mopardave Posted January 27, 2019 Author Share Posted January 27, 2019 11 hours ago, Schu said: Congratulations on the new hobbie... ^That is untrue... the psvane your new amplifier shipped with are not special, but Shuguang and Psvane both offer premium versions (they actually have several levels) of their tube lines that are WONDERFUL. Thanks schu. What are the sonic differences in the psvane kt88 T and the kt88 mk2? Quote Link to comment Share on other sites More sharing options...
mopardave Posted January 27, 2019 Author Share Posted January 27, 2019 On 1/25/2019 at 10:01 PM, mopardave said: Been listening to this amp only a couple hours. Not bad for a $500 Chinese KT88 amp. Has great detail, but not the low and mid bass punch my 25w/ch Audcom EL34 amp delivers. I use GL KT77 in the Audcom. This little 12w/ch amp came with psvane KT88 in it. Not sure if the tubes need burn in or just the low watt is where some of the magic is missing. I'll order up a couple GL KT88 to try in it at a later date, but right now i'm pleasantly surprised with what I'm hearing. Gonna try to get some magic out of this little amp like I did with the Audcom and Super Heresy combo. Someone said earlier that the psvane tubes were not the best. Just gonna let things burn in 20-30 hrs before making any changes. Tried checking the bias setting today. Wasn't sure what pins to measure from, but thought i would follow similar measure points as I do with the Audcom amp. Didn't quite measure like I thought. Found a 1.4ohm resistor between pins 7 and 8 and measured from there. Measuring between pins 8 and 3 I found plate voltage to be 350v. Set bias at.69ma as per the weber bias calculator. OOTB it was set at .66ma. Still not sure I measured at the correct points, but the on board dc/ma meters read the same as my multimeter. Take a look and see what ya think about the measuring points. Pin 8 runs directly to the meter and back to the end of the board where it meets a 1.4ohm resistor where it runs through the resistor, then splits off to the big blue caps one way and to pin 7 the other. I took measure from each side of that resistor. outer sockets only Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted January 27, 2019 Share Posted January 27, 2019 18 hours ago, mopardave said: I use the weber bias calculator, but can you give the procedure to find it? The Weber bias calculator looks good just be sure to take into account the assumption listed for each calculator. I only mentioned the caution about just comparing bias ma without taking into account the voltage drop across the plate/cathode or plate/filament (of true triodes like 300b, 2a3, etc). miketn Quote Link to comment Share on other sites More sharing options...
mopardave Posted January 27, 2019 Author Share Posted January 27, 2019 1 minute ago, mikebse2a3 said: The Weber bias calculator looks good just be sure to take into account the assumption listed for each calculator. I only mentioned the caution about just comparing bias ma without taking into account the voltage drop across the plate/cathode or plate/filament (of true triodes like 300b, 2a3, etc). miketn I'm no expert in this, that for sure, but I think the weber calc gets me there. I don't know how to measure that voltage drop and don't want to die trying to figure it out. Thanks Quote Link to comment Share on other sites More sharing options...
mopardave Posted January 27, 2019 Author Share Posted January 27, 2019 33 minutes ago, mikebse2a3 said: The Weber bias calculator looks good just be sure to take into account the assumption listed for each calculator. I only mentioned the caution about just comparing bias ma without taking into account the voltage drop across the plate/cathode or plate/filament (of true triodes like 300b, 2a3, etc). miketn Would figuring the voltage drop be as easy as dividing the plate voltage by the resistor value? 350/1.4=250v? Quote Link to comment Share on other sites More sharing options...
Schu Posted January 27, 2019 Share Posted January 27, 2019 You should go into the tube section of the website... it's lonely in there, but there is the knowledgeable that visit Quote Link to comment Share on other sites More sharing options...
mopardave Posted January 27, 2019 Author Share Posted January 27, 2019 10 minutes ago, Schu said: You should go into the tube section of the website... it's lonely in there, but there is the knowledgeable that visit I'll check it out. Thanks schu Quote Link to comment Share on other sites More sharing options...
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