two questions to be sure I understand correctly:
is that the potential between the two ends of each primary?
If so, can I then assume safely that I can put one of those ends at any voltage relatively to ground?
Thanks
xformer is part which allows galvanic isolation ...... so , you can put primary and secondary on whole different potentials
however , that's common knowledge that signal xformers ( not made to have any significant DC flow through any of windings) are happy dealing only with AC through each/any winding
however , that's common knowledge that signal xformers ( not made to have any significant DC flow through any of windings) are happy dealing only with AC through each/any winding
Yes! F6, BAF2015 .... for examples.
all xtrans are still happy with some vdc bias or event 100-200vdc but depend on it's size and core they can not stand with some ma. Eg: fermalloy JS core will be saturated.
If xftrans must be stand some ma dc, do not use fermalloy core like Jensen xtrans. You could try some big trans have M6 core(Edcore) or amcc core(Lundahl)
YES AND NO
I am still using the scaled down version of the BAF Schade amp. But with regard to motorboating i think the problem remains the same for mine and the original version.
Currently i have put 10k from input to ground as suggested by Nelson. Most of the time this is working both with LuminAria and BA3 preamps. But sometimes one channel suddenly starts motorboating....especially on big changes in volume.
I find it a pity to have to add a buffer between these preamps and the BAF Schade. We should be able to control the problem without.
Nevertheless the buffer option should exist as many preamps simply would not cut it with regard to impedance.
I am puzzled by the discussion about DC flowing through the secondary of the input transformer. As far as I can see for this circuit there would only be 0.47 ma which is not exactly huge.
Am I missing something?
ray
Am I missing something?
ray
Since i have built versions with very different mosfets i came to the conclusion that the motorboating problem is more likely to occur with high transconductance devices. Maybe i am wrong...(and it was just coincidence)
But in any case it is probably advisable to build something that is stable, particularly if you build a 50 watt version...
When motorboating occurs this might damage your speakers. Even with my low power version that idles at only 1.2 amps the peerless woofer on the Boenicke W5 clones moves +- maximum (more than 1cm excursion).
Of course we can lower the resistor value but i do not feel totally at ease with it.
Depends. What circuit are you talking about? If you're talking about the original unbuffered BAF amp, that's not why I asked the question.
And I was asking about the primary.
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Interesting news from Papa about fresh diy projects and novembre BAF2017 !
FIRST WATT WATT'S NEW
Sensational ! Thanks a lot Mr Pass
Kindest regards
FIRST WATT WATT'S NEW
Sensational ! Thanks a lot Mr Pass
Kindest regards
Attachments
Do you remember Papa write us about 220R 10 watts resistor if needed.
50w Single-Ended BAF2015 Schade Enabled
and decrease 10K resistance
50w Single-Ended BAF2015 Schade Enabled
🙂
Attachments
Thank you soundhappy for the reminder. I may try this 220 Ohm resistor. It may help to compensate for the heatsinks that are a bit small in my case.
But after all it would be nice if Michel would make available a PCB with the integrated buffer.... it would solve part of the problems for many
But after all it would be nice if Michel would make available a PCB with the integrated buffer.... it would solve part of the problems for many
That will do it. If your supply is quiet, you can also do D-S
on the current source (gives more bias instead of subtracting
some bias).
on the current source (gives more bias instead of subtracting
some bias).
Do Mr Pass LSK line pre from BAF look like perfect companion to Schade50 ?
LSK pre - BAF 2013
Cheers
LSK pre - BAF 2013
Cheers
