I've used two L-1000Ms,top and bottom,on my diy active 846A Altec Valencias.They sounded wonderful.
Many people are of the opinion that Altec don't like Solid State.I have found that they like very good SS amps and don't like ordinary SS.In other words,they like Quality.
The amps that I have tried with my Valencias are:
Treble(800Hz and above):Kenwood Basic M1,Yamaha B-2,Kenwood L-A1,Kenwood L-1000M and presently,Kenwood L-06M monoblocks.
Bass(800Hz and below):Kenwood Basic M2A,Kenwood Basic M2(Sigma Drive),Denon POA-4400 monoblocks,Kenwood L-1000M and presently Kenwood L-06M monoblocks.
On the Treble section,I preferred the Yamaha B-2 to the Kenwood Basic M1,the Kenwood L-1000M to the Yamaha B-2 and the Kenwood L-06Ms(in Sigma Drive mode only)to the Kenwood L-1000M.
On the Bass section,I preferred the Kenwood Basic M2(Sigma Drive)to the Kenwood Basic M2A and the Denon POA-4400 monoblocks.I preferred the Kenwood L-1000M to the Kenwood Basic M2(Sigma Drive) and I preferred the L-06Ms(in Sigma Drive mode) to the L-1000M.
The L-06Ms in non-Sigma mode are on a par with the L-1000Ms.In Sigma Drive mode they are the best Solid State amps I've had in my system(Please note that I am not saying the are 'The Best Solid State Amps Available',just the best I've used in my system)
Unlike a lot of speakers nowadays which are 4 ohm,the Altecs are(nominally)16 ohm.That seems to be of little consequence in practice.
The L-1000Ms are very nice amps(as you have obviously already found-out). :yes: