What has been your costliest mistake in this hobby?

i made the same mistake exactly with the same sub (Miller and Kreisel) :)

I draw the same exact conclusion....

After that i embark in my intense experiments in listenings 2 years ago....

:)

I never use the sub more than an hour and is here always.... I was too lazy to put it for sale i think....I will never need a sub, neither four one....  :)    

Probably not in keeping with the general path of this thread but: buying any stereo gear new. 

Thanks for listening.

@brownsfan ,

I used to swap spade connectors for soldered ones but on one occasion the heat from the gun melted/burnt out its voice coil wire.

Why oh why can't all companies, at the very least, just use non tarnishing spades and connectors for their drivers?

Seriously, how much are they saving on connectors which will look pitted a few years down the line?

I somehow got what was left resoldered and working but it was an unhappy experience.

As was my decade long foray into the bottomless-moneypit Linn/Naim nexus... 

@cd318, indeed!  I will never understand the thinking behind parts selection on speakers.   It seems that I do not understand the underlying economics.  On the other hand, it also seems that a few of the direct to customer guys are beginning to run in a different mode.  If I knew a bit more, I'd be inclined to try building my own.   

Going through loads of mid-fi equipment in the vain hope to find, by sheer ’magic’, some satisfying sound quality. Didn’t.

’Außer Spesen, nichts gewesen’...

Maybe the learning exercise was of *some* value.
The sound quality was just NOT getting there until very many years later.

Good sound doesn’t come easy - and not quite at bargain prices either. 😕
Be surprised if YMMV.
M. 🇿🇦
PS: oh dear, and one more nasty learning exercise.
When I connected my ML39 CDP, used as a pre-amp, to the digital satellite TV decoder.
One lightning strike, - the connected coax cable screen/ground must have gone sky-high, some 10k Volt for a split second and fried the Levison no.39.
One stinker of a repair bill. 

Some years later, I had a connection, to my ML36 DAC, from my DVD player, to my TV, to my Decoder -
and from there, wiress to the good Lords lighting.
Boom, - decoder, TV, not the DVD?!?, but the DAC nailed.
So, so sad, eish! 😭