Diyfactory Forum
Основные форумы => Гитарное оборудование => Тема начата: armkon от Июня 07, 2011, 01:34:59 pm
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Have a little problem with the PSU of Avenger preamp and the biger one with heater.
I will use the transformer without CT:
In 220V, out 1st. 250V 0.03A
2nd. 6.3V 1.66A
Will use the virtual CT: 2x100ohm betwean 6.3V outs of transformer connected to the GND
I'm thinking abuout elevate, or change AC->DC, the heaters but don't know what ist the best way to do it.
Inside the archive there are the pdf file with whole connections, layout and schematic. If anyone can help with it. Please help :)
Layout is design in Sprint-layout.
http://www.onlinedisk.ru/file/675891/ (http://www.onlinedisk.ru/file/675891/)
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I think, raise heater with virtual CT to the positive potential +30V - +70V is easier than rectifying it. This is more than enough to not have problems with 50Hz noise in the high-gain amplifiers.
Positive potential can be taken from the anode power supply. For example, as in this schematic (look at R25-R29-C15):
[img width=\\\'500\\\' src=\\\'http://diyfactory.ru/forum/uploads/img-1898-b1f71c6767.GIF[/img] (http://diyfactory.ru/forum/uploads/img-1898-b1f71c6767.GIF)
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Is that a good idea ?
http://www.onlinedisk.ru/file/677391/ (http://www.onlinedisk.ru/file/677391/)
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a little update :)
Have 2 questions:
1. Are heaters ok?
2. I use the PSU from x88r. Can someone check it?
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The schematics of x88r
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Armkon, regarding heater supply:
You should elevate it's PS above ground by 30 - 70 vdc, up to 80vdc, and I think it is not enough to rectify heater supply and use it for elevation, the potential will too little.
Do not connect any terminal of heater supply to ground when using elevation, it already linked to ground though elevation network.
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I have made a soldano avenger preamp mod and add a extra tube to it, just like in x88r preamp. Need a little help with checking the components, in last layout i have find that i don't add the 330k resistor, so i del...
If someone want the layout, i will share the sprint layout file.
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I see your point Andy, hmm
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Look at last tube terminal 7 and 8. 8 - cathode must be connected to ground trough 2k2, as we can see from schematic of X88r, but in layout you connect term. 8 to 470K. Tha same situation with terminal 7.
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ok i have forget about that connections, as have you see on the pinout 12 and 13 on the two boards i forget to swap them :P my foult sorry... now it's ok i think. And what about the addational Blocking 16uf 450V? it is connected properly?
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I have back to version with 3 tubes and fet buffer, anyone can check it please? :)
Andy look it is what you have writing about, i have find this on the x88r schematics ?
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Hi Armkon!
You made a mistake in the heater elevation network. Look at my picture below.
Don't be afraid to apply 70vdc to virtual center point of heater supply. Voltage difference between heater terminals will keep about 6.3 vac and appropriate rectified vdc values, so tube will not burn out (I mean it will be in order).
Just carefully check your layout stage by stage and receive good expirience.
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Andy, but i connect the 70V to vct heaters point with the blue line, that vct point i have name vref.
It's not ok? i have do this like in x88r psu schematics i think