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Does anyone know if you use the overdriven sound ( as opposed to a clean sound ) on a guitar amp will it wear out the tubes quicker ? I have a little tweed style amp and just love cranking it up now and then. Cheers Peter.
Follow Ups:
did you ever convert your blues jr from el84 to 6v6? pls let me know your thoughts as i'm considering the same thing myself (glassy thing w/ el84s gets annoying a bit)
mahalo
rhyno
Just as in hi-fi. Strong chassis, good iron, a good PSU, soldering and layout --- can lead to good tube life, even in "pushed" amps. Good sockets, too!
8^)
If you're worried about "tube wear," get an outboard tube driven box. I've been using a Tonebone almost daily for close to 10 years with the same nos 5751. The amp is essentially acting like an PA driving the distorted signal from the box.
Easy to get all your favorite tones at low volume.
Pushing a normally clean amp like that into an overdriven (cliping) range can shorten the life of power tubes. How much shorter is anyone's guess. You just have to listen for a lack of power and/or focus in the tone.
The preamp tubes should be fine.
"If the audio industry built gear that sounded as good as it did 50 years ago, there would NEVER be a need to re-issued anything!"
I love the sound of overdriven power tubes in a small guitar amp. I have several tweed Gibsons with two 6V6's running Class A that sound amazing when driven hard.
It's a different sound from most modern amps that get their distortion by overdriving the preamp tubes. Older amps did not have "Preamp gain" and "master volume" controls. When you turn them up, it's the power tubes grinding that you hear. Nothing compares except very early Marshalls, which are too loud to suit me.
I noticed that signal tubes in guitar amps tend to get noisy a bit sooner than ones in hi-fi amps. Maybe, from overdriven 12AX7 and mechanical jarring.
As a guitar amp tech, I've noticed that combo amps have a lot more failures due to mechanical problems than separate heads. It's very loud inside the cabinet of a guitar amp, and the tubes take a beating from that.
For example, JJ 6V6S output tubes frequently succumb to mechanical rattling before they wear out in terms of emission & transconductance. Shuguang 12AX7s sound good in V1 positions, but they go microphonic.
Ahoy hoy!I can say for certain, yes, it does wear out the tube quicker. However, there are a few things to consider:
- If I understand what I've been reading, there are two ways you can "overdrive" a triode: grid current limiting, and plate cut-off as a function of the plate resistor. I haven't discovered the exact difference in the wear, but if I had to poke a guess, the first has more to do with the tube's cathode and grid, and the latter has more to do with the plate resistor fatiguing, creating noise, or failing outright.
- The DC-Coupled cathode follower design, in its raw form, is hard on tubes when HT is initially applied. Bonus: it's extremely common to find it in guitar amps! It can damage a tube fairly easily, as I have learned both by textbook example (site provided below) and real-life practice. (I usually get sputtering and crap performance). Many of the amps I've worked with use this design, and I've replaced a fair share of 12AX7's because of it (thank you, Ampeg V5). If you're interested, the site provides a nifty work-around to save tubes, I'd suggest looking into it.
- Mechanical wear from the on/off transitions and high-volume rumbles-and-jumbles. Microphonics are really your ultimate killer.My solution to this exact problem was this: seek out recording tones with NOS/hard-to-find tubes, and gig with personal favourite new production tubes.
EDIT: Forgot about power tubes. I noticed power tubes are a little more "forgiving" in the sense they are more "predictable" as far as their replacement schedule. They generally follow the same rules as above save the DC-coupled thing... And with a transformer rather than a plate load... Ya... lol
Tubes...
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
May your tubes be lively and long-lasting. Holy be thy heater.
Edits: 08/09/14 08/09/14
Hi Peter, I'm assuming a little tweed is one that runs a single 6V6 output tube and is single ended/Class A. Being Class A it is always running the power tube the same. It won't matter on wear. If it was a larger push pull amp, ie has two or four output tubes, then if you cranked it to distort it would wear the output tubes faster.
Hi Yes, it uses a pair of 6v6's cathode biased in ultra linear mode with no negative feedback. Cheers
Duffman, tube life seems to be dependent on several factors. I have this old (woodie era) Fender Champion 600, that had the original OEM metal 6SJ7 and GE 5Y3GT. When I got it in 1992, still sounded great. That's also Class "A," single-ended amp --- made with the cheapest parts available, at the time. Though those Triads irons have since been proven nice in this era.
Anyhow, I changed the tubes, just to be anal. And updated the 'lytics. Amp still sounds great.
8^)
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Nice. The amps not bad either !! Cheers.
It's true that a Class A amp draws about the same plate current at all power levels, but when overdriven heavily, they also draw grid current.
I suspect that stresses tubes more quickly than full power operation clean.
Hi guys, thanks for all the answers. I guess my question was simply posted out of a sense of curiosity. I'm not too worried abut tube wear as I only use Russian tubes in the amp. Actually, come to think of it, I prefer modern tubes in my guitar amp. NOS tubes seem to lack bite and crunch or the ones I've tried anyway. The reverse is true with my hi-fi gear.
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