to use "one bridge per one secondary" approach, establishing common point/GND after two bridges
that way secondary can never see tiniest amount of DC, which arouse in case of unequal load of two rails, when using common arrangement of CT/GND established at xformer secondaries
unequal rails loading is especially high in case of SissySIT and all OS-es having unequal xconductance/current gain of upper and lower devices
even if recipe is known from Yore, I didn't think of it until Pa published it in one of his amps, and explained why
little thingies are ones differentiating Boyz and Men
well, in Papaland, Men are often more a Man (with white hair and aroundhead Green)
Studley, my guess is that is ZM's general recipe for his transformers and not just for the F2. Don't forget that a dual secondary transformer can be used in stereo and dual-mono F2, as well as the bipolar supplies used in many of the other builds (F4, F5, F6, SissySIT, etc).
aha, I see now that confusion is maybe because I did mention dual secondaries in context of amp having just one rail, and one Donut dedicated to one channel
so, that was a recipe for my usual amps, and majority of them are with dual rails; as said - recipe as example of proper (for me) approach
of course in case of amp with one rail, no reason to think about two secondaries for Donut which is going to serve one channel
so, that was a recipe for my usual amps, and majority of them are with dual rails; as said - recipe as example of proper (for me) approach
of course in case of amp with one rail, no reason to think about two secondaries for Donut which is going to serve one channel
Yes that was the cause of my confusion ! 😉. It would have been upsetting to discover after that I’ve been wrong all these years in thinking that I was reasonably smart 🤣
Yup confusion now cleared up, as can be seen from last couple of posts. I have 2 of XRK’s single rail SLB boards, so I’m inclining towards a dual mono PS
Does the F2 J exhibit any turn on thump? ie do I need a soft start? (I’m going to make monoblocks with 300VA trafos).
You still need a softstart. Use a thermistor or something in series with the primaries.
But yes, the big caps on board take care of thumps 🙂
What Dennis said^^^
I built my F2J monoblocks with one Antek 4218 per monoblock.
I wired each Antek’s pair of secondaries with their own bridge rectifier which feeds a stereo single rail CRC board. I paralleled the outputs of the CRC board to my amp board.
At some point in the future I may build a second set of F2J boards and convert the monoblocks to a pair of stereo F2J.
The option of using the same power supplies for either a monoblock or stereo F1, F3 or trying it with an ACA is there too.
😉
I built my F2J monoblocks with one Antek 4218 per monoblock.
I wired each Antek’s pair of secondaries with their own bridge rectifier which feeds a stereo single rail CRC board. I paralleled the outputs of the CRC board to my amp board.
At some point in the future I may build a second set of F2J boards and convert the monoblocks to a pair of stereo F2J.
The option of using the same power supplies for either a monoblock or stereo F1, F3 or trying it with an ACA is there too.
😉
Attachments
Good point re possible future use, although having heard just an F2 I doubt I’ll ever dismantle the F2J. My understanding is that with dual secondaries you can just combine the 2 pairs to effectively make one pair for a single rail supply.
My trafos will be from Tiger Toroids. I believe that’s where Bonsai sources his from.
Do they have striped? And roar instead of hum?
Agree, you likely won’t wanna dismantle 🙂
I’m hoping they will be timorous beasties 😂Do they have striped? And roar instead of hum?
Agree, you likely won’t wanna dismantle 🙂
Well I had previously said I was going dual mono, but then I thought what the hell as I’m going to use bespoke enclosures . . . .
Hey MZM, your brain has been super fertile in recent years, coming up with so many amp designs, so I have a suggestion for you. Constant current source amps like the F2J are obviously pretty rare. I think there would be a fair amount of interest in a more powerful current source amp given there seems to be an increasing number of people going active with their speaker designs. Does the idea stir your creative juices?
It has been suggested before, and I am sure it stirs his juices. Though, recently, Mighty is so full of juice that time is the only constraint he encounters