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RMS
 Post subject: Re: Weak distortion
New postPosted: Sun Feb 28, 2010 11:38 am 
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acgfilho wrote:
.. In V5 (Pin 6: 470V, pin 1: 36.9 mA) is OK, but in V4 (Pin 6: 471V, pin 1: 27.4 mA) the voltage is pretty small.


Yeah, that 1V difference should not create such a drastic change in the bias reading. Are you using 1% - 1-Ohm biasing resistors? Are you using a matched set of power tubes?

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acgfilho
 Post subject: Re: Weak distortion
New postPosted: Mon Mar 01, 2010 6:51 am 
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Yeah, I'm using matched valves ... Until changed by others but the value is always the same. Tonight I will check the resistors...
Thanks
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acgfilho
 Post subject: Re: Weak distortion
New postPosted: Mon Mar 01, 2010 8:34 am 
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by the way, what do you think about Eminence legend 1258 (75w) 2X12"?
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the_haunted
 Post subject: Re: Weak distortion
New postPosted: Mon Mar 01, 2010 3:59 pm 
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RMS wrote:
acgfilho wrote:
.. In V5 (Pin 6: 470V, pin 1: 36.9 mA) is OK, but in V4 (Pin 6: 471V, pin 1: 27.4 mA) the voltage is pretty small.


Yeah, that 1V difference should not create such a drastic change in the bias reading. Are you using 1% - 1-Ohm biasing resistors? Are you using a matched set of power tubes?


Also try to swap the tubes over. If the low Bias follows the tube, it's a tube problem.

As for the Legend 1258, I couldn't find too much info on them, but they seem to be mainly used for Clean amps, like fenders.
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RMS
 Post subject: Re: Weak distortion
New postPosted: Mon Mar 01, 2010 4:49 pm 
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acgfilho wrote:
by the way, what do you think about Eminence legend 1258 (75w) 2X12"?


Well I am not sure, but I have read good things about this one:
LEGEND GB128 50W

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