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Old 28th September 2008, 02:53 PM   #101
Salas is online now Salas  Greece
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The simulator shows that you can try 7mA BL with no source resistor and 24V B+, 2K4 Rd. I did it because I know that people will not find GR as easy as BL, and the latter averages 7-8mA Idss. Use no higher!

The lower the Idss the more Vds on a given resistor, you can increase the Rd a little and go 11V as in the original, when using 4mA GR.

You can fine tune by ear, many options, depends on system and taste.

Also the nF value caps need measuring so to know their real value. Broad 1dB lifts or cuts are very audible.

Those things refer to the original Pacific.
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Old 28th September 2008, 02:56 PM   #102
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thanks salas

iPS I have spare 0,47mf mundorf can I put in the series caps back second jfer (100n) ? need change resistor 2m2?
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Old 28th September 2008, 02:59 PM   #103
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Talking about the Salas Riaa now? If talking about the Mad-K, bigger cap is ok if that is your best quality, but changing the resistor changes the load impedance that the Riaa network sees. If not too drastic a change, say go down to 1Mega, that I recommend for stability with BLs, it will not change appreciably.
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Old 28th September 2008, 03:11 PM   #104
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thanks Salas ,

are for mad_k ....as with supex sound sweet I can push on extract detail...

next step are your suggestion on bl...


caps and resistor are all matched

but my ear are matched???
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Old 28th September 2008, 03:49 PM   #105
Salas is online now Salas  Greece
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Our ''ears'' are the wildest factor...asking too much, listening for specifics, losing the big picture...etc etc

Anyway, if you go coupling with 0.47uF to 1Meg in the Mad K, you need to make the 100R riaa resistor 10R too.
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Old 9th October 2008, 07:26 PM   #106
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Default Re: ultrasimple mm/mc riaa preamp 2

Quote:
Originally posted by Mad_K

Well, enough rambling; do yourself a favour and try this circuit!

Hi Mad K

Just finished and installed a discrete ouput stage on my CDP using fet´s.... sound is unbelievably good.... So I searched for a RIAA with fet´s and found your juicy thread.

Can you provide a PCB for this design ?

I would really apreciate this because I am not a electronics wizz and need all the help you can provide.

Best regards

Ricardo
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Old 9th October 2008, 07:35 PM   #107
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HI go to point to point work very well , I suggest the Salas riaa as have do very hard work for optimize the jfet phono
link
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Old 9th October 2008, 07:51 PM   #108
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Quote:
Originally posted by nicoch46
HI go to point to point work very well , I suggest the Salas riaa as have do very hard work for optimize the jfet phono
link
Thank you
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Old 10th October 2008, 06:58 AM   #109
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You guys really should try cascoding this thing. It really elevates this beatiful little pre to compete with most circuits out there. I agree, when doing the "simple version" P2P is the way to go! When you start cascoding and buffering etc it is often more convenient to have a pcb. I have previosly built versions with 10 transistors/channel. The current version uses 6 transistors/ch. If I should redesign it today, I would probably go with 4 transistors/ch (2 fet + 2 bipolar in cascode)
I was forced to try a new picup recently (My Clearaudio Virtuoso was killed). As a temporary solution I bought the Denon DL160 as it seemed a good value (about 4 times cheaper!) and good match for my Clearaudio Solution/RB250/JFET phono rig. And it works extremely well. It is not as hyper-detailed as the Virtuoso, but has a more balanced sound, with great musical enjoyment. The DL160 stays, and I'm spending all the $$$ saved on records instead!
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Old 10th October 2008, 09:17 AM   #110
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HI Mad_K you are welcome in your threads

as you can see we like your work ,have new thinks about ?

Salas (great boy) in the meantime work hard with jfet
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