Here's what I was able to gather at this point. I ordered 100 pcs of both 2SA and 2SC devices, but the sums say I have lost almost ten of each. 
Anyway, it seems that the HFE values are much higher with the batches I got compared to the Fig. 5 in the pdf guide. The overlapping region with my devices is approx. 590-625 while in the pdf it is 480-520.
Anyway, it seems that the HFE values are much higher with the batches I got compared to the Fig. 5 in the pdf guide. The overlapping region with my devices is approx. 590-625 while in the pdf it is 480-520.Attachments
The hfe distribution of the 2SC3324/2SA1312 shown by SB is consistent with my experience and that of Morde.
Judging from what was shown in the photos I believe you can find enough pairs for the build.
As already mentioned in the article,
"For minimising even harmonic distortion, it is important that :
1) Q1,2,7,8 are hfe matched;
2) Q11,12, are hfe matched, as are Q13,14;
3) Q3,5,9 are hfe matched; as are Q4,6,10;
But the hfe between 1), 2) and 3) can be different.
Patrick
Judging from what was shown in the photos I believe you can find enough pairs for the build.
As already mentioned in the article,
"For minimising even harmonic distortion, it is important that :
1) Q1,2,7,8 are hfe matched;
2) Q11,12, are hfe matched, as are Q13,14;
3) Q3,5,9 are hfe matched; as are Q4,6,10;
But the hfe between 1), 2) and 3) can be different.
Patrick
Here my own distribution, tested using PEAK DCA55 semiconductor analyzer and the PEAK SOT23 adapter.
Indeed the HFE reading change slightly from measurements to measurement, but remain in the range I indicated... And the actual HFE reading may be different from meter to meter, but whit the same meter, in the same condition, temperature, etc, the same batch measurements are an indication of the range of HFE. To make sure I re-tested the NPN or PNP to make sure the tester was not changing/Drifting, but the reading were consistent, and repetitive, within a range, for example I was measuring 410 on time, then 418 the next time, but certainly not 480. As usual the PNP have a greater variation of HFE than the NPN that are more consistent. I saw this behavior with other transistors. Seem to make sense...
Indeed the HFE reading change slightly from measurements to measurement, but remain in the range I indicated... And the actual HFE reading may be different from meter to meter, but whit the same meter, in the same condition, temperature, etc, the same batch measurements are an indication of the range of HFE. To make sure I re-tested the NPN or PNP to make sure the tester was not changing/Drifting, but the reading were consistent, and repetitive, within a range, for example I was measuring 410 on time, then 418 the next time, but certainly not 480. As usual the PNP have a greater variation of HFE than the NPN that are more consistent. I saw this behavior with other transistors. Seem to make sense...
Attachments
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Yes I will. This board fits nicely into the ebay chassis I bought, and left enough space at both chassis ends for the input connectors and AC inlet on the back, and ALPS pot (with your XFeed pcb, headphone connector and power switch on the front.
Also I'm limited to 6''x9'' pcb material size, so my pcb has to be smaller than that...
SB
Also I'm limited to 6''x9'' pcb material size, so my pcb has to be smaller than that...
SB