Orange-ish build

[SilverFox]

Bridge Rectifier. http://hyperphysics.phy-astr.gsu.edu/hb ... ectbr.html

I checked out the site and there's lots of cool stuff there. I may end up getting the DVD.

silverfox.

[C Moore]

Sorry about that! http://hyperphysics.phy-astr.gsu.edu/hb ... ectbr.html

.....Are you still saying that is a bridge rectifier.?
Thanks

[BLT]

Unless proven otherwise, yes.

[darryl_h]

.....Are you still saying that is a bridge rectifier.?

It certainly is. The transformer centre-tap in that circuit has a DC potential of exactly half the B+ voltage. This is why it is being used as a reference for the mid-point of the series filter caps - note that there are no balancing resistors needed across the capacitors.

This power supply topology is very economical in circuits where the screen voltage is 50% of the plate voltage. Some 6550 and EL34 output stage designs use this configuration. Many years ago I used it to supply 800 volt B+ and 400 volt screens to six 6CA7's, to deliver over 200 watts output.

[C Moore]

Yeah...Thank You.
I was wondering about those (typically 220k) resistors.
I Think this is the first time I have ever seen this rectifier, and the first time I have ever seen a "bridge" rectifier used with a PT CT.
I did not even notice the screen voltage.....never really looked at an Orange schem before.
That is why I kept asking. I am probably confusing it with another rectifier that I also have no experience with.
Thanks for the explanation.
and Thank YOU BLT.......

[SilverFox]

Is it confusing due to the stacking of diodes, (use of 8 diodes) or the fact the CT is centered between the caps. Added diodes increase peak inverse voltage and reduce transient noise in the output.

But wait- "A" is the Plate voltage. "B" is the Screens. Is the plate voltage half the screens? It appears "A" is half "B"

Where could I read up on this approach now that I'm totally confused...

silverfox.

[darryl_h]

There is information about this rectifier configuration at Merlin's Valve Wizard website: http://www.valvewizard.co.uk/bridge.html

Merlin does not describe the circuit as a bridge rectifier, but rather as a pair of two-phase rectifiers orientated in opposite directions. Perhaps C Moore was justified in questioning the description "bridge rectifier".

[dcribbs1412]

Using this PT I get right at 500V B+
notice the diag of the rectifier

D

[SilverFox]

That makes it a little more clear.

silverfox.

[Bob S]

Beautiful build. Lots of good stuff in there.
Nice !!!

[dcribbs1412]

Beautiful build. Lots of good stuff in there.
Nice !!!

Thanks Bob
Got her up and running
had some wiring issues
She is very quiet a little hiss at higher gain settings
She can be bright and sweet and loud and aggressive/dark
FAC control seems to really define the tones along with the presence/HF drive
This circuit (my interpretation it ) is different than MarFenDumWreck
stuff Ive been messing with. Not sure if it has the vintage Orange tone
but I kinda like it right out of the gate. I think it has potential
still trying to find a nice balance using the guitar volume
Gonna try different guitars and some effects in the loop
not really sure if these voltages are close to normal/vintage Orange
Thanks to Gaz,gldtp99,gingertube for info

Bias at 31,33 ma
493 B+
V1
1. 200
3. 1.6
6. 220
8. 1.6
V2
1. 85
3. .8
6. 298
7. 85
8. 88
plates 490

D

[dcribbs1412]

Just wanted to update build with pics of head cab.
kind of Orange look to it?
D

[M Fowler]

Nice looking amp.