2 toroids in monoblock?

[magnoman]

To me it looks mostly like the B version, but with each of the two secondary windings shown, made up from the pair of windings from of each transformer.
Net result one transformer for the positive one for the negative, each transformer has 2 secondaries wound in phase (parallel).

Thanks
-Antonio

[oz7aff]

The princibels are like B

[Rundmaus]

Originally Posted by Ian Finch

However, neither follow the wiring of the posted image, where there is, effectively, only 1 secondary winding in each trafo, because each pair of leads from each trafo is simply paralleled before rectification. ergo: It cannot be either A or B circuits.

Hi there,

it is schematic 'B' indeed. The fact that it uses two transformers doesn't matter - just take the 'B' scheme and 'cut' the transformer in two between the two secondary windings to make it clear.

Doing a symmetric +/- rail supply using two windings of the same transformer is just the same as using two separate transformers. In the case shown, each transformer seems to have two windings which are paralleled, for what reason ever. Maybe simply because they had the transformers and needed more power.

Apart from the transformer question, the housing looks quite empty and 1000µF of filtering per rail is next to nothing - to me this amp looks somewhat like a lot of show and much less on the inside....

Rundmaus

[a.wayne]

This is hilarious, Where is the rest of it ....

[gugi100]

MMMM just two cheap 2*12 volt transformers to make two times 24v before rectification, and add wieght to the total amp to feel really "heavy". Or am I very wrong on this....

Gr GJ

[TANDBERGEREN]

The two windings of each toroid is paralelled.
Then the two toroids are connected in this way:
Look at example B over here, and the picture of the rectifier.

The Yellow and Grey to the left is connected to the top of the rectifier.
The Blue and Red AND the Yellow and Grey are connected to GND/Center tap for the caps.
The Blue and Red are connected to the bottom of the rectifier.

[KatieandDad]

Certainly very odd. Why such a poorly specced amp would need two huge transformers is indeed a mystery.

1000uF caps in the PSU... ?

Something like a Pass F5 wouldn't have too many components either and may have two transformers but the rest of the space would have at least a couple of respectable reservoir caps.

[jacco vermeulen]

Lots of VA, and a low profile case with standard toroidals.
Cheaper (plus fits in the GM philosophy).

[TANDBERGEREN]

Originally Posted by KatieandDad

Certainly very odd. Why such a poorly specced amp would need two huge transformers is indeed a mystery.

1000uF caps in the PSU... ?

Something like a Pass F5 wouldn't have too many components either and may have two transformers but the rest of the space would have at least a couple of respectable reservoir caps.

On the amplifier board there is a bit more capacitance, so no problems.
This amp really delivers the current needed to obtain a "stiff" amp, disreggaqrding the load.
The power doubvles from 8 Ohms to 4 Ohms and nearly that to 2 Ohms.
Only possible my having sufficient VA fon the transformers.
And as stated here: Cheaper than a single BIG Toroid, needing a mmuch larger enclosure.

[KatieandDad]

Originally Posted by jacco vermeulen

Lots of VA, and a low profile case with standard toroidals.
Cheaper (plus fits in the GM philosophy).

But wouldn't that normally go hand in hand with a few more uF.

I can see where you might need lower profile so you are forced to use a lower VA transformer, but custom made cores are available for that task. I can't believe that a manufacturer would find it cheaper to fit two transformers in such a low spec amp.