OK, it’s probably a good time to discuss relatively easy mods that you can do with your own amps without having to learn a whole bunch of stuff about the technical aspects of building one!
This is an easy topic, because there’s really two areas you can play with; changing speakers and changing tubes.
Now, before we do that, two caveats:
1. TUBE GUITAR AMPS HAVE COMPONENTS THEREIN THAT RUN VERY, VERY HIGH VOLTAGE, and
2. A GUY FRIES REAL QUICK STRUCK BY LIGHTNING.
Got that? The voltage inside these suckers IS lethal and WILL kill you, no joke. If you are not 100% comfortable with the components inside your amp that you want to modify, as well as the potentially lethal ones, DON’T mess around inside one!
Here is a great safety page from the AX84 site: You should go there and read it, rather than having me paraphrase:
http://ax84.com/safety.html
OK, so on to changes! The first question that comes to mind is; should I change my tubes on some sort of regular basis anyway? The answer is unequivocally YES – When tubes go of their own accord, they can and do take other stuff with them, and can cause a mess; they won’t always do it, but they can, so why risk additional damage and cost? If you play several nights a week, you should change your tubes once a year or so; maybe a couple years for less use. And again, read that AX84 page and do what they suggest as to use and maintenance of your amp, AKA, treat them as well as you do your axes!
The second question I hear a lot is this; can I just change the tubes in my amp without worrying about bias, etc? I wondered the same thing and asked just that over at the AX84 site. Those nice folks advised that changing tubes to another set of the same thing you have now, (ie replacing somebody’s EL84s with another set), should be no problem. After reading and following the safety rules for handling amps, you can safely change the tubes without doing any further tweaking to your amp and do so with reasonable assurance that you won’t hurt the amp. Furthermore, you can also change compatible different tubes without doing anything else to your amp – Check out this link -
http://tdsl.duncanamps.com/tubesearch.php; if you punch in an EL84, and then click the link, you’ll see a great sheet that shows what other tubes are close or identical, (Others that have the same rating, general performance, pinout, and filament voltage). Pretty cool, huh? Makes it easier and safer to try other things if you’re of a mind!
OK, third common question; will changing the speaker and/or the tubes actually change the sound of your amp? The answer is a resounding yes! Let’s say that yours uses AX7As in the preamp phase and EL84s for the power tubes as mine does. Will a set of AX7As from Groove Tubes sound different from a set produced by Electro-Harmonix? Yes, they will, somewhat, although the diffs may not in and of themselves be profound. In a low gain amp like mine, some tubes may be quieter while others may have more noise, albeit in a way that you like. To me, the E-H tube pushes less bass than the GTs, (Which I want), and is a smoother and cleaner sound up through the gain, (Which I also want), so it’s a natural selection for me; you obviously might be looking for something else. The trouble is that the sound you get is certainly subjective, and as you start researching tubes and speakers, you begin to feel like your reading reviews in Wine Spectator, it’s the same kinda hype in a lot of ways: Nonetheless, they do all sound different, and you do kinda need to poke around and try different stuff to find what you like – Just like pickups or strings, you’ll likely land on a preference that works for you.
Speakers, in my opinion, can make a much wider difference than tubes in the sound of your amp. From Eminence to Celestion to Jensen and Electro Voice to Fender, there’s a ton of variety out there. And be ready, ‘cause here’s where the descriptive hype gets thick; check out the schpiel on the one I chose; “The Celestion G12H is a reissue of their 12" guitar speaker that was re-released in 1994 for the Celestion 70th anniversary. Loud and proud thanks to its heavy magnet structure, the G12H provides a fusion of the Vintage 30 and the Greenback speaker characteristics, producing a thick, warm and syrupy sound while still retaining a tight and focused bottom end. When played clean the G12H remains clear and musical without ever sounding harsh. In overdrive, pick attack is vividly articulated with sustained notes trailing off into warm harmonic tones.†Wow, I’ll take a case of that stuff in ’99 please! Anyway, you get the idea, they all DO sound different, some more than others, so the ability for you to tweak your sound with a speaker change alone is pretty vast.
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