So ive been playing a mesa 290 for about 7 years now . I got my student loan back in the day and ordered a 2:90 from ebay usa to ireland , over £100 delivery , but hey , its the business !
A while back i read you can run half el34s in certain models , so mailed mesa my serial number etc for absolute verification, they replied saying which tube sockets to use. Even though i followed it specifically i got the feeling this is where problems begun
After that i went back to all 6L6 and started experiencing volume swells , total dropout of audio during recording sessions , and generally unpredictable operation. I retubed the entire thing , a local store made me a great deal of £200 for the retube , instead of the retail £300. Unfortunately not much changed it was still inconsistent ....
Eventually it gave off a burning smell one night , and i found the plastic block connector melted inside ; An apparently common error in the 290 , SO i performed the "solder to board" mod , and managed to get it running again , however only Side B was working ! Side A is totally silent ; i tried switching each sides tubes , A still silent, B still fine.
Now Side B is working for about 20minutes then goes totally silent. Im left in the position of possibly replacing side A transformer , £300ish , plus £90 shipping each way to mesaUK (£180) . I also have a 10kilo usa to uk power block that has to be shipped with it , no doubt adding more costs. Mesa said they would look at it but highly recommend a full MESA brand retube (as they would) ; and mesa tubes are literally double the cost of JJs.... So im at the point where its around £600-£700 to repair , all in .
Not sure what to do with it ; I certainly dont trust the courier to deliver it with 8 power tubes intact. It arrived from usa with 5 smashed. Currently im just running the 3TM/Gmaj straight into cab for bedroom levels , and into the ADA monstercab to record .... The 290 is currently packed away , so damn expensive just to get playing guitar again !