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Bijou All Tube Futterman Headphone Amplifier - Page 99

post #1471 of 3981
10/2/08 at 12:13pm
Quote:
Originally Posted by miky View Post
Will IRF840 be ok?
Yes, I'm pretty sure that it will. You may see slightly different adjustment of the B+ because they are not exactly the same. But it certainly will regulate.
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post #1472 of 3981
10/2/08 at 12:54pm
Thanks, I will give it a try.
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post #1473 of 3981
10/2/08 at 2:06pm
Quote:
Originally Posted by pabbi1 View Post
And forget my ramplings about air wired Bijou - Ferrari's is a SOHAII - getting the build threads confused...
Bah i searched the whole thread...
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post #1474 of 3981
10/2/08 at 5:43pm
Yikes… the casework of this amp give me some serious headache!

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post #1475 of 3981
10/2/08 at 5:51pm
Quote:
Originally Posted by Ferrari View Post
Yikes… the casework of this amp give me some serious headache!

http://i72.photobucket.com/albums/i1...eelding566.jpg
suddenly, I feel inadequate...
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post #1476 of 3981
10/2/08 at 6:28pm
Quote:
Originally Posted by Ferrari View Post
Yikes… the casework of this amp give me some serious headache!

http://i72.photobucket.com/albums/i1...eelding566.jpg
wow ...


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post #1477 of 3981
10/2/08 at 6:40pm
I'm not a big fan of putting a tube amplifier into a cardboard box.
What' that thing with the two knobs by the way?

Regards
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post #1478 of 3981
10/2/08 at 7:01pm
Quote:
Originally Posted by GeWa View Post
I'm not a big fan of putting a tube amplifier into a cardboard box.
Me neither. Hee… how do you know my amps boards are in the cardboard box?
Anyway, the amps boards will coming out of the cardboard box soon, very soon... since the tubes really need some fresh air.

Quote:
What' that thing with the two knobs by the way?
Regards
No idea, …you???
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post #1479 of 3981
10/3/08 at 3:29am
I would quite like to lick that.

ferrari, isnt it also you that has a stock of super expensive russian tubes to go in there?
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post #1480 of 3981
10/3/08 at 5:20am
Very impressive amp Ferrari!

Pabbi, I have just finished mounting the PS boards. It's on a roll once again. ;-) Edit: I will be leaving on Saturday morning for the finalization of the Beta22 group build, arriving back home on Sunday evening.
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post #1481 of 3981
10/3/08 at 5:51am
i have a question... are there any problem to apply 7.1V at the heater in place of 6.3V ?
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post #1482 of 3981
10/3/08 at 10:26am
re: power switch contact rating.

how many amperes does each DAX 370 draw - is it equal to the Filament #1 at 3.5 A? i will have 2 transfos and need an appropriate power switch.

thanks!
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post #1483 of 3981
10/3/08 at 10:28am
Quote:
Originally Posted by Dantes View Post
i have a question... are there any problem to apply 7.1V at the heater in place of 6.3V ?
Dantes, this will shorten tube life and cause the tubes to draw much more current than what the PS is expecting.

For 6922 the range of heater voltages (on the spec sheets) is 6.0V to 6.6V. This will be similar for the other tubes.

Is there a way you can make it lower? Decreasing the heater voltage will also help with the B+ because it will reduce the current drain by the amp boards.
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post #1484 of 3981
10/3/08 at 10:33am
Quote:
Originally Posted by fishski13 View Post
re: power switch contact rating.

how many amperes does each DAX 370 draw - is it equal to the Filament #1 at 3.5 A? i will have 2 transfos and need an appropriate power switch.

thanks!
The current drawn is determined by the power relationship on both sides of the transformer. For example:

On the secondary side the heaters draw 3A and the 260V draws 70mA. This is a total power of about 37W. Lets say 40W for some headroom.

The primary must, therefore, deliver 40W. If you're using the 120V primary, then the current is 40W / 120V = 330mA of RMS current draw.

Any power switch rated at 5A will do to account for the current pulses from the rectifier. You can probably even do 2.5A if you have to.

Edit: This is for one transformer.
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post #1485 of 3981
10/3/08 at 10:56am
thanks.
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