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Beast with a Thousand JFETs
Beast with a Thousand JFETs
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Old 4th September 2009, 01:29 PM   #101
jan.didden is offline jan.didden  Europe
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Quote:
Originally Posted by zhoufang View Post
Does it read 0.0024% THD at 1W without any NFB?
Not only that, it also reads 0.02% at 20W if my eyes don't desert me. This is examplary performance with no fb. I don't know how Nelson comes up with these schemes, but he picks winner after winner. My virtual hat goes off for him.

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Old 4th September 2009, 02:44 PM   #102
oliverniekamp is offline oliverniekamp  Germany
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This thing is realy fascinating for me.
But there shurely is a huge problem, how can i build this by myself?

Mr. Pass you realy know what patience and endurance are, do you?
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Old 4th September 2009, 02:48 PM   #103
Nelson Pass is offline Nelson Pass  United States
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Beast with a Thousand JFETs
It's the parts.

So far I only have the one, as it takes about 12 hours
to stuff it up, and I have 3 more to go.

Of course I still have to build a front end for it, so we'll see
what the final result might be.

If you want to think really tweaky, here's the 8 ohm
curve on a pair of car batteries:
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Old 4th September 2009, 03:20 PM   #104
Spooky Electric is offline Spooky Electric  Germany
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Old 4th September 2009, 04:15 PM   #105
zhoufang is offline zhoufang  Singapore
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As a follow DIYer, I'll be more interested if it will be a similiar project using thousands of N-jfet in single-ended setup.
Even if it take twice the number of Jfets to get the same output power and the THD is slightly higher.
Of course N-jfet has much lower capacitance, so for a set amount of output power, SE setup might actually have lower capacitance load for the front-end.

Unless the LSJ74 is released, then it will be a different story.
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Old 4th September 2009, 04:24 PM   #106
Rembulan is offline Rembulan  Indonesia
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Quote:
Originally Posted by zhoufang View Post
As a follow DIYer, I'll be more interested if it will be a similiar project using thousands of N-jfet in single-ended setup.
Even if it take twice the number of Jfets to get the same output power and the THD is slightly higher.
Of course N-jfet has much lower capacitance, so for a set amount of output power, SE setup might actually have lower capacitance load for the front-end.

Unless the LSJ74 is released, then it will be a different story.
I need 3 weeks to find 2 pcs sj74 in my local (indonesia) market, N Jfet is far far easier

Last edited by Rembulan; 4th September 2009 at 04:29 PM.
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Old 4th September 2009, 05:25 PM   #107
flg is offline flg  United States
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Quote:
Originally Posted by Nelson Pass View Post
It's the parts.

So far I only have the one, as it takes about 12 hours
to stuff it up, and I have 3 more to go.

Of course I still have to build a front end for it, so we'll see
what the final result might be.

If you want to think really tweaky, here's the 8 ohm
curve on a pair of car batteries:
Ohh, starting to sound like my paralell LU1014s in B1 configuration... Like Mosnter B1??? But as John Curl might like to read, lower Rg!!!
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Last edited by flg; 4th September 2009 at 05:27 PM.
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Old 4th September 2009, 06:12 PM   #108
slam is offline slam  United States
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Papa are we going to see this in BA09? It would be a big attraction.

I start to see a big jfet group by now... 1000 pcs per person, and we will get a better rate if we reach a 100K lot
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Old 4th September 2009, 06:19 PM   #109
Nelson Pass is offline Nelson Pass  United States
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Originally Posted by slam View Post
Papa are we going to see this in BA09?
I don't know. Maybe.

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Old 4th September 2009, 09:33 PM   #110
Nelson Pass is offline Nelson Pass  United States
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Beast with a Thousand JFETs
BTW, I have a batch of Sony 2SK82 and 2SJ28's coming in.

Does anyone know the pinouts on them?

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