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Simplistic NJFET RIAA
Simplistic NJFET RIAA
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Old 16th October 2010, 04:54 AM   #5101
keantoken is offline keantoken  United States
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It's one of those modern record players, from Technics. Has one of those snap-on plastic cartridges. It doesn't say.

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Old 16th October 2010, 09:02 AM   #5102
Joao@AltheaMusica is offline Joao@AltheaMusica  Switzerland
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Salas

did you experiment with BJT / FET current source in the 2nd / output stage as well and what are your results? Thinking of using an ZTX450 as current source...
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Old 16th October 2010, 10:41 AM   #5103
Salas is offline Salas  Greece
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Simplistic NJFET RIAA
Quote:
Originally Posted by keantoken View Post
It's one of those modern record players, from Technics. Has one of those snap-on plastic cartridges. It doesn't say.

- keantoken
Do you have the model number so we can check better? It is most probably an MM cart. One SRPP simple one for you is Alex Nikitin's that I have tweaked the published values so to simulate nice for Riaa, and to use film cap couplers. Don't change any values. It has been used in various guises for Creek as OBH-8, and from Cambridge Audio in A3i. Also presented in 2003 here from Alex (member X-Pro) as well as in Radio Hobby magazine of Kiev. So its an Anglo-Russian theme with a Greek Tweak, as good as a vintage double-o seven flick as they come.
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File Type: gif ANMM840.gif (20.7 KB, 395 views)
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Old 16th October 2010, 10:48 AM   #5104
Salas is offline Salas  Greece
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Quote:
Originally Posted by Joao@AltheaMusica View Post
Salas

did you experiment with BJT / FET current source in the 2nd / output stage as well and what are your results? Thinking of using an ZTX450 as current source...
Have cascoded the second stage, didn't like it. No CCS load test.
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Old 17th October 2010, 10:42 AM   #5105
Joao@AltheaMusica is offline Joao@AltheaMusica  Switzerland
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Quote:
Originally Posted by Salas View Post
Have cascoded the second stage, didn't like it. No CCS load test.
Cascoded like in the first stage? What about using a simple current source in the source of the stage?
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Old 17th October 2010, 01:35 PM   #5106
Salas is offline Salas  Greece
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What you have made up to now post it so I can sim it with and without, see the FFT and let you know.
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Old 18th October 2010, 12:34 AM   #5107
keantoken is offline keantoken  United States
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Mine is the Technics SL-Q300.

How do Technics products fare? I've heard there's some good Technics stuff, and I see the name a lot in pawn shops.

- keantoken
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Old 18th October 2010, 12:54 AM   #5108
Salas is offline Salas  Greece
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Much better arms and drive than others in same category. Its a decent consumer one. Cart is MM 2.5mV.
Doing that phono with BC550 I posted for you they match well. It is not a difficult CCT to find parts for I believe.
http://www.youtube.com/watch?v=mK8QpXP3inc
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Old 27th October 2010, 08:49 PM   #5109
sonata149 is offline sonata149  Malta
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Default Are these FETs too weak?

I'm new to fets and as I'm interested in this project I bought 10 pieces 2SK170 and checked them using the method described earlier in this thread: Transistor matching They all measured between 3.5 and 4.5mA. Now Salas's circuits specify 7-8mA. Does this mean they can / should not be used here in the gain stages? Are they at least good for the buffer and the Zener CCS fets or are they to 'weak' to complement the gain stages.

Sorry for the newbie questions but this is how I learned a lot from this Forum.

Regards,
JA
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Old 27th October 2010, 08:59 PM   #5110
Salas is offline Salas  Greece
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Are your parts having the description ''GR'' on them?
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