ADA Power Amps > B500B (G500S)

B500B Transformer

**rnolan**:

So have attached what MJMP sent me re the transformer and amp specs and schematics.

**Ravendk**:

Hi Again....

I have been looking over the specs for the tranny and did some calculations in order to figure out what kind of AC voltage we´re looking for on the secondary side of the tranny before the rectifier.....

We have 79vdc unloaded and rectified, so it will be 79Vdc divided by 1,4142 (Square root of 2) = 55,86vac (lets just say 55vac). This we have x 2 .....the outtake(s) on the tranny should then provide us with 55Vac - 0v (CT) - 55vac.

The schematic for the 220/240v tranny and the 110/117v tranny both say that if we have a current draw of 5Adc the dc voltage will be 64v. This provide us with some values for calculating the power consumption in VA (watt). This will then be 64v x 5A = 320VA, and we have 2 outtakes, so the total will then be 64V x 5A x 2 = 640VA, or in plain English 640 Watts.

This goes well with the 675 Watts that is printed on the back of the amp close to the AC cord. My guess is that the fan uses about 15-30 watts, so this is within the limit of the 675 Watts total at normal use....and it goes well with the main fuses of 7A for 117V use and 4A for 240V use

On the schematic for both trannies there are some numbers that reflect the the size of the bobbing (the plastic thing were the coils are wound around. they used a standard EI-125 bobbing, but there is a slight differens between the 117v tranny and the 240v tranny. In the 117V tranny the size (I guess lenght or Width) is 2 7/16 inches and in the 240V tranny it´s 3 inches (more wire on the 240V tranny on the primary Windings...this is also why the 240V tranny is slightly bigger in pfysical size.

So all in all we´re looking at a tranny with the following specs: 240V pri and 55V-0-55V sec. and a capacity of delievering around 640-650 VA or Watts.

Then there is the pfysical size of the tranny that the producer has to stay within (3.125in x 3.75in x 4.50in)(240V tranny). In cm this is roughly 8cm x 9,5cm x 11,5 cm calculated with the international standard that 1 inch equals 2,54cm....

Ok...now we have something to go with on the search for a tranny Company that will make the damn thing :whoohoo!: :banana-jazz-smiley-emoticon: :headbanger: :banana-dance: :banana:

**rnolan**:

Cool, thanks Ravendk, hopefully someone can make one.

**MarshallJMP**:

I'll takes some pics this evening Raven

**MarshallJMP**:

Here you go

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