AC15 Power Transformer

[Glenn]

Hi: I was looking at Power transformers and saw a Hammond 290cz
it has
300 0 300 taps
2 wires for 25v taps
6.3 v taps
I was wondering what is the 25v taps are used for?
I looked at AC15 schematics but can't seem to find anything about the 25v taps.
Is this PT used for a modern AC15 that might have a need for this?
any insight would be appreciated, thanks

[SILVERGUN]

The 290CZ is spec'd for the "newer" AC15-C1. The 25V winding is probably there for their switching.
Here's the page for the entire line
Tube Guitar Amplifier - Power Transformers (290 Series) - Hammond Mfg. (hammfg.com)


Take a look at the 290PX

[Glenn]

Hi, thanks for the link and the info.
That 290px is a better fit, with the 5v rectifier tap, if other than using the ez81 rectifier

Glenn

[sluckey]

I used the Hammond 270FX in my AC-15 clone.

[Glenn]

thanks Steve

[SILVERGUN]

I used the Hammond 270FX in my AC-15 clone.

I like that it is a stand up mount.
Especially for a non-clone in a smaller chassis.

[uki]

290cz
300 0 300 taps
2 wires for 25v taps
6.3 v taps
I was wondering what is the 25v taps are used for?

For a hybrid SS/tube amp maybe 
could use the 25v tap for bias, maybe need  a voltage doubler for that depending on the bias voltage

[dwinstonwood]

Here is another option - Hammond 270DAZ:
https://www.hammfg.com/files/parts/pdf/270DAZ.pdf

It's a laydown/horizontal "Z" type. 260-0-260 should be safe for EL84's. But, there's no 5V secondary, so you'd need to use an EZ81, or diode rectification.

[Glenn]

Thanks all for your input. I was only wondering what that 25v tap was used for on that PT.
Silvergun suggested that it was probably for relay switching. Which makes sense to me.
I was looking to build a Maz18 Reverb, someone here posted a schematic awhile ago, but then I saw the other day that sluckey created an ac15r schematic and it looks cool. (I think I would use a 5879 tube instead of the ef86 with a rewire)

I have an Edcor 270 0 270 ~ 6.3v Amp PT and a 15 watt Edcor OT
I was just weighing between the 2 amps as one has 5 preamp tubes and sluckey's has 4
So a 5 preamp tubes with el84's is 3.17A vs 4 preamp tubes with el84's is 2.84A current draw according to calculator I was using.

thanks again everyone

[SILVERGUN]

If you're considering using the EZ81 don't forget about the 1 amp - 6.3V requirement

I was just weighing between the 2 amps as one has 5 preamp tubes and sluckey's has 4
So a 5 preamp tubes with el84's is 3.17A vs 4 preamp tubes with el84's is 2.84A current draw according to calculator I was using.

Just to keep things clear, the power tubes are not considered preamp tubes.
For sluckeys recently posted AC15 litey' lite:
2- EL84 power tubes @ .76A each = 1.52A
1- 12AX7 PI @ .3A
1- EF86 preamp tube @.2A   (or your 5879 @.15A)
1- EZ81 rect @ 1A
total 3.02A @ 6.3VAC

[sluckey]

Hi: I was looking at Power transformers and saw a Hammond 290cz

I was wondering what is the 25v taps are used for?

Is this PT used for a modern AC15 that might have a need for this?

That's a replacement for the Vox AC15C1, a modern amp with lot's of SS circuitry. The schematic is easy to find on the net if you want to take a look.

[Glenn]

Thanks Silvergun.

Steve: I did google ac15 first before posting, but got the older schematics- I guess I didn't google ac15c1 for the modern ac15

[mresistor]

you could look at other series Hammond PTs   like the 300 series https://www.hammfg.com/electronics/transformers/classic/300