Dual La2a - [silent:arts] version

This section is for registered users to discussspecific projects and troubleshooting.

Moderatoren: TVPstudio, kubi

ChuckD
Beiträge: 462
Registriert: Fr Okt 26, 2007 10:49 pm
Wohnort: Irvine California US
Kontaktdaten:

Beitrag von ChuckD »

Hey Volker,

Why do we need 2x6.3 supplies? Can't I just run all the heaters together?

-Chuck

[silent:arts]
Beiträge: 3520
Registriert: Sa Jun 10, 2006 5:54 pm
Wohnort: BLN
Kontaktdaten:

Beitrag von [silent:arts] »

of course you can run the heaters all together (6.3V 4A)
volker
olafmatt hat geschrieben:Strom kann tot machen

ChuckD
Beiträge: 462
Registriert: Fr Okt 26, 2007 10:49 pm
Wohnort: Irvine California US
Kontaktdaten:

Beitrag von ChuckD »

The transformer I picked out is

250-0-250 / 6.3 @ 3A / 12.6 @ 2A

Hopefully the 6.3 @ 3A will be enough to heat up all the tubes?

The 12.6 will be the source for the 5VDC circuit. The LM7805 input range is 5-18V for a fixed 5VDC output, so it should work fine.

Found it here :
http://www.toroid-transformer.com/
For $23.00 USD which is very cheap.

I already bought from this guy and he is really great to deal with. The quality is very high.

-Chuck

[silent:arts]
Beiträge: 3520
Registriert: Sa Jun 10, 2006 5:54 pm
Wohnort: BLN
Kontaktdaten:

Beitrag von [silent:arts] »

ChuckD hat geschrieben:Hopefully the 6.3 @ 3A will be enough to heat up all the tubes?
12AX7A Ih = 0.3, 12BH7A Ih = 0.6, 6AQ5-A Ih = 0.45
all together this is 3.3A :?
volker
olafmatt hat geschrieben:Strom kann tot machen

ChuckD
Beiträge: 462
Registriert: Fr Okt 26, 2007 10:49 pm
Wohnort: Irvine California US
Kontaktdaten:

Beitrag von ChuckD »

Damn I better keep looking thanks for the specs on those tubes Volker I should have looked that up myself.

-Chuck

[silent:arts]
Beiträge: 3520
Registriert: Sa Jun 10, 2006 5:54 pm
Wohnort: BLN
Kontaktdaten:

Beitrag von [silent:arts] »

volker
olafmatt hat geschrieben:Strom kann tot machen

ChuckD
Beiträge: 462
Registriert: Fr Okt 26, 2007 10:49 pm
Wohnort: Irvine California US
Kontaktdaten:

Beitrag von ChuckD »

I am doing a little research into the power supply:
Trying to figure out the max-min VAC transfomer I can use.

Here are 2 schematics of it :

Bild


Bild

I can't read the voltages on the second schematic but I am thinking that the numbers don't match the Full Wave CT Rectifier Calculation:

VAC = 1.7 x ( VDC + 1 )
IAC = 1.2 x IDC
WATTS = VDC x IDC ( output )


That would give 500VAC --> 293 VDC roughly.
Then Across a Voltage divider of 4.7K to 470k
Gives 290VDC

But the schematics read 275 VDC ?

Someone want to explain? And if this is true I could get away with a 460VCT or 550VCT ?

-Chuck

[silent:arts]
Beiträge: 3520
Registriert: Sa Jun 10, 2006 5:54 pm
Wohnort: BLN
Kontaktdaten:

Beitrag von [silent:arts] »

load (just what I think)
this is unregulated, the whole circuit does matter, not only the PSU.
and just because of this, the tolerance they had with components AND voltage: my bet is you will be fine with either, 460VCT or 550VCT.

(I even don't know the internal voltages mine has, didn't thought of it, didn't measured it - since it just worked)
volker
olafmatt hat geschrieben:Strom kann tot machen

waldorfcave
Beiträge: 265
Registriert: Sa Jun 03, 2006 6:26 pm
Wohnort: Kölle
Kontaktdaten:

Beitrag von waldorfcave »

now i finally got the original Rondo 60VA V. Mayer

but it works primär also for 115v. unfortnely this is the first transformer with this feature on my desk.

it has two pair of yellow-white Litze primär. How should i connectthem for 240v

Intuitivly i would put one pair yellow-white to L and one pair yellow-white to N. :? :?:

Or should i connect one Litze together, and the other two to L and N?


Lars.

Harpo
Beiträge: 463
Registriert: Fr Jun 22, 2007 12:22 am
Wohnort: Rahden NRW

Beitrag von Harpo »

Hi Lars,

think of it as a transformer with a center tap, for this beast at the primary side. Measure first, to assure yourself wich wires belong to each winding. Then connect one wire of the transformers primary side to the next of the other primary winding. This junction would be your (for no further use, don't connect anything other to this point) center tap, connecting your primaries in series, giving the required 230V terminals at the remaining 2 outer wires.
In case its white/yellow for each primary, it would look like
Bild

Paralleling the two windings will most probably result in a blown fuse or a smoking transformer because of core saturation.

-Harpo
mische lauter - Ohren wachsen nach
Ist mir Scheißegal wer dein Vater ist. Solange ich am Angeln bin, gehst Du hier nicht übers Wasser !

[silent:arts]
Beiträge: 3520
Registriert: Sa Jun 10, 2006 5:54 pm
Wohnort: BLN
Kontaktdaten:

Beitrag von [silent:arts] »

Harpo hat geschrieben:Paralleling the two windings will most probably result in a blown fuse or a smoking transformer because of core saturation
... but would be right for 115V :D

the drawing is right Harpo made is right.
but why don't you do it switchable ?
if you move to the states, or the EU decides to go 115V ...

same thing with the two 250V secondary: they have to be connected in series, but to get the 250 - 0 - 250 right they have to be in phase.
since Frau Müller doesn't mark the beginning and end of secondary windings you have to measure it :o
volker
olafmatt hat geschrieben:Strom kann tot machen

Harpo
Beiträge: 463
Registriert: Fr Jun 22, 2007 12:22 am
Wohnort: Rahden NRW

Beitrag von Harpo »

Like this
Bild
mische lauter - Ohren wachsen nach
Ist mir Scheißegal wer dein Vater ist. Solange ich am Angeln bin, gehst Du hier nicht übers Wasser !

[silent:arts]
Beiträge: 3520
Registriert: Sa Jun 10, 2006 5:54 pm
Wohnort: BLN
Kontaktdaten:

Beitrag von [silent:arts] »

yes, thats the way I do it in all my DIY equipment :wink:
volker
olafmatt hat geschrieben:Strom kann tot machen

Gast

Beitrag von Gast »

but to get the 250 - 0 - 250 right they have to be in phase
Ok Thx. But how can i measure it? :roll:

waldorfcave
Beiträge: 265
Registriert: Sa Jun 03, 2006 6:26 pm
Wohnort: Kölle
Kontaktdaten:

Beitrag von waldorfcave »

Hmm, das einloggen vergessen...

Antworten