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can anyone help with valve advice?


captain chaos

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Hello there,

 

I bought a silver face fender twin reverb with a push out volume (think its a mid 70s?)off ebay a year ago,

 

It had new mesa boogie 6l6 valves in. One out of the four valves has just blown (two of the valves are short and fat with a big kinda nipple thing on it, the other two valves are taller cylinder shapes ( of which one has blown) . I play a sigma jazz style fat bodied guitar and play jazz/ blues through it, Im after a clean sound thats nice and warm/fat sounding. my amp sounds prity bright/trebly at present. Im not sure about which set of 4 valves i need to get to replace the mesa boogie ones ive just blown

 

so far ive been tempted from loooking at the watford site of.

 

6L6WGB/5881/JAN PHILIPS

6L6GC/7581A/G.E

6L6GC/SVETLANA/WINGED C

 

but im not sure which to get or if i should actually get these. unfortunatly im skint so i dont really want to get the most expensive if it means spendin £200 for 4 new valves. but on the other hand i dont want to get inferior valves to what have just blown so if i need to spend the cash then i'll have to, can anyone help either with adice or anything? got a few gigs coming

up v v soon so any help i'll be forever grateful

yours desperatly,

kieran

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All of those are very good tubes for that amp, really!

 

If you can, get a full quartet. Much better than mixing and not matching a bunch of very different tubes.

 

If you can get any of them in a matched quartet, that'd be best.

 

Have the amp biased for the new output-tubes by a competant, experienced tech, it's kinda like setting their collective "idle". They'll sound their best and last longest. Easily worth the money, if they run too hot they can wear out extremely soon and then your original outlay is wasted, right?

 

It'd also be a very good idea to get a new "phase-inverter" (the single little preamp-type, 12AT7 or 12AX7, etc., tube closest to the big output-tubes, that drives them) to go with the new output-tubes, they work and wear-out together as a team; better yet, get a "Matched Phase Inverter", aka "MPI" (one that's been tested for close uniformity between its inner triodes), it''l get the absolute most out of those matched output-tubes, and also the longest life. The combined difference and improvement can be dramatic, like night-and-day!

 

If you can only get a pair of new output-tubes, a quick-&-dirty way to get by for now would be to only run with the two new ones (discard the other old ones), while simultaneously wiring-up only one of the two twelve-inch speakers inside the cab (leaving the other one disconnected) so as to be running into 8 ohms, effectively halving the output-impedance (a 4-ohm out going into an 8 ohm speaker, as opposed to the normal '4 ohm out/ two 8 ohm speakers wired in parallel for a 4 ohm load'). "Half the tubes, half the impedance". A good 50 watt Twin with one 12" speaker beats a not-so-good 100 watt Twin with two 12s! The difference in volume and headroom shouldn't be very noticable here.

Ask yourself- What Would Ren and Stimpy Do?

 

~ Caevan James-Michael Miller-O'Shite ~

_ ___ _ Leprechaun, Esquire _ ___ _

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