GND on several output voltages

[Infernal_Death]

Hi all

I am working on a project right now where i have combined tube and ic circuit. So i just did the layout for a psu board which should deliver everything. It's a mix between Jakob's G9 supply and TK's bipolar PSU design.

Here is a pic of it:

Now i am a bit irritated. Can i combine all the gnd planes without any problems ? Not sure about this. Sorry if that's a dumb question.

This should drive ok 7x TL072 (both the +/-15V supply rails). On the tube side there is 1x 12ax7 and 2x EL84. I would guess this should be enough for all of them ?! I plan on using one 50VA 2x15V torodial trafo as the first and one 30VA 2x15V in reverse (it's really a cool trick of Jakob,saving a expensive special trafo) for getting up to the 245V.

Thanks for looking

Flo

 

[moamps]

Hi,

2xEL84? 100mA? Then you need to redesign your HV part.
LM3x7 don't need the heatsinks for powering 7 TLs (or one small on-board will be just fine).
Is it part around the 78s12 intended for heaters powering?

It's possible to connect all gnds to one point; starground.
Lm337 isn't connected to -15Vout ?!

Regards,
Milan

 

[Infernal_Death]

Thanks for the reply.
Ok i will look into another hv part, thanks for telling me.
Yes the 78S12 is for heaters powering, i plan on using it just like in the G9.
Will do a starground. And yes i forgot to connect the LM337 out. Thanks for pointing out. I just wanted to ask those questions before i finalize the layout and so i didn't go over it once more.

Again thanks for your reply. :thumb:

Flo

 

[CJ]

can you post a schematic of the pwr supply?

 

[Infernal_Death]

Well there really isn't a schematic as i just combined TK's bipolar psu design from his homepage with the heater and HV part of Jakobs schematic from the G9.
Just thought i could use them as they together provide all the voltages i need.

Flo

 

[moamps]

[quote author="Infernal_Death"]
Yes the 78S12 is for heaters powering[/quote]
Hi,
The 2xEL84 heaters in serial + ECC83 in 12V heaters mod draw slightly under 1A. Use then 540x diodes instead of 40xx types. Move one of 2200uF cap from each 15V rail to the heater power supply. Also, you don't need 30ohm resistors in the regulators, the TLs will be happy with 14,8V also. Or just use 2k7 instead of 2k61 + 30R.

Regards,
Milan

 

[CJ]

is it kind of like this ground wise?

 

[Infernal_Death]

Moamps, thanks again for your answer.
Will change the diodes. Yes i also thought that the two 2200uf caps for each of the +/-15V might be overkill but that's how TK made it (those rails should be plenty to drive much more) and i had the space.
But i will do as you said and change those caps to the 12V rail. Also i will change the 3 1000uf to one or two bigger caps.

Ok but is there any reason to left out the 30ohms ? I mean if it's nearer the 15V it should be ok. I don't mind one more resistor. Maybe it's more precise than it needs to be but this shouldn't be a problem, right ?


CJ take a look at the gyraf g9 schematic.

Right now i did it the same way. I just added the +15V rail to where the 12V heater rail is and the -15V rail where the 48V rail is (which i don't need). GND from all the transformers isn't connected right now, just like on the schematic of the G9.
I just begin to wonder if i should do it exactly like Jakob did and move the two 15V secondaries of the second trafo (for the 245V) on the secondary 15V of the first trafo which doesn't supply the 12V heater. I guess this winding will have to supply the most current so maybe it isn't wise to also drain it with feeding the second trafo.
Like i said i will use a 50VA for the first transformer.

As always this place is a big help, cheers :guinness:

Flo

 

[moamps]

[quote author="Infernal_Death"]
I don't mind one more resistor. Maybe it's more precise than it needs to be but this shouldn't be a problem, right ?[/quote]
Correct.

I just begin to wonder if i should do it exactly like Jakob did and move the two 15V secondaries of the second trafo (for the 245V) on the secondary 15V of the first trafo which doesn't supply the 12V heater.

Good idea.

I guess this winding will have to supply the most current ..

The HV PS will be drawn also by up to (for example ) 80mA at 250V, what's 20W.
Anyway, I suggest you using the first sec only for heaters, and second for the +/-15V PS (using the half wave rectifiers) and the HT PS.

Regards,
Milan