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Old 14th July 2010, 09:37 PM   #271
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Just looking at the four 2sk370's in parrallel at the input.
Does this lower distortion?
Or is it to run the input stage at higher bias levels?
Why do you need 4?
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Old 14th July 2010, 09:41 PM   #272
massimo is offline massimo  Italy
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Quote:
Originally Posted by thanh1973 View Post
Why do you need 4?
Lower noise.
Read original Pearl artcle: front end is very similar if not the same
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Old 14th July 2010, 09:47 PM   #273
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I am not sure I understand?
Based on my logic (which I am starting to question these days), I would have thought 4 would give you more noise, because your dividing the signal by 4 across the devices, while the noise of each device is the same.
So the signal to noise ratio has reduced by 4.
I know I am most definitely wrong here, I just want to explain what I am thinking.

Hope you can explain this.

Last edited by Melon Head; 14th July 2010 at 09:50 PM.
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Old 14th July 2010, 09:52 PM   #274
massimo is offline massimo  Italy
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Lower noise (6 dB) and even higher gain.
Again: read the original Pearl article.
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Old 14th July 2010, 10:38 PM   #275
gotoma8 is offline gotoma8  United States
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read the article and it would seem that 4 stages are better than two..
also, is the article on the Pass DIY Site, for the Pearl, valid for the Pearl 2? What's the difference, if any? Thanks
T
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Old 14th July 2010, 10:42 PM   #276
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Quote:
Originally Posted by massimo View Post

Lower noise (6 dB) and even higher gain.
But that doesn't really answer my question. I believe it, I just don't understand why
Is that lower noise for the complete preamp, or lower noise for the input stage?

Where do I find the original article?
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Old 14th July 2010, 10:43 PM   #277
massimo is offline massimo  Italy
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Gotoma8, not 4 stages (the whole phono has 2 SE stages only), but 4 cascoded critters in parallel in the front end.
AFAIK Pearl and Pearl 2 are sharing the same topology in the front end (some value might differ) while the new circuit has a different output stage (2nd stage)
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Old 14th July 2010, 10:46 PM   #278
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http://passdiy.com/pdf/pearlphono.pdf
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Old 14th July 2010, 11:00 PM   #279
gotoma8 is offline gotoma8  United States
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Quote:
Originally Posted by massimo View Post
Gotoma8, not 4 stages (the whole phono has 2 SE stages only), but 4 cascoded critters in parallel in the front end.
AFAIK Pearl and Pearl 2 are sharing the same topology in the front end (some value might differ) while the new circuit has a different output stage (2nd stage)
Thanks for the clarification.
I had just ordered a set of the XONO Boards from Anadigit, they have not arrived yet, but hope that they will be good as i hear good things. The Pearl 2 is the next project after the XONO. Is the part's list on the article for the Pearl valid? I asked Sherilyn at Pass about the parts list, and she wasn't sure. She's going to ask Wayne to find out where we can get the parts list for the P2.

t
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Old 14th July 2010, 11:54 PM   #280
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Quote:
Originally Posted by thanh1973 View Post
while the noise of each
Hey dude, give me a little privacy in the John's, i don't want your Johnson so close to my Johnson.
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