Thanks of both expertise
The offset is - Vdc, I'll tail the story. I completed my F5 mono block are very good work and very good sound normal. I burn in about 100 hrs go by and once I saw my speaker' cone one is sucked in I'm hurry switch off my F5, and resume SW on is not happen again till I complete listening. The day after I try again take off speaker cable and put my DC volt meter to biding post switch on F5 the DC offset is normal at the beginning once I play CD player the DC offset go up again and I off and on SW F5 is normal till I complete listening. And now DC offset is -20 Vdc all the time.
Thank You
The offset is - Vdc, I'll tail the story. I completed my F5 mono block are very good work and very good sound normal. I burn in about 100 hrs go by and once I saw my speaker' cone one is sucked in I'm hurry switch off my F5, and resume SW on is not happen again till I complete listening. The day after I try again take off speaker cable and put my DC volt meter to biding post switch on F5 the DC offset is normal at the beginning once I play CD player the DC offset go up again and I off and on SW F5 is normal till I complete listening. And now DC offset is -20 Vdc all the time.
Thank You
Melon Head is quite right to suggest poor joint in first instanceto start fault but now dammage is there to stay?
How hot is inside box?
Remove J fet and test them
See what came out of mosfets whit no Jfet (VGS = 0)
If this is more easy to see current protection you don't need for testing
http://www.diyaudio.com/forums/atta...r-amplifier-f5-no-tempco-no-current-limit.jpg
Many different F5 SCH during much time Q5 Q6 (is this corect?) no need.
Put picture your SCematicH here next time to make beter help.
And no more speaker connected till all work ok
Use resistor but if you don't have dont use. Test ok with no connection.
I know is late now for poor speakers look at NTE7100 data sheet
Picture beter than 1000 words
I have NTE7100 and speakers ok since a long time.
If I like IODA write don't like tell please
more fun this way and many professor angry because of this.
(we also reserve the right to use typo and miss spelling from time to time)
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Only if your driving low impedance or 'difficult' loads.
Highly recommended if you haven't already done so.
F5 p3 adjustment
Hello,
Thanks for the advice, I will start with a standard rev1 F5. In regards to the P3 adjustment, I have spend 2 hrs searching for a solution and can't find the answer.
Would a USB scope with FFT be adequate for P3 adjustment?
I was thinking about DSO-2250 USB Scope or the VT DSO-2810F. In that case the sound card would be the signal generator. Is that ok? (i'd imagine the FFT functions compares input with output to generate THD graphs?)
Otherwise what is a acceptable setup for this? I'd like to avoid buying an expensive sound card, unless necessary.
Thanks,
Hello,
Thanks for the advice, I will start with a standard rev1 F5. In regards to the P3 adjustment, I have spend 2 hrs searching for a solution and can't find the answer.
Would a USB scope with FFT be adequate for P3 adjustment?
I was thinking about DSO-2250 USB Scope or the VT DSO-2810F. In that case the sound card would be the signal generator. Is that ok? (i'd imagine the FFT functions compares input with output to generate THD graphs?)
Otherwise what is a acceptable setup for this? I'd like to avoid buying an expensive sound card, unless necessary.
Thanks,
This sound card is not expensive and work great for THD measurement:
http://www.amazon.com/M-Audio-US41750-Audiophile-Hi-def-Card/dp/B00064ABSG
Looks like a good deal indeed! What about the recommended software?
I found this thread: http://www.diyaudio.com/forums/software-tools/208541-measuring-thd-n.html
ARTA does not look like the screen shots i see on this thread...
Thanks.
Yes The sound card will only accept about 1Vrms in, which doesn't give you a very good picture.
Cheap easy buffer is an O2 (see the headphone section) set to no gain. It certainly isn't as good as pmillets interface but it probably introduces less noise/distortion.
