Burning Amplifier BA-3

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BA3 Gain and Output boards

I a building the single-ended version from DIYAUDIO. It appears they gain board does not output enough to drive the power boards hard enough. The gain board clips at 19v and the output board only amplifies current, not voltage. Has anyone else experienced this? Is there a solution?
 
matched JFET selection for BA3

Good day,

I understand this thread was started many years ago and hopefully members will still reading my post.

I am building BA3 to drive F5 in my recent project, and I bought 2 sets of LSK170/LSJ74 double matched pair from DIYAudio store since I am building two sets of them together with my friend. Upon receiving the parts from store, I performed one round of VI curve tracing using Keysight IV Measurement software on all of them.
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The original matched pair is labelled as LSK170/LSJ74 & LSK170_3/LSJ74_3 in one group, then LSK170_1/LSJ74_1 and LSK170_2/LSJ74_2 in another group.

Below is the measured Idss value.
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And this is the default matching suggestion.
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Below is another table showing the delta of each LSJ compared to all LSKs.
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And from the delta above, I notice that if I rearrange it with yellow color matching, I can get a more balanced on left and right channel of each BA3 as shown below.
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My question is, how I should choose the best matching pattern for a balanced Left and Right system? Is my new matching pattern make sense? Or is there anything that I should consider on selecting the matched pair?

Regards,
Liew
 

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  • LSJ74 IV plots.PNG
    LSJ74 IV plots.PNG
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  • LSK170 IV Plots.PNG
    LSK170 IV Plots.PNG
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  • Ids at 10Vds 0Vgs.PNG
    Ids at 10Vds 0Vgs.PNG
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  • Default matched pair.PNG
    Default matched pair.PNG
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  • New matched pair.PNG
    New matched pair.PNG
    5.2 KB · Views: 1,431
  • Delta of LSJ to LSK.PNG
    Delta of LSJ to LSK.PNG
    4.7 KB · Views: 1,448
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