Wow, it almost looks like some Ghz RF receiver with that cooper wave guides, I'm wondering what noise floors this beast is hitting for all this screening taking place there, have to find this thread.... I didn't had to go to such extremes as my noise floor is bearly -70, -90dB on 50Hz and harmonics sensitive frq area. I traced every cm of wiring and now have 100% confidence that whats left is from cart, if I put foil on it, everything is clean. I refuse to post my cookie box shielded proto pic versus this peace of art 😀 So if what is left can't be taken care off by running balanced in stage I'm afraid it looses the whole point. Now I could be dumb or blind or both this evening, but I'm having second thoughts about this affair. It seems that the only reason why it works in proto is finite resistance of sk170 current sources. If I cascode them, everything starts to swing widely. Current just has no return path so it circulates between mirrors. Sim's do confirm this. So we have to reference inputs to ground, but then we have 2 noise sources that isn't shunted with cart resistance. I guess they would not add precisely by sqr root because of balanced CMRR but for sure they will lift up the noise floor by some amount. Have to check it in proto, and that I'm afraid would have to wait for tomorrow.
Attachments
Current mirror
Hi Joachim,
Now this is what I call a phono amp 😀
I'm gonna dream about it tonight 😛
you never cease to amaze me.
Cheers,
Audiofanatic 😉
Hi Joachim,
Now this is what I call a phono amp 😀
I'm gonna dream about it tonight 😛
you never cease to amaze me.
Cheers,
Audiofanatic 😉
Good you stashed, because right now almost everything listed as J74 is as real as Milli Vanilli.😀
Jose, circuit Post 5083 has not being tested but i think we will find a solution.
Salas, i am using the 2SJ74 in many circuits and i looked quite early where to get them.
If there is interest i can organize a group buy.
Salas, i am using the 2SJ74 in many circuits and i looked quite early where to get them.
If there is interest i can organize a group buy.
Hi there,
sad news from the Milling front.
Due to a suspected serious Heart-attack,
my "Milling-man" is off the Job for at least
three month.
So i have to see what i can do as a alternative.
Keep you informed...
@Joachim,
this Motor-thingie is very interesting too.
Because i've build two variations for AC-motors.
the first was this one;
SinCos - die Motorsteuerung
After a bigger GB i've still got some sets in stock.
The second;
Roehren-und-Hoeren :: Thema anzeigen - Luxusnetzteil für Synchronmotoren mal anders
They are almost the same concept except serial/usb connectivity.
Sorry, both links are german.
sad news from the Milling front.
Due to a suspected serious Heart-attack,
my "Milling-man" is off the Job for at least
three month.
So i have to see what i can do as a alternative.
Keep you informed...
@Joachim,
this Motor-thingie is very interesting too.
Because i've build two variations for AC-motors.
the first was this one;
SinCos - die Motorsteuerung
After a bigger GB i've still got some sets in stock.
The second;
Roehren-und-Hoeren :: Thema anzeigen - Luxusnetzteil für Synchronmotoren mal anders
They are almost the same concept except serial/usb connectivity.
Sorry, both links are german.
Then a Premotec could be used for example.
We should really open up a new thread. I do not have much time the next 3 month though.
We should really open up a new thread. I do not have much time the next 3 month though.
I tried to buy Morgan Jones book "Valve Amplifiers! 4th edition. It is sold out at the moment so it has sold very well.
That input stage looks a bit strange. I'd return the collectors to the supply rails. I think this arrangement as shown will work for JFETs, but is sub optimal for bipolars.
Yes, returning the collectors to the opposite supplies gives a diamond buffer. That will work better, sure. The circuit shown is based on an idea of Baxandall who found that base and collector of a BJt can be on the same potential. It was used by QUAD and later others but with feedback.
I have a better idea that works fine. I have already build that input stage and presented it on this thread under the name "Hulk". I think i have that stage still lying around somewhere in perfect working condition. I will put it in the system tonight. As far as i remember, it sounded pretty damn good. Martina and i also used it on ETF2010 to good advantage.
I have a better idea that works fine. I have already build that input stage and presented it on this thread under the name "Hulk". I think i have that stage still lying around somewhere in perfect working condition. I will put it in the system tonight. As far as i remember, it sounded pretty damn good. Martina and i also used it on ETF2010 to good advantage.
