Does a 412 greenback cab have enough power handling...

[threadkiller]

This is more like it. I got involved in a bit of a shitstorm on TGP today as well on a stupid pedal post of all things, where I called out the moderators for being douchenozzles. I'm guitarspaz over there.

Sounds like the take home message is I could probably get by with it since I won't likely be near maxing my amp but I do have some risk of blowing some speakers.

 

[TheMagicEight]

What about running a 50w head (lets say even a plexi type) into something similar...like a 4 x 12 with 30w G12H blackbacks (55hz)? Fairly safe, even cranking a bit?

Totally safe. EL34s have a max output of about 25 watts each at close to 0% total harmonic distortion (putting the next bit in bold to point out solid theory). As you increase distortion on the output tubes, you transition from a theoretical sine wave to a square wave. Square waves contain twice as much power as sine waves.

This means the theoretical max output of two EL34s is 100W. Two 6L6s is 120W, and so on.

 

[TheMagicEight]

This is more like it. I got involved in a bit of a shitstorm on TGP today as well on a stupid pedal post of all things, where I called out the moderators for being douchenozzles. I'm guitarspaz over there.

Sounds like the take home message is I could probably get by with it since I won't likely be near maxing my amp but I do have some risk of blowing some speakers.

You should be okay. Just listen to the speakers, and be wary of entering power tube saturation (anything below this should be totally alright).

 

[VC4Ever]

LMAO. Consider yourself a moron. No where in this link do I see 240Watts for 4 6L6. For 2 6L6 it shows max of nothing more then 60 Watts. Thanks for trying to enlighten me though...

 

[TheMagicEight]

LMAO. Consider yourself a moron. No where in this link do I see 240Watts for 4 6L6. For 2 6L6 it shows max of nothing more then 60 Watts. Thanks for trying to enlighten me though...

Hrm...you don't know how to read, do you. Do you know what THD is?

 

[VC4Ever]

HMMM do you know how to read specs. "Typical Operation
(Values are for two tubes) "

 

[Crunchity]

What about running a 50w head (lets say even a plexi type) into something similar...like a 4 x 12 with 30w G12H blackbacks (55hz)? Fairly safe, even cranking a bit?

Totally safe. EL34s have a max output of about 25 watts each at close to 0% total harmonic distortion (putting the next bit in bold to point out solid theory). As you increase distortion on the output tubes, you transition from a theoretical sine wave to a square wave. Square waves contain twice as much power as sine waves.

This means the theoretical max output of two EL34s is 100W. Two 6L6s is 120W, and so on.

Thanks for the info. I've always prefered the sound of my particular 100w main head at 50w (but cranking a bit ). Good to know I'm safe with my very vintage speakers.

 

[TheMagicEight]

HMMM do you know how to read specs. "Typical Operation
(Values are for two tubes) "

Typical Operation
(Values are for two tubes) 6L6 6L6GC
Plate Voltage 360 360 450 volts
Total Harmonic Distortion 2 2 1.8 %
Maximum-Signal Power Output 26.5 18 55 watts

Total harmonic distortion is 1.8%. Nearly a pure sine wave. To quote myself:

As you increase distortion on the output tubes, you transition from a theoretical sine wave to a square wave. Square waves contain twice as much power as sine waves.

This means the theoretical max output of two EL34s is 100W. Two 6L6s is 120W, and so on.

 

[VC4Ever]

Typical Operation
(Values are for two tubes)
Plate Voltage 360 360 volts
Grid-No.2 Voltage 225 270
Grid-No.1 (Control-Grid) Voltage -18 -22.5
Peak AF Grid-No.1-to-Grid No.1 Voltage 52 72
Zero-Signal Plate Current 78 88 ma
Maximum-Signal Plate Current 142 205
Zero-Signal Grid-No.2 Current 3.5 5
Maximum-Signal Grid-No.2 Current 11 16
Effective Load Resistance (Plate-to-plate) 6000 3800 ohms
Total Harmonic Distortion 2 2 %
Maximum-Signal Power Output 31 47 watts

 

[TheMagicEight]

Typical Operation
(Values are for two tubes)
Plate Voltage 360 360 volts
Grid-No.2 Voltage 225 270
Grid-No.1 (Control-Grid) Voltage -18 -22.5
Peak AF Grid-No.1-to-Grid No.1 Voltage 52 72
Zero-Signal Plate Current 78 88 ma
Maximum-Signal Plate Current 142 205
Zero-Signal Grid-No.2 Current 3.5 5
Maximum-Signal Grid-No.2 Current 11 16
Effective Load Resistance (Plate-to-plate) 6000 3800 ohms
Total Harmonic Distortion 2 2 %
Maximum-Signal Power Output 31 47 watts

 

[VC4Ever]

Ok I understand the THD stuff its only 2%. That won't add up to twice the wattage. In any case just rock two 412's if your going to crank your amp..which hardly anyone does these days...

 

[VC4Ever]

here man I found something that explains it a lot better. I am enlightened. Apparently the amps rating is for clean signals not distorted ones.

NBC commercial " The more you know"

Guitar Amplifier Power Output Ratings

The power output rating of a guitar amp is mostly a ballpark figure for what it can put out. Amp specifications commonly list power output in a form similar to the following:
Power Output: 50W into 8Ω at 5% THD
This type of power output rating is obtained by using a sine wave from a signal generator (usually 1 kHz) as the input signal. The 5% THD (total harmonic distortion) figure means that the sine wave was able to generate 50W of power output with relatively low distortion (near the threshold of clipping or overdrive). THD measurements were one of the first conventions used to objectively compare the fidelity of audio amplifiers. Guitar amps are unconventional audio amplifiers. While most audio amplifiers are designed to keep distortion as low as possible, guitar amplification has evolved to where overdrive distortion is usually a requirement. For example, the Marshall® JCM800 2203 is a 100W tube amp that has a highly regarded overdrive sound. The owner's manual lists the power output as follows: Typical power at clipping, measured at 1kHz, average distortion 4% 115 watts RMS into 4, 8, 16 ohms. Typical output power at 10% distortion 170 watts into 4 ohms. This example shows that for many guitar amplifiers, the power output rating (100W in this case) is not a maximum power output rating, but more of a ballpark clean power output specification.


Here's the link: http://www.amplifiedparts.com/tech_corn ... r_handling

 

[madrigal77]

Works just fine with the EVH 5150III head/cab. I crank mine all the time playing de-tuned metal and have never had a problem.

Crank? You mean into power tube saturation?

Good luck....

Loud enough for band levels. I think the danger of blowing them is overhyped. I mean, think about it. Would Fender/EVH release the cab that way if the speakers bow easily!!? And I've never heard of anyone blowing an EVH cab using it with the 100w head. I know a few metal bands are using them live too (Gojira, Testament, ect..).

 

[stratotone]

I guess I'm the idiot...please enlighten me.

I can agree with that, I'm sure someone else will take the time to teach you in this thread if you're able to learn. If not, do some research then come back.

 

[TheMagicEight]

Works just fine with the EVH 5150III head/cab. I crank mine all the time playing de-tuned metal and have never had a problem.

Crank? You mean into power tube saturation?

Good luck....

Loud enough for band levels. I think the danger of blowing them is overhyped. I mean, think about it. Would Fender/EVH release the cab that way if the speakers bow easily!!? And I've never heard of anyone blowing an EVH cab using it with the 100w head. I know a few metal bands are using them live too (Gojira, Testament, ect..).

Ah. Band levels (as opposed to arena levels) I'd think should be good. As for blowing speakers, I had a P50E that I used with three V30s of same impedance in a 4x12 for recording. They're rated at 50W, and I figured that would be close enough for 4x6L6s. Nope.

Although they're known to handle more, those EVH speakers are technically rated at 20W. I'd have to figure the touring bands are using full stacks. Probably doesn't matter much as long as you're not in power tube saturation, which probably isn't what the 5150 III is meant for anyway.

I guess I'm the idiot...please enlighten me.

I can agree with that, I'm sure someone else will take the time to teach you in this thread if you're able to learn. If not, do some research then come back.

Actually, he posted something pretty helpful just a couple posts up...

 

[ericsabbath]

people should worry more about proper use of the amps than actual speaker power handling
in my understanding, no equipment is made be constantly used "up to eleven"
there's a reason a 100w amp is rated 100 watts and not 170 watts
eddie, angus, jimi and all those guys could afford fucking up speakers, tubes, capacitors, transformers every week
they didn't give a fuck cause they were in the top of the fucking world
I'm pretty sure they constantly blew up lots of speakers in full stack setups
a 100w cab can be paired with a 100w amp regularly at LOUD volumes without a problem
but a 300w cab still can be damaged by a fully cranked 100w or less amp
overheating can happen even in huge power speakers and cones can be damaged no matter the power handling
and using a tube amp cranked most of the time isn't healthy for the amp at all (neither for your ears)
I certainly wouldn't risk overheating my beloved 40 years old 50w jmp stock transformers (the only thing still original in the amp) just to play the brown sound rockstar for an hour

 

[TheMagicEight]

people should worry more about proper use of the amps than actual speaker power handling
in my understanding, no equipment is made be constantly used "up to eleven"
there's a reason a 100w amp is rated 100 watts and not 170 watts
eddie, angus, jimi and all those guys could afford fucking up speakers, tubes, capacitors, transformers every week
they didn't give a fuck cause they were in the top of the fucking world
I'm pretty sure they constantly blew up lots of speakers in full stack setups
a 100w cab can be paired with a 100w amp regularly at LOUD volumes without a problem
but a 300w cab still can be damaged by a fully cranked 100w or less amp
overheating can happen even in huge power speakers and cones can be damaged no matter the power handling
and using a tube amp cranked most of the time isn't healthy for the amp at all (neither for your ears)
I certainly wouldn't risk overheating my beloved 40 years old 50w jmp stock transformers (the only thing still original in the amp) just to play the brown sound rockstar for an hour

I dunno...I'd definitely agree that playing on 10 all the time isn't as good for the amp as playing on 2, but really it's shouldn't be "bad" for anything - assuming you're within all rated specs - except for the tubes (and your ears for sure).

Transformers should be able to handle everything you throw at the amp with no problem as long as other components don't go first. The worst thing for caps is actually to not use them at all. Power your amp up at least once a month and they'll last longer, though of course the electrolytics will eventually go regardless. As for speakers, as long as you don't overheat them by putting too much power in, you should be okay there too.

The bottom line for me with my plexi is this. At 5, you're already pushing the power section about as hard as it's going to be pushed. Past that, you're adding more saturation in the preamp; the transformers and speakers don't "see" much of a difference. So if I'm playing on 5, I might as well play on 7-8. 10 doesn't sound good to me.

 

[stratotone]

This is why I love my Kemper - I can crank one of my vintage marshalls for a few minutes, capture it and have that tone for recording at will.

 

[FIREBALL]

i crank my herbert through a cab with greenbacks........thought id hate it ......its cool ,tight as hell.....i was schocked

 

[Cirrus]

Celestion generally under rate their speakers, and in a closed back cab the cones' movement is cushioned by the trapped air behind them. So they'll do better than you think. It's just that one time when you play big power chords for too long, or find a cool sound using an octave down pedal, or crank the bass too high etc, that's when they'll get pushed too far. But if you're sensible it'll never be an issue.