The distortion figures are high enough that if you have a scope and oscillator
you can cobble together a circuit which compares the input signal to the
inverted output signal and by tweaking the relative amplitude and finding
the midband frequency where you get the best cancellation you can see
the distortion pretty clearly.
😎
YEEPEEEEEEEE YEAHHHHHHHH , wonderfull , merveilleux ,c'est Formidable!!!!
Awesome!
What do you mean by too much gain?
As for hum, does it go away when you unplug the input? With 100+ dB speakers some is too be expected, but I'm sure we can get it under control.
🙂 lay my hand on the heatsink 10 seconds before huting is it ok for dissipation ?
Sounds reasonable. The chip temp is what matters most, of course. At 17V, 2.77A, you're pushing it. What is your supply voltage and resistor value?
i have a 40V 800VA transfo and i make fig 10 with lm337 negative bias. my load resistor is 12ohm and 8 ohm speaker
my First Solidstate Amp , Thanks Michael !! ..🙂
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Very nice. Congratulations!
Your Vds seems a bit high. I notice your load resistors are quite small and must be really hot inside the case. Could you measure the voltage across them when the amp is fully warmed up (30 minutes or so)? While you're at it, measure your power supply voltage. Also, what's the PCB in the lower left? Thump relay?
And for your hum issue, in addition to my previous question, which word best describes the noise: hum, hiss, or buzz?
Your Vds seems a bit high. I notice your load resistors are quite small and must be really hot inside the case. Could you measure the voltage across them when the amp is fully warmed up (30 minutes or so)? While you're at it, measure your power supply voltage. Also, what's the PCB in the lower left? Thump relay?
And for your hum issue, in addition to my previous question, which word best describes the noise: hum, hiss, or buzz?
yes the module is a sofstart.. power supply is at 50,5V voltage drop across the loads resistors (10 + 2ohm) is 32V
i'v got 16V and 2.68 amp ..
the resistor 200W variable resistor is too hot, i will change it for a 800w thick film.
the hum is a transformer noise , i ithink ringing in the case and in the speaker ..
i'v got 16V and 2.68 amp ..
the resistor 200W variable resistor is too hot, i will change it for a 800w thick film.
the hum is a transformer noise , i ithink ringing in the case and in the speaker ..
That sounds closer to the mark. You'll probably want to move your load resistors to the top so they get some air. If you switch to the big thick film types, don't foget they must be attached to a large heatsink.
If it sounds like mechanical hum, it could be that your transformer is running too hot with the load resistors inside the case.
Have you had a chance to listen, or is the hum too bothersome?
the problem is that i come from a little gain tube amp (26 triode / AD1) with 2/3 watt and lots of good distorsions.. and now yours is like a 100W amp with no distorsion ( or i can"t hear them).. the hum is boring now at night session but i think that i could build later an external box for the power supply ( transfo /bridge and Capacitors) i have three problem , so 2 the hum , 2 the heat and 3 the gain with my active preamp , one or 2 clic on the volume pot and it"s war at home😱but in the end, i never had a sound like that with my commercial or DIY past amp... best sound ever 😀
Mes félicitations! 😀
Seulement pour comparer, j'ais pris 14,2 Ohm pour descendre de 44V jusque au 14V à la drain du SK82 avec 2,55 Ampère.
Je suis ravi que tu aime le son aussi!
🙂🙂🙂
Seulement pour comparer, j'ais pris 14,2 Ohm pour descendre de 44V jusque au 14V à la drain du SK82 avec 2,55 Ampère.
Je suis ravi que tu aime le son aussi!
🙂🙂🙂
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thanks , so i think i will go with 1O ohm and 3ohm to run cooler . for the hum do you think i can put just the 800va transformer outside and just keep the small 12V one for the bias in the case , and the 2 bridge and caps also.. ?
can i also put the 2X 40V AC in parrallele to have just one big power cable between the power and the Amp ?
🙂
so I am not convinced of the absolute values of my sound card distortion measurement ....
and I cannot handle even the program completely....
it is very interesting to see what Mike meant with the quick change of the distortion with small variations of the Vgs...
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....🙂
and I cannot handle even the program completely....
it is very interesting to see what Mike meant with the quick change of the distortion with small variations of the Vgs...
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....🙂
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It's really more useful to see it in terms of Ids and Vds, as these change
more dramatically for small variation of Vgs, and also the Vgs figure varies
much more from part to part than the performance at given Ids and Vds.
😎
more dramatically for small variation of Vgs, and also the Vgs figure varies
much more from part to part than the performance at given Ids and Vds.
😎
O.K. Mr. Pass! Thanks for the explanation...next pictures will enclose the values of Ids and Vds.....
So when Mike gives values for the sweet spot the pairing of Ids and Vds is more valuable than merely adjusting the Vgs ....... I suppose?
So when Mike gives values for the sweet spot the pairing of Ids and Vds is more valuable than merely adjusting the Vgs ....... I suppose?
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Yes, that's why I always try to give you the Id, Vds (operating point) as well as the loads (load line). They all have to be accounted for in this circuit.
Isn't this fun 🙂
O.K Mike I understood it now even a little better .......
And it is fun, I am waiting for my second set of resistors to hear finally in stereo.
They are more non inductive, I hope they have a small advantage....
And a little bit on the SIT trip, I will try to build the input stage from Corrado as a pre..
And it is fun, I am waiting for my second set of resistors to hear finally in stereo.
They are more non inductive, I hope they have a small advantage....
And a little bit on the SIT trip, I will try to build the input stage from Corrado as a pre..
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