transistorised step
Hi
having made this h900 transistorised step only problem i am facing is negative side
step i am not getting 55 volts dc on collector outputs positive side i am getting correct
55 volts dc i have changed 2n3906 to BC560 but still high voltage on negative collector can any one help me
thanking you
samee rx1
Hi
having made this h900 transistorised step only problem i am facing is negative side
step i am not getting 55 volts dc on collector outputs positive side i am getting correct
55 volts dc i have changed 2n3906 to BC560 but still high voltage on negative collector can any one help me
thanking you
samee rx1
hi apex sir,
I provide 50hz sinewave to h900 and i checked the out , with clipping showing 52v ac.
is this ok?
another question is that two 15v zd half watt showing 0v near the stepdriver ic 2nd pin.
why is that?
I provide 50hz sinewave to h900 and i checked the out , with clipping showing 52v ac.
is this ok?
another question is that two 15v zd half watt showing 0v near the stepdriver ic 2nd pin.
why is that?
hi apex sir,
can u check last post, is that normal?
52v ac is 676W on 4R, what is rail voltage and power of transformer on your amp?
52v ac is 676W on 4R, what is rail voltage and power of transformer on your amp?
thanks for reply sir,
my rail voltage is 45-90-0-45-90dc.
thanks for reply sir,
my rail voltage is 45-90-0-45-90dc.
Thats OK, for 900W/4R you need 60v ac on amp out, and rail voltage 100-50-0-50-100v dc
thanks for reply sir,
is that two 15v zd half watt showing 0v near the stepdriver ic 2nd pin, is that normal?
is that two 15v zd half watt showing 0v near the stepdriver ic 2nd pin, is that normal?
Dear sir Apex,
Hello my PCB is complete please check if it is OK so i can post PCB layout for Diy to make Apex sir please guide
Thanking you
Sameer X1
sir,forgive if i m wrong -if 2sc4793 and 2sa1837 placed wrong place.
please give give me your schematic ,pcb layout,and measurement so that i can
make one.----please again
-with regards.
Join Date: Jan 2012
Location: Iloilo
mj777, can i replace IRF2807 with IRF540 in transistor type step driver of H900?
Location: Iloilo
mj777, can i replace IRF2807 with IRF540 in transistor type step driver of H900?
Transistor stepdiver
So there is no question to replace IRF2807? In our place, hard to find this trans.
So there is no question to replace IRF2807? In our place, hard to find this trans.
You can use 2pcs. IRF540 per rail instead IRF2807So there is no question to replace IRF2807? In our place, hard to find this trans.
This 2 module of H900 with discrete step driver use 2 IRF540 per rail without any problem encountered
power supply used is +/- 110-55-0-55-110 volt
power supply used is +/- 110-55-0-55-110 volt

Last edited:
Hey AndrewT look at this original schematic of H900 and ask apex and others who build this amp why they use IRF540 at +/- 120-60-0-60-120 volt railirf540 are 100Vds devices.
How do you make them reliable with a +-110Vdc supply?

irf540 while supplied from 120volt supply sits atop 60volts.....if Apex is confident with them, you can use them...
irf540 are 100Vds devices.
How do you make them reliable with a +-110Vdc supply?
On IRF540 is only 55Vdc.
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