FirstWatt J2 - Page 9

Nelson Pass · 24th September 2009, 09:02 PM

You know me. I use whatever part I have too many of.

tms0425 · 24th September 2009, 09:09 PM

Quote:

Originally Posted by Nelson Pass

You know me. I use whatever part I have too many of.

So that's why it looks like maybe two J109's per channel - you must have them all

A little old, a little new...

R-K Rønningstad · 24th September 2009, 09:53 PM

Sony VFET paper from the AES.

Nelson Pass · 24th September 2009, 11:02 PM

I do have a copy of that in pdf.

R-K Rønningstad · 25th September 2009, 05:43 AM

Going to take your advice/proposal and buy some old V-FETs and give them a try. Hope I do not fry them the first thing I do...
I read somewhere (The Vintage Knob probably) that at least for the early V-FET amps (Yamaha B-2), one should not use a variac - dunno what Variac says about this....

V-FETs are depletion devices and normally on. Does it somehow have anything to do with this, or is it just bad engineering?

RK

Nelson Pass · 25th September 2009, 11:51 PM

It depends. What topology were you thinking of?

fredlock · 12:34 AM

J2.JPG

I'm just wondering if these are the (2) J109 and (2) K170 discussed in the manual? Also, that 6 legged chip is still a mystery? What is the role of this chip in the circuit?

Nelson Pass · 26th September 2009, 01:59 AM

Trying to tease information out of me. So naughty.

Lee35210 · 26th September 2009, 02:33 AM

Only 6-legged chips I can recall ever seeing are opto-couplers. Those others may be Magna-Fets, the wonder gain device.

Zen Mod · 26th September 2009, 08:07 AM

Quote:

Originally Posted by Nelson Pass

Trying to tease information out of me. So naughty.

greedy kids

this time I'm not even thinking about J2 ;

I'll wait Papa's schm patiently to learn something new .
in fact - I'm curious just about that 6-legged critter

26th September 2009, 12:30 AM	#87
fredlock diyAudio Member Join Date: Jan 2008	J2.JPG I'm just wondering if these are the (2) J109 and (2) K170 discussed in the manual? Also, that 6 legged chip is still a mystery? What is the role of this chip in the circuit? Last edited by fredlock; 26th September 2009 at 12:34 AM.

26th September 2009, 02:33 AM	#89
Lee35210 diyAudio Member Join Date: Jan 2004 Location: Irondale, AL	6-legged creature Only 6-legged chips I can recall ever seeing are opto-couplers. Those others may be Magna-Fets, the wonder gain device. __________________ Been there, Heard that, Forgot what I was listening to!

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24th September 2009, 09:02 PM	#81
Nelson Pass The one and only Join Date: Mar 2001	You know me. I use whatever part I have too many of.

24th September 2009, 11:02 PM	#84
Nelson Pass The one and only Join Date: Mar 2001	I do have a copy of that in pdf.

25th September 2009, 05:43 AM	#85
R-K Rønningstad diyAudio Member Join Date: Jan 2006 Location: Oslo	Going to take your advice/proposal and buy some old V-FETs and give them a try. Hope I do not fry them the first thing I do... I read somewhere (The Vintage Knob probably) that at least for the early V-FET amps (Yamaha B-2), one should not use a variac - dunno what Variac says about this.... V-FETs are depletion devices and normally on. Does it somehow have anything to do with this, or is it just bad engineering? RK

25th September 2009, 11:51 PM	#86
Nelson Pass The one and only Join Date: Mar 2001	It depends. What topology were you thinking of?

26th September 2009, 01:59 AM	#88
Nelson Pass The one and only Join Date: Mar 2001	Trying to tease information out of me. So naughty.

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