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Old 21st November 2012, 11:33 PM   #1671
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Default thanks I will

I take you mean the one on the pass site?
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Old 23rd November 2012, 08:11 AM   #1672
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http://www.passdiy.com/pdf/PEARL 2.pdf

Page 3 : "The overall gain of the circuit as shown is 55 dB @ 1K Hz. Decreasing R14 from 1K to 300 Ohms gives 10 dB more gain when desired for lower output cartridges. R15 which normally would be shorted to 0 ohms can be replaced by a resistor to provide more gain as an alternative to reducing the value of R14. C15 has been placed on the board to allow for additional adjustment of equalization. In both cases these values are up to you."
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Old 24th November 2012, 11:01 PM   #1673
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Default My Pearl II

Finished the Pearl II. I guess I'm having the same issue as other where there is an output inbalance. Right channel is louder than left channel.
All things being equal, is it the LED reference voltage that's not correct?
Is there a way to match the LEDs? Seen LED matching in another phono thread, but would like to know if the Pearl II LEDs require different type of matching.


Also, 60db gain is not enough for the Denon 103R. Has .25mV output.
Have to crank it past 3 o'clock on the BOZ-J volume.
Should I go for a SUT or can the Pearl II handle the low level by rising the gain further?

Thanks,

Vince
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Old 24th November 2012, 11:04 PM   #1674
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Beauty! How do you know there's an output imbalance? Is it audible or did you measure it?
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Old 24th November 2012, 11:08 PM   #1675
Mr. dB is offline Mr. dB  United States
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Quote:
Originally Posted by vdi_nenna View Post


Also, 60db gain is not enough for the Denon 103R. Has .25mV output.
Have to crank it past 3 o'clock on the BOZ-J volume.
Should I go for a SUT or can the Pearl II handle the low level by rising the gain further?
Apart from the position of the volume knob, how is the noise when you get things to a satisfying level?
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Old 24th November 2012, 11:11 PM   #1676
6L6 is online now 6L6  United States
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Measure the voltage across the LED, see if it's different. Although it has little to do with gain as far as I can tell...

If you are dying to have an adjustment to get your outputs even, make R15 a multi-turn variable reistor and tweak it there.

Quote:
Originally Posted by Mr. dB View Post
Apart from the position of the volume knob, how is the noise when you get things to a satisfying level?
I was going to ask the same thing. Do you not have enough system gain with your pre turned all the way up?
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Old 24th November 2012, 11:43 PM   #1677
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Quote:
Originally Posted by vdi_nenna View Post


Also, 60db gain is not enough for the Denon 103R. Has .25mV output.
Have to crank it past 3 o'clock on the BOZ-J volume.
Should I go for a SUT or can the Pearl II handle the low level by rising the gain further?

Thanks,

Vince

Vince, I put step-ups in front of mine, after trying the resistor tricks. Very happy with it.
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Old 24th November 2012, 11:46 PM   #1678
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It's totally audible imbalance.

No noise when playing a record past 3 o'clock, beteen tracks I hear s hiss, but it's not bad.

My previous phono is a Vincent pho 111.
It has better gain. Only have to turn it to 1-2 o'clock for nice level.
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Old 25th November 2012, 12:36 AM   #1679
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Quote:
Originally Posted by Tea-Bag View Post
Vince, I put step-ups in front of mine, after trying the resistor tricks. Very happy with it.
Tea-bag,

I placed a switch on the front to switch between 55 and 65 db.
Was thinking of using a SUT that brings up the gain 2x or 3x, instead of the usual 10x.
This way I can continue to use the MC levels instead of the MM levels.
Any thoughts on this?

If its not the LED causing the imbalance, what else could it be?


PS. On a hunch I went back to listen again. The imbalance has to do with switching between 56 and 65 db.
I cracked the volume using the 56 db setting and its fine. The imbalance happens when its switched to the 65 db setting. The resistors must not be matched somehow, although I checked them before installing them.
That's a relief!
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Last edited by vdi_nenna; 25th November 2012 at 12:52 AM.
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Old 25th November 2012, 02:49 AM   #1680
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What power amp are you using?
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