Thanks for swift reply ... h_a ? please send private message, I do not know who we are speaking about ! Regards, Raoul
F5_spreadsheet
Dear all!
Right know I finished reading all the posts on this thread. It took me more than two weeks. In parallel I prepared a spreadsheet based on the articels of Nelson Pass (F5 & F5T) and what I have learned following this thread.
I hope that some of the skilled members will go thru it and make some comments in order to create a powerfull tool which will answer a lot of questions raised again and again.
The values in the orange cells can be modified and all the others will be updated according.
I am using since about 5 years an aleph_X and IMO the F5T-V3 is now the next step to do.
Dear all!
Right know I finished reading all the posts on this thread. It took me more than two weeks. In parallel I prepared a spreadsheet based on the articels of Nelson Pass (F5 & F5T) and what I have learned following this thread.
I hope that some of the skilled members will go thru it and make some comments in order to create a powerfull tool which will answer a lot of questions raised again and again.
The values in the orange cells can be modified and all the others will be updated according.
I am using since about 5 years an aleph_X and IMO the F5T-V3 is now the next step to do.
Wondering if there is anyone in the Seattle area who can help me troubleshoot an F5T V2 having issues with the amp board (trimpots not adjusting anything, something might be shorted somewhere)
Well-lit, in-focus photos please. 🙂
You will be surprised what some members can see in a good photo.
Can you describe the issue in more detail?
Do you have a variac or light-bulb test lead?
You will be surprised what some members can see in a good photo.
Can you describe the issue in more detail?
Do you have a variac or light-bulb test lead?
photos are in dedicated thread , just posted
http://www.diyaudio.com/forums/pass...-area-willing-take-challenging-f5t-issue.html
however , taking in account wiring/placement of half mosfets , that's case for not faint in heart ........ in vivo
http://www.diyaudio.com/forums/pass...-area-willing-take-challenging-f5t-issue.html
however , taking in account wiring/placement of half mosfets , that's case for not faint in heart ........ in vivo
The DC on the terminals and the voltage across the source resistors are way too high right off the bat.
With 20VAC input I get .896V on the speaker outputs,
.524V on R17, R18
.507V on R19, R20
.474V on R21, R22
.543V on R23, R24
Ambient temperature 26.5°C with the MUR diodes at 2°C above that, and the output transistors at 6° above ambient.
I've tried the trimpots P2 and P3 at all the way CCW and also full CW and they don't change any of the measurements.
P1 does nothing either.
Pulled P2 and the parallel resistor to check their values and see if they are functioning and they measure just fine out of circuit.
I also measured for shorted to ground output devices, all checked OK.
All polarities are correct.
No miswirings.
I checked every part on the board for value (visually) and they all match the schematic.
Both amplifiers exhibit the same issue on both the N and P side.
Power supply is working fine, I have 33.5V unloaded on both rails, both amplifiers, ±.1V.
Here is the link
http://www.diyaudio.com/forums/pass...-area-willing-take-challenging-f5t-issue.html
It's not ideal, I know, originally I was going to do just a single chassis build, but the friend I'm building this for pressured me into making them into monoblocks and then after that into smaller and smaller monoblocks, so what you see is the result. I'm at wit's end here, normally I just build speakers, and can trouble shoot those much better.
Swapped them around, I think everything is working now, just need to do some more testing, and slowly bring it up. Gun shy at this point though.
Wow, I feel stupid, one amp had only TWO output devices out of 8 in the right place. I guess I wasn't paying attention when I put them in OR when I checked them after I installed them.
Had MURs where I should have had IRFs...
Had MURs where I should have had IRFs...
next time paint MURs in red , N type in blue and P type in brown , prior to mounting them on pcb/heatsink
next time paint MURs in red , N type in blue and P type in brown , prior to mounting them on pcb/heatsink
No ****, maybe I need to hire a team of people to check my work at each step 😛
I think I have this under control, just need to have a day and maybe a helper to finish this up.
Congrats SirByrd. Glad you found it. It's not at all easy to get something complex done in one shot. I have every intent of having someone backcheck my build before powering up.
GND - BRDIGE???
A question from my side to the more advanced audio cracks here. Do I really need that gnd bridge? I'm actually planning to use only thar thermistor to the gnd and I'm wondering myself why I should need that bridge?
In my last F5 build everything worked fine without tha bridge.
Any suggestion?
Cheers,
Mallard
A question from my side to the more advanced audio cracks here. Do I really need that gnd bridge? I'm actually planning to use only thar thermistor to the gnd and I'm wondering myself why I should need that bridge?
In my last F5 build everything worked fine without tha bridge.
Any suggestion?
Cheers,
Mallard