Hi I have been on and off this good forum over several years, but always turn back
I have had 604-g8s in DIY 620 cabinets for the last 5years. I had som issues in the beginning but eventually got them to sing with german autoformer crossovers (Werner Jagusch) and augmented by JBL0075s in the top ( severly padded down by autoformer). In the course of these 5 years I have only heard (in 2013) one set of speakers that seriously challenged my 604s ...and I managed to exhange som electronics for them last week
So now I have Altec A5s to play with The set consists of battered 828 cabs, Hiraga inspired crossovers, 1505B multicells , Altec 299-8As and a choice between 416c or 515g woofers.
Im testing the 416c now.
Regarding amps, the 604s preferred my pp kt88 amps and Hypex Nc400, 300b got too big and loose in the bass. The A5s with 416c don't sound good with the class D amps, sound ok with the PP amps once I put in some 6L6 in stead of Kt88s, but really sing with my 300b LD91 amps.
My next steps will be to choose between the 416c and 515g woofers.
But alerady now they are awesome on all kinds of music, im a happy man