Members A Very Special Piccolo Posted May 18, 2015 Members Share Posted May 18, 2015 Is it safe to play a high wattage amp through law watt speakers, like G12H30s, if the volume is kept down low? Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 18, 2015 Members Share Posted May 18, 2015 Absolutely. In fact, since the G12H30 is rated to produce 100 dB with an input of 1 Watt, you probably won't be feeding it a whole lot of power anyway unless your intention is to deafen yourself. Link to comment Share on other sites More sharing options...
Members camer138 Posted May 18, 2015 Members Share Posted May 18, 2015 It is no problem. Aryeon records guitars through a 1x12 with all sorts of high wattage amps. Arjen says he prefers the push it gives the speaker. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 18, 2015 Members Share Posted May 18, 2015 Can you do it? yes. Is it safe? No. Its impossible for the ears to know just how many watts you're pushing by judging the loudness. The DB's a speaker produces vs the wattage an amp produces are not linear. Adjusting the volume 1/3 is no guide either because some amps can produce maximum clean wattage with the volume at max and others at 50%. Second its heat is that blows or deforms the voice coil. The damage can be very subtle. The speaker may sound great one second and the next its toast. Its can go out like a flash bulb or just sizzle out. I've had it happen both ways. You may not even hear the cone deforming and rubbing on a magnet right away, especially when using a gain box. Speakers are very inexpensive. I suggest you get another that can be used along with the one you have already to match the amps RMS wattage. That's the only safety solution you can trust. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 18, 2015 Members Share Posted May 18, 2015 ^ Sorry but No. The original question was (emphasis added): Is it safe to play a high wattage amp through law watt speakers' date=' like G12H30s, [b']if the volume is kept down low?[/b] The answer is "Yes," based on actually reading and understanding the question. Speaker loudness measured in dBs is logarithmic, meaning that an increase of 10 dB means a n increase in Wattage of 10X. I'm going to take the OP at his word that he intends to keep the volume "down low". I could make my ears ring with my 25 Watt Roland amp so it shouldn't take much more than that to get decent volume out of the OP's G12H30. A "100 Watt" amp doesn't pump out 100 Watts continuously except in testing conditions. Actual music is a series of peaks. If the OP had said he wanted to play gigs with a 100+ Watt amp and a 30 Watt speaker, the answer would be very different and you'd be correct but context is everything. This sounds more like a practice situation although a 100+ Watt amp is overkill for that. Link to comment Share on other sites More sharing options...
Members A Very Special Piccolo Posted May 19, 2015 Author Members Share Posted May 19, 2015 I appreciate everyone's answers. One of the amps I'm looking to use through a 2 speaker cabinet with a V30 and G12H30 in it is a Mesa Strategy 500 - which is a 200 watt amp. But the S500 has a wattage meter on the chassis, showing how many watts are being put out, so that's fortuitous (and awesome). The other amp I'd use through the cabinet is a 1982 JCM 2203 - and for that I guess I just have to play below ears ringing level, lol. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 19, 2015 Members Share Posted May 19, 2015 If you have (2) 30w speakers in the cab you have a total of 60w there not 30. Wattage is additive. I surely wouldn't be hooking that Mesa up to a single cab. Its a 400w amp, not 200. Its 200w per side. If you only have one cab you cant run just one side and not the other. Tube amps "Must" have a load on the output or you can damage the power tubes and or output transformer when the tubes go. That things a monster with 6 power tubes per side and has no business being hooked up to low wattage speakers, meter or not. The dynamic peaks for tubes is huge and its unlikely the meters will accurately capture the actual peaks due to slew rate. The only way Meters are accurate is with a continuous sine wave pumped through where you aren't seeing the meter rise and fall. with a guitar the best you may get is an average level at best with many peaks occurring faster then the meters can respond. The other item is the Mesa is a power amp, not a guitar amp. You need a preamp to drive it. you cant just plug a guitar into it and expect it to work properly. I suggest you stick with the JMC for now and get some cash together some cash for decent speakers. I wouldn't even run that mesa unless I had a pair of 120W speakers per side. I can see it being used for a bass player in a very loud metal band playing large gigs, but for guitar its way too loud for anything realistic. Luckily that power head is a valued item that will get a good price. I suggest you sell it for around $1200~1500 then buy yourself a decent cab for the Marshall. Heads alone are useless without equally decent speakers. I picked up a Slant 1960 cab with 4 Celestins 75's awhile back for $450 You could easily get a full stack or maybe a cab and another lower wattage head to use with those 30w speakers you have for light gigs. Link to comment Share on other sites More sharing options...
Members 1001gear Posted May 19, 2015 Members Share Posted May 19, 2015 It is possible the Strategy can be driven by a guitar. My 20 has driver tubes and can be played audibly by just a guitar. Both sides with a splitter. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 19, 2015 Members Share Posted May 19, 2015 It is possible the Strategy can be driven by a guitar. My 20 has driver tubes and can be played audibly by just a guitar. Both sides with a splitter. The head accepts a line level in which means the guitar needs to be preamps. The driver tubes in a 500 are preamp driver tubes that accept line level inputs, not instrument level. You may get some signal through but no where near what you're supposed to. You wouldn't have any tone controls, gain adjustments effects loops or any of that. Its just a power head with main volumes. You cold probably use it as a PA head if its got a flat enough response curve. Many guitar Preamp/effects units designed to drive that kind of power head have stereo outputs. You could even drive it with a line out form a regular guitar head. Don't know how good it will sound Y Jacking the inputs. It may have a bridged mono/stereo button on it some place. I didn't google the full manual. I suspect Mesa made a matching tube preamp for the head If you had a pair of bottoms and decent preamp that thing would sound great, but again, you're talking 400W tube power which is more like 800W transistor power. Its not exactly a bedroom amp and again, I wouldn't even bother connecting low watt speakers. Just the power up current thump a high watt head can produce can be enough to damage low end speakers. I've done it more then once and its why I advise others to be careful. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 19, 2015 Members Share Posted May 19, 2015 Heres a video of one of their preamps driving a 400 head. he looks to be using some ampeg cabs Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 19, 2015 Members Share Posted May 19, 2015 Okay, I officially stand corrected. My answer is now "No." You said 100+ Watts so I was thinking maybe 120-150 Watts, and my initial answer and follow up were predicated on the information you supplied. With 400 Watts there's a level of risk involved I personally wouldn't want to accept. If you had said 400+ Watts my answer would have been different. Link to comment Share on other sites More sharing options...
Members 1001gear Posted May 20, 2015 Members Share Posted May 20, 2015 The head accepts a line level in which means the guitar needs to be preamps. The driver tubes in a 500 are preamp driver tubes that accept line level inputs, not instrument level. You may get some signal through but no where near what you're supposed to. You wouldn't have any tone controls, gain adjustments effects loops or any of that. Its just a power head with main volumes. You cold probably use it as a PA head if its got a flat enough response curve. Many guitar Preamp/effects units designed to drive that kind of power head have stereo outputs. You could even drive it with a line out form a regular guitar head. Don't know how good it will sound Y Jacking the inputs. It may have a bridged mono/stereo button on it some place. I didn't google the full manual. I suspect Mesa made a matching tube preamp for the head If you had a pair of bottoms and decent preamp that thing would sound great, but again, you're talking 400W tube power which is more like 800W transistor power. Its not exactly a bedroom amp and again, I wouldn't even bother connecting low watt speakers. Just the power up current thump a high watt head can produce can be enough to damage low end speakers. I've done it more then once and its why I advise others to be careful. Mine sounds quite good with just guitar. albeit at a very polite volume. Guessing that all Boogie dual mono amps can serve in hifi systems as well so JFTR there'd for sure be no low output problems. Not that that was the concern mind no one. The powerup danger can be avoided with the Standby function. One cab for a dual sided amp might be an issue. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 20, 2015 Members Share Posted May 20, 2015 I'm guessing when you say you have a 20 you mean a 20/20? When you plug straight in you're connecting your guitar at line level. You will get some amplification connecting an instrument to a power amp. The sound you get is likely pristine clean at 1/10th the wattage. You surely wont hurt anything by doing that but you're missing out on at least 2 or more stages of signal amplification when you do that. Its a matter of signal voltage gain before it hits the power amp and impedance matching. The tonal response will likely be off too because you wont be coming anywhere near the sweet spot in the amplification curve. Most ever amplifier has an amplification curve. At the bottom you have a noise floor. At the top you have saturation and clipping. In between you have the spot where the transistors or tubes produce the best tone and dynamics. This is usually between 50~70% of max amplification on this curve. Guitar preamps often push this limit up above 70% to get juicy power amp saturation from tubes and transformers. The components in the power amp are durable enough to withstand this abuse. Nice clean tones would be in the 50% range and below say 30% the dynamics and tone response becomes anemic. There are special Linear amps used for studio and PA work which will remain flat at low levels but most of your guitar stuff starts sounding muffled. This muting occurs for a number of reasons. The pots used to attenuate the signal, the limited dynamics occurring at the low end of the amplification curve creates a funnel effect on the signal. In simple language, if the signal is too weak its fails to properly gate a tube and its resultant amplified waveform isn't an exact duplicate of the original signal. It lacks detail and dimension. If you don't own a preamp, there are many inexpensive solutions you can seek out. I was on EBay the other day and came across a number of inexpensive rack units that would drive that head very nicely. I saw an ART SG2000 which is an older 90's preamp effect unit being sold for around $75 with free shipping. That unit sold for nearly a grand back in the 90's and even though its a bit dated, its a wonderful unit. Its got a preamp tube, multiple effects loops, and you can run any or all of its effects in any order, plus you can buy a midi pedal to switch between 300 different settings. I use one for recording and they do a great job. There are many others. Some basic some complex. Boss, Rocktron, Marshall, Line 6, Digitec, Sans amp, Fulltone Tech21, TC Electronics, Avid pro all make some great stuff that will drive that power head nicely. You don't even have to use a rack unit. Many of the multi effect floor boars will drive a power head at line level. You simply crank the output up. If its not quite enough you can simply use a driver pedal afterwards. You could also use a driver pedal straight into the head and kick the signal up 10~20db's Problem is you will essentially be pushing a full frequency signal and have no tonal control or preamp saturation other then what you get overdriving the inverter tubes. This probably would sound OK for an acoustic guitar that uses a fuller frequency response but electric usually shaped to fit a mix of instruments. Maybe if you had active guitar electronics with EQ, Gain etc you could get away with it, but I'd still opt for a preamp myself. Having the ability to drive the speakers at a tuned frequency and gain is the key to good electric tones. Link to comment Share on other sites More sharing options...
Members 1001gear Posted May 20, 2015 Members Share Posted May 20, 2015 Preamps I has several besides pedals. Just saying you can get decent sound straight in. The 20/20 also has dual gain and presence so there's rudimentary control even with just a guitar. Link to comment Share on other sites More sharing options...
Members A Very Special Piccolo Posted May 21, 2015 Author Members Share Posted May 21, 2015 If you have (2) 30w speakers in the cab you have a total of 60w there not 30. Wattage is additive. That's good, I had forgotten about that. I surely wouldn't be hooking that Mesa up to a single cab. Its a 400w amp, not 200. Its 200w per side. If you only have one cab you cant run just one side and not the other. Tube amps "Must" have a load on the output or you can damage the power tubes and or output transformer when the tubes go. As you say, it's 200w per side. The sides have independent standby switches, so a 2nd speaker cabinet is not necessary to put a load on the other side's output. I emailed Mesa about this, and they said it's OK, but for added safety to turn the volume all the way down and the presence all the way up on the side that's not being used. The other item is the Mesa is a power amp, not a guitar amp. You need a preamp to drive it. you cant just plug a guitar into it and expect it to work properly. I have a couple, a JMP-1 and an ADA MP-1. Link to comment Share on other sites More sharing options...
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