scott wurcer said:
There is a special obsession in our technical culture with finding out who did what first and reminding everyone of it ad nauseam. For instance I'm sure Jim Williams would not complain if you pointed out Lord Kelvin did such and such first. You can probably bore yourself to death reading about how Steve Jobs lifted the MAC interface from Xerox PARC and at least a 100 persons views on what "really" happened.
Hmmm... I thought it was DEC who inspired research projects in universities in order to promote X11 instead of Sun's NeWS based on Adobe's PostScript?
Speaking of a Steve Jobs, my wife's friends' boyfriend told once how a man wearing worn out jeans come to his father who had a PCB business asking to make PCBs promising to make him rich... His father trusted the guy.
John,
Regarding the now identified Hitachi parts, I am a little puzzled that you didn't latch onto them after you had samples. We heard about them around 1975 in a publication from a UK company called AMBIT, and have been able to get supplies consistently since then, and they have become our general purpose transistors in all designs where their ratings fit.
While still in Australia we bought them from the UK, but since moving to Europe we have a stable source in Germany, as linked in a post above.
Did your Hitachi source not supply?
Regards, Allen (Vacuum State)
Regarding the now identified Hitachi parts, I am a little puzzled that you didn't latch onto them after you had samples. We heard about them around 1975 in a publication from a UK company called AMBIT, and have been able to get supplies consistently since then, and they have become our general purpose transistors in all designs where their ratings fit.
While still in Australia we bought them from the UK, but since moving to Europe we have a stable source in Germany, as linked in a post above.
Did your Hitachi source not supply?
Regards, Allen (Vacuum State)
Modern electronic industry don't stay on place:
http://cgi.ebay.com/ZTX1053A-ZETEX-NPN-MEDIUM-POWER-TRANSISTOR-300-EA_W0QQitemZ110288808442
http://cgi.ebay.com/ZTX1053A-ZETEX-NPN-MEDIUM-POWER-TRANSISTOR-300-EA_W0QQitemZ110288808442
Told you so, Allen!
As I said before, these devices did NOT work properly in my patented circuit that I was using at the time. They had about 10 times more distortion than expected. PMA, please take note, since you modeled my circuit on SPICE.
I have been asking those who should be in the know what the problem was. It is still a mystery to me, EVEN with the multipage data sheets I have now in front of me, and the only clue that I have gotten so far is 'quasi saturation' or something like that, from Scott Wurcer. I would like to know more. It is an interesting problem, to me, at least.
As I said before, these devices did NOT work properly in my patented circuit that I was using at the time. They had about 10 times more distortion than expected. PMA, please take note, since you modeled my circuit on SPICE.
I have been asking those who should be in the know what the problem was. It is still a mystery to me, EVEN with the multipage data sheets I have now in front of me, and the only clue that I have gotten so far is 'quasi saturation' or something like that, from Scott Wurcer. I would like to know more. It is an interesting problem, to me, at least.
john curl said:Told you so, Allen!
As I said before, these devices did NOT work properly in my patented circuit that I was using at the time.
The current seems low but the Hitachi parts definately have sat problems. (see pic 2N4403 on right) 2N4403 remains low out to 100mA 2SA1084 has Vsat of 2 volts at 40mA.
Attachments
john curl said:
This one, right?
http://www.diyaudio.com/forums/showthread.php?postid=1527569#post1527569
Tino
Right on, Zinsula, it has been so long ago, that I even forgot where I put the patent number.
Scott, I want to say thanks, because this is just the sort of info I was looking for. You have a better eye for it than me, but can you imagine what I thought when these devices seemed to behave completely differently in a circuit that I had made commercially for more than 5 years already, compared to all other parts?
Scott, I want to say thanks, because this is just the sort of info I was looking for. You have a better eye for it than me, but can you imagine what I thought when these devices seemed to behave completely differently in a circuit that I had made commercially for more than 5 years already, compared to all other parts?
Scott, if you would and if you have the complete data sheet on the 2SK1084, please look at the OTHER parameters, not just Rbb'. Where are the trade-offs? This is an almost perfect device, except for F(t) which is still fairly high. Betas up to 800? Vceo up to 120V? Cob = 3.5pf? Everything at once? It is SUPER COMPLEMENTARY PAIR!
Dear Lumba;
words without context mean nothing, as you know. If some topology is close to linear one that does not mean it is linear. And if to screw down bias of one transistor of that particular topology linearity may be worse. Of the topology, not of the transistor! Transistor is a highy non-linear device, by definition. No linear devices exist that can amplify signals.
The magic of high end audio is the art of reproducing of audio with the minimum of audible errors using non-linear devices. Be devices linear, there would be no such art.
Please ask the next time your source of information to explain you phrases that you repeat here: what, where, and when. Otherwise they are meaningless. They may be true in one context, wrong in another context, but most of the time they are irrelevant to the discussion.
Sorry for a bitter pill.
Edit: the rest deleted. You may ask by e-mail if you want to continue.
words without context mean nothing, as you know. If some topology is close to linear one that does not mean it is linear. And if to screw down bias of one transistor of that particular topology linearity may be worse. Of the topology, not of the transistor! Transistor is a highy non-linear device, by definition. No linear devices exist that can amplify signals.
The magic of high end audio is the art of reproducing of audio with the minimum of audible errors using non-linear devices. Be devices linear, there would be no such art.
Please ask the next time your source of information to explain you phrases that you repeat here: what, where, and when. Otherwise they are meaningless. They may be true in one context, wrong in another context, but most of the time they are irrelevant to the discussion.
Sorry for a bitter pill.
Edit: the rest deleted. You may ask by e-mail if you want to continue.
homemodder said:
I was eyeballing the output impedance, it is very nonlinear, much worse below 2V @40mA. The actual Vsat becomes moot since there is that quasi-sat like behavior. It is correct the 2N4403 does not have exactly the same graph. The graphs provided do not allow an exact extraction of the Vbe modulation with Ic at near 0 Vcb. It does not take much for a small amount of distortion.
scott wurcer said:
High collector saturation resistance was common for all high voltage devices (Kirk effect, effective base's grow in thickness with current).
Edit: what happens to Ft @40mA? It may be the clue. I don't know your terminology, we used to call it Critical Current where Ft drops by square root of 2 times
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