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Simplistic NJFET RIAA
Simplistic NJFET RIAA
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Old 14th March 2013, 03:11 PM   #9411
Salas is offline Salas  Greece
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Simplistic NJFET RIAA
Not of major importance, but use a K117GR left off from some SSLV1.1, or degenerate a BF245B down to 5mA instead of a K170. BF245A are plenty here BTW.
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Old 14th March 2013, 03:14 PM   #9412
massimo is offline massimo  Italy
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Salas suggested 2SK117.
BF245A are available from Germany on eBay
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Old 14th March 2013, 03:15 PM   #9413
massimo is offline massimo  Italy
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Ops... too late
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Old 14th March 2013, 03:16 PM   #9414
massimo is offline massimo  Italy
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Quote:
Originally Posted by Salas View Post
BF245A are plenty here BTW.
Found one in a Pitagyros last year
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Old 14th March 2013, 03:17 PM   #9415
Salas is offline Salas  Greece
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Simplistic NJFET RIAA
Yes, it biases the tzatziki.
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Old 14th March 2013, 03:38 PM   #9416
merlin el mago is offline merlin el mago
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Quote:
Originally Posted by massimo View Post
Found one in a Pitagyros last year
Quote:
Originally Posted by Salas View Post
Yes, it biases the tzatziki.
Plenty of reasons to come back to Greece.
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Old 14th March 2013, 03:43 PM   #9417
massimo is offline massimo  Italy
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You won't believe, but I was just planning my summer island hopping today
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Old 15th March 2013, 02:42 PM   #9418
Jallhalla is offline Jallhalla  Norway
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Haha. I got five on ebay from some colder islands. Britain. They were cheap in piles from hong kong, but I guess they will arrive quicker from within europe. Are these really only available from islands? People are not kidding when they say you can learn stuff from diy audio.
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Old 16th March 2013, 10:06 AM   #9419
RCruz is offline RCruz  Switzerland
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Simplistic NJFET RIAA
Another one up and running.

4 x k170 input fets
K72-6 Teflon 15n caps
K71-4 Polystyrene 47n caps
Full on second stage buffer (with fet ccs)

Now listening with a DL160.... no clipping... super silent... dynamic... Tone seems correct, must let it settle for a while, then retrim voltages and serious listenning ahead.
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File Type: jpg Wallis 2 4 x k170.jpg (419.9 KB, 210 views)
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Old 16th March 2013, 10:16 AM   #9420
RCruz is offline RCruz  Switzerland
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Simplistic NJFET RIAA
First channel worked right away.... the second one was build during rush hour so I was not able to set correct voltages on 1st stage.... I had .3v offset in the input and too much current on the fets (150mV Vdrop on the Rs).... I decided to remove the fets and place one at the time so I could track the culprit..... One bad fet I found (maybe due to too much heat).

After that, I had to cover the four trannies with a special "enclosure" so they should share the same heat... now music
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