Ohh, that is my IPS you show here, apart from the drive on the VAS cascode you made, which by the way is really good.
This IPS show things in the recordings I newer heard before. Layerings I didn't even imagine was there. Phase-margin is huge and unity gain stable (at least with my OPS)
/michael
This IPS show things in the recordings I newer heard before. Layerings I didn't even imagine was there. Phase-margin is huge and unity gain stable (at least with my OPS)
/michael
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I don't think I agree. Miller compensation DOES increase the required input signal CURRENT to the VAS, but any voltage input increase to the VAS is relatively incidental. The Miller compensated VAS is a transimpedance stage.
Cheers,
Bob
Your circuits are pretty much 2 symmetrical opposing "blame-less's".
I tried the helper diode/no helper diode in simulation (below 1 and 2).
Besides the fact that the diode brings both sides of the CM to Bob's
optimum (1.3V CM + .3V VAS Re) , the plots look (almost) the same.
A more careful exploration show H4 and H5 drop a couple of db. I did
not have any large (10db) increases with or without the diode.
Just a 1-2ppm THD20k drop with the diode.
I'm not sure if you could hear those couple db H4/5 .... but the diode
does even the CM out (voltage wise).
Some call the diode " magic" , my present blameless simulation is the
first one good enough to actually see those couple PPM.
10c diode - why not ??
OS
Hi OS, thank you for going through the circuit.
What was the 0db level your FFT plots was referring to? I was doing 56.7Vpk or 200w into 8-ohm in simulation and got the 11db difference. Have just tried at 50W and got the similar results you did, i.e., no difference in THD-20K, helpered or not. I guess the diode made a bit difference only at the extreme levels where the amp is about to clip.
It would always make me uncomfortable if a transistor works at a Vcb around 0 so I would bite the bullet and put in that 10c diode helper. Maybe I am just being irrational.
And if you run out of pads you can get a non profit license for cheap.
I have one good to 1000 pads.
You still should enter the schematic first with the 500 pin version. The software will compare your finished design to the schematic. It's silly not to take advantage of all the functionality of the software.
Yes i would like to do thatif I had right software
Use open source software: no limits, no cost, free to use
e.G.
- Kicad
- gschem and pcb from geda-project (I'm using this tools since > 10 years)
Hi astx,
Actually, I am running Fedora Workstation 22 now and have tried gschem. I got as far as schematic capture and that's all. Ever wonder why I didn't redo that work in DipTrace? I hate doing work twice. New projects are being done from the start, but it's nice to be able to simply manually route a simple PCB without having to go the whole route.
Any hints on the package you are using? BTW, DipTrace is running fine on the Linux emulator for Windows XP - Wine. I love the name!
-Chris
Actually, I am running Fedora Workstation 22 now and have tried gschem. I got as far as schematic capture and that's all. Ever wonder why I didn't redo that work in DipTrace? I hate doing work twice. New projects are being done from the start, but it's nice to be able to simply manually route a simple PCB without having to go the whole route.
Any hints on the package you are using? BTW, DipTrace is running fine on the Linux emulator for Windows XP - Wine. I love the name!
-Chris
A lot of these programs can import files from other software. That schematic may be useful.
A good part of the work is actually picking out your components. This is all done automatically when the schematic is drawn. Having ratlines and highlighting connections really speeds up the laying out of the components when doing the board design too. You really don't save that much work skipping part of the process. This is really apparent if you're working on larger scale projects.
I actually ran out of pads once so I bought the nonprofit license. Also felt it is a great app so I wanted to help out with development. It's paid off in ease of use and more features I care to learn. Bit of a learning curve but once past that it's great.
Hi David,
I can only hope I get to the point where I run out of pads! For a guy who is use to working with pen and paper, this automatic stuff takes some work to get comfortable. The first larger project I will work on is a nicer transistor matcher PCB.
I tried the HCL and H2O2 etchant today. I can see it etches very clean lines, fine detail is preserved nicely. My first patterns were the transistor matcher and some CFP transistor substitute boards. Had some problems, so the matcher boards will take more time. I did get some resistors in today for them. About $75 worth, and I am still waiting for some other parts to arrive. Fun.
Hi jwilhelm,
I do see your point. I just never worked like that. I did use Orcad back when it was very young. All it did was schematic capture, but I did use it faithfully to keep records. I will work with these programs to try and get entire future projects documented. If if saves me work, so much the better.
-Chris
I can only hope I get to the point where I run out of pads! For a guy who is use to working with pen and paper, this automatic stuff takes some work to get comfortable. The first larger project I will work on is a nicer transistor matcher PCB.
I tried the HCL and H2O2 etchant today. I can see it etches very clean lines, fine detail is preserved nicely. My first patterns were the transistor matcher and some CFP transistor substitute boards. Had some problems, so the matcher boards will take more time. I did get some resistors in today for them. About $75 worth, and I am still waiting for some other parts to arrive. Fun.
Hi jwilhelm,
I do see your point. I just never worked like that. I did use Orcad back when it was very young. All it did was schematic capture, but I did use it faithfully to keep records. I will work with these programs to try and get entire future projects documented. If if saves me work, so much the better.
-Chris