I think LTSpice results may give good ideas of differences between circuits. But they many not show correct absolute values. I have had LTSpice results that were much higher and much lower than real life measurements.
My build power supply is +62V, and the measured distortion was not half of Nelson's measured distortion.
My build power supply is +62V, and the measured distortion was not half of Nelson's measured distortion.
Yeah, we are in agreement, i think these are the weak and strong spots of spice simulations, high precision, but low absolute accuracy.
I thought so too that the amount by which THD drops with increased voltage is unrealistic, it has been elsewhere in the thread that it occurs but not by this much, so again accuracy issue.
For completeness, attached simulation if anyone wants to play with Pa's updated design from #686. Thanks to EUVL for template.
I thought so too that the amount by which THD drops with increased voltage is unrealistic, it has been elsewhere in the thread that it occurs but not by this much, so again accuracy issue.
For completeness, attached simulation if anyone wants to play with Pa's updated design from #686. Thanks to EUVL for template.
Measure the I-V curves of a real J113, and overlay them upon the simulated I-V curves of a J113 from LTSPICE. How big is the error? Is it 0.001% ?? 0.01% ?? 0.1% ??
Do you expect a simulation of a 5-transistor circuit's "distortion", to have greater accuracy than the simulation of the individual semiconductors?
Do you expect a simulation of a 5-transistor circuit's "distortion", to have greater accuracy than the simulation of the individual semiconductors?
The model for J113 in Spice itself is way out, not even close.
We found out when building the UDNeSS.
Same can be said for the "official" LU1014 model.
But to be fair, these models are created for their intended use -- switching, and not linear amplification.
Toshiba models are more reliable.
Patrick
We found out when building the UDNeSS.
Same can be said for the "official" LU1014 model.
But to be fair, these models are created for their intended use -- switching, and not linear amplification.
Toshiba models are more reliable.
Patrick
Thanks for all the constructive replies! I am also often quite surprised by how helpful people are - in hifi and other sub-communities.
@Nelson Pass - thanks for the sympathies. It was truly meant as constructive feedback - I checked out Jim Tieman - they look like solid guides! Thanks! Wished we have a Burning Amp Camp in Denmark! p.s. had to google "Heathkits" 😅🎶
@Markjohnson Absolutely, I can walk away. But I heard so much great about Nelson (admiration and respect) that I get a bit stubborn and also, without critique nothing gets better.
@william2001 Thanks for trying to explain the different parts, I built the Akitika Power Amp kit but I had little idea what I was doing, other than soldering resistors, as stated in the manual. IPS+VAS+OS - I certainly want to understand those different concepts better and how they can be applied in different scenarios, much appreciated. I did revisit a few high school electronics concepts. I got an M.Sc. in economics and I am OK in math and statistics and picking up new stuff.
@myleftear Yeah, I think it was more the frustration of not being able to even figure out what was meant by "Front End" - is this a preamp, a power amp, or a preamp with gain, etc? Also, English is not my first language, so when you get into electronics or any other sub-topic, sometimes it is harder to understand.
@ianbo Thanks for the encouragement - I was a bit hard, and I agree with your assessment there, however, It was a critique of the PDF paper and specifically its ability to lure in a new DIY like myself with the label "simple" - he might have meant a simple design. Anyway, It was not a critique of Mr. Pass - I actually praised his strong brand in the community in the post.
For comments on my personal character, intelligence - I assume you wrote it for fun and joking to lure me more into the community and test persistence 🙌👏💕
Happy Saturday!
/OJ
How big is the error for Toshiba transistors (measured real devices vs SPICE simulation)? 0.001% ?? 0.01% ?? 0.1% ??
Do you expect a simulation of a 5-transistor circuit's "distortion", to have greater accuracy than the simulation of the individual semiconductors?
If you would bother to take a look at the UDNeSS thread, you would see how good Spice simulations could agree with measurements.
I know analogue IC companies who only use simulations before they spend any money to make reticles for lithography.
Of course they have better tools, but it also depends on how you use those tools.
Cheers,
Patrick
I know analogue IC companies who only use simulations before they spend any money to make reticles for lithography.
Of course they have better tools, but it also depends on how you use those tools.
Cheers,
Patrick
Sorry, have to ask again. Can't find any R6, 682 ohm 0.5W 1%. Only 681 ohm at 0.5 W or 682 ohm at 0.1W. What to use?
For those who want to maybe glean some more information, the book i was reading conveniently had some pretty related chapters, especially chapter 4 (page 67 - 74), but also the preceeding and succeeding chapters.
http://www.designinganalogchips.com/_count/designinganalogchips.pdf
Shouldnt be an issue sharing i hope, since it's hosted by the author.
http://www.designinganalogchips.com/_count/designinganalogchips.pdf
Shouldnt be an issue sharing i hope, since it's hosted by the author.
Can this trick be applied to the Stasis FE? I need someone smarter than me to smack me on the head with a learnin' stick.. Can it be done? Would it help? What to do with all the VAS current limit stuff on the Stasis..R12,R13,R14,Q8? Can both "features" live in harmony?
Fearless Amplifier Builders don't need current limiting...
Hello! I bought 100 pieces of J113. All IDSS have 5-7 ma. Can they be used?
I live in Moscow and will not be able to purchase the kits. Can anyone share the Gerber file? I will be very grateful.
I live in Moscow and will not be able to purchase the kits. Can anyone share the Gerber file? I will be very grateful.