Right basically i have a Engl Thunder 50 head and 4x12 cab and i was looking into getting another head (one with more channels) maybe a Peavey. But i didn't know if you could mix brands as some people have said effects your amp sound? So i was wondering if any of you guys have any opinions or experienced this matter. Cheers
Speakers are speakers. You can plug any head into any cab as long as the cab is rated to handle as many watts as the head is.
Marshall JCM2000 DSL401
Roland Micro Cube
Les Paul Studio
Ibanez Rg440 Roadster II Series
Gibson Flying V
SE Custom Paul Allender edition
Frankenstrat Replica (that I made)
Guild Madeira Nylon acoustic.
Fender P Bass
Ampeg 1x14
if you look at most pro bands they all mix equipment. line 6 mesa marshall bogner all mixed together to create one kick ass sound

Live Arsenal

Schecter C-1 Hellraiser
ESP H1000 Deluxe
Ibanez RG7321

Line 6 Valve HD 100 Head
Line 6 Spider Valve 412VS 412 Cab

Shure PGX14 Wireless
Korg DTR-1000
Just check to make sure the impedances of the amp & cab match!
Moving on.....
and if the cab is the right impedance for the head. Most 4X12s are 16 ohm, 2X12 is 8 ohm, and 1X12 is 4 ohm, but read the back of the cab because some have a mono/sterio switch, and some use 2 ohm speakers instead of 4 ohm speakers (4x12 would be 8 ohm, 2x12 4 ohm, 1X12 2 ohm). If you mess up the impedance you can destroy the head, so be sure that the ratings are right. Remember, what's printed on the head is the minimum load, so if the head says "8 ohm" you can plug in a 16 ohm cab, but NEVER a 4 ohm cab.