john curl said:Jan, negative impedance drive, what is it, and what is dangerous about it?
Like putting instant coffee in a microwave, it could affect the fabric
of the universe and send us all into a wormhole?
Seems some things are mixed up here. The cancelling negative impedance approach of the various types found in the literature (Jung, Lundahl, etc) is not a feedback method (although the circuit driving the xformer may use "mixed feedback" to create that negative Zout. A variation of it that hasn't been mentioned so far is the "zero field" approach, which is reversing the roles of voltage and current and which also cancels the winding resistance with it's negative counterpart, this time on the secondary side.
There are also true feedback schemes accross the xformer, see CineMag AppNote 102 (IIRC) for example.
- Klaus
There are also true feedback schemes accross the xformer, see CineMag AppNote 102 (IIRC) for example.
- Klaus
Nelson Pass said:
Like putting instant coffee in a microwave, it could affect the fabric
of the universe and send us all into a wormhole?
Starbucks instant coffee, now there's a concept.
Hey guys,
This is supposed to be a vacation weekend (US only of course). I read through all the posts to notice that no one mentioned that AP uses Jensen transformers in their input so they can't be that bad.
This is supposed to be a vacation weekend (US only of course). I read through all the posts to notice that no one mentioned that AP uses Jensen transformers in their input so they can't be that bad.
I didn't know they were Jensen. At any rate, they're heavily customized probably.
/OT: You should see the customization they (AP) had done to the ADI (?) DAC's in the freq setting circuits, to the point that they had an extra resistor added on the chip to temp-comp the DAC R-networks. This is real cutting edge design!
Jan Didden
/OT: You should see the customization they (AP) had done to the ADI (?) DAC's in the freq setting circuits, to the point that they had an extra resistor added on the chip to temp-comp the DAC R-networks. This is real cutting edge design!
Jan Didden
PMA said:This:
You mean that roughly 0.0025% difference relative to the minimum?
se
Want to post a schematic or two to prove 'where' API uses audio transformers and how? What is the 'definition' of 'negative impedance'? Come now, some of you studied it in college.
SY said:Your evangelizing paid off in my case.😀
Yeah? Then where's my check? 😀
se
Dimitri, don't remind ME, remind SE. I already read through that this morning, on my own. (I know how to Google). That is where I got the transformer spec sheet example.
john curl said:Good work, PMA. I have seen 'worse' from Jensen, but they don't appear to publish those results anymore.
Don't publish what results anymore?
If you're talking about the THD+N versus input level at fixed frequencies plot that Pavel posted just prior to your post, that came straight from Jensen's datasheet and I think you should retract your comments about what they don't publish anymore and how "lost" they have got.
se
Dimitri showed.
You discuss for discussion, Steve. Such a debater. John said that distortion rose for lower levels and it was proven true, even in the datasheet from which I posted the graph.
You discuss for discussion, Steve. Such a debater. John said that distortion rose for lower levels and it was proven true, even in the datasheet from which I posted the graph.
john curl said:Want to post a schematic or two to prove 'where' API uses audio transformers and how? What is the 'definition' of 'negative impedance'? Come now, some of you studied it in college.
Sure. I'll scan it tomorrow. John, you don't really think I say these things without having the facts, don't you?
Jan Didden
Coffee Experiment!
Wow!.................I guess that cables are old news now! 😀
Mr.Pass you might be on to something...........and since it is a holiday here in the good old USA
http://amasci.com/weird/microwave/voltage2.html
Please go to the bottom of the page.
Enjoy.
Jam
Wow!.................I guess that cables are old news now! 😀
Mr.Pass you might be on to something...........and since it is a holiday here in the good old USA
http://amasci.com/weird/microwave/voltage2.html
Please go to the bottom of the page.
Enjoy.
Jam
Want to post a schematic or two to prove 'where' API uses audio transformers and how?
calm down, John
Attachments
Thanks Dimitri, negative Z drive is fascinating. We even offered it in a power amp, and in that case it is called 'negative damping factor'. You can't use much, why everyone? (Dimitri probably already knows)
Because it is not so good to get amplitude rise "on demand" above all limits 😉 😀 . The lower load impedance, the higher output.
- Status
- Not open for further replies.
- Home
- Amplifiers
- Solid State
- John Curl's Blowtorch preamplifier