Spec'ing a PT to Heyboer

[Gaz]

So I can't quite find the PT I'm looking for for a high-gain build with 4 EL34s and 4 12AX7s and 1 12AU7

I need:

120 VAC mains

335VAC, 400mA HV winding (trying to get about 450vdc loaded).

It does not matter if it's FWB or FW, unless one is cheaper???

100 volt 50mA bias winding (although probably cheaper without it).

6.3 CT @ 8A for heaters

and another 6.3V CT @ 2A for 5V relays

I'm just super paranoid about notating it wrong, and would like some advice to be as clear as possible. If anyone has any other advice, or additional info to give Heyboer, I would really appreciate it.

Thanks!

[ToneMerc]

So I can't quite find the PT I'm looking for for a high-gain build with 4 EL34s and 4 12AX7s and 1 12AU7

I need:

120 VAC mains

335VAC, 400mA HV winding (trying to get about 450vdc loaded).

It does not matter if it's FWB or FW, unless one is cheaper???

100 volt 50mA bias winding (although probably cheaper without it).

6.3 CT @ 8A for heaters

and another 6.3V CT @ 2A for 5V relays

I'm just super paranoid about notating it wrong, and would like some advice to be as clear as possible. If anyone has any other advice, or additional info to give Heyboer, I would really appreciate it.

Thanks!

Do you have to have CT for relays and does it have to be 2A? if it's only a couple of Omron 5V relays then 500-600mA is plenty. I assume you are just going to do a FW. The fact that's is a FW, FWB or doubler doesn't matter in pricing as it's a custom wind.



This is my simple email format to Heyboer, you can modify it accordingly. I do include the mounting centers and whether it's laydown, standup, endbell color etc. You also can specify lead color as well. Here's 2 formats, one with HT bias tap and another with a seperate winding.

PRI: 120V


SEC: 335-100-0-335 @ 400mA
3.15-0-3.15 @ 2A or 6.3V @ 2A
3.15-0-3.15 @ 8A



SEC: 335-0-335 @ 400mA
100-0 @ 50mA
3.15-0-3.15 @ 2A or 6.3V @ 2A
3.15-0-3.15 @ 8A



TM

[Colossal]

Gaz,

As ToneMerc noted, it's a simple affair to spec custom iron with Heyboer. Just write down what you want. I even make a drawing illustrating the transformer's windings and their respective voltage and current, just so there is a document showing exactly what my expectations are. I try to make it as easy as possible for the vendor.

As for your relay winding, I would do it without a center tap and use a full wave bridge. Ground the entire circuit at one point down the line. If you plan to do regulated DC which would be advisable, a 7805T regulator (5VDC) for example can provide up to 1A of current, many times more than adequate to run a bunch of relays and some indicator LEDs.

[ToneMerc]

You can copy your info into here and attach a drawing if you like.

[Luthierwnc]

You just need to know what you want. I have a 100w PT and OT in the shop that they wound for me as one-offs. $100 each + S&H. The PT is 700VCT with two 6.3 taps -- one for the heaters and one I'll dumb-down for 5v relays. Big sucker designed for a true 100 watts.

I called to tell them what I wanted and would they get back to me with a price. Three days later the PT showed with an invoice so I think they are used to people who know the freight and are good for it.

Unfortunately, they are on a shelf staring at me while I get some other projects done. sh

[Gaz]

You guys are awesome!

Tonemerc and Colossal, you're right about not needing the CT for either of the 6.3V windings, and about the current rating of the relay winding as well (I was thinking 300mA, not 30mA for some reason, then doubled the current for FWB.

In fact, I don't even need a CT for the HV winding if it's a FWB. Would this make it cheaper, and would I need to notate it differently? I guess that'd mean I need a separate bias winding as well... Jeez, this is the stupid stuff I need help with.

Luthierwnc, what did you rate your big PT's secondary for? I wanted it more stout than a Marshall, but not too stout. Does my 400mA sound reasonable?

Thanks Again.

[ToneMerc]

On the last two PT's I had relay supply winding at 500mA. The PT that should be on the way to me was setup as a doubler with a bias winding. I haven't seen an invoice but the quote price was the same as most of the other FW style PT's that I have ordered.

TM

[Gaz]

Thanks TM. So the 500mA in a FWB would get about 250mA for the relays on the other side? That's more than enough.