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Old 26th May 2008, 09:07 PM   #1
gionag is offline gionag  Italy
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Default voltages on a zen v.9

in the end i was able to get work the Zen v9 i'm happy but....

the toroid is a 300VA and get off-load voltage of 36volt. i used a 47000uf filterbank. on the drain of Q4 i get "only" 47volt... and now... on the drain of Q3 i get 42volt.

is it normal that i am unable to get 21 (one-half of the voltage of Q3) but i can't do this because the lower voltage i can get on the drain of Q2 is 24volt. the p1 is work correctly and is a 25k one.

the only part that is different from mr.pass original design is the Bc639 in place of ztx450.

what can i check ? is it normal ?

thanks guys, you are my hope
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Old 27th May 2008, 01:55 AM   #2
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Try a little lower value for R14, the 33K resistor.
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Old 27th May 2008, 05:04 AM   #3
gionag is offline gionag  Italy
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30k is a good value ? the shops has only E24 value....
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Old 27th May 2008, 07:59 AM   #4
gionag is offline gionag  Italy
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it works great. i used a 22k resistor and now is ok...

the last think... is it normal the big voltage drop between Q4 and Q3 ? in the original design is excpected to be 2 volt, in my case the are about 6 volt...

thanks
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Old 28th May 2008, 03:23 PM   #5
gionag is offline gionag  Italy
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Another little question about voltage and amperage:

the toroid emits a noise like a fuzz (very low...) but a fuzz on a 300VA toroid isn't espected to be.

i measured each current and here you are the values:

on the primary of toroid : 0.53 A
on the secondary of toroid : 3.15 A
on the output of the bridge : 3.51 A
on the ouput of the filter : 2.1 A

voltages are :

on the secondary of toroid : 34V
on the output of filter : 45V

Q4 (drain) : 45V
Q3 (drain) : 40V
Q2 (drain) : 20V (adjusted by P1).

the test filter bank is formed by :

2x 10000uf 160V --> 0.25 ohm 25W resistor (parallel of 4x 1ohm) --> 1x10000uf 160V -> 2 x 6800uf 100V. NO FILTER on the AC line and a 2.2K 3W resistors is putted between + and GND as bleeder.

the toroid is 300VA then : 300VA / 34V = 8.8A (twice the current that really flows in my case).

is the toroid broken ? is it normal that fuzz with these "high" currents ?

What can i check for you ?

thanks a lot !
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Old 28th May 2008, 03:42 PM   #6
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Quote:
Originally posted by gionag
Another little question about voltage and amperage:

the toroid emits a noise like a fuzz (very low...) but a fuzz on a 300VA toroid isn't espected to be.

i measured each current and here you are the values:

on the primary of toroid : 0.53 A
on the secondary of toroid : 3.15 A
on the output of the bridge : 3.51 A
on the ouput of the filter : 2.1 A

voltages are :

on the secondary of toroid : 34V
on the output of filter : 45V

Q4 (drain) : 45V
Q3 (drain) : 40V
Q2 (drain) : 20V (adjusted by P1).

the test filter bank is formed by :

2x 10000uf 160V --> 0.25 ohm 25W resistor (parallel of 4x 1ohm) --> 1x10000uf 160V -> 2 x 6800uf 100V. NO FILTER on the AC line and a 2.2K 3W resistors is putted between + and GND as bleeder.

the toroid is 300VA then : 300VA / 34V = 8.8A (twice the current that really flows in my case).

is the toroid broken ? is it normal that fuzz with these "high" currents ?

What can i check for you ?

thanks a lot !

The fuzz of the toroid , in my experience , depends of other AC loads connected in the line at the same time, such soldering iron ( some types ) and other inductive loads .
When I use the CL60 thermistors at the imput of them , toroids seems to fuzz less . Perhaps also the bridge diodes arrangement makes some difference .
For instance , the original First Watt PS arrangement for the F3 fuzzed lot less in my case .
If better toroid quality makes differences .... I dont know .
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