This amp seems to work beautifully at lower voltages, but has random failures that need explanation. So I analyzed it. I noted a few issues and shared them from my perspective as an experienced engineer. The 1815s are an obvious issue, but I think the more serious problem is with the floating buffer shorting power and burning out, probably blowing the MOSFET gates and burning out speakers at the same time.
I like this amp, which I think is quite clever and they say sounds good -- when it works. It's just that it burns out randomly. There must be a reason for that, buried in the design details. My hope is to find some minor rework that cures the problem, and I think I have. Time will tell. I'm pretty sure the floating buffer parts explode when they short +- power without current limit. My fix is fairly easy, but it's only on paper and must be tested on a real amp. I should have parts soon and make the mods. Then I'll look forward to using this little gem.
Be careful, 2N5551 is not the same component as the NC 5551 supplied with the L7 kit.
Probably has reversed connections.
I tell you my experience.
Like you, I expected that 2N 5551 and NC 5551 were just the same, but noticed the difference between them when my first pair of L7 had an amp that when hot began to crackle.
No way to resolve making all the solderings again.
So I purchased a new set of active components, apart the output devices, with 2N 5551, but after changing them it didn't work at all.
Tried to bend the pins from EBC to ECB, as you suggest, but with no results.
Then I asked my ebay seller to supply me some NC 5551 and then the amp worked again.
I temporarily does not provide L15D - PRO OSCON capacitance version.
Because the capacitance is not cheap, HA HA.
You may want to consider L15D - POWER ，But 2 stereo need 2 *transformer. AC 36-0-36
the offset of all 4 amp are about 7 to 10mV DC.
The power to the amp are 36+/- VDC with 40,000uF to 2 amplifiers
I also have a thermistor at each of the transformer.