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Old 25th August 2014, 02:49 PM   #91
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Thanks ZM. With the output connected to ground measurement, please see attached drawing.
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Old 25th August 2014, 03:28 PM   #92
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it seems everything is ok

remove bridge from output to gnd , put one pair of (checked!) mosfets in place and power it up

report here

when you have functional amp with one pair , you'll put second one
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Old 26th August 2014, 02:13 AM   #93
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Thanks ZM. Should I disconnect the input from the ground as well? I also noticed that the board vibrates when it's powered up and the transformer buzzes.
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Old 26th August 2014, 08:46 AM   #94
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Quote:
Originally Posted by pmchoong View Post
Thanks ZM. Should I disconnect the input from the ground as well?.......
all the time - until it's ready to sing

Quote:
Originally Posted by pmchoong View Post
T...... I also noticed that the board vibrates when it's powered up and the transformer buzzes.
??!

with or without mosfets in circuit ?

even if I can't see anything wrong on your pictures , you're th eone who need to check every connection

insert Ampermeter in each rail (one by one ) , between cap bank and pcb and measure - without mosfets you'll have up to 20-30mA , no more

with mosfets - increased for Iq
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Old 27th August 2014, 04:41 PM   #95
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Quote:
Originally Posted by Zen Mod View Post
all the time - until it's ready to sing



??!

with or without mosfets in circuit ?

even if I can't see anything wrong on your pictures , you're th eone who need to check every connection

insert Ampermeter in each rail (one by one ) , between cap bank and pcb and measure - without mosfets you'll have up to 20-30mA , no more

with mosfets - increased for Iq
Hi ZM. You mean ground the inputs all the time until it is ready to sing?

The board vibrates with and without the mosfets connected. It wasn't there before.

So, one probe on the negative rail and one probe on the negative of the amp board pcb to test the ampere and then repeat the same for the positive rail, is this correct?
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Old 27th August 2014, 05:55 PM   #96
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Quote:
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Hi ZM. You mean ground the inputs all the time until it is ready to sing?

yup

Quote:
Originally Posted by pmchoong View Post
........

The board vibrates with and without the mosfets connected. It wasn't there before.
....
that's confusing .......

Quote:
Originally Posted by pmchoong View Post
..........

So, one probe on the negative rail and one probe on the negative of the amp board pcb to test the ampere and then repeat the same for the positive rail, is this correct?
yup

find some tutorial on web , how to make basic measurements

look here , for instance :Basic Car Audio Electronics

look at right menu - Digital Multimeter
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Old 29th August 2014, 02:48 PM   #97
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i have 0.54 mA on the negative rail and 0.21mA on the positive side.
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Old 29th August 2014, 05:14 PM   #98
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you mean - one pcb is drawing 0,54mA from pos and and 0.21mA from neg rail ?

with JFets in place , just mosfets removed from circuit ?

as I said :

Quote:
Originally Posted by Zen Mod View Post
.......

insert Ampermeter in each rail (one by one ) , between cap bank and pcb and measure - without mosfets you'll have up to 20-30mA , no more

with mosfets - increased for Iq
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Old 30th August 2014, 03:40 PM   #99
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you mean - one pcb is drawing 0,54mA from pos and and 0.21mA from neg rail ?

Yes, please see attached picture on how I took the measurement.

with JFets in place , just mosfets removed from circuit ?

Yes, with JFets in place and mosfets removed from the circuit.

as I said :
Should I take the measurement as in picture 'fets measurement.png4'?

Thanks, ZM.
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File Type: png fets measurement.png3.png (882.4 KB, 47 views)
File Type: png fets measurement.png4.png (351.0 KB, 44 views)
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Old 30th August 2014, 03:46 PM   #100
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that right one
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