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OLD THREAD DAC End by Andrea Ciuffoli

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#521
Low voltage tubes?

adamus said:
yes it can, but it would need a redesign of the PSU (i would forget using the PS pcb, unless you want to keep the filament supply section) and then as you say, changing values.

if you are worried about the voltage.... read read read, then bite the bullet and do a high voltage project.,
Click to expand...
The PSU pcb could remain, the 6.3V filament supply is OK, only the high voltage part must be adapted for lower voltage, 12 or 24 V.

A single simpler transformer could be used that would fit all.
And yes, maybe I'm worried a bit of the high voltages and if there is an alternative I would try that.

Is somebody who can help on this?

Thanks!
 
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#522
vzs said:
The PSU pcb could remain, the 6.3V filament supply is OK, only the high voltage part must be adapted for lower voltage, 12 or 24 V.

A single simpler transformer could be used that would fit all.
And yes, maybe I'm worried a bit of the high voltages and if there is an alternative I would try that.

Is somebody who can help on this?

Thanks!
Click to expand...

I had similar aversion and fear towards tube amplifiers.. until I've heard the sound, then all fear went away including my solid state amplifier.🙂

There are low voltage tubes, I know a company using for buffering CD players output. But I don't think you should trade good performance for volts. You need to be methodic and careful as there is a level of danger. First until you are confident work with only one end on HV parts the other keep it in your pocket so if it happens the current does not go from one hand to the other through your heart.

I'll find out anyway if you wish to get used to HV little by little. But this project is mostly all on PCB...
 
#523
Im Finis DAC-end2! that is ok! Can you see!
 

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#531
audiodesign said:
My choise about power supply transformers has been:

LS70-1 0-15X2(0.8A) 0-12X1(0.8A)
R80-55 0-9 X2 (3A),0-250(200mA)

I will test soon.
Click to expand...

Have you tested these? Is that 15VAC still ok?

audiodesign said:
To get the best performance by this DAC project it is necessary use on DAC output module a 200ohm MK132 Caddock resistor.
Click to expand...

How accurate that 200R is? Partsconnexion has only 220R.. Any other good sources for those?
 
#536
Is it possible to use a single 12v output from a transformer (at say 2a) and use this to run the entire shunt board?

Or are we better off using individual windings for the AD1865 and a separate one for the CS8414?

Also how critical is the 250v requirement onto the valves?
Could 220-250v be ok? Or is 250v an apsolute must?
 
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