Re: Okay! Enough bickering!
Why not strip out all posts that are not pertinent to "Krill - The little amp that might..."?
Moderate the personalizing. Shouldn't this thread be about the amp rather than some peoples' design prejudices and some peoples' emotional sensitivities?
anatech said:
I guess we may have to split some stuff out, and trash the noise. My first inclination would be to split the sim stuff out, but I'm open to suggestions here. To that end, what do you people want to have stay, and what should be in a different thread?
Why not strip out all posts that are not pertinent to "Krill - The little amp that might..."?
Moderate the personalizing. Shouldn't this thread be about the amp rather than some peoples' design prejudices and some peoples' emotional sensitivities?
MJL & ostripper:
It depends on how much bias voltage is needed for the output stage, the devices used and so on.
If the output stage only needs a little bias voltage they will probably do harm. If the output stage needs more bias voltage for some reason those resistors are needed so that the bias transistors are kept close to (but not in total) saturation. DC offset and strange behaviour will happen otherwise.
If there is DC offset at the output it's probably an indication that they might be needed. Perhaps not the full 56 ohms, and I see there are trimmers in parallell to adjust this.
BTW, have you measured voltage drop C to E on those bias transistors in the built circuit?
It depends on how much bias voltage is needed for the output stage, the devices used and so on.
If the output stage only needs a little bias voltage they will probably do harm. If the output stage needs more bias voltage for some reason those resistors are needed so that the bias transistors are kept close to (but not in total) saturation. DC offset and strange behaviour will happen otherwise.
If there is DC offset at the output it's probably an indication that they might be needed. Perhaps not the full 56 ohms, and I see there are trimmers in parallell to adjust this.
BTW, have you measured voltage drop C to E on those bias transistors in the built circuit?
OK, MJL, I thought you were being divisive in building what you did & then saying it was close enough. You can see how I felt that some major elements were left off what I considered the circuit we were all talking about, hence my accusations towards you & my request to understand what you were trying to prove!
Apologies if what you built was a genuine effort to build an accurate Krill OPS! No hard feelings, I hope
Edit: Can we all agree on a definitive schematic for the 50W, 100W & 200W output stages? The VGS isn't important, its the OPS that is unique & interesting.
Chris I don't know how you can facilitate this so that anybody visiting the thread will see these agreed schematics without having to wade through 40 pages?
Apologies if what you built was a genuine effort to build an accurate Krill OPS! No hard feelings, I hope
Edit: Can we all agree on a definitive schematic for the 50W, 100W & 200W output stages? The VGS isn't important, its the OPS that is unique & interesting.
Chris I don't know how you can facilitate this so that anybody visiting the thread will see these agreed schematics without having to wade through 40 pages?
You had to change values since you didn't use steves parts
a "nobrainer".
Same with using the 2sc/sa 's for the drivers , my krill
oscillated , so I added resistors.
I also used the KSA's for the bias gen, but had to up the
CCS currents to 10mA to get crossover distortion to
a acceptable level. VERY predictable outcomes.
None of this "bastardizes" the original design , since the
outcome is the same...it works.
OS
megajocke said:
Again, I wasn't looking for audio nirvana here, just to see if this configuration behaves as my sim suggests.
The sim indicated "relatively low distortion"- this is not visible on a waveform on my scope - check.
The sim said "stable" - this is definitely visible on the 20k squarewave - check.
Sums up what I wanted to know for now. I may build a more permanent version (but, like everything else I build, it will not be the "by the book design").
I have reviewed the latest schematic and stripped out the ancillary BS (not entirely necessary to the circuits basic operation). It's attached - compare it to mine.
Attachments
c2cthomas
When you are referring to an old schematic and some values on resistors and so on, I think it would be ok if you post the schematic you are talking about in your post. As you know it has been some schematics in this thread.
megajocke
You are right in what you are saying.
Cheers
Stinius
When you are referring to an old schematic and some values on resistors and so on, I think it would be ok if you post the schematic you are talking about in your post. As you know it has been some schematics in this thread.
megajocke
You are right in what you are saying.
Cheers
Stinius
That is matter of device choice. I have noticed that in
the most popular DIY amps (DX and quasi amps) they
use MJE340/350 or TIPXXX almost exclusively. The reason for
this is worldwide availability.
In most of the diy amps a substitute can be used (standard EF)
with no problem, but not in the krill.
maybe multiple groups of krills (power levels / common devices)
this would allow more to build it.
OS
anatech said:
Ha, and this is what you wrote to me in the Blowtorch thread:
anatech said:
And:
anatech said:Hi Joshua_G,
LOL!
You really don't add much here, except for comic relief. You are acting like you've always wanted to moderate a forum, but you haven't a clue when to moderate and when tobe quiet.
I understand you want to be John's little cheering section, but he really doesn't need one. He can stand on his own two feet, all by his little self.
Suggest that some folks here need to switch to "decaf" and/or try some doctor prescribed "mellowing" medicine?
I think that the sim is good to discuss. Discuss, not confront or be contentious.
If I were a moderator, I think that i would have "adjusted" some attitudes by one means or another long ago. I think this shows that there is a wide latitude and relative lack of censorship.
Imho this comes roughly under the heading of "shouting fire in a crowded theater". To make the idea clear, I'm referring to the idea that there should be no self censorship nor moderator "censorship" - meaning that everyone should just spout off the very first thing that comes into their head. Eh?
It's not the technical or informational content of some posters, it is the deliberate and explicit or implicit tone, attitude, that has nothing to do with anything factual or informational.
Let's say this about what I just said: I'm being diplomatic.
_-_-bear
"...comes a time when the blind man takes your hand and says don't ya see..." - Jerry Garcia & Robert Hunter
I think that the sim is good to discuss. Discuss, not confront or be contentious.
If I were a moderator, I think that i would have "adjusted" some attitudes by one means or another long ago. I think this shows that there is a wide latitude and relative lack of censorship.
Imho this comes roughly under the heading of "shouting fire in a crowded theater". To make the idea clear, I'm referring to the idea that there should be no self censorship nor moderator "censorship" - meaning that everyone should just spout off the very first thing that comes into their head. Eh?
It's not the technical or informational content of some posters, it is the deliberate and explicit or implicit tone, attitude, that has nothing to do with anything factual or informational.
Let's say this about what I just said: I'm being diplomatic.
_-_-bear
"...comes a time when the blind man takes your hand and says don't ya see..." - Jerry Garcia & Robert Hunter
Nobody seems to "get it" here. if you use different devices
you MUST make a variant of the circuit. It is not "improved",
,but needed for proper operation with
different devices.
The same as if you swap LTP devices , your input stage
would require different degeneration resistors and/or
a different compensation scheme.. not improved , but
required for proper operation.
OS
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