So I'm running two Heritage G12Ms with a 50w head...

[Random Hero]

A 5150III 50w to be exact. Sounds amazing. Master isn't ever really gonna go above 5, should I be concerned? Highest it's ever been is 5 on the master but usually 3-4 tops with a clean boost in the loop for leads.

Is this any different to running a 100w head into a 4x12 with greenies a la the 100w EVH head and cab setup?

Reason I ask is I've read so many horror stories and advice over this but I went ahead and did it anyway as the H30s I had in my cab previously were bugging me. I'm much happier with the tone and besides, is two 30w speakers really that much better than two 25w in terms of power handling?

 

[some dude]

I've put a 100w Recto through two G12M-25s for extended durations. Like 5150s Rectos aren't required to max out their headroom before they start sounding good, so I choose a volume that's appropriate. So far I've had zero issues.

I found that with G12Ms there's a point where they start to sound worse as I drive them harder. I use that as my limit guide and keep the volume where they still sound nice.

 

[Random Hero]

Yeh I guess I gotta just be wary.

 

[MississippiMetal]

The thing you have to understand is that 50W rated output power is the *clean* output power, which is to say power before distortion. When the power tubes begin to clip, the harmonics generated occupy a greater bandwidth and wattage dissipation increases. In the very least I would wire the speakers in parallel (which will probably change the overall tonal response if you're running them in series right now) so that should a speaker blow open, your amp isn't left without a speaker load.

 

[Scumback Speakers]

The thing you have to understand is that 50W rated output power is the *clean* output power, which is to say power before distortion. When the power tubes begin to clip, the harmonics generated occupy a greater bandwidth and wattage dissipation increases. In the very least I would wire the speakers in parallel (which will probably change the overall tonal response if you're running them in series right now) so that should a speaker blow open, your amp isn't left without a speaker load.

Good post, MM.

Random Hero:
There are plenty of variables in an amp for voltages/tubes/etc. I'm sure Marshall took that into account when they built their amps and wrote the JCM800 manuals for players. I have one of those manuals in PDF format onine. Go to page 5 and read the 1959 and 1987 power output specs:
http://www.scumbackspeakers.com/faqs/jcm800specs.pdf

It will show over 90w for the 50w amp with 10% THD, and over 170w for the 100w amp with 10% THD.

 

[blackba]

Is it a good idea to run a 50Watt head into 2 G12M's? Not really. Its all in the risk you are willing to accept. There are plenty of higher power rated greenbacks out there now if you don't want to take the risk.

 

[some dude]

It will show over 90w for the 50w amp with 10% THD, and over 170w for the 100w amp with 10% THD.

Yeah, but who drives the piss out of a 5150 the way people used to drive the piss out of Marshalls?

 

[SBlue]

A 5150III 50w to be exact. Sounds amazing. Master isn't ever really gonna go above 5, should I be concerned? Highest it's ever been is 5 on the master but usually 3-4 tops with a clean boost in the loop for leads.

Is this any different to running a 100w head into a 4x12 with greenies a la the 100w EVH head and cab setup?

Reason I ask is I've read so many horror stories and advice over this but I went ahead and did it anyway as the H30s I had in my cab previously were bugging me. I'm much happier with the tone and besides, is two 30w speakers really that much better than two 25w in terms of power handling?

Are you using the master volume maxed out, the gain and the tone controls above 1:00 all the time without an attenuator?
If the answer is yes, then you should be concerned. If no, then you're fine.

 

[MississippiMetal]

A 5150III 50w to be exact. Sounds amazing. Master isn't ever really gonna go above 5, should I be concerned? Highest it's ever been is 5 on the master but usually 3-4 tops with a clean boost in the loop for leads.

Is this any different to running a 100w head into a 4x12 with greenies a la the 100w EVH head and cab setup?

Reason I ask is I've read so many horror stories and advice over this but I went ahead and did it anyway as the H30s I had in my cab previously were bugging me. I'm much happier with the tone and besides, is two 30w speakers really that much better than two 25w in terms of power handling?

Are you using the master volume maxed out, the gain and the tone controls above 1:00 all the time without an attenuator?
If the answer is yes, then you should be concerned. If no, then you're fine.

You must know something a backline tech and loudspeaker designer don't. Please share.

 

[SBlue]

A 5150III 50w to be exact. Sounds amazing. Master isn't ever really gonna go above 5, should I be concerned? Highest it's ever been is 5 on the master but usually 3-4 tops with a clean boost in the loop for leads.

Is this any different to running a 100w head into a 4x12 with greenies a la the 100w EVH head and cab setup?

Reason I ask is I've read so many horror stories and advice over this but I went ahead and did it anyway as the H30s I had in my cab previously were bugging me. I'm much happier with the tone and besides, is two 30w speakers really that much better than two 25w in terms of power handling?

Are you using the master volume maxed out, the gain and the tone controls above 1:00 all the time without an attenuator?
If the answer is yes, then you should be concerned. If no, then you're fine.

You must know something a backline tech and loudspeaker designer don't. Please share.

I really don't know the reason for your post. I never said I know more than anyone, and my reply does not contradict Jim's one. But since you've asked, here we go.
Unfortunately I didn't go to school of speakers... but I have and use a 50w Laney Supergroup from 1970 through it's original 2x12 with 25w greenbacks and 80% of volume all the time. Also, my 5153 100w is always recorded with the master volume at 1:00 and gain at least on 11:00 on a 5153 4x12. Never blew a speaker. Now I have a lot of friends who don't even know what EVH means. They hate rock music, but they are graduated at a physics college. They know everything about numbers. Me, I'm stupid, cause I just play and use the gear.
Now, if I need school before posting this info, please forgive.
I apologize in advance and if it's your desire, I can remove my posts on this thread, in case it might hurt someones amp... or feelings.
No, my turn to ask... did you ever had an amp like his and used it the way he asked to judge who is right and who is wrong? Please share.

 

[some dude]

You must know something a backline tech and loudspeaker designer don't. Please share.

That the average dude who uses a 5150 isn't driving the piss out of it the way people used to drive the piss out of their Marshalls.

As a backline tech that one should've been obvious...

 

[Random Hero]

Tone controls above 1:00 yes. Gain is above 1:00 on the blue from time to time. Master volume never goes above 5-6 and rarely above 4. That kinda stage volume is generally inhospitable!

 

[MississippiMetal]

That the average dude who uses a 5150 isn't driving the piss out of it the way people used to drive the piss out of their Marshalls.

As a backline tech that one should've been obvious...

That's a tremendously generalizing statement. "The average dude" is an as-of-yet undefined demographic of amplifier owner.

Number one, you don't need to "drive the piss out of a 5150" to put strain on a 60 watt load. Number two, depending on how the amplifier is EQ'd and how the person plays, spikes in the signal due to heavy pick attack and or front end overdrive can easily damage the speaker when the amplifier is only at a third of its maximum volume. This isn't to say you're certain to cook a pair of greenbacks if you have a 50 watt amp at club-gig volume, but it's certainly not outside the realm of possible. Talk to Wes Jeans about him blowing Greenbacks in a 4x12 running a 50 Watt Voodoo Plexi. I doubt very seriously it was dimed, as Wes seldom plays venues large enough to get away with that kind of volume.

EDIT: I realize we're talking about the Heritage series, but 5 watt difference is negligible.

 

[Random Hero]

This would all mean that the matching EVH 4x12 is underrated for the 100w head too, right?

 

[MississippiMetal]

This would all mean that the matching EVH 4x12 is underrated for the 100w head too, right?

That's exactly what it means. But Ed also drives more than one cabinet with a single head.

 

[Scumback Speakers]

For the record, I'm basing my comments and recommendations on the real world experiences my clients have related to me. I'm not talking hypothetical "what if" scenarios. I'm talking clients saying "I'm a frigging idiot. I did exactly what you told me not to do and I blew my speakers, and fried my OT." Here's some of those failures below.

I've had clients with one of my 10 watt Gibson GA-8 conversions blow a G12-65 in 14 months. Should it have lasted forever? Sure. Did it? No. Why? He played the amp wide open, used an attenuator, too. Did that save him? Nope. Why did it blow? Beats me. Weak coil, poor build quality, who knows.

I've had clients with Komet 60's and Concordes (KF 50) blow two 30w Scumbacks in a 2x12. They've been fine with two 65w models, or four 25/30w models with the same amp.

As for 100w amps, a client had a Super Bass Metro he built, plugged it into four H55 30w speakers, turned it up to 6, and poof. He didn't believe me about the power handling either. He does now. He got all four reconed to 65w H55's. Been good to go every since.

A well known producer took his M75 65w loaded 2x12 to a jam with his 68 Plexi 100w. He said it sounded great at 6, awesome at 7. Sounded so good he turned it up to 7.5, and "poof", both speakers blew.

The facts are simply that it's just always better to have twice as much power handling as your clean rated power of your amp so you can do stupid shit at will... like twisting the master volume knob to 10, kick in the OD/clean boost, and stand there with your pants or shirt sleeves flapping while you listen to an A chord feeding back in monstrous swelling harmonics.

Or you can believe that 100w of speaker power handling is all you need for your 100w amp...like the guys above did...right up until they fried their speakers or amps.

Any questions?

 

[SBlue]

For the record, I'm basing my comments and recommendations on the real world experiences my clients have related to me. I'm not talking hypothetical "what if" scenarios. I'm talking clients saying "I'm a frigging idiot. I did exactly what you told me not to do and I blew my speakers, and fried my OT." Here's some of those failures below.

I've had clients with one of my 10 watt Gibson GA-8 conversions blow a G12-65 in 14 months. Should it have lasted forever? Sure. Did it? No. Why? He played the amp wide open, used an attenuator, too. Did that save him? Nope. Why did it blow? Beats me. Weak coil, poor build quality, who knows.

I've had clients with Komet 60's and Concordes (KF 50) blow two 30w Scumbacks in a 2x12. They've been fine with two 65w models, or four 25/30w models with the same amp.

As for 100w amps, a client had a Super Bass Metro he built, plugged it into four H55 30w speakers, turned it up to 6, and poof. He didn't believe me about the power handling either. He does now. He got all four reconed to 65w H55's. Been good to go every since.

A well known producer took his M75 65w loaded 2x12 to a jam with his 68 Plexi 100w. He said it sounded great at 6, awesome at 7. Sounded so good he turned it up to 7.5, and "poof", both speakers blew.

The facts are simply that it's just always better to have twice as much power handling as your clean rated power of your amp so you can do stupid shit at will... like twisting the master volume knob to 10, kick in the OD/clean boost, and stand there with your pants or shirt sleeves flapping while you listen to an A chord feeding back in monstrous swelling harmonics.

Or you can believe that 100w of speaker power handling is all you need for your 100w amp...like the guys above did...right up until they fried.

Any questions?

Now that's a pro response!!!
How are you Jim? Have you spoke with D. Berlin recently? I miss him and Belzer a lot! I really want to check out Drew's studio, Bamboo. Should stop by next time I'm in LA.
Anyway, back to topic, I'm a very lucky guy for not blowing any of my speakers yet.
I thought a 50w amp with a master no louder than 4 (even with gain maxed) would be safe.
I'll be more careful from now on.

 

[Scumback Speakers]

I've been so busy I haven't seen Drew in months. Talked to him a couple of times in the last year but with all the fallout from he & Dave leaving GC and starting their own business together, I'd imagine he's been busy. My cab guy has seen him for some work for the studio, but that's about it.

As for your 50w...they're not all created equally. Some of the later Marshalls are just 50w regardless, limited by the amp circuit and output tranny specs.

The classic Marshall designs (1987x 50w, 1959 100w, etc) generate more power than their rating says, as they like to be conservative on the clean power rating. The fact is, they can and do make more clean power than their rating, and once you pass that level, they can put out almost double the clean rated power. That leads to smoke and silence in some cases, as I've posted above.

Long story short...Marshall told players to get two 4x12's with their 100w amps, and one 4x12 with their 50w amps when all they offered were 25 & 30w speakers. That's not a coincidence.

 

[SBlue]

I've been so busy I haven't seen Drew in months. Talked to him a couple of times in the last year but with all the fallout from he & Dave leaving GC and starting their own business together, I'd imagine he's been busy. My cab guy has seen him for some work for the studio, but that's about it.

As for your 50w...they're not all created equally. Some of the later Marshalls are just 50w regardless, limited by the amp circuit and output tranny specs.

The classic Marshall designs (1987x 50w, 1959 100w, etc) generate more power than their rating says, as they like to be conservative on the clean power rating. The fact is, they can and do make more clean power than their rating, and once you pass that level, they can put out almost double the clean rated power. That leads to smoke and silence in some cases, as I've posted above.

Long story short...Marshall told players to get two 4x12's with their 100w amps, and one 4x12 with their 50w amps when all they offered were 25 & 30w speakers. That's not a coincidence.

Thanks Jim,
I bet Drew and Dave are working a lot happier now!
Regarding the 50w amp, I was talking about the 5153 50w with the master volume knob on 4 and preamp gain knob on 10 through a 50w 2x12 cab.
But I've got it anyway.
I also would love to see your shop and buy some Scumbacks to bring them home with me, so I can load a cabinet with them for the studio. Would love to load a cabinet with some of your higher powered speakers, since the only higher powered Celestion I have are V30s and C90s. And different speakers are always welcome during a recording session!
Thanks again Jim!
Cheers

 

[cnote]

My Question is how did the Bluesbreaker Clapton used work with 2 Alnico 15 watt speakers, given that he dimed it?
Were they just made better back then?