question:
What guidelines are given - how to measure Beta?
I would do that arranging fixture to get them at prescribed current in amp, not using puny DMM or small universal tester - testing current is simply too small
...... back to Popcorn munching
What guidelines are given - how to measure Beta?
I would do that arranging fixture to get them at prescribed current in amp, not using puny DMM or small universal tester - testing current is simply too small
...... back to Popcorn munching
Or left them on heatsink and applied voltage to all and measured voltage over emitter resistors
Well the MJ15023 in the left hand column are not within the On Semi spec of 15 to 60 min to max hfe. These were replaced previously before the member bought the amp - obviously chinese fakes.
All others are within the range as advised by Jon Soderberg, so we will be able to get matched sets, more genuine MJ15023G types will need to be purchased unfortunately to make up the numbers.
The voltage over the emitter resistors is what lead to this exercise in the first place - the current sharing in the OS was way out.
All others are within the range as advised by Jon Soderberg, so we will be able to get matched sets, more genuine MJ15023G types will need to be purchased unfortunately to make up the numbers.
The voltage over the emitter resistors is what lead to this exercise in the first place - the current sharing in the OS was way out.
Still a great looking amp, even after all these years.
Good luck with the testing - fingers crossed.
Good luck with the testing - fingers crossed.
Hi Mike ,
Been tinkering all day now and I think the bias is going to be 0.85mv at 45c , dc offset is at 0.9mv and 0.2mv .
Can’t seem to get the temperature any higher, might get the dc offset to zero on both channels eventually.
if you start taking care of units, we can start trusting you 
I can understand 0.9mV and 0.2mV for offset, but I can't understand 0.85mV for bias
what's wrong calling Iq by its proper name - Iq, describing it as "xxxmV across xxxOhms" ?
I can understand 0.9mV and 0.2mV for offset, but I can't understand 0.85mV for bias
what's wrong calling Iq by its proper name - Iq, describing it as "xxxmV across xxxOhms" ?
OK, so it is 85mV across 1R0 emitter resistors = 85mA bias per transistor.
Jon Soderberg has confirmed to me that factory spec for the Stasis 2 was 85mA at 45 deg heat sink temp. Factory spec for Dc offset was better than +/- 50mV.
Jon Soderberg has confirmed to me that factory spec for the Stasis 2 was 85mA at 45 deg heat sink temp. Factory spec for Dc offset was better than +/- 50mV.
0.09mV?... as in less than one millivolt? If so then you are done. Congratulations! The goal is loosely zero.
Most of the credit should go to Gary and then to you all for your input and reassurance ( I almost threw in the towel several times)
Thank you so very much guys .
Thank you so very much guys .
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