this picture was taken at about 2,9V and 2,4A and shows at least the dominance of the second harmonic and the absence of higher distortions at lower input levels....
Very high 100Hz rectification buzz plus its first harmonic and their beat though. Should be pushed down further. But no 50Hz hum, that's good. I.e. no fields or gnd loops.
Yes Salas .....you are right! I was very astonished to see that 100 Hz and 200 Hz peak! Normally I have a 50 Hz peak.
Why do I get this different peak and what can I do against him and I hear no hum....!
Gerd
100Hz is double the mains frequency (as coming out from bridge rectification cycling), 200Hz is its first harmonic, 300Hz is 1st's and 2nd's beating product plus smaller ones up higher. If you can't hear any ZZZZ noise then its just something in your measuring rig. Such harmonic noise gives ''grunge'' to midbass when present making it seemingly bigger also. What you can do is increase amp's PSRR with CCS or use filtering in the PSU. Choke or capacitance multiplier.
Hi Salas, thanks for your answer....
I just creeped into my open baffles to the tone tubby, there is only a very very faint hum... so I suppose it is this time more the measuring rig.
At any case you had a very good look at my data.......
still waiting for resitors and the IRF you suggested.... good that only the amp is mono and not me.....
I just creeped into my open baffles to the tone tubby, there is only a very very faint hum... so I suppose it is this time more the measuring rig.
At any case you had a very good look at my data.......
still waiting for resitors and the IRF you suggested.... good that only the amp is mono and not me.....
Way too hot inside that case, and that's probably not making your transformer happy either. Move those resistors outside or get bulbs. Have a look at my post on resistors, the ones I used are 4 times as big, and I used three for each channel.
Keep going, you're almost there.
At approx. .1% THD, predominant second, I'd say you're doing quite well.
Now, twist the knob and watch the spectrum change. Fun, fun, fun.
BTW, are those 50V caps?
Way too hot inside that case, and that's probably not making your transformer happy either. Move those resistors outside or get bulbs. Have a look at my post on resistors, the ones I used are 4 times as big, and I used three for each channel.
Keep going, you're almost there.
i lost my AAA but i ordered 2X 800W thick film resistor with heatsink and 2 3,3ohm 100W .. and a isolation TRansformer .. i' m on the run
I am speechles........even with AAA.....what big jump!
That will solve your problems I suppose, do you need more heatsinks?
Would be nice if you could keep your wooden case, looks better than these mostly cheap metallic cases that are mine.
Maybe I will change too, but keeping the heatsink area!
Hope my trans- and re- sistors will come soon...
And I built up in the evening the SK79 and SB624 circuit I posted some days ago, again too late to hear loud, but it seems not contra productive to the SIT amp.....
That will solve your problems I suppose, do you need more heatsinks?
Would be nice if you could keep your wooden case, looks better than these mostly cheap metallic cases that are mine.
Maybe I will change too, but keeping the heatsink area!
Hope my trans- and re- sistors will come soon...
And I built up in the evening the SK79 and SB624 circuit I posted some days ago, again too late to hear loud, but it seems not contra productive to the SIT amp.....
Hi everybody,
some news,
1. I could change my wire resistors today against thick film resistors.... that is a heavy difference.......I was shocked.....I like it much more!
2. my new arranged Mufollower was better than the wire resistor version, more alive...but more cap dependent, two caps.....and now compared to the thick film solution, less precise and a bit veiled, but more bass with my tone tubby/lowther and more gain.....
the affair stays amusing.......
and Salas, CCSs must wait still a bit, I have to change the PSU from 48V again back to 27 or 18......
some news,
1. I could change my wire resistors today against thick film resistors.... that is a heavy difference.......I was shocked.....I like it much more!
2. my new arranged Mufollower was better than the wire resistor version, more alive...but more cap dependent, two caps.....and now compared to the thick film solution, less precise and a bit veiled, but more bass with my tone tubby/lowther and more gain.....
the affair stays amusing.......
and Salas, CCSs must wait still a bit, I have to change the PSU from 48V again back to 27 or 18......
