Mesa Mark 4 Output Tranny swap ?

[evh_slash]

I'm thinking of swapping out my Mark 4 output transformer for a different transformer that also has a 16 Ohm speaker out tap. I hate using impedance mismatches as the amp gets duller and muddy so I'm not interested in using the 8Ohm out with my 16 ohm 4x12 .

I'm not bothered about resale value as I will be keeping this amp until the day it dies. I'm no stranger to amp modding & circuit tweaks but I always prefer to be careful when dabbling with an amps power section.

All I want to know, is theoretically, could I whack a completely different output transformer in here such as a marshall plexi style transformer etc. without frying the amp ? The only thing that concerns me is the fact the amp is 6L6 and Simul-class ... I would also be happy to have the amp fully operating in AB Pentode so if the Simul class is the only thing affecting output tranny choices (+/- 16 ohm outs) then I'll happily ditch it.

 

[Gtrjunior]

Re: Mesa Mark 4 Output Tranny swap ?

Can’t you just wire the cab at the impedance that matches the amp?

https://portcityamps.com/wiring-diagrams/

 

[evh_slash]

Re: Mesa Mark 4 Output Tranny swap ?

I use a multiple amp setup with switching and WDW . I also dont want to change the cab specs because I love how the cab sounds and feels in 16 ohms with semi parallel wiring and combination of greenback and creamback in a X pattern.

Money and resale value etc. is of no issue to me here. I just want to be able to fit this Mesa amp into my existing rig without altering the current set up as it is very complex.

I'm thinking about installing a Fender style OT as this should be a good compatible replacement .

 

[chadd]

Re: Mesa Mark 4 Output Tranny swap ?

Contact Mesa, their support folks have been able to easily answer any odd questions that I have had.

 

[JMP/HBE]

Re: Mesa Mark 4 Output Tranny swap ?

Have a loadbox made man ... 2 x 8 ohm resistors = [16 ohm] inline with the 16 ohm cab > amp see's 8 ohm load.







Despite MESA assuring me it was a "safe mismatch" having gone to electronics school i can assure you ohms law is real and there is no such thing as "safe" only "mismatch" And my MK III sounded crappy with a 16 ohm Marshall cab mismatch.

For best results always match impedance.