F5X -- the EUVL Approach - Page 4

EUVL · 03:21 AM

I have revisited the cascode options in the last couple of days, and read some of Borbely's paper again. He has abandoned the use of bipolar cascode in favour of JFETs in all his new designs, with reasons.

So I have come up with a new JFET cascode which will give better performance than the J111/J174 and yet not more complex than the bipolar cascode. And we shall include that on the PCB layout, together with the J111/J174 option. The amplifier will then remain an all-FET design.

Again, this is only for experimentation purposes. Only actual test will decide whether it brings anything.

Patrick

.

AndrewT · 10:29 AM

Hi,
I have just found this new thread.
Hopefully this will stop all the complainers, moaners, etc from distracting the interested from their goal.

EUVL · 22nd February 2011, 02:07 PM

Thanks for your continued support.

Patrick

kannan_s · 22nd February 2011, 02:15 PM

Quote:

Originally Posted by EUVL

I have revisited the cascode options in the last couple of days, and read some of Borbely's paper again. He has abandoned the use of bipolar cascode in favour of JFETs in all his new designs, with reasons.

Patrick

.

hi Patric
sorry to bother you - take your time to reply
what is the reason for Borbely to switch to FET cascodes?
thanks
Kannan

EUVL · 22nd February 2011, 02:36 PM

Ease of distortion cancellation, if I understand correctly.

Patrick

qusp · 23rd February 2011, 02:12 AM

well i have received no reply from fitzfish on the transformer query. perhaps he will see here. perhaps i am not worthy?

anyone else in the build team i can contact who might know?

perhaps the switch to fets also was congruent with his advertising byline creating 'all fet' designs hehe

pchw · 23rd February 2011, 02:27 AM

Here is what the invoice said:
RC0600 915 5 banded transformer
My invoice number is 5149.

Hope this will help.

qusp · 23rd February 2011, 03:12 AM

thats perfect thanks!!

qusp · 23rd February 2011, 06:36 AM

it has come to my attention that my post above if taken seriously could be taken the wrong way. my post

Quote:

well i have received no reply from fitzfish on the transformer query. perhaps he will see here. perhaps i am not worthy?

was more me thumbing my nose at the sometimes deserving attitude that seems to be going around lately. it was not meant to be taken seriously thus the smiley, as i know others like myself have their own lives they must get on with. so Dave if you read it like this my apologies, i was not being serious, but i guess its still a bit raw for some people at the moment.

all sorted thanks to pchw anyway, so as you were

EUVL · 23rd February 2011, 06:20 PM

I can give you a small piece of good news.

We have been in touch with the forum and are discussing details of the PCB prototyping run.
So we are back on schedule.

Patrick

22nd February 2011, 03:16 AM	#31
EUVL diyAudio Member Join Date: Oct 2003	I have revisited the cascode options in the last couple of days, and read some of Borbely's paper again. He has abandoned the use of bipolar cascode in favour of JFETs in all his new designs, with reasons. So I have come up with a new JFET cascode which will give better performance than the J111/J174 and yet not more complex than the bipolar cascode. And we shall include that on the PCB layout, together with the J111/J174 option. The amplifier will then remain an all-FET design. Again, this is only for experimentation purposes. Only actual test will decide whether it brings anything. Patrick . Last edited by EUVL; 22nd February 2011 at 03:21 AM.

22nd February 2011, 10:28 AM	#32
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, I have just found this new thread. Hopefully this will stop all the complainers, moaners, etc from distracting the interested from their goal. Last edited by AndrewT; 22nd February 2011 at 10:29 AM. Reason: allows me to search for all threads in which I have posted

23rd February 2011, 02:27 AM	#37
pchw diyAudio Member Join Date: Apr 2006 Location: Fremont, California	Here is what the invoice said: RC0600 915 5 banded transformer My invoice number is 5149. Hope this will help. __________________ - Fred -

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22nd February 2011, 02:07 PM	#33
EUVL diyAudio Member Join Date: Oct 2003	Thanks for your continued support. Patrick

22nd February 2011, 02:36 PM	#35
EUVL diyAudio Member Join Date: Oct 2003	Ease of distortion cancellation, if I understand correctly. Patrick

23rd February 2011, 02:12 AM	#36
qusp is choosing a less facetious title... diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	well i have received no reply from fitzfish on the transformer query. perhaps he will see here. perhaps i am not worthy? anyone else in the build team i can contact who might know? perhaps the switch to fets also was congruent with his advertising byline creating 'all fet' designs hehe

23rd February 2011, 03:12 AM	#38
qusp is choosing a less facetious title... diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	thats perfect thanks!!

23rd February 2011, 06:20 PM	#40
EUVL diyAudio Member Join Date: Oct 2003	I can give you a small piece of good news. We have been in touch with the forum and are discussing details of the PCB prototyping run. So we are back on schedule. Patrick