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Old 11th July 2012, 08:27 AM   #1611
nar is offline nar
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Quote:
Originally Posted by Siberia View Post
Not sure if major, though. I can only guess, I would be better off with upgrading TT and cartridge. Planar 3 has a lousy coupling between motor and plinth. I would love to dismount the motor off the plinth onto some solid base and add a Geddon PSU to it. A cartridge change would benefit too. My current one was bought used on ebay. Some german gentleman sworn he used it less than 100h correctly mounted. As it was my first cartridge, I can't really judge.
You're right about Rega setup. It's good but you can find even better. The major upgrade to Regas is to change the cart for something better. Your cart seems fine, but mind the VTA of the RB 300 might need to be re-adjusted. Rega carts are not very high and higher cartridges need the arm to be set up "higher" on the plinth to have the right cutting angle intended. Extra accessory is needed.

More even careful you must be installing the cart on the arm finding for the "right" position. Please do use Vacuum State free protractor. It can take 2 hours mounting !!! and weeks of patient fine tuning to be well set.


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Originally Posted by Siberia View Post
Back to PEARL II, I'm thinking weather some more precise R matching, different caps or getting closer voltage values to Wayne's would benefit? In other words, is there's anything left to tune? Or perhaps it's too silly, as my current rig wouldn't be able to carry out the differences.
Let us hear Wayne about that

Best,

AnaŽl
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Old 11th July 2012, 09:06 AM   #1612
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Quote:
Originally Posted by nar View Post
Second is Pearl II with Salas Shunt Reg PSU
That goes without saying! I'm not building anything without it hehe

VTA spacers are there to be tested. But then again, every record is different and you can't adjust every time accordingly. I've tried Guru protractor, which I couldn't get right. Maybe it really takes too much patience?

Joining you for waiting Wayne to chime in.
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Old 11th July 2012, 09:47 AM   #1613
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Hi all,
I presume the total gain for the given circuitry is 55db. What do I need to change to reduce the gain to 40db total gain. This is because I intend to use permanently install a MC SUT which will have about 30db gain. About 70db is ideal for my requirement.
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Old 11th July 2012, 10:04 AM   #1614
Salas is online now Salas  Greece
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I think that the wav files that end with 2 are easily more dynamic and defined.
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Old 11th July 2012, 10:58 AM   #1615
Siberia is offline Siberia  Lithuania
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Thanks for listening, Salas. Stage 1 will go for sale which will hopefuly fund my new cartridge.
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Old 11th July 2012, 12:56 PM   #1616
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Originally Posted by Salas View Post
I think that the wav files that end with 2 are easily more dynamic and defined.
Youpeeee

Quote:
Originally Posted by Siberia View Post
Thanks for listening, Salas. Stage 1 will go for sale which will hopefuly fund my new cartridge.
My bro has P3, mounted a Denon DL 110 on it in replacement of the old Elys cart. It took 2 hours to find roughly the guru points. But once break in is done, what a difference !

Best,

nAr
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Old 11th July 2012, 03:00 PM   #1617
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Quote:
Originally Posted by coolmaster View Post
Hi all,
I presume the total gain for the given circuitry is 55db. What do I need to change to reduce the gain to 40db total gain. This is because I intend to use permanently install a MC SUT which will have about 30db gain. About 70db is ideal for my requirement.
You need to lower R16. To what exact value, it remains a mystery to me and, again, maybe Wayne could help us here. I was aiming for 40 dB too and installed 47K instead of 100K. This resulted in a bit more than 42.5 dB, which I can tell by comparing to my previous stage.
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Old 11th July 2012, 04:25 PM   #1618
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Quote:
Originally Posted by Siberia View Post
You need to lower R16. To what exact value, it remains a mystery to me and, again, maybe Wayne could help us here. I was aiming for 40 dB too and installed 47K instead of 100K. This resulted in a bit more than 42.5 dB, which I can tell by comparing to my previous stage.
Gain figure of 1st stage is roughly 35dB gain
Losses in passive RIAA about 20 dB
2nd Stage gain as per schematic is (R16+R14)/R14 as non inverting opamp
Per schematic x 101 times so, about 40 dB

Total Pearl gain by default 55 dB

To get 40 dB total gain for Pearl II you need to reduce 2nd stage gain to 25 dB or so (= increase feedback !!!)

R16 can be lowered, but you change Cx adjustment too I guess
Passing R16 to 20k gives you : (20+1)/1 = 21 times or 20 log21 = 26,4 dB


Another option is to change R14 value, with a 5k you get

(100K+5K)/5K = 21 times or 20 log21 = 26,4 dB

Ball park maybe

Best,

nAr
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Old 11th July 2012, 04:38 PM   #1619
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I think nar deserves some kind of award here... for helping out so many people in this thread! Good work!
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Old 11th July 2012, 04:41 PM   #1620
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I think nar deserves some kind of award here... for helping out so many people in this thread! Good work!
It is always subject to caution ... and verify by your own experience ... I can make mistakes, epecially whilst doing 3 things at the same time

Click the image to open in full size.

nAr
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Last edited by nar; 11th July 2012 at 04:47 PM.
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