Cranking the amp all the way up

[Vladimir]

How safe is to run an amp turned all the way up?
At a recent practice, I realized that it does sound good with the volume turned all the way up on the clean channel, while playing with the guitar volume knob for lead to rhythm.
It's a 15watt tube Laney VC-115 with a 10" Jensen speaker.
I didn't keep it there for too long, as I was afraid of something going wrong.
Does anybody ever use their amp in this way for, lets say, an hour or two?

[keithb7]

No problem there. Yes by all means crank it up, all the time!

[Justinvs]

Well, it will eat your tubes up faster, but...
Sometimes, you just got to crank 'em up!

[sax4blues]

Originally Posted by Vladimir

How safe is to run an amp turned all the way up?
At a recent practice, I realized that it does sound good with the volume turned all the way up on the clean channel, while playing with the guitar volume knob for lead to rhythm.
It's a 15watt tube Laney VC-115 with a 10" Jensen speaker.
I didn't keep it there for too long, as I was afraid of something going wrong.
Does anybody ever use their amp in this way for, lets say, an hour or two?

I play an Orange Tiny Terror with the master all the way up and the gain about 1oclock, then use guitar volume down for rhythm, up for leads. I have always understood amps are made to be used within the range of control the manufacture gives you.

As for "burning up tubes"; I play almost every day and in bands twice each week. I have my gear to be used, not preserved. I don't know if I burn up tubes or not, but in ten years of playing I've only replaced amp tubes twice as best I remember, and if it was twice that much I wouldn't be concerned.

[Riffraff12571]

Crank it to the moon! As long as your amp is healthy you will be fine. If it isn't you will find out soon enough.

'78 SFVC

Not only are all controls on 10 but I'm smashing the front end with stacked boosts too.



I felt pretty good about this because I replaced the filter caps just before making this clip.

[Bob W.]

The volume control on a typical tube amp simply adjusts the signal level that the preamp delivers to the output tubes. It does not raise or lower the power that the tubes operate at. If you are using the guitar's volume control to adjust how hard you drive the amp, the output tubes won't 'know' whether it's the amp's volume control or the guitar's volume control that lowers the signal. There is no danger of eating up your tubes any sooner. Tube life is a matter of time in operation, and to some extent, the actual output volume. If you were to run your amp at 50% on the volume control and full up on the guitar, it's not really any different that vice-versa.

I have run most of my tubes amps with the volume full up for many years. The guitar's volume control becomes very useful to go from clean to dirty. I almost never use an overdrive pedal, I prefer to use the tube amp's natural overdrive. For me that's the whole point of it.

[Justinvs]

Originally Posted by Bob W.

The volume control on a typical tube amp simply adjusts the signal level that the preamp delivers to the output tubes. It does not raise or lower the power that the tubes operate at. If you are using the guitar's volume control to adjust how hard you drive the amp, the output tubes won't 'know' whether it's the amp's volume control or the guitar's volume control that lowers the signal. There is no danger of eating up your tubes any sooner. Tube life is a matter of time in operation, and to some extent, the actual output volume. If you were to run your amp at 50% on the volume control and full up on the guitar, it's not really any different that vice-versa.

I have run most of my tubes amps with the volume full up for many years. The guitar's volume control becomes very useful to go from clean to dirty. I almost never use an overdrive pedal, I prefer to use the tube amp's natural overdrive. For me that's the whole point of it.

I stand corrected. That's good to know, too, since I like the sound of my amps being pushed a bit. Okay, I like the sound of them cranked to the rafters if the truth be known!

One question. Do most of you guys who control your volume with the guitar instead of the amp use an EQ pedal or adjust your tone in any to compensate for the highs rolling off at lower guitar volumes?

[backline]

Originally Posted by Bob W.

The volume control on a typical tube amp simply adjusts the signal level that the preamp delivers to the output tubes. It does not raise or lower the power that the tubes operate at.

Then why bias at "Max 70 Percent" of a fixed bias amp.?

[tele salivas]

I always crank all amps all the time. sometimes my guitar's volume control is only on 2 or 3, but I believe in whipping that pre amp black and blue like the donkey it is. It likes it! I like a cleanish sound, but I prefer it kind of craggy. I don't like that kind of pretty clean. Might eat up tubes faster, I don't know. Don't have anything to compare it to.

[Scantron08]

Hope so. That's the only way I ever run my '63 Gibson Falcon.

[old goat]

With my BF Fender there's definitely a difference in tone as the amp volume knob is turned up and the guitar volume knob is turned down to keep volume steady. With the amp volume turned up the sound is much thicker. BF Fenders have a bright switch that increases the treble at lower volumes--it doesn't do anything at high amp volumes.

[Jakeboy]

All my amps get dimed.....I like natural amp OD and distortion.....this is the sound that the OD pedals try to capture. I dont own an OD or distortion pedal....I just crank the amp.

[jdaunt]

Originally Posted by Jakeboy

All my amps get dimed.....I like natural amp OD and distortion.....this is the sound that the OD pedals try to capture. I dont own an OD or distortion pedal....I just crank the amp.

I just traded my only remaining OD pedal (an OCD-which I really liked but...) for a 2nd tube amp. I was running an SCXD and a Marshall MG30, with the SCXD at about 8, so just breaking up a little, and the OCD running into the Marshall to make it dirty. But now I have an Excelsior to go along with my SCXD, so no more "fake" distortion, just pure tube OD.

And I don't usually dime the amps, the Excelsior I've messed with dimed some, only had it a couple days so haven't experimented too much yet, but I've found my SCXD is too shrill dimed, so I go between 8 and 9 tops on that and it's perfect. I'm also using Cobalt strings, which might also be causing the shrill-ness, but I've found both the guitar and volumes just a little below full tilt is perfect for me, still getting the tubes working, but it's not over the top.

[alnicopu]

Tube amps aren't happy til their dimed. They are made to push out the mojo.

[backalleyblues]

Originally Posted by backline

Then why bias at "Max 70 Percent" of a fixed bias amp.?

You don't want to over-juice the power tubes-they have a certain amount of working voltage and dissapation (expressed as heat) that they can deal with-the bias control puts them into that range. Cold bias=lower working percentage, and higher bias=higher working percentage. If you run the bias too hot, you're going to wear out your tubes faster (regardless of the volume you play) and you won't necessarily get any better sound...

As an example, most 6L6s want to be biased around 68ma... Fender sets its bias at the factory @ 60ma, this sounds kinda lifeless and flat. 68ma sounded really good with this amp, but I went through power tubes about every 500 running hours (or about 100-110 average gigs; I know, did this with my HRDX!). If you goosed the bias up to 75ma, it probably will sound warmer, livelier, but would shorten tube life by a fair amount...IIRC, 75ma is pretty much the upper limit for a 6L6 (and it better be a good one!!!) 80ma is flirting with disaster...YMMV of course...

Franc Robert

[Crumpletone]

Originally Posted by backalleyblues

You don't want to over-juice the power tubes-they have a certain amount of working voltage and dissapation (expressed as heat) that they can deal with-the bias control puts them into that range. Cold bias=lower working percentage, and higher bias=higher working percentage. If you run the bias too hot, you're going to wear out your tubes faster (regardless of the volume you play) and you won't necessarily get any better sound...

As an example, most 6L6s want to be biased around 68ma... Fender sets its bias at the factory @ 60ma, this sounds kinda lifeless and flat. 68ma sounded really good with this amp, but I went through power tubes about every 500 running hours (or about 100-110 average gigs; I know, did this with my HRDX!). If you goosed the bias up to 75ma, it probably will sound warmer, livelier, but would shorten tube life by a fair amount...IIRC, 75ma is pretty much the upper limit for a 6L6 (and it better be a good one!!!) 80ma is flirting with disaster...YMMV of course...

Franc Robert

Pretty good explanation and please don't take this as critisism.

But not every 6L6 wants to be biased around 68ma, it all depends on the plate voltage in any given amp and the tube type being fitted (there are various 6L6 tube types, not all the same), a 6L6 running at 450vdc on the plates should be biased at around 30ma (per valve) using the 70% max dissipation rule, the same valve running at 375vdc volts can be biased hotter at around 36ma, it all depends on the plate voltage. Also be aware of different 6L6 type tubes as they have differing dissipation specs, 6L6, 6L6GC, 5881, 6L6WGB as this will also affect the bias current setting you are looking for.

You can adjust the bias higher or lower if you so wish or if you prefer the tone that way, even up to 80% + of max dissipation, but be aware of what the setting should be in the first place before you do it.

Higher plate voltage = lower bias current
Lower plate voltage = higher bias current


Blackface fenders typically run higher plate voltages than the older tweeds so bias points can be very different. The 70% rule is usually only relevant to fixed/adjustable bias amps, cathode bias can run alot hotter, nearer the 90% dissipation, and more, and still be good, i've serviced old vox's and fenders that are cathode biased around the 14watt dissipation mark on a 12watt tube on vox's and even higher on some old tweeds (way above manufacturers spec) and the valves hold up fine, just make sure the screen dissipation is kept in check, The dissipation value is a measurement of heat dissipation not audio output.

Before you bias any amp, be sure you are aware of the plate voltage as this is a major factor in biasing the amp.

As for driving the amp hard, in a well built amp this should never be a problem, tube life is finite (manufacturer spec's will give you an expected lifespan) and they will eventually require replacement, that will happen wether you drive the amp hard or not, Backalleyblues is right in what he says, fender nearly always bias amps cold from the factory, i expect they want them to last longer !!!

[bigben55]

Having simplified my rig to amp plus one OD pedal plus guitars, one cant discount what different pickups do in correlation to diming the amp. If I dime my Dr.Z Z28 210 combo, with my 335, its almost impossible to get a crystal clean tone. Lead sounds awesome though. A little past noon on the vol knob is about as loud as it'll get, right at the edge of OD. Having it there then using the pedal and pickhand dynamics gives me clean an d crunch. With the strat, I can dime it. With the P90s tele, in between. So its more than just diming the amp. Few amps will sound their best dimed in all playing parameters with three different guitar/pickup combos.

[fezz parka]

RAWK!

[fezz parka]

Originally Posted by backalleyblues

As an example, most 6L6s want to be biased around 68ma...

That's for two tubes, and plate voltage matters here.