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Old 14th January 2012, 08:52 PM   #391
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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
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Old 14th January 2012, 09:41 PM   #392
generg is offline generg  Germany
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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!


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Old 14th January 2012, 10:15 PM   #393
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...one or 2 clic on the volume pot and it"s war at home...
You could try some series resistance to attenuate the input.
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Old 14th January 2012, 10:43 PM   #394
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or attenuate your ears. Kids, booze, age or earplugs all work in varying degrees.
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Old 15th January 2012, 06:44 AM   #395
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Quote:
Originally Posted by generg View Post
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!



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 ?

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Old 15th January 2012, 06:34 PM   #396
generg is offline generg  Germany
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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....
Attached Images
File Type: jpg SIT.jpg (80.9 KB, 429 views)
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Old 15th January 2012, 08:17 PM   #397
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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.

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Old 15th January 2012, 08:51 PM   #398
generg is offline generg  Germany
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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?
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Old 15th January 2012, 08:58 PM   #399
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So when Mike gives values for the sweet spot the pairing of Ids and Vds...
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
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Old 15th January 2012, 09:06 PM   #400
generg is offline generg  Germany
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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..

Click the image to open in full size.
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