Zen mode,
I have not adjusted the trim pot yet!
Nothing needed that can improve the 2nd harmonic if I am not wrong ?
Thanks
I have not adjusted the trim pot yet!
Nothing needed that can improve the 2nd harmonic if I am not wrong ?
Thanks
what is DC offset at output , when amp is at full temperature ?
(even if M2 id good regarding that , changing nothing or just a little from cold to hot)
there is nothing to set in M2 , besides output offset
(even if M2 id good regarding that , changing nothing or just a little from cold to hot)
there is nothing to set in M2 , besides output offset
Hi zen mode,
Dc at right channel output is 0.685v
Left side is 0.441v
I took measurement between out-g and out of the board! That’s correct ?
Thanks
Dc at right channel output is 0.685v
Left side is 0.441v
I took measurement between out-g and out of the board! That’s correct ?
Thanks
Now running for 50 minutes
R8 r9 : 58 degre
R13 r14 : 57 degre
Heat sink 54 case open
I have to get better prob, but just wondering how much it will be box top closed!
R8 r9 : 58 degre
R13 r14 : 57 degre
Heat sink 54 case open
I have to get better prob, but just wondering how much it will be box top closed!
did you tried correcting that offset ?
do you know how?
anyway , your build is full with problems and you're not helping much - pictures and explanations are necessary so we can deduce what's problem and how to easier explain to you
if you need help , you need to learn either how to post pics here or successfully link them here
do you know how?
anyway , your build is full with problems and you're not helping much - pictures and explanations are necessary so we can deduce what's problem and how to easier explain to you
if you need help , you need to learn either how to post pics here or successfully link them here
Whaaaat? Between l and r channel? Who measures that.
DC on output is measured at speaker terminal, live to ground.
We care what DC our expensive speakers and headphones will get, its detrimental to them.
Here's a link to Teabags blog if you haven't already seen it.
M2Clone boards with 120mm UMS spacing - diyAudio
M2Clone boards with 120mm UMS spacing - diyAudio
answer to Syl20m
Hello Syl20m,
for me this sounds like you did no offset adjustment.
To do this:
DMM - you want to measure Volts - millivolts! at your speakeroutput
You put the red probe of your DMM to speakerout + and DMM black probe
to speakerout - (you do this first ONLY! on the left channel)
Now you adjust your trimpot for offset adjustment on the main pcb (left channel!) till you get close as possible to 0,0 mV on your DMM. Turn slow!
You will not get 0,0mV but try to get close. All below 1mV is super, below 10mV acceptable. Up to 50mV is my personal absolut maximum.
Now go to right channel:
same procedure
Greets Dirk
Hello Syl20m,
for me this sounds like you did no offset adjustment.
To do this:
DMM - you want to measure Volts - millivolts! at your speakeroutput
You put the red probe of your DMM to speakerout + and DMM black probe
to speakerout - (you do this first ONLY! on the left channel)
Now you adjust your trimpot for offset adjustment on the main pcb (left channel!) till you get close as possible to 0,0 mV on your DMM. Turn slow!
You will not get 0,0mV but try to get close. All below 1mV is super, below 10mV acceptable. Up to 50mV is my personal absolut maximum.
Now go to right channel:
same procedure
Greets Dirk
P1 is for offset adjustment.
Don't touch anything inside during adjustments! There can be/is lethal voltage!
Greets
Dirk
Don't touch anything inside during adjustments! There can be/is lethal voltage!
Greets
Dirk
Thank all for your advises!
The amp is not fully warm yet, but I have been able to lower the offset to
On left channel to 7.9mv
And right to 244.7 my
Both now at max of trim pot p1!
I guess next is to replace the 47k resistor I am using in r6 and r7?
Should I increase r7 to 52.3k?
Thanks
The amp is not fully warm yet, but I have been able to lower the offset to
On left channel to 7.9mv
And right to 244.7 my
Both now at max of trim pot p1!
I guess next is to replace the 47k resistor I am using in r6 and r7?
Should I increase r7 to 52.3k?
Thanks
-7.9mv is fine; if you can get the other board to a similar figure by changing R7 but not sure what value to try. Start with 52.3k and hopefully it will get you close. Reset the trimmer to midway. Good luck.
Hi all,
I have replaced r7 to 52.3k on both channels to get more window for tuning the offset.
After running the amp for 20 Minutes, I have set both channels below 0.5mV . It is now occilating between 0 and 0.5!
I will check it again when the amp is fully warm!
I will check temperature of the components again tomorrow!
I have noticed that the amp seems to take about 4-8seconds to load the capacitors when powered up which result of bad sound if the source is already playing!
I supposed the CL-60 inrush limiter i put at primary of the transformer is one of the reasons for this long charging!
Also the CL-60 is quite hot, I was not able to measure , but I guess above 50 degrees
Is that a problem?
You gonna tell the that I should power up the amp and them turn the source On after a while. Which I would normally do!
I have been using a cl-60 also between ground of chassis and ground of power sypply!
The toroidy transformer 500w 2x18vac I am using is not dead silent, there is very small vibrating sound coming form it, it does not seems to spread up to the speakers at least.
Any advises are welcome !
I have replaced r7 to 52.3k on both channels to get more window for tuning the offset.
After running the amp for 20 Minutes, I have set both channels below 0.5mV . It is now occilating between 0 and 0.5!
I will check it again when the amp is fully warm!
I will check temperature of the components again tomorrow!
I have noticed that the amp seems to take about 4-8seconds to load the capacitors when powered up which result of bad sound if the source is already playing!
I supposed the CL-60 inrush limiter i put at primary of the transformer is one of the reasons for this long charging!
Also the CL-60 is quite hot, I was not able to measure , but I guess above 50 degrees
Is that a problem?
You gonna tell the that I should power up the amp and them turn the source On after a while. Which I would normally do!
I have been using a cl-60 also between ground of chassis and ground of power sypply!
The toroidy transformer 500w 2x18vac I am using is not dead silent, there is very small vibrating sound coming form it, it does not seems to spread up to the speakers at least.
Any advises are welcome !
so , you got it without my help ...... which is good 🙂
gradual rising of Iq is the reason why you're hearing starved sound form start ...... that big capacitor between mosfet gates needs time to be juiced
now enjoy ....... all you wrote about is normal behavior of M2
gradual rising of Iq is the reason why you're hearing starved sound form start ...... that big capacitor between mosfet gates needs time to be juiced
now enjoy ....... all you wrote about is normal behavior of M2
answer to Syl20m
Hello Syl20m,
enjoy the music! I hope you have a smile on your face and your ears smile too!
😀
Greets Dirk
Hello Syl20m,
enjoy the music! I hope you have a smile on your face and your ears smile too!
😀
Greets Dirk