Pearl Two

[Russellc]

Scuse me.
"in situ" is fancypants latin for "at location", you measure the cap while it's mounted on the board, 5pF is uncanny little.

The 5pF and the 1M resistor make a high pass filter, ~31.847 Hz with f = 1/(2*Pi*R*C) , dampens everything below that by 10dB per decade.
Means, if you feed the cap a signal from a sinus generator that's 1/10th of that frequency, you'd see an amplitude on the output that's 10dB smaller if the cap is 5pF.
If you use two known caps of different value, you can precisely figure out the stray capacitance of the board.

(stuff i had poly-u classes in, both math classes and audio amp electronics, so please don't see me as some wise-guy jinni)

Thank-you for describing the technique in detail. I knew what you meant be "in situ" I just wasnt following on the "how to" of it. I'll have to wait until I have a little more equipment to pull that off. All in good time.

Thanks again,

Russellc

 

[Zen Mod]

F=1/(2xPixRxC)=1/(2xPix1000000x0,000000000005)=31830=31K830Hz

 

[jacco vermeulen]

What is missing?

Sorry about that, i just ran an estimate by head.

pF times a Million is 1/Million, so 1 divided by (5pF *1M) is 1/5th times a Million, is 200,000
200,000 divided by 2*3 is 33,333
3 is 4-2/3 % off for a rounded off pi of 3.14
Makes 31.847Hz, so the real corner frequency is ~31.847Hz or ~31,847 for the US.
(i'm a turd)

 

[Nelson Pass]

Are we sending out 8 FETS or 12 with the boards?

I just got back from the coast, and I checked to confirm that
concurrent with the new price it will be 6 matched parts per board.

 

[godfrey]

200,000 divided by 2*3 is 33,333

i.e. about 30 kHz, not 30 Hz

 

[ichiban]

I just got back from the coast, and I checked to confirm that
concurrent with the new price it will be 6 matched parts per board.

Is there an option for the early purchasers, that were sent 4 per board, to get the needed 2 more matched sets.

 

[Russellc]

Is there an option for the early purchasers, that were sent 4 per board, to get the needed 2 more matched sets.

Same here, glad to pay up for the matched pieces needed!

Russellc

 

[Benedetto]

If this world would be fair,
your need would be heard......

 

[ichiban]

Same here, glad to pay up for the matched pieces needed!
Russellc

Yes, I wasn't looking for freebees, but would like to purchase the matched pairs we would need.

 

[Russellc]

Yes, I wasn't looking for freebees, but would like to purchase the matched pairs we would need.

exactly. The deal was what it was, I would have to purchase them anyway.
I just dont want to have to buy a bunch of them, learn to match them, obtain what I need and match them, if I can just purchase them. Hardly a reason to declare a "perfect world" unless someones's world is WAY messed up. Its only a component. I've had the ZEN aand Bride of Zen for over 10 years with out building them, I'm sure this can wait without anyone's world not being perfect.

Otherwise, how are these dudes matched? If its doable for me, I'll match a load of them. Now, everythings perfect again!

I'll call and see what the dealio is at Pass Labs.

Russellc

 

[Tea-Bag]

Guys, member BLUES sells matched Toshiba little FETs and BIG fets. I would PM him.
My guess is that the first Q6-Q9 will work with set of four received in kit, and Q4-Q5 need to be matched. I am not sure if matching between channels is needed.

 

[Russellc]

I called Pass Labs, they are still deciding what to do about this. They will announce when all is worked out. So I'm just going to sit tight and wait.

Russellc

 

[Blues]

Guys, member BLUES sells matched Toshiba little FETs and BIG fets. I would PM him.
My guess is that the first Q6-Q9 will work with set of four received in kit, and Q4-Q5 need to be matched. I am not sure if matching between channels is needed.

Thanks for the assist once again Mike! You're closing in on John Stockton...

Wormhole to my Thread on my signature line...

 

[ichiban]

Just wondering, can the 2SK170BL be used inplace of the 2sk370s?
Would there be any resistor value changes required?

 

[Zen Mod]

Just wondering, .......

same part , just different case .

 

[ichiban]

same part , just different case .

Thanks.

 

[Zen Mod]

NB - because of different package - 370 have different dissipation rating

in any case - 170 always can substitute 370 , but 370 can't always substitute 170

 

[Nelson Pass]

For those who bought the original sets, we will offer the
4 extra matched Jfets for $20.

 

[BoilermakerFan]

For those who bought the original sets, we will offer the
4 extra matched Jfets for $20.

Do the new boards sets include two sets of matched quads?

 

[Nelson Pass]

The standard offering is one channel board + 6 matched Jfets
for $100 + frt. You need 2 of these for stereo.