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DOGC-H by Dr. Jagodic
DOGC-H by Dr. Jagodic
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Old 22nd January 2018, 04:46 PM   #21
kacernator is offline kacernator  Czech Republic
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Quote:
Originally Posted by Machina View Post
Hmm
I wonder so, my power supply is 2x37ac (old trafo on 220V), sometimes its +- 53Vdc. AC lines can show 223-234Vac. Irfd110 has Vds100V, can it be the reason of burning?
Do you have proper heatsink on input mosfets? You should hold you hand on the heatsink, otherwise it is too hot.
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Old 23rd January 2018, 10:40 PM   #22
Machina is offline Machina  Poland
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Heatsink is not small it, about 70C when playing 2h.
Dont know if it will help me to find the cause why its burning, but, when the amplifier is turned on, then, I turned it off, maybe four seconds have passed, I turned on again, and VUALA finished, burned!
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Old 30th January 2018, 06:24 PM   #23
Machina is offline Machina  Poland
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Originally Posted by kacernator View Post
Do you have proper heatsink on input mosfets? You should hold you hand on the heatsink, otherwise it is too hot.
80W Hybrid Audio Amplifier!
I will try, and incrase Irfd110 capacitor, maybe it will help for future .
Or add a capacitor to 100k resistor, (input/gnd,150pF), mayby a hi frequency is gaining when Im turning off.

Update.
I forgot to mention, there are two monoblocks, and one that breaks down, the transformer shows 2x37VAC, the other is 2x36V and does not show this propensity of burning irfd110 on input side.

Last edited by Machina; 30th January 2018 at 06:51 PM.
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Old 12th April 2018, 04:24 PM   #24
year98 is offline year98  Armenia
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DOGC-H by Dr. Jagodic


Instead of 630/9630, IRF530/9530 can be used?
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Old 12th April 2018, 07:55 PM   #25
kacernator is offline kacernator  Czech Republic
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Originally Posted by year98 View Post

Instead of 630/9630, IRF530/9530 can be used?
Yes, no problem.
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Old 12th April 2018, 08:26 PM   #26
year98 is offline year98  Armenia
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Originally Posted by kacernator View Post
Yes, no problem.
Thanks a lot. 530/9530 are 100v devices. Is it enough for 48v?
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Old 13th April 2018, 04:20 PM   #27
kacernator is offline kacernator  Czech Republic
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Originally Posted by year98 View Post
Thanks a lot. 530/9530 are 100v devices. Is it enough for 48v?
It should be OK.
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Old 13th April 2018, 06:29 PM   #28
year98 is offline year98  Armenia
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Originally Posted by kacernator View Post
It should be OK.
Thank you.
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Old 9th April 2019, 08:57 PM   #29
mgottwa is offline mgottwa  Germany
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I have a question: After Building my Dogc mk3, I found out it has about
24dB gain. I would like to reduce it to about 12dB. Any advice
which resistor to be changed?

Thank you for advice.

Regards
Michael

Last edited by mgottwa; 9th April 2019 at 09:07 PM.
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Old 9th April 2019, 09:12 PM   #30
mlloyd1 is offline mlloyd1  United States
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DOGC-H by Dr. Jagodic
To avoid playing with the frequency compensation (which you should do if you adjust the gain by playing around with the feedback resistors), why not just add 100K in series with the input?
With the roughly 100k already there, the gain is chopped in half.
Sure, you'll take a little noise hit, but what's a little noise between friends?

mlloyd1
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