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JFET BoZ (Bride of Zen by Nelson Pass)
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Author:  mwhouston [ 22 Oct 2010, 22:00 ]
Post subject:  JFET BoZ (Bride of Zen by Nelson Pass)

After building the Nelson Pass B1 buffer preamp I was looking for something just as simple but with voltage some gain. Once more from Nelson Pass comes-up this simple creation - BoZ (Bride of Zen):

JFET BoZ: http://www.diyaudio.com/forums/pass-lab ... ost1226532

So I thought I may give it a try. Anyone else built one of these? Any comments?

Author:  Gio [ 23 Oct 2010, 11:41 ]
Post subject:  BoZ (Bride of Zen by Nelson Pass)

HI Mark, I have not tried one but I am looking forward to see how you make out! :)

Here is the link to the original Nelson Pass Bride of Zen PDF article: http://www.passdiy.com/pdf/brideofzen.pdf

Cheers

Author:  mwhouston [ 23 Oct 2010, 16:30 ]
Post subject:  Re: BoZ (Bride of Zen by Nelson Pass)

Gio:

Zen must have married twice because it is not the one I'm building. Mine is the one on my link.

Author:  KrammeAcoustics [ 23 Oct 2010, 19:42 ]
Post subject:  Re: JFET BoZ (Bride of Zen by Nelson Pass)

Yep ...there are both a BoZ and a JFET BoZ, so it's easy to mix up names. :? ( two different constructions ).

Author:  KrammeAcoustics [ 23 Oct 2010, 19:51 ]
Post subject:  Re: BoZ (Bride of Zen by Nelson Pass)

The Zen list, as we know of: http://www.passdiy.com/projects.htm

But, are names like CoZ Cousin of Zen, FoZ Father of Zen, DoZ Daughter of Zen used ( ? ).

I would prefere names like NoZ Neighbour of Zen or MoZ Mistress of Zen. :mrgreen:

Author:  mwhouston [ 23 Oct 2010, 22:45 ]
Post subject:  Re: JFET BoZ (Bride of Zen by Nelson Pass)

MoZ is looking good. In Australia a Mozzy is a mosquito. Mistress of Zens is cool then. I may just call it the Mozzy! Great if it really flys (from an audio point of view).

Have all the parts. May start tonight.

Author:  KrammeAcoustics [ 24 Oct 2010, 16:03 ]
Post subject:  Re: JFET BoZ (Bride of Zen by Nelson Pass)

Cross my fingers :xfingers: , hope your MoZzy Image are capable to sting the following coupled amplifier of yours.

I would also like to build this ( BoZ ) amplifier, because it's capable ( as buffers are ), to wear long signalcables. I could use this instead of, or as suplement to my Bastard 6J5GT Tube Buffer.

I also got all parts except of the JFET 2SK170, instead i've got some PN4302. Anyway i guess they will work fine, if PS stays below 30 VDC. If i've understanded NP right, the IDSS of the FET will be around 5 - 10 mA.

2SK170, Drain current IDSS
VDS  10 V, VGS  0 2.6  20 mA

PN4302, Drain Current IDSS
VDS  -15V, VGS  0 0.5  5.0 mA
( Q = are max of 5 mA enough ...hmmm ). :?
A lower constant current through the FET should be solved, by a higher value of loadresistor ( ex. 20 Ohm ), but then the amplifier maybe won't work as intended.

Author:  mwhouston [ 28 Oct 2010, 06:56 ]
Post subject:  Re: JFET BoZ (Bride of Zen by Nelson Pass)

BoZ cct. brd.completed.

See imges below. Once again I used the Russian 0.1uf PIO, and 10uf poly (input cap and output cap respectively) (snubbed with 0.1uf ploy). All on vero-brd. spare central tracks shorted to ground to act as a gatherer. Alps blue velvet 25k pot and slim solid brass knob.

PS: 1R0 to 10,000uf cap, 10R0 to second 10,000uf cap. 5% WBT silver solder used. This will go into a Hammond anodised Al case.

Attachment:
BoZ_IIss.jpg
Attachment:
BoZss.jpg

Author:  dtsup1 [ 28 Oct 2010, 12:19 ]
Post subject:  Re: JFET BoZ (Bride of Zen by Nelson Pass)

Hi Mark,

As usual, pls write a review on the sound ;)
I think the jfet preamp designs are awesome.
Natural warmth. I see that you have mixed some carbon and metal film resistors.

Those Topcon caps were the same types I used in my first ever chip amp in Melbourne.
Well they exploded 1 feet from my face. (from inverted polarity) :mrgreen: :mrgreen:
Fun times...hahhaa...

PS: I still have a phobia whenever wiring up a chipamp.

Author:  Dan [ 28 Oct 2010, 15:25 ]
Post subject:  Re: JFET BoZ (Bride of Zen by Nelson Pass)

Where are the pics Mark ?

-Dan

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