| Author | Message | ||
| Jimmie Akerstrom (rudeez) Username: rudeez Registered: 12-2012 |
Hey! Im new here and that is because i recently bought my first ever head, a Musicman HD130 head with 12AX7 PI. Didn't really know much about it before i bought it, i got it for a really good price. It was recently served with new tubes when i got it a month back, EHX EL34. Took it to the rehearsal space for testing it out, and ofc flipped the HI switch because i thought it was 65W/130W switch. Played for 30 mins and the room started to smell more and more burnt, checked at the head and yeah, it was smoking from the tubes and they were glowing like hell broke loose. Two of them even died there. Turned it off, went home and read about the switch and realized that most of the EL34 can't handle the 700+ plate voltage on HI mode. Went back the day after and all tubes were alive again but my guess is that they taken damage. The amp sounds really good to me, it just lacks volume really. My friend plays a Orange Overdrive II from the 70's and he has alot more volume, punch and clarity to his sound. And we play LOUD, like really loud, last time i rehearsed with the musicman master vol was set at max and channel vol at 5-6, higher it distorts to much. This at LOW power mode ofc. After reading up on the subject a bit i contacted eurotubes and bought a quad set of JJ E34L tubes that are supposed to handle to plate voltage at HI mode. What i need to know is how to set the bias on these to be able to run it on HI mode and also push the volume alot. And as i said it's one of the early models with 12AX7 PI. Chassis NO 2100-130 EX. I never biased before and i guess it's a bad idea to DIY, i do build alot of pedals tho so i have some sort of knowleadge, just nothing on tube heads really more then that it can kill you. What should the mV be set to and what else is there to think about when retubing it with those tubes? There is a local amp repair guy who has knowleadge with vintage amps but i also know that the Musicmans differ from the more common ones when it comes to biasing etc. Also, what else should/could be upgraded to it? Change the caps? which ones are the crucial ones to swap? And also, how hard would it be to make a FX loop on this head? Anyone has knowleadge of that? Maybe even instructions? Thanks in advance for any help on this subject. //Jimmie, Sweden Btw, here's a sloppy video of me playing it. Sounds pretty bad thanks to the camera and high volume. Ofc my own pedals were used  http://www.youtube.com/watch?v=mprlhTxDa MQ https://www.facebook.com/reaperpedals | ||
| jnewmark (jnewmark) Username: jnewmark Registered: 11-2012 |
Unless you are real comfortable with digging around inside a vintage amp, I would take it to your tech, along with one of the schematics that are available here for that head. You can also navigate around on this site to find some diy answers for this head, but, for peace of mind, I would take it to a tech. |
Tue, 03/25/2014 - 09:53
#1