Tomorow i will get 1ohm resistors.
Just to make sure, when i use the resistors in series with ps rails do i disconnect the dbt or not?
I reversed the leds on second board and it is working, vas biasing done.
Hello all, i m happy.[emoji846] my boards are working.
I did the mosfet bias in both boards... and everything is as Shaan wrote on manual.
I tested both boards in a full range small driver.. and there is music playing very nice.
Now i need to connect everything and final test on main speakers.. maybe in the weekend.
I did the mosfet bias in both boards... and everything is as Shaan wrote on manual.
I tested both boards in a full range small driver.. and there is music playing very nice.
Now i need to connect everything and final test on main speakers.. maybe in the weekend.
here is a small video with one board playing in test speakers and test psu
peeceebee vh4 test - YouTube
peeceebee vh4 - YouTube
peeceebee vh4 test - YouTube
peeceebee vh4 - YouTube
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Not yet.. in the beginning will be on an wood base.[emoji846][emoji6]Congrats Pistollero!!
Do you have a plan for a chassis yet?
Enjoy your new V4H
Hi Pistollero.
My apologies for not be able to be involved in your case. Suddenly all my existing projects got on halt due to market closure, there is no transport, and I can't reach the city on my bike as the watchmen are busy punishing anyone on the roads who is not a Govt. employee. It's still the same way and will be until the end of this month, but I decided to turn a blind eye to it for the time being.
Now I'm back to typing.
Very happy to know you found the problem and successfully biased the boards. Looking forward to know how they perform after being integrated in your main system.
Thank you for your thorough reports on the work and also for your patience with the project.
I need to apologize for one more thing. In post#1598 I responded with paralleling four 1.8ohm. That was a mistake in my part as I had the rail resistors for the power supply in mind. (No idea why, I guess I was a little disoriented.)
If you still have the 1ohm 1watt resistors with you then yes you can use one of them per rail to set the total bias. Dissipation in these resistors at 250mA bias will be 250mW, which is fine and within safe range.
edit: My thanks to bullittstang for the help!
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No problem Shaan i notice that you must had some trouble to not answer.Hi Pistollero.
My apologies for not be able to be involved in your case. Suddenly all my existing projects got on halt due to market closure, there is no transport, and I can't reach the city on my bike as the watchmen are busy punishing anyone on the roads who is not a Govt. employee. It's still the same way and will be until the end of this month, but I decided to turn a blind eye to it for the time being.
Now I'm back to typing.
Very happy to know you found the problem and successfully biased the boards. Looking forward to know how they perform after being integrated in your main system.
Thank you for your thorough reports on the work and also for your patience with the project.
I need to apologize for one more thing. In post#1598 I responded with paralleling four 1.8ohm. That was a mistake in my part as I had the rail resistors for the power supply in mind. (No idea why, I guess I was a little disoriented.)
If you still have the 1ohm 1watt resistors with you then yes you can use one of them per rail to set the total bias. Dissipation in these resistors at 250mA bias will be 250mW, which is fine and within safe range.
edit: My thanks to bullittstang for the help!
Everything is ok but now i want to build the final psu but i neet some advice regarding the fuses.. i see some designs with one fuse on primary of the transformer and other with two fuses after the cap filter bank on supply rails..or before the brigde...
What should i do?
The new psu will have the same 22000uf x2 as the test psu.
Once the amplifier is biased is there need when change something in the psu for new adjustments or once calibrated is ok forever?
Two fuses after the capacitor bank.
As long as you are using the same transformer (or same AC secondary rails), no need to change anything.
Hello all, my amplifiers are working on main speakers.
Thank you Shaan, you made a great amplifier!!![emoji6][emoji3]
It sounds superb! Great sound. Dynamic and clean.
Need some opinion on the transformer needed:
I'm using a 200va 2x39v transformer for each amp. Do i need more va's or this is ok?
Thank you Shaan, you made a great amplifier!!![emoji6][emoji3]
It sounds superb! Great sound. Dynamic and clean.
Need some opinion on the transformer needed:
I'm using a 200va 2x39v transformer for each amp. Do i need more va's or this is ok?
Hi Pistollero.
With 200VA you will get a maximum of about 110watt from each channel. If that is a high enough power ceiling for your speakers then no need to change. If not, then maybe 300VA. If not used yet, install speaker protection modules (as this is a fully DC coupled amp).
Thanks for the kind words. Happy to know you like its sonics - dynamic and clean.
With 200VA you will get a maximum of about 110watt from each channel. If that is a high enough power ceiling for your speakers then no need to change. If not, then maybe 300VA. If not used yet, install speaker protection modules (as this is a fully DC coupled amp).
Thanks for the kind words. Happy to know you like its sonics - dynamic and clean.
hello... bad news... after an hour of playing i heard a pop on one speaker a music stoped then bzzz... when i got close to the amp i see the little firework and smoke and very bad smell... so.. one amp is gone... i have to check later if was something related with the dac (once i had a problem with one channel of the dac blown away) or the speakers... i don´t know why the fuses on rails did not break (8a fuses), the transformer was hot and main filter caps also....this amp is not an easy animal...
i was controlling the temperature since beginning and the amps were around 40 º celcius but after a wile they got hotter around 55/60º.
i think the amp over heated.. what should be the normal working temperature?? any problem with 4 ohm speakers?
... i have to check later if was something related with the dac (once i had a problem with one channel of the dac blown away) or the speakers... i don´t know why the fuses on rails did not break (8a fuses), the transformer was hot and main filter caps also....this amp is not an easy animal...i was controlling the temperature since beginning and the amps were around 40 º celcius but after a wile they got hotter around 55/60º.
i think the amp over heated.. what should be the normal working temperature?? any problem with 4 ohm speakers?
Hi Pistollero,
My congratulatory message for getting your V4H powered up has now turned to troubleshooting. From your pictures I noticed the heatsinks are mounted flat to the board. The fins need to overhang the board and be raised so proper convection airflow is enabled. As built, the heatsinks are ‘suffocating’ and will not effectively cool the V4H. Also, as Shaan pointed out, please use some sort of dc speaker protection, rail fuses are not sufficient protection.
Once you get your ‘bug’ worked out, the V4H is a fantastic amplifier!
Enjoy
My congratulatory message for getting your V4H powered up has now turned to troubleshooting. From your pictures I noticed the heatsinks are mounted flat to the board. The fins need to overhang the board and be raised so proper convection airflow is enabled. As built, the heatsinks are ‘suffocating’ and will not effectively cool the V4H. Also, as Shaan pointed out, please use some sort of dc speaker protection, rail fuses are not sufficient protection.
Once you get your ‘bug’ worked out, the V4H is a fantastic amplifier!
Enjoy
hello... bad news... after an hour of playing i heard a pop on one speaker a music stoped then bzzz... when i got close to the amp i see the little firework and smoke and very bad smell... so.. one amp is gone
Hi.
This amp is a very easy animal when there is no sustained short circuit or inadequate cooling. The fact that the transformer and filter caps are hot seems to suggest the channel has been under immense stress for more than just a few minutes. If that was due to a short circuit, the mosfets didn't die immediately possibly because their on resistance (around 1ohm each) and the zener diodes were trying to limit the current.
I have been running the amp in 43C summer heat with heatsinks similar to yours and with fins open to the air and it has no issue driving 4ohm speakers.
I think you are right, it overheated. Looking back at the pictures you shared, it seems there would be problem for fresh air to reach the heatsink fins.
Before dismantling the channel, carefully check for shorts between the mosfets' Pin 2 and heatsink metal.
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That has been sorted out in rev2. It looks like he is using rev2 boards.
Yes it is rev 2.
You are right the amp strougle 30 seconds or more before blow up... the problem is that i was resting listen to music and heard the pop and get up and tried to find witch amp was connect to the speaker making noise...should disconnet the power faster.
In the weekend i will try to troobleshoot.
I m using that thermal pads instead mica and grease.. could that be also a problem?
I will not give up on this amp[emoji6]
Also need to put speaker proctection..
As Vunce and I suspected before, when the fault happened, were the channels situated like in the pictures you shared? If yes, then this can slowly push any amp into the thermal danger zone!
Thermal pads are fine.
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