Transformer wire layout help

[copperheadroads]

I created a small board layout for the regulator for the DC preamp heaters

[loudthud]

Check the data sheets on the pin-out of the three terminal regulators. The positive and negative versions do not have the same pin-out. They will need some kind of heat sink. This needs to be part of the layout.

Check the size of the electrolytic caps you intend to use. They will likely be much larger than your layout shows.

[copperheadroads]

I was hoping on using the stock ic 7912 v& the 7812 along with the heat sinks ...i did have trouble sourcing them as an alternative in case the original's failed .
According the the schematic no cap values no more than 25v .. I will run through the physical board itself . & let you know

[copperheadroads]

Using this amp as the basis ,I've decided to attempt to build a TrainWreck express using 2 5881 tubes for the power section & the DC heater circuit .
My Question is about the full wave bridge as i have no center tap, In the Ashdown schematic ,I see there some small caps & a 220k resistor before the filter caps ,I guess this is necessary part of the Full wave bridge ?
Here's the layout & schematic & the Ash down schematic

[g1]

Consider the 220K as a bleeder resistor (for first cap) and the 4n7 caps as noise suppression for the diodes.
Neither are necessities or really part of a bridge, but both are useful additions.

[loudthud]

It is unclear which 220K you are talking about. There is one that is part of the bias Voltage generator. That bias Voltage circuit won't work when a full wave bridge rectifier is used.

[copperheadroads]

It is unclear which 220K you are talking about. There is one that is part of the bias Voltage generator. That bias Voltage circuit won't work when a full wave bridge rectifier is used.

looks like R87 maybe just before (left) of the first 47uf filter cap

[g1]

Yes, R87 is just a bleeder for the cap. But take note of what loudthud said, the bias circuit will not work with a bridge, you will have to find a different source for bias voltage. How does the Ashdown in your example do it?

[copperheadroads]

There is one that is part of the bias Voltage generator. That bias Voltage circuit won't work when a full wave bridge rectifier is used.

what would we need to do ?

[loudthud]

what would we need to do ?

Basically, you need a capacitor instead of the 220K. Here is an example, bias circuit is on page 2: http://el34world.com/charts/Schemati...0-02-iss14.pdf

[copperheadroads]

Sorry I'm not seeing it in the schematic ,,I will do some more research .

[g1]

Look at the D5 sector of the schematic (pg2). Cap is C12. WH point comes off the power transformer.

[copperheadroads]

Thanks I did look at that
Wouldn't this be a similar schematic
At the bottom of the page
Capacitor Cupled Bias Supply
http://www.valvewizard.co.uk/bias.html

[g1]

Yes, very similar. That will get you a bias supply without a CT in your HV winding.

[copperheadroads]

Here's the Chassis ,
My plan was to to cover larger holes that are towards the center & install my turret or eyelet board in that area & possibly drill holes (atleast one new hole ) for the power tubes , but I am not liking how close V1 will be to the Output transformer this build will have dc heaters on the preamp tubes . I wonder would if it be better if i move the OT up next to the power transformer , this is a combo amp but i think there is enough room to move the OT next to the PT .let me know what you guys think ?