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Citation 12 complimentary MosFET version PCBs

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#46
What NOT to do...lol

Tazzz pcb are great, perfect fit with the heatsink but don’t mount Q5,Q6 like I did unless you like a little smoke...

After changing Q5,6 it’s now biased at 150mA and stable. Thanks Tazzz.
 

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#47
Hi Tazzz, my struggle for 2SA970 is not yet over, any chance I can use BC327A instead, the specs read as:
VCEO = 60 V
VCES = 60 V
VEBO = 5 V
IC = 800mA


I am not sure of the noise parameter, please let me know if this works or please suggest a substitute that is still available in market
 
#55
Hi, can someone help me with bias?
I can measure it but I have doubt about the volume of the source signal.
I'm measuring the bias at minimum volume, which is the closeset to zero but not zero.
When I push up the volume of the source the Bias goes up, is it normal?
I'm doing correct? or I have to put the volume source at maximum or zero?
Many thanks
 
#57
Hi,
I'm struggling with my C12, when I sterted it first I had a little humm and very low volume. I had to put the volume source at maximum to have a decent sound.
One of the mosfets was warmer than others and when I moved the amp from the test loudspeaker to the good ones I had only one channel worked, then even that one stopped working. So silence and no more humm.
I've set the bias to 250mA and the radiators was less than 35degree after one hour.
There is something I noticed, the power supply give me +/- 34,65V with a Tx 24V.
I guess the Mosfets died, and I don't know why the volume was so little.
Please whoever has any idea don't hesitate.
 
#59
cucuclock said:
Hi, can someone help me with bias?
I can measure it but I have doubt about the volume of the source signal.
I'm measuring the bias at minimum volume, which is the closeset to zero but not zero.
When I push up the volume of the source the Bias goes up, is it normal?
I'm doing correct? or I have to put the volume source at maximum or zero?
Many thanks
Click to expand...

Hello

Sorry if I might be wrong. But BIAS adjustments are normally done without an input signal and the input shorted.

Kind Regards

Phil
 
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