#1
Can I use DC to heat up the power tubes?

Thanks!
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#2
yes, I use it, it works (there should also theoretically be less hum compared to AC heaters).
#3
Of course you can =]
"Everybody, one day will die and be forgotten. Act and behave in a way that will make life interesting and fun. Find a passion, form relationships, don't be afraid to get out there and fuck what everyone else thinks."
#6
Quote by call1800ksmyazz
What exactly are you building? Not that it matters, just that you asked me some other tube amp questions in PMs so im interested haha


ahh
on the pry are we mr kerry?
haha

but yes, it would be nice to know more details about this mystery amp mr wolf...
#9
Quote by sempri_fi
^nah
i recall him talking about more gain than that...

maybe a 5 preamp tube 18w?


Something like that, yes.

1 GZ34 as a rectifier.
4 or 5 12AX7´s in the preamp.
1 12AX7 phase inverter.
And 2 EL84´s push-pull.

The whole plan is a high gain, medium wattage, Like 10 to 20 watts.
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#10
And, on all datasheets, it says that filament voltage should be 6,3V or 12,6V. Is this measured in AC or DC? Couse 6,3VAC is equal to 4,4VDC... And 6,3VDC is equal to 9VAC.
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#12
The transformer im gonna use dosen't have a 6.3v tap. Only High voltage B+ and 5v.

Quote by call1800ksmyazz
If you are doing DC (via pedal) you would use 12v

What?
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#14
Why, I dont know.
The Hammond 363CX.
I have to use the universal primaries couse I live in Sweden and we got 220/240 volts here.

So I guess I have to use seperate transformer/s to all the filaments except for the GZ34.

Btw. The universal primaries are 100, 110, 120, 200, 220, 240. I´ve measured the voltage of the mains here in my house, and its 233-235 lol. I wonder, can I use the 220 tap? or even the 200 tap? That way, I'll get higher secondary voltage. I know its unnecessary but I just want to know.
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#15
Another question. When you are measuring AC voltage, are you measuring from the "0 point" to the peak or peak to peak?
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#16
You will want to use the 240v primaries. I am getting low secondaries on my amp build. I thought about using thr 110v primary instead of the 120v primary, but that would raise my heaters and such.
#17
the 6v and 12v are arbitrary, you can use them for either AC or DC. It's whether you want to heat them in parallel or series. Parallel (6v) is alot easier since you can just hook it up to the same heaters as your power tubes and common pins 5 and 4 on your preamp tubes (12ax7?).

Atleast, that's what I think you're talking about.
#18
Greenbox:
the 6v and 12v are arbitrary, you can use them for either AC or DC. It's whether you want to heat them in parallel or series. Parallel (6v) is alot easier since you can just hook it up to the same heaters as your power tubes and common pins 5 and 4 on your preamp tubes (12ax7?).
Atleast, that's what I think you're talking about.

6.3 and 12.6*
Anyway, yeah = 12AX7´s
________________________________________________________________

Kerry
Yeah... right the heater winding, forgot that
Is there anything I should think about when using GZ34 as a rectifier, I mean couse one of the heater pins also is the cathode? Will I get 5V AC in my B+ suply?
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
Last edited by Thewolf_and_man at Jun 19, 2007,
#19
You wont get 5v from the B+ supply. 5v taps, 6.3v taps, and high voltage taps are all seperate. B+ voltage will be around 380-400v. Then of course its lowered into different B+'s (B+1, B+2, B+3) through the filter caps and resistors in the power supply. These different B+'s are for different parts of the amp.
#20
Quote by call1800ksmyazz
You wont get 5v from the B+ supply. 5v taps, 6.3v taps, and high voltage taps are all seperate. B+ voltage will be around 380-400v. Then of course its lowered into different B+'s (B+1, B+2, B+3) through the filter caps and resistors in the power supply. These different B+'s are for different parts of the amp.


Yeah, an example: B+ to center tap on output transformer, and B+2 and 3 for the preamp tubes

Concerning the 5V winding and high voltage winding, I mean that I would get 5Vac in my B+ supply because of the GZ34 rectifier...

http://www.jj-electronic.sk//pdf/GZ%2034%20S.pdf

Take a look there, Pin 8 is combined filament and cathode. Will I get 5Vac in my B+ supply if I use this? Not? Right?
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#21
And now, I need an answer to this question! I´ve asked you guys so many times.
What voltage would my B+ supply have after rectification if I use Hammond 363CX (180-0-180) 250mA???

I read on www.allaboutcircuits.com that DC is AC * 0.7
Example:

10 Vac is equal to 7 Vdc...

Would it be a bit less than 180, a bit less then 360? or like 250?
Thanks!
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
#22
Thinking about it now, I dont think that transformer has enough voltage on the high voltage tap.

My 18watt build used 3 preamp tubes, 2 power tubes (EL84s), and 1 rectifier tube (EZ81). The high voltage taps for that were 290 each. On my VF-10 build, the high voltage taps are 275 each, and I had a problem with getting too low voltage when I was only using 1 preamp tube (6U8) and 1 power tube (6V6). So really, you will probably need more like 290v each at least on yours sinces its going to be supporting even more preamp tubes.
#23
How about the 370BX (275-0-275) ? Only 50 milliamps though...

or 370FX... 275-0-275, 150mA

or 372BX... 300-0-300, 100mA

All those three have both 5V and 6.3V windings...
"I never liked those Deep Purples or those sort of things. I always hated it. I always thought it was a poor man’s Led Zeppelin"
// Angus Young

+1
Last edited by Thewolf_and_man at Jun 20, 2007,