Because I’ve had a lot of experience with lots of different amps, invariably people ask me for advice – especially on what power tubes to go with. They ask, “Should I get EL34? 6L6? 6V6? EL84, etc.” My answer to that question is: Yes. 🙂 On a more serious note, I do tell them that they have to play several amps to find out what appeals to their sense of tone the most. After all, it’s what is pleasing to your ear that matters.
I used to drink the cool-aid and say something like this: “If you want real chimey clean tones, then you’ll get that with 6L6’s,” or some other rubbish like that. That’s all a bunch of crap because I’ve got EL84-based amps that have that kind of chimey clean tone as well. It’s all about how the builder voiced the EQ circuitry AND what guitar you play through the amp!
What I do see a difference between the different tubes is in how they distort once overdriven. This is NOT hard and fast, but in general, I’ve found that the ELx varieties tend to compress their signal a bit more when saturated as compared to their 6×6 brethren. The 6L6 and 6V6 amps that I’ve played usually have a more open and dynamic overdrive tone. But again, that is also affected by how the amp is wired. For instance, designs based upon Fender amps have fairly open distortion, while the Marshall-style amps have a more compressed, in-your-face distortion. And I’ll say it again: There are NO hard and fast rules here. So how do you decide?
Well, while power tubes do affect the tone, you shouldn’t make an amp decision based upon just that; though I shared a very general rule of thumb, wiring topology can strike that generalization down fairly quickly. What you probably should consider is the power rating and your application of the amp. EL84 and 6V6 tubes are generally used in lower wattage amps, anywhere from 5 Watts to 45 Watts. Generally, you’ll see numbers such as 5, 6, 10, 15, 22, 30, 36, and 40. For the top three, four tubes are usually used to achieve those wattage ratings.
On the other hand, 6L6 and EL34 power tubes are used for high-wattage applications from 40 Watts up to 200 Watts (40, 45, 50, 60, 75, 100, 150, 200), again with the top three employing four power tubes to achieve that wattage rating.
The rule-of-thumb with respect to wattage is that the higher the wattage, the more clean headroom you will have; that is, the amp will be totally clean at increasing volume levels (in decibels) before the amp goes into overdrive. For instance, taking a 5 Watt amp to the edge of breakup will be at a much lower volume level than a 100 Watt amp taken to the edge of breakup.
Another thing that I’ve found is that with high wattage amps, when they break up, their tone seems to be so much more “beefy” than their low-wattage brethren. When doing A/B tests at equivalent volumes with let’s say a 6L6-based amp versus a 6V6 amp, there is so much more sonic content through the EQ range with the higher-wattage amp versus the low wattage amp. For instance, my 22 Watt 6V6-based Aracom VRX22 sounds “bigger” than my 6 watt Fender Champ when played through the same speaker at the same volume. Conversely, that same 22 Watt amp sounds “smaller” at the same volume level than my Fender Hot Rod Deluxe at the same volume level. A lot of this has to do with the higher wattage amp producing more bottom-end by nature. This is especially evident when pushing the amps into power tube saturation.
Some may have caught the phrase, “equivalent volumes” in the previous paragraphs, and wondered how I could get equivalent volumes with a low-wattage and high-wattage amp breaking up. The only way you can get that is by using a power attenuator, of which there are many on the market, though I use the Aracom PRX150-Pro.
Finally, what advice do I have? It’s actually fairly simple:
- First, evaluate the average usage (i.e., the application). Will you need lots of clean headroom? Do you play large venues? Then a higher-wattage amp might make sense. On the other hand, if you play mostly small venues, in the studio, or in your room, a lower-wattage amp may make more sense. BUT, if you have a great attenuator like the PRX150-Pro (or DAG), my personal preference would be to go to the higher-wattage amp. While I love the tones that I get with my low-wattage amps, with the PRX, I don’t have the volume considerations to take in to account any longer that had me go with low wattage amps in the first place.
- Once you’ve determined your power needs, then you have to test amps – lots of ’em – there’s no way around it.
Then once you’ve done the evaluation, you might throw that all out the window and go for what sounds good to you, regardless of your power needs. 🙂
Hey! No one said it was easy…
Guitar Gear 
Excellent response Dawg! Don’t play large venues (yet) but in the living room for practice there is a Mesa Eng. Dual rectifier Solo Lead full stack and a Marshall JCM 900 twin with satellite cabinet – the equivalent of a half stack; the two amps sound remarkably different and are run in stereo. Since it is the living room the master volumes are dialed down to almost nothing. I do, rarely, get the opportunity to run them in a warehouse so I can appreciate the number 4 on the M.E. and the Marshall at 8…. the point about playing what you like and associating that with the venues you will play at is well taken; you should not only practice the guitar but practice the guitar/amp/pedal – that is your true instrument – there is nothing like practice at your concert/presentation volume – it reduces the chances for surprises and will really up your confidence levels. When playing in combos in will keep your band mates far happier if you come across as not swamping them and knowing what you are doing to boot. Oddly I have a Fender Champ re-issue – a nice enough amp but it turns out to be less than useful for me – it sounds different (but ok) and does not match what I do when performing – a bad investment not because the amp is in anyway deficient but bad simply because it is not about what I do.
Here are some links that may be of use prior to shopping (and Dawg my apologies in advance for making reference to another site… forgive me please)
http://guitardesignreviews.com/2011/12/the-tone-chain-part-1-tailoring-your-guitar-sound/
http://guitardesignreviews.com/2012/01/the-tone-chain-part-2-guitars-amplifiers-and-speakers/
http://guitardesignreviews.com/2012/01/the-tone-chain-part-3-guitar-pickups/
Finally never hesitate to buy used – but do try it before you buy it – new or used – and crank it up to see what happens at that end; particularly if it is used. Hit that E7 chord at the bass of the neck, grind through the opening to Beck’s take on Superstition – then fly to the top of the neck and see how the higher frequencies come out. Consider who used it prior to your looking at it. Some baby them and there should be no issues; some flog them so there may be surprises. Also consider the age of the unit – speaker replacement may cost you more than the unit to begin with… with my Marshall JCM I am now considering cone uplift and simultaneously with that an output transformer upgrade. It is all about what Covey said – start with the end goal in mind. For the record I enjoy playing material by Mountain circa Climbing and Flowers of Evil and Santana circa Abraxus. Enjoy!
and Dawg thank you for providing and maintaining a facility where we can share and grow to boot! Your a good fellow for taking the time and making the effort for this to happen. Please know that I have gotten good things from your writings – attenuators – who knew?
Thanks, Ron! I can’t believe that this blog celebrated its fifth year last month. And though I’ve slowed down a bit with posting (I’m going back and forth between writing about guitars and writing about wine), I still love writing about gear.
Have you tried an attenuator on your Marshall? There is nothing like the sound of a Marshall totally cranked up. Unfortunately, without one, it’s deafening. But with an attenuator, you can get the Marshall into its real sweet spot, and that’s driving the power tubes. Doesn’t make much difference with the Mesa as its overdrive tone really comes from the preamps, so you can control volume with the Master.
Dawg I have not tried an attenuator but am lookinf to get one down the road a bit – need to get back on my employment feet first. Rest assured that your work has exposed me to them and caused me to start thinking – and well simply get on with it. I did not know that you were a wine guy – I’ve been searching for a good Merlot for some time now…. will let you know when I find it.
Watts are dynamic headroom and bandwidth in accord to the speaker(s) used. It is not about loud as most misunderstand and buy low watt amps for loudness sale, just different animals really. A little amp clips out and distorts early on but can be very mid rangey especially a smaller speaker which cannot produce the low freq of a larger speaker, it is just physics.
You do not need to crank a 50/100 head to get great tones but you will not get the same level of response and feel on a low watt amp. The difference between a 100 watt and 50 watt amp is only 3db. As for tube types, truthful information indeed, it depends on the design and intent of the amp circuit. In my 100 watt head I cannot tell much difference in EL34s or 5881s (6L6) both sound great clean or gained. I cannot say the EL34s have less low end as the low end is so deep on my amp but again it is the design of the amp. Rule of thumb, use what the designer intended and make sure the bias is adjusted correctly.
Great input, Paul! Thanks