[eric343]

Quote:

Originally posted by Tomo I think significant amount of them cannot simply obtain by few years of experience (which is tiny in comparison to Walt Jung or Jan Didden who are professionally involved.) So I wouldn't say experience is everything. Heck I don't wanna build amps if I had to train for 20 years. But fact is that you can learn great deal from materials without actually experiencing.

Yes, that's the more or less the point of textbooks - so you don't need to dedicate your whole life to electronics (like ppl has; afaik he's been doing this for ~30 years) yet you can still do some pretty damn good work in the field (case study: Apheared). Quote:

I think we are too much into simply experience oriented. We could use some orientations where we can collectively learn stuffs. Perhaps invite some DIY masters like Mr. Pass to give a talk few times a year? Perhaps young ones (me!) to post some paper?

Cool idea! We need some more electro-educational materials, and that would be seriously fun.

Maybe we should orginize a conference...

 

[jeffreyj]

Quote:

Originally posted by binary_digit .... A zener and CRD is all that is required. Hardly complex...

It is needlessly complex, which is what I said the first time. And I was referring specifically to the PPA in which there are a 10k resistor, a 2n5484 FET and a CRD - which is just a more expensive, pre-packaged version of a fet with shorted gate to source - all feeding the power-on LED.

And this circuit won't even reliably work as a "battery is dead" indicator because the 10k resistor bypasses the zener diode/fet/crd mess to feed the LED directly. The total battery voltage would have to drop quite a ways below the zener voltage of 9v before the LED will go out (most LEDs these days will light up with surprisingly small amounts of current.... less than 700uA is not unusual.)

 

[ppl]

On the PPA the 10K resistor is intended to be used as an alternative to the CRD not in Concert with the CRD. This was Morsels and tangent's Idea to use this resistor for those making Home Units only where battery operation is Not required. You will also notice a place on the Board for a JFET. this also is an alternative to the CRD not somthing to be used with the CRD.

Now i don't think that 3 Components to give a Battery Indication is complex at all. Now Back in 1998 when i put this in my First Portable Amp, and went online looking for battery Indicators I found circuits that were IMHO overly complex using 2 or 3 opamps for some. But this is getting way off topic.

 

[ppl]

oops

 

[binary_digit]

jeffreyj>

Sorry, didn't know you were being specific to the ppa.

Would agree that a more expensive part for this function would not be NEEDED but ppl will try and use the best components no matter what. This also means he will use a less expensive part if it performs better for what he intends. It is about the music with this guy not statis of expensive or hard to find rare parts. Kind of a weak link avoidance thing. I asked him if the CRD was NEEDED and he replied "No, use a jfet if ya want. The CRD is small like a resistor and convenient ." and a bunch of other things that destroyed my fragile mind.

If you think thats crazy you should see what he has in mind for the PPRT.

Just thought I might paint a small picture of PPL so you may better understand his madness.

Peace All

 

[jeffreyj]

There seems to be a lot of misunderstanding going on in this particular thread, and I include myself in that claim.

When a part of a circuit is intended to be optional or a substitution, it's supposed to be drawn with broken lines. No broken lines meant, to me, that all of that junk feeding the LED was supposed to be there at the same time. Hence, my eye-rolling.

Finally, there is obviously a substantial difference of opinion here concerning amplifier compensation. I'm not budging in my belief that pole-zero tuning is necessary and often the optimal way of making flexible, high-performance op-amp circuits. ppl feels otherwise. We'll agree to disagree, then, and I'll make no further comment with respect to this thread (which is so far off topic now it ain't funny...)

Regards

edited for clarity

 

[binary_digit]

Right on

Be well
B_D