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B1 Buffer Preamp
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Old 11th December 2008, 03:16 PM   #1001
AndrewT is offline AndrewT  Scotland
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Originally posted by sandstorm33
I will order matched 170's from Tech-DIY.
They do not need to be matched.
The upper jFET is the common drain/source follower amplifier and the lower is the CCS load for that single transistor amplifier. All that is needed is similar Idss.

read post 983.
regards Andrew T.
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Old 11th December 2008, 03:27 PM   #1002
Blues is offline Blues  United States
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Default Re: Poor Serbian Man B1

Originally posted by Zen Mod

you can try this
After all this years, now I get it...Choky you are the Zen (Master's) Mod(ifier).
Life simplified! Leap into the Warpspeed wormhole... http://www.6moons.com/audioreviews/warpspeed/1.html
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Old 11th December 2008, 03:47 PM   #1003
Babowana is offline Babowana  South Korea
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Originally posted by AndrewT
because the designer says to use BL grade.
If so, you had to quote the designer's from the beginning.
Or, you should know the reason by yourself.

As far as I understand, the voltage gain of the source follower is dependent on the transconductance, not on the Idss. But, it seems that Idss is to be considered in design because the load might need certain amount of current. Nevertheless, I have thought that we could use LSK389A of the lower Idss--with somewhat higher distorsion. This why I was giving you the question.

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Old 11th December 2008, 04:13 PM   #1004
Zen Mod is offline Zen Mod  Serbia
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B1 Buffer Preamp
Default Re: Re: Poor Serbian Man B1

Originally posted by Blues

After all this years, now I get it...Choky you are the Zen (Master's) Mod(ifier).

naah ...... I feel more like The Little Match Girl ....... Papa is constantly refusing to adopt me .......

( speaking of that - I always think that H. C. A. was one sick baztardo , selling that story to kids - as kids-tale )
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
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Old 11th December 2008, 06:11 PM   #1005
vitalstates is offline vitalstates  United Kingdom
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H.C.A or Oscar Wilde?
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Old 12th December 2008, 01:25 PM   #1006
jacco vermeulen is offline jacco vermeulen  Netherlands
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Even today, some might still view Mr Wilde more as an H.anti-C.A because of not complying to Queensberry rules : no match lighting below the waistline.
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Old 12th December 2008, 04:10 PM   #1007
WithTarragon is offline WithTarragon  United States
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Default four channel version

Please indulge my simple-minded questions.

I will be constructing a 4 channel version of the B1 on perf board.
The first question regards the power supply section to the four channels. My first thought is to leave the power supply as it is. Then tap the connections for channels 3 and 4 from
A) the line going to R103/R203
B) the line going to Q200/Q200
C) the line returning from R105/R205

I assume the current draw is still trivial even for the extra 2 channels. I also assume the voltage at all 4 Gates will still be 1/2 the PS voltage.
I will also try to make sure the grounds are all tied as closely together as possible.

My second question is about the capacitors. I assume my money is best spent on getting the fanciest capacitors for C101 & 201 (and in my application C301 & C401)

Have I missed something?

Thanks in advance,
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Old 16th December 2008, 03:33 PM   #1008
merlin2069er is offline merlin2069er  Canada
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hmm, I didn't realize that the led diode was directional.

Click the image to open in full size.

I'll have to pull them out. I've got plenty.
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Old 17th December 2008, 04:20 PM   #1009
vonfilm is offline vonfilm  United States
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I have populated my Pass-DIY B1 board but I am a little confused about hooking up the 24 stepped ladder mono attenuators that I purchased on ebay from 8Audio. They have an In, Out and Ground connection. How does this correspond to the CCW, W, And CW of the Pass boards? Also how do I hook up the DPDT switch? See the link below to 8Audios wiring diagram:


Does anyone have any pictures of their completed Pass DIY boards to show and tell?
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Old 17th December 2008, 09:02 PM   #1010
Nelson Pass is offline Nelson Pass  United States
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B1 Buffer Preamp
Most likely In = CW, Out = Wiper, Ground = CCW
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