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OLD THREAD DAC End by Andrea Ciuffoli

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#1,481
Andrea,

What is that green pcb on top of the I/V board? Is that a modification to your DACend2? On this attached photo, are you using the E182CC?

I noticed that your not using filters and bypass caps. So maybe this is the way to go.
 

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#1,488
Hello Andrea,

What value of the output capacitor and Rload are you using? What's the minimum voltage of the output capacitor? Is 200V OK?

Regarding the jumper on the DAC board, is it correct to hard wire pin 1 & 3 and leave pin 2 untouched?

Thanks for your response in advance.

housing
 
#1,492
housing said:
Hello Andrea,

What value of the output capacitor and Rload are you using? What's the minimum voltage of the output capacitor? Is 200V OK?

Regarding the jumper on the DAC board, is it correct to hard wire pin 1 & 3 and leave pin 2 untouched?

Thanks for your response in advance.

housing
Click to expand...

200v is not ok.

you should always spec the output cap to be B+ with an extra margin. you need 300v or more caps. if something goes wrong you want the output cap to survive. You do not want 260v going to your next piece of kit!

Andrea is using a different operating point for the CCS. Using a CCS allows you to pick different operating points due to the horizontal load line created (Constant Current, so horizontal). The plate voltage is then just set by the grid bias.

for normal (not using the extra CCS PCB) then the 90v plate voltage is more suitable.
 
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#1,493
adamus said:
200v is not ok.

you should always spec the output cap to be B+ with an extra margin. you need 300v or more caps. if something goes wrong you want the output cap to survive. You do not want 260v going to your next piece of kit!

Andrea is using a different operating point for the CCS. Using a CCS allows you to pick different operating points due to the horizontal load line created (Constant Current, so horizontal). The plate voltage is then just set by the grid bias.

for normal (not using the extra CCS PCB) then the 90v plate voltage is more suitable.
Click to expand...

Hello Adam,

Thanks for your explanation. I think I understand now. 🙂
 
#1,500
audiodesign said:
Fred,
where you don't see "filters and bypass caps" ?
Click to expand...

Andrea,

Sorry, I meant L1 and L2 was omitted as well as C4, C5, C9 and C10.

Would this heater power supply for the phono preamp applicable to the DACend? The 2.2ohms resistors and the bridge rectifier are too hot, can't stand it. This might be better that the original one. Please advise.
 

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