one myself because it sounds great with his table. However, I think my Ortofon cart with 5.5 mV output is a little hot for the standard configuration because it sounds VERY wrong hooked up to my table. I've seen a couple different solutions mentioned in this thread, but they're kind of spread out and I'm not sure what exactly is the right way to set up a Pearl 2 with such a high output MM cart. What value changes do you all recommend I implement to make a Pearl 2 compatible with my cart? I will be using a B1 preamp after the Pearl 2.
 
Yeah, it just sounds like there's a huge dip in the middle of the response when hooked up to my P6 + Ortofon Blue. Since it sounded so off, we didn't leave it hooked up for long. Bass was there, and ultra-highs were there (maybe a little too there), but something in the middle sounded super recessed. We thought there was just something wrong with his Pearl 2 altogether, but when we went back to his Sota + Grado cart, it sounded great again. His Grado cart has a 3.5 mV output, so I am just kind of assuming the issue is due to the high output of my cart, but I could be wrong. At the moment, the only other phono stage I have on hand is through my surround receiver, and my table sounds fine through that.
 
tayj10 #2031

Hello tayj10,


the Ortofon 2M Blue (moving magnet) wants to see 150pF to 300pF capacitance at the input.(C22 ? on the Pearl2 board) and 47kohm (normal value in Pearl2)

Your phonocables capacitance + capacitance at the input of the Pearl2 should be in that range. Tried that?
Outputvoltage of the 2m Blue is 5.5mV. Could be high.But should work.
A lot of bass and highs and reduced mids sounds to me like wrong input capacitance. But I can be wrong....:rolleyes:


Greets
Dirk
 
Yeah, it just sounds like there's a huge dip in the middle of the response when hooked up to my P6 + Ortofon Blue. Since it sounded so off, we didn't leave it hooked up for long. Bass was there, and ultra-highs were there (maybe a little too there), but something in the middle sounded super recessed. We thought there was just something wrong with his Pearl 2 altogether, but when we went back to his Sota + Grado cart, it sounded great again. His Grado cart has a 3.5 mV output, so I am just kind of assuming the issue is due to the high output of my cart, but I could be wrong. At the moment, the only other phono stage I have on hand is through my surround receiver, and my table sounds fine through that.

R12 -- the combination of R12 and C17 set the time constant "T4", 3.180e-4 seconds. 909 ohms * 333nF = 3.027e-4 seconds. Le voila:
 

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