Hi there
Just as mighty ZM suggested, I would like to start a thread about my F4-build. This is my second power-amplifier after ACA, so many details are really obscure to me.
The build-process and everything that comes with it is a great, no, a fantastic experience, thanks to all here @ diyaudio.
Although it is nearing completion, I very well may have one or the other question.
I will post those, as well as presentations of the process, as follow-up posts right here.
I‘m confident they will be answered [emoji4]
Before I begin to shamelessly exploit your knowledge [emoji83], let me say thank you so much for your patience, sense of humour, sharing expertise, and above all of course, thank you very very much Mr. Pass!
Just as mighty ZM suggested, I would like to start a thread about my F4-build. This is my second power-amplifier after ACA, so many details are really obscure to me.
The build-process and everything that comes with it is a great, no, a fantastic experience, thanks to all here @ diyaudio.
Although it is nearing completion, I very well may have one or the other question.
I will post those, as well as presentations of the process, as follow-up posts right here.
I‘m confident they will be answered [emoji4]
Before I begin to shamelessly exploit your knowledge [emoji83], let me say thank you so much for your patience, sense of humour, sharing expertise, and above all of course, thank you very very much Mr. Pass!
1) continuity
Almost everything‘s installed.
I just wanted to make sure there’s no continuity between hot and neutral on the IEC... and there are 40 something Ohms.
Must be the toroid‘s primary?
Will unplug it and repeat the measurement...
Almost everything‘s installed.
I just wanted to make sure there’s no continuity between hot and neutral on the IEC... and there are 40 something Ohms.
Must be the toroid‘s primary?
Will unplug it and repeat the measurement...
You have the resistance of the primary windings plus the resistance of the thermistor.
This seems about right
Are you on 240V AC?
how many NTCs you have ?
in fact, pics can help
40R sounds too much, even if having 2 NTCs in series
in fact, pics can help
40R sounds too much, even if having 2 NTCs in series
Yes, 240V
Question was early because... chassis ground and that thermistor (1pc) isn‘t connected yet.
I closed the switch and measured IEC hot against neutral.
Will replace battery, connect the rest and come back.
Will have to be more cautious about my silly questions.
[emoji849]
You should have two thermistors
1) Soft Start Thermistor between dual primary windings
2) Ground Lift Thermistor between PSU 0V and Chassis
The soft start thermistor should be installed already if your transformer is wired up.
1) Soft Start Thermistor between dual primary windings
2) Ground Lift Thermistor between PSU 0V and Chassis
The soft start thermistor should be installed already if your transformer is wired up.
if you switch off ( with switch
) , it must be open circagain, post pictures
we will ask for details, if needed
Dumb measurement (new battery) IEC hot (brown) to IEC neutral (blue):
All disconnected, switch open: no continuity
All disconnected, switch open: 8.3 ohm
Small xformer connected, switch open: 2 ohm
Both xformers connected, switch open: 45 ohm
1) from IEC towards switch
2) from switch towards softstart-board
3) PSU 0v to chassis
4) IEC Ground to chassis
Thermistor from toroid primary 0 not yet installed...
All disconnected, switch open: no continuity
All disconnected, switch open: 8.3 ohm
Small xformer connected, switch open: 2 ohm
Both xformers connected, switch open: 45 ohm
1) from IEC towards switch
2) from switch towards softstart-board
3) PSU 0v to chassis
4) IEC Ground to chassis
Thermistor from toroid primary 0 not yet installed...
aha
I see we still have missing info ........... you have softstart circuit there, so reading 40 or so ohms is to expect
anyway - give us larger plan pictures so we can see arrangement of everything
and - you got me veery confused here :
switch open in all cases ?!?!
post pics, plenty of them
I see we still have missing info ........... you have softstart circuit there, so reading 40 or so ohms is to expect
anyway - give us larger plan pictures so we can see arrangement of everything
and - you got me veery confused here :
switch open in all cases ?!?!
post pics, plenty of them
Argh.
No of course, the switch was closed I repeat the switch was closed.
Sorry my bad.
grounding the tranny...
As you could see in the last image I posted (last, above) my toroid comes with a yellow-green "0" wire...
Shield between primary and secondary?
I am not sure (haven't got the question confirmed before) wether it directly goes to chassis ground, or wether it should be lifted with a thermistor too?
Pico, your answer was the closest I got:
1 thermistor between primaries (got the softstart-board instead)
1 thermistor @ PSU 0V
no mention of CL60 @ tranny-0V =
right?
TIA
david
(and, just to have it said, I (bloody) did listen to your cap-recommendation, and it scared the **** out of me, I mean, 8 * 47000 😀😀😀)
As you could see in the last image I posted (last, above) my toroid comes with a yellow-green "0" wire...
Shield between primary and secondary?
I am not sure (haven't got the question confirmed before) wether it directly goes to chassis ground, or wether it should be lifted with a thermistor too?
Pico, your answer was the closest I got:
1 thermistor between primaries (got the softstart-board instead)
1 thermistor @ PSU 0V
no mention of CL60 @ tranny-0V =
right?
TIA
david
(and, just to have it said, I (bloody) did listen to your cap-recommendation, and it scared the **** out of me, I mean, 8 * 47000 😀😀😀)
I still can't see how you did connect small aux xformer, big one and soft start circ........
few things - rouiting just one wire through hole in metal plate is no good practice - you need to do that with pair of wires , both of same circ ( lead and return)
also - be sure that you connected primary of small xformer to mains side (not secondary to mains!), taking in account that you wrote "Small xformer connected, switch open: 2 ohm"
frankly, I can't make sense of list you wrote , even when knowing that you made typo with "switch open"
few things - rouiting just one wire through hole in metal plate is no good practice - you need to do that with pair of wires , both of same circ ( lead and return)
also - be sure that you connected primary of small xformer to mains side (not secondary to mains!), taking in account that you wrote "Small xformer connected, switch open: 2 ohm"
frankly, I can't make sense of list you wrote , even when knowing that you made typo with "switch open"
Ok. I'll make corrections, check everything again and try to make a diagram. (already 2 aux-trannies blown)
Thank you!
)