chilipeppermaniac
Ambassador of Decibels
Even at 80 years old LOL Revised. B E is 91. HOLY MOLY
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Ohm setting question
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chilipeppermaniac
Ambassador of Decibels
The sound of the G12M tends to be very pronounced on the midrange, with a sweet, woody, warm and smooth sound. It also tends to compress a lot when pushed too hard, because of the lower power handling and so, it can sound a bit muddy if you are not careful with the amp EQ. It’s not a very loud speaker, since it has an efficiency of 96db (or 97db or even 98db in a few versions).
it’s not the power handling (watts) that will determine if a speaker is “louder”, but the efficiency (db). The power handling will only tell how much wattage it can take safely without blowing.
it’s not the power handling (watts) that will determine if a speaker is “louder”, but the efficiency (db). The power handling will only tell how much wattage it can take safely without blowing.
Jethro Rocker
Ambassador of Live & Loud Action
Some things I read state that a say 100 watt guitar speaker is supposed to handle 100 watt amp tube pushed, which of course can output quite a bit more than it's rated output.
Other things state 100 watts RMS is MAX.
Wonder which is true...
Other things state 100 watts RMS is MAX.
Wonder which is true...
chilipeppermaniac
Ambassador of Decibels
How easy is it to blow a lower wattage speaker?
Have been considering getting a pair of Greenbacks but they are 25w (I am aware about the newer and other speakers with more watts) So lets say I have a 2x12 and a 120w amp. Or hell even a 4x12 and a 120w amp. Are these things gonna blow? I have heard you only get full wattage from an amp if...
www.rig-talk.com
chilipeppermaniac
Ambassador of Decibels
This was at that last link I posted.
Not sure what your amp is, but look at this Marshall JCM800 amp manual I found online and posted on my site.
50w amps put out well over 90, 100w amps are 115w clean, and put out over 180w.
chilipeppermaniac
Ambassador of Decibels
Like the above, this is posted by Scumback speakers
Speaker ratings are all over the map, quite frankly, and the quality of what's used can change (not here, I've had a set formula for over a 1/2 dozen years since I took over production).
That falls under the "specifications subject to change without notice" disclaimer. I don't believe in that. You build a product to a spec, and you maintain the materials/workmanship to your spec.
That's not what happens elsewhere, though, sorry.
Rule of thumb for speaker survival, you have a 50w amp, you crank it to 6-7, hit an OD pedal, and you'll be near, or past 100w of power handling. I've had clients to do it with their 50w Marshall heads.
Now if you have an amp that's biased cold, dying power tubes, low testing preamp tubes, and weak pickups & pedals, you might be able to get away with running said 100w not up to spec head into a 4x12 100w (or 120w) cab.
But if Marshall figured a 100w head needed 8 25w speakers, and this was before exotic pedal gain boosts were available (usually a wah, flanger, echoplex, and maybe a fuzz like Jimi Hendrix), they knew why you needed 200w of speaker power handling.
I've had too many clients try the 100w head into a 100w cab thing for years. Right after they fry their favorite greenbacks, they ask me for a 65w recone. And Marshall usually sells 65 to 75w speakers in their single 4x12's now. There's a reason they did that, too.
Look, you can roll the dice, be my guest. I'm just telling you it's better to be safe than sorry, unless you have an unlimited output tranny and speaker budget, then do what you want!
Speaker ratings are all over the map, quite frankly, and the quality of what's used can change (not here, I've had a set formula for over a 1/2 dozen years since I took over production).
That falls under the "specifications subject to change without notice" disclaimer. I don't believe in that. You build a product to a spec, and you maintain the materials/workmanship to your spec.
That's not what happens elsewhere, though, sorry.
Rule of thumb for speaker survival, you have a 50w amp, you crank it to 6-7, hit an OD pedal, and you'll be near, or past 100w of power handling. I've had clients to do it with their 50w Marshall heads.
Now if you have an amp that's biased cold, dying power tubes, low testing preamp tubes, and weak pickups & pedals, you might be able to get away with running said 100w not up to spec head into a 4x12 100w (or 120w) cab.
But if Marshall figured a 100w head needed 8 25w speakers, and this was before exotic pedal gain boosts were available (usually a wah, flanger, echoplex, and maybe a fuzz like Jimi Hendrix), they knew why you needed 200w of speaker power handling.
I've had too many clients try the 100w head into a 100w cab thing for years. Right after they fry their favorite greenbacks, they ask me for a 65w recone. And Marshall usually sells 65 to 75w speakers in their single 4x12's now. There's a reason they did that, too.
Look, you can roll the dice, be my guest. I'm just telling you it's better to be safe than sorry, unless you have an unlimited output tranny and speaker budget, then do what you want!
chilipeppermaniac
Ambassador of Decibels
And yet again he says
Just an example for you. I bought a G12M blackback 7 years ago from a guy online. He sent it out to me, 25w 16 ohm, standard 1777 cone, T1221 model from 78.
I hooked it up to my Egnater Rebel 20, set the volume on 4. The speaker lasted 8 strums, literally, about 10 seconds.
So either I have the loudest badass Rebel 20, or a 25w speaker that tested good on my waveform generator just decided to take a dump after 10 seconds, although it shouldn't have.
I wonder if there was not something else wrong with the amp that caused a speaker failure, or was it indeed a speaker that had something wrong going on before he got it installed into the amp
Just an example for you. I bought a G12M blackback 7 years ago from a guy online. He sent it out to me, 25w 16 ohm, standard 1777 cone, T1221 model from 78.
I hooked it up to my Egnater Rebel 20, set the volume on 4. The speaker lasted 8 strums, literally, about 10 seconds.
So either I have the loudest badass Rebel 20, or a 25w speaker that tested good on my waveform generator just decided to take a dump after 10 seconds, although it shouldn't have.
I wonder if there was not something else wrong with the amp that caused a speaker failure, or was it indeed a speaker that had something wrong going on before he got it installed into the amp
chilipeppermaniac
Ambassador of Decibels
Here ya go, the perfect clueless person or newb type amp/speaker guy.
Blown Greenbacks
<t>Hi guys, this is my first post here, thought I've been reading a long time.<br/> <br/> I run a 2266 through a 1936 cab, though recently changed out the scratchy GT12-75s for Greenback G12M's. Even though they were only 25W I figured that's what the 50W VM combo uses so ...
musiciansroadhouse.com
chilipeppermaniac
Ambassador of Decibels
From the above Blown Greenbacks thread.
Postby DeanM » 24 Jan 2010, 05:02
are you absolutely sure it was the speakers? did you plug in another amp to test them? lets say for example the power tubes blew, which would be much more commen, and as you said your technical knowledge is limited, so maybe if the tubes blew and you heard the volume drop off you would automatically assume it was the speakers? plug in another amp if possible and make sure it is actually the speakers! or turn on the VM and check do all the tubes light up the same.
as was stated the greenbacks should have been perfectly safe in there so it seems odd that they would blow. did you buy them new?
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Postby scottn » 28 Jan 2010, 03:44
Update: tested the cab with another head and guess what? Worked fine. DeanM was right, something going on with the head. I'll have to have a look at that in the next few days. I'll have to rename the thread..
Re: Blown Greenbacks
Postby DeanM » 24 Jan 2010, 05:02
are you absolutely sure it was the speakers? did you plug in another amp to test them? lets say for example the power tubes blew, which would be much more commen, and as you said your technical knowledge is limited, so maybe if the tubes blew and you heard the volume drop off you would automatically assume it was the speakers? plug in another amp if possible and make sure it is actually the speakers! or turn on the VM and check do all the tubes light up the same.
as was stated the greenbacks should have been perfectly safe in there so it seems odd that they would blow. did you buy them new?
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scottn <25
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Re: Blown Greenbacks
Postby scottn » 28 Jan 2010, 03:44
Update: tested the cab with another head and guess what? Worked fine. DeanM was right, something going on with the head. I'll have to have a look at that in the next few days. I'll have to rename the thread..
chilipeppermaniac
Ambassador of Decibels
I am glad for ScottN that his speakers were ok, now hopefully his amp got healthy in the meantime.
Robert, not so lucky. His amps and chops killed speakers.
Robert, not so lucky. His amps and chops killed speakers.
Jethro Rocker
Ambassador of Live & Loud Action
That's what I mean. The speaker specs don't really account for that.This was at that last link I posted.
Not sure what your amp is, but look at this Marshall JCM800 amp manual I found online and posted on my site.
50w amps put out well over 90, 100w amps are 115w clean, and put out over 180w.
I never get my amps up to that range so I am not concerned about blowing a speaker.
chilipeppermaniac
Ambassador of Decibels
How To Test A Vintage Celestion Greenback Speaker - Bygone Tones
How to test a speaker for: voice coil rub, blown speaker, torn cone, and other common problems. Using an audio generator for 'sweep testing'.
www.bygonetones.com
chilipeppermaniac
Ambassador of Decibels
Power wise, Jethro.
BUT as some other folks may know or have experienced, or be able to explain "electronics wise" better than I can.
Maybe there are other ways to blow your (a) speaker without exceeding the power exerted upon it.
I sure know AND have learned, there are many ways to damage an AMP and once I learned these, I do my best to prevent damage to both ends of the equation by doing tests, learning how amps work, how to fix them and good practices for maintaining my amps. While playing I use sensible settings, etc instead of extremes.
SG John
Ambassador of Cool Guitars and Amps.
Exactly. Most of my amps are in the 30-40 watt range. The exceptions are my Hiwatts and my '79 Marshall 2203 100 watt JMP. With the Hiwatts, I'm using the Hiwatt cab which I believe is rated for 220 watts with four 55 watt Fanes. If I play any gigs with my JMP, I'll use my Silver Jubille 4x12 which is rated at 300 watts with G12T-75 speakers. My JTM45s, 50 watt JPM, and DST heads can be used with my multiple cabinets loaded with 20 and 25 watt green backs, black backs, and 30 watt anniversary speakers. I'm usually not above 5 volume wise, and not concerned about overpowering the speakers.
What I should do, is spend an entire weekend moving the speakers around in each cabinet so that they are rotated 180 degrees. That will help fight coil rub caused by gravity.
Jethro Rocker
Ambassador of Live & Loud Action
My 2x12 is 130 watts rated, the 4x12 is 300. Should be no worries there. When I run a 1x12 or 2 - 1x12s they are 25 and 30 watts so 50 watts for the pair.
I am changung them out for the 2 V series in the SC212 at 70 watts EACH. Who needs 140 watts for 20 watt amps? So the Greenie amd H30 go in there giving me 50 watts of speaker and the 2x70s each go in a 1x12.
chilipeppermaniac
Ambassador of Decibels
Ampmad, I am pretty sure some videos are presented here which show what the presenter explains about things he tests for including Voice Coil rubbing. I posted it up thread, but I also will repost it here and show a few of the video clips.
How To Test A Vintage Celestion Greenback Speaker - Bygone Tones
How to test a speaker for: voice coil rub, blown speaker, torn cone, and other common problems. Using an audio generator for 'sweep testing'.
www.bygonetones.com
Jethro Rocker
Ambassador of Live & Loud Action
Incidentally, for those mixing speakers in a cab or smaller speaker cabs in parallel, just a note.
The max power is equal to the lowest power rated speaker x the number of speakers. Not really a biggoe in a 4x12 but in a 2x12.
Example.
Running say a greenback 25 watt with a T75 one might think that's 100 watts of speaker but no.
The load is split between both speakers of same impedance.
Each speaker gets half.
A 100 watt amp means half, or 50 watts, is going through the 25 watt Greenie.
Oh oh.
Even a 50 watt amp means Greenback is pushed to the limit even though it seems like there is 100 watts of speaker.
The max power is equal to the lowest power rated speaker x the number of speakers. Not really a biggoe in a 4x12 but in a 2x12.
Example.
Running say a greenback 25 watt with a T75 one might think that's 100 watts of speaker but no.
The load is split between both speakers of same impedance.
Each speaker gets half.
A 100 watt amp means half, or 50 watts, is going through the 25 watt Greenie.
Oh oh.
Even a 50 watt amp means Greenback is pushed to the limit even though it seems like there is 100 watts of speaker.
SG John
Ambassador of Cool Guitars and Amps.
I have a 4x12 that has two 25 watt Green Backs and two 30 watt Anniversary speakers. And yes, it's rated for 100 watts, not 110 watts.
chilipeppermaniac
Ambassador of Decibels
chilipeppermaniac
Ambassador of Decibels
Are Creambacks M65s bassier and darker than 25W Greenbacks?
I've tried Creambacks in a few occasions and owned a pair for a while. Currently, i have chinese Greenbacks G12M. Four of them, 16 ohm each in my 1960tv cab. I have mixed feelings for Creambacks. In 1x12 or 2x12 in closed back config, they sounded a bit constipated, sludgy, with a bassy...
www.thegearpage.net