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Old 25th January 2006, 10:41 PM   #1041
gl is offline gl  United States
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Looking at the ZV8 schematic in fig. 7 it strikes me that replacing the lightbulbs with a ccs would produce a first class transconductance amp.

The self biasing feature eliminates any connection (high resistance or otherwise) from the output. reduces the input cap and distortion over similar mosfet amps. It seems almost too simple.

I haven't been paying too much attention the last few weeks so apologies to all if this has been brought up already.

Graeme
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Old 14th February 2006, 07:23 PM   #1042
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Those of you who bother to read this thread deserve a tidbit:

Next week I will release ZV9 "JFET en Regalia" which will get us
an order of magnitude improvement over ZV8.

You will be able to use the ZV8 power supplies and much of the
original circuit, but the light bulbs will go.

Also, those of you wanting to play with current sources will
find allowances for that.

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Old 14th February 2006, 07:46 PM   #1043
gl is offline gl  United States
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Very cool.

Graeme
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Old 14th February 2006, 08:21 PM   #1044
Blues is offline Blues  United States
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Quote:
Originally posted by Nelson Pass
Next week I will release ZV9 "JFET en Regalia" which will get us
an order of magnitude improvement over ZV8.
How can we ever keep up with you Mr. Pass? Do you keep a sample of every Zen version for your personal museum?...if you have one or plan to have one. I'd like to someday just sit down at your museum and just listen to the Zenvolution of sound from V1 to Vn.

Looking forward to an evening of good read and things to learn about the Jfet.
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Old 14th February 2006, 08:40 PM   #1045
steenoe is offline steenoe  Denmark
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Thanks for the splendid news, cant wait to see ZV9
BTW Have a look at the size of those J-fet devices They are pretty small indeed. There are 60 pcs on the pic, with a IRFP240 on top.


Steen
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Old 14th February 2006, 09:51 PM   #1046
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Hmmm...those JFETs look familiar...
Yes, they're pretty small. It'd be nice if they'd make a TO-247 version, but I'm just glad to have them.

Grey
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Old 15th February 2006, 04:50 AM   #1047
Blues is offline Blues  United States
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steen,

you also have a CCSed Zv8 design there for your jfets.
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Old 15th February 2006, 06:05 AM   #1048
steenoe is offline steenoe  Denmark
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Quote:
those JFETs look familiar...
No wonder, I guess
Thanks again, Grey
Quote:
you also have a CCSed Zv8 design there for your jfets.
Yes Blues, I am fiddling with a project like that, but now that NP is putting up ZV9 on PassDIY next week, I think I will wait and see what he has in mind for us this time

Steen
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Old 15th February 2006, 06:49 AM   #1049
Blues is offline Blues  United States
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Quote:
Originally posted by steenoe
I think I will wait and see what he has in mind for us this time

Steen

I'm just drooling in anticipation At this point in my DIY life, it's a cycle of read, , post, read....
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Old 15th February 2006, 08:31 AM   #1050
steenoe is offline steenoe  Denmark
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Quote:
I'm just drooling in anticipation
So am I
Blues, this is what I was planning on. (more or less at least) Its just some cut and paste work for now. The CCS is the one we used for the F2 clone and the capacitance multiplier is the Zen reg. without the zeners Nevermind the designations for now.
I will draw it in Eagle later on. I am looking forward to see if it has the slightest resemblance with the ZV9

Steen

Edit. Be warned, the circuit on the schematic is not a tested design!
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