The Holy Grail Follower Output Stage

[Vunce]

Awesome! 🤩

Thanks lhquam.

 

[ACnotDC]

This is a great project, lhquam. Many thanks for your time and effort
P. S. The country names in the list are translated to Romanian, I think. Vitalica knows it better, how it happened

 

[generg]

Vitalie rules.....!

:--))

 

[Chri12]

If still available, I am interested.

gary s - Australia
dBel84 - USA
yoaudio - USA
EIArte - USA
kannan_s - USA
von Ah - USA
tom1066 - USA
ACnotDC - Germany
Arthur-HK
william2001 - USA
ItsAllInMyHead - USA
Integra - Canada
Sonnenschein - Germany
birdbox - USA
eriksson-Sweden
Asanden - The Netherlands
manniraj - USA
Robert8 - USA
mordikai - USA
lucadvt - Italy
aud1out - Canada
brimax - Italy
E_Fortier - Canada
CodyT - USA
ml48 - UK
Zigi - Poland
Myleftear - Switzerland
woofertester - USA
wg45- USA
Rush USA
geoturbo- Italy
Vitalica - Romania
Chri12 - Finland

 

[brian.goodman]

If still available, I am interested.

gary s - Australia
dBel84 - USA
yoaudio - USA
EIArte - USA
kannan_s - USA
von Ah - USA
tom1066 - USA
ACnotDC - Germany
Arthur-HK
william2001 - USA
ItsAllInMyHead - USA
Integra - Canada
Sonnenschein - Germany
birdbox - USA
eriksson-Sweden
Asanden - The Netherlands
manniraj - USA
Robert8 - USA
mordikai - USA
lucadvt - Italy
aud1out - Canada
brimax - Italy
E_Fortier - Canada
CodyT - USA
ml48 - UK
Zigi - Poland
Myleftear - Switzerland
woofertester - USA
wg45- USA
Rush USA
geoturbo- Italy
Vitalica - Romania
Chri12 - Finland
Brian Goodman - Canada

 

[Murdoc]

If still available, I am interested.
gary s - Australia
dBel84 - USA
yoaudio - USA
EIArte - USA
kannan_s - USA
von Ah - USA
tom1066 - USA
ACnotDC - Germany
Arthur-HK
william2001 - USA
ItsAllInMyHead - USA
Integra - Canada
Sonnenschein - Germany
birdbox - USA
eriksson-Sweden
Asanden - The Netherlands
manniraj - USA
Robert8 - USA
mordikai - USA
lucadvt - Italy
aud1out - Canada
brimax - Italy
E_Fortier - Canada
CodyT - USA
ml48 - UK
Zigi - Poland
Myleftear - Switzerland
woofertester - USA
wg45- USA
Rush USA
geoturbo- Italy
Vitalica - Romania
Chri12 - Finland
Brian Goodman - Canada
Murdoc - Austria

 

[Alain Dupont]

If still available, I am interested.
gary s - Australia
dBel84 - USA
yoaudio - USA
EIArte - USA
kannan_s - USA
von Ah - USA
tom1066 - USA
ACnotDC - Germany
Arthur-HK
william2001 - USA
ItsAllInMyHead - USA
Integra - Canada
Sonnenschein - Germany
birdbox - USA
eriksson-Sweden
Asanden - The Netherlands
manniraj - USA
Robert8 - USA
mordikai - USA
lucadvt - Italy
aud1out - Canada
brimax - Italy
E_Fortier - Canada
CodyT - USA
ml48 - UK
Zigi - Poland
Myleftear - Switzerland
woofertester - USA
wg45- USA
Rush USA
geoturbo- Italy
Vitalica - Romania
Chri12 - Finland
Brian Goodman - Canada
Murdoc - Austria
Alain DUPONT - France

 

[lhquam]

Progress Report:

• I now have over 170 each of the FQA28N15 and FQA36P15 FETs. The last shipment of 100 each has a more favorable parameter distribution and will improve the sorting process.
• 100 PCBs have been fabricated and shipped.
• I have measured and sorted all FETs. The FQA28N15 FETs have a much better parameter distribution than the FQA36P15, which limits the good matches to not much more than 36 stereo channels, about the present count of sign-ups.

FETs sorted into bins by gm.

black=#28N15 FETs, yellow=#36P15 FETs
Left image: gm with 8R load line. Right image: gm with 8R load line and -.3S shift of black

 

[e_fortier]

This is very impressive work, thank you so much.

 

[lhquam]

I need feedback from those signed up for the ZD25-Mini PCBs and FETs.
I just discovered an artwork error of the boards that requires about 10 minutes per board to fix. What is weird is that bench tests did not reveal the error and when I run simulations of the erroneous circuit they look bad, unlike the bench behavior.

If enough diyers are willing to wait, I will reorder at a rather nominal cost (about $1.20 per board).
Otherwise I need to know how many are willing to live with the sub-optimal circuit or willing to do the modifications themselves.


Multiple approaches to dealing with the artwork error:

1. Live with the artwork error, informing the diyers of the error and how to correct the artwork if they wish.
2. Reorder PCBs with the corrected artwork. This would add about $2.40 per diyer and 3 weeks delay.
3. Make the artwork correction before shipping the PCBs. About 10 hours of tedious work by me.
4. To correct the error requires cutting a trace and adding a wire. These two images show two alternatives to correcting the error. The first image is the easier way where the wire is added after components are soldered into place.
5. The requires cutting the trace and removing solder mask in two places for wire attachment. This is a more tedious operation.

 

[gary s]

I would be happy to correct the error - by the way the images you refer to are not showing.

 

[lhquam]

Refresh the post. For some reason I have problems adding image until some security check has been done. I have to post the replay and edit it to add the images.

 

[geoturbo]

I am fine correcting the error too, thanks

 

[gary s]

Yes images are now showing in the post.

Easy enough correction, I would be happy with your option 1.

 

[lhquam]

BTW: PCBs just arrived. The fabrication quality is first rate.

 

[kannan_s]

Hi I can do the correction and would happily do for all you have done so far. This is a simple work.

 

[william2001]

I can easily perform the modification myself. But happy to go with majority rule here.

 

[dBel84]

I too am happy to correct the board.. dB

 

[brian.goodman]

Happy to do the correction. Thank you for all the work you’ve done in design, board layout, ordering, matching devices, and shouldering the costs to get this far.

 

[Chri12]

I am happy to do the correction.