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STEREO FET BUFFER  on ebay
STEREO FET BUFFER  on ebay
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Old 29th December 2008, 05:03 PM   #11
Zen Mod is online now Zen Mod  Serbia
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STEREO FET BUFFER  on ebay
Default Re: 2sc2240 & 2sa970

Quote:
Originally posted by rlim
What are the bipolars there for? Aren't the fets followers?

cascodes ;

that way fets are working in constant voltage mode
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Old 29th December 2008, 05:37 PM   #12
sivan_and is offline sivan_and  India
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can i replace the opamps in my system with these ? i have 2 opamps per channel..first one comes after the volume control then the second one constitutes the baxindall tone control circuit, will it be really worth all the trouble i use NE5532 opamps.
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Old 9th April 2009, 02:42 AM   #13
feathed is offline feathed  United States
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Will this e-bay buffer work with +/- 12V? or +/- 18V?
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Old 9th April 2009, 03:22 AM   #14
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STEREO FET BUFFER  on ebay
Default Re: Re: Re: Re: STEREO FET BUFFER on ebay

Quote:
Originally posted by lineup

...
In UK the seller of this stuff at ebay is tubeshunter
http://stores.ebay.co.uk/tubeshunter
Good luck if you want to deal with this "tubeshunter". I have received half the part listed in one of its kits and after 2 months he does not even bother to respond to me anymore after using all kind of excuses. Finally I never got the missing parts and this seller is out of my list forever!
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Old 9th April 2009, 08:41 AM   #15
DorinD is offline DorinD  Romania
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Default Re: Re: 2sc2240 & 2sa970

Quote:
Originally posted by Zen Mod



cascodes ;

that way fets are working in constant voltage mode
Sorry, I'm not understanding yet. Without bipolars those FETs are also in the same "constant voltage mode" as drains are connected to a voltage source, or not?!
Personaly, I'm thinking that this is not a cascode at all because is not used as intended. If you make good decoupling of the V+/- sources with some good capacitors, bipolars could be taken out with no problem.

Thanks.
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Old 9th April 2009, 01:57 PM   #16
h_a is offline h_a  Europe
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Yeah, a little strange part choices; low noise bipolars for cascode, but no low noise jfets. I see it the same as Dorin, the cascode is of little use here. Also it seems - although the point in the schematic is missing - that the cascode is output-modulated for which I also don't see much reason here.

Nevertheless I don't see a reason why the buffer shouldn't perform well.

Have fun, Hannes
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Old 2nd July 2010, 12:38 AM   #17
idlehands is offline idlehands  United Kingdom
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I found was a huge benefit of adding caps from the power rails to ground on the board itself, in this case 100uf, 10uf and 0.1uf. Without the caps it was pretty poor.
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Old 20th January 2012, 04:30 PM   #18
colin.hepburn2 is offline colin.hepburn2  Scotland
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Hi All
Well just got the buffer today from china on a slow boat again I have been sent an updated version in that the board is now double sided now it seems to me that the screen print is wrong in the power supply pin ID from left to right -15volt 0v +15volts which seems the wrong way round plus the + 15v is connected to 0V
i have emailed the seller on this but he denies this and said the board is same as the old one and refuses the help this image is the old board the one I was expecting to get
Click the image to open in full size.
And this is the new double sided board
Click the image to open in full size.
And the underside of new board you can see that the -15volt connects both channels and the +15volt connects to ground
Click the image to open in full size.
Here is the old schematic
Click the image to open in full size.
can anyone help me get the supply wiring correct thanks
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Old 20th January 2012, 07:56 PM   #19
feathed is offline feathed  United States
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Good Luck! The SOB still owes me money!
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Old 20th January 2012, 08:08 PM   #20
colin.hepburn2 is offline colin.hepburn2  Scotland
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Quote:
Originally Posted by feathed View Post
Good Luck! The SOB still owes me money!
Yep thatís the second time this seller has refused to help after he has been paid second change an all that he wonít get my money again thatís for sure
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