50/50 Stereo power amplifier (need help)

[ytse_jam]

Hi, I play a Mesa Studio Pre into a Mesa 50/50 Stereo (the old one, not the newer 2:50). The 50/50 Stereo outputs are 8 ohms or 4 ohms. So, I'm gonna buying a 2x12 for home-playing (don't have space for a 4x12 at home!). The cab's got 2 x Celestion Vintage 30 and can be used in mono (8 ohms) or stereo (2 x 16 ohms), so I was wondering what would be less stressful for my poweramp:

1) to use only channel 1 (8 ohm output) and the cab in mono at 8 ohms (no impedance mismatch but channel 2 output will not be connected to anything);
2) to use both channels with an impedance mismatch (poweramp outputs: 2 x 8 ohms, cab: 2 x 16 ohms).

All that keeping in mind that the 50/50 Stereo user manual states the following:

1) "If you opt to use only one channel of the Fifty/Fifty with speakers
connected to only one channel's output(s), you must turn the unused channel's Level control
to zero! Otherwise the channel will be operating without a load, and damage to the tubes
and/or the transformer will result."

2) "Mismatching of speaker
impedance will not cause damage or severe loss of power. (Extreme mismatches will
decrease tube life, however)."


So the manual allows for both the options, but which is less stressful for the poweramp?

Thanks.

 

[Triaxstasy]

Hi YJ,

I also have a 2x12 cab with 2 V30s that can be run in 8ohms mono and 16ohms stereo operation...
I run it in 16ohms stereo out of the 8ohms outputs of either my 50/50 or my 2:90 with no problems at all. The sound of the 16ohms speakers run by the 8ohms outs is *subjective* somewaht more mellow or smoother (if that makes any sense)...at least in my experience...

This is an absolute safe mismatch and you´re good to go stereo

 

[ytse_jam]

Thanks Triaxstasy, it's great to get help from one who's got direct experience.