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Post by vonFrenchie on Feb 12, 2007 22:16:04 GMT -5
I am planning on buying two epiphone valve junior heads. I like the simplicity of it all. No mucking up the signal with gain, drive, eq's and all that mumbo jumbo (some of which I love). My problem is... will the 1 watt I will usually have it putting out damage my 125 watt rated speakers (wired in stereo 1 head to one speaker)?
Also I was thinking of buying a standard Valve Junior and removing the speaker and placing a board over that spot. Then I would mount effects boards to that with true bypass switches. Then I could have a valve junior that has... distortion, overdrive, a phaser, chorus... or just about anything else. Is this a good idea?
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Post by sumgai on Feb 13, 2007 5:12:12 GMT -5
vF, Little known is the phenomenon of distortion. Well known is the hearing of it, but the actual effects of it, little known. When an amplifier distorts, it is changing the signal in some undesirable way. We, as guitarists, have learned to harness some of those distortion products, and turn them into musical tones. But there are other kinds of distortion that don't work so well for us, and they can definitely damage a speaker while you're busy not hearing them! In essence, if you drive an amp hard enough (and at 1 watt, you will drive it hard), the upper frequencies tend to distort before you can hear any problems. This effect is greater above the hearing range of most humans, and virtually all guitar players. (You know I'm right, don't try to deny it.  ) That ultrasonic distortion will get into a speaker's voice coil, and cause it to heat up. That's because the VC is trying to work the cone at those frequencies, and the cone is standing there looking like a dumb jock, going "D'oh" - it literally can't move that fast, so it just sits there. In short, the VC reacts to the non-movement by converting the incoming signal into heat..... and you know what that does to speaker innards, right?  Bottom line is, you can do it, but there is a slight chance that you'll one day turn it up all the way, wail away for all you're worth, and then wonder why the speaker has crapped out on you. It's up to you to determine how slight that chance is. Surely you jest.  If you place the cabinet in any other position than standard, you risk: 1) stepping (or falling onto) the innards; 2) heat rising in a direction that will cause damage to other components/units; 3) gross deteoration of the cab covering, making it worth much less. Don't do this, unless you have a scapegoat lined up! ;D sumgai |
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Post by ChrisK on Feb 13, 2007 13:15:43 GMT -5
Hmmmmm..................;
I are cornfuzed here.
Is this a trick question?
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Post by vonFrenchie on Feb 13, 2007 16:55:12 GMT -5
Well the Valve Junior is rated at 5 watts. I've heard from many people that if you dont push your speakers hard enough (aka too low of a wattage going in them) they can be damaged. By your reaction... I'm guessing the answer is no. How are you "cornfuzed" I have a stereo cabinet. Two heads, two speakers, stereo sound. This is how it is wired.  I dont plan on turning a single head past 12 oclock. Heck, right now my Peavey Musician (puts out roughly 170 watts at 4 ohms) has the volume set to the minimum and its too loud for nighttime playing. Thats why I want a Valve Junior or some low wattage Valve head. |
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Post by sumgai on Feb 14, 2007 4:26:58 GMT -5
vF, (Nice diagram, BTW.) Bear in mind that no amplifier is using the maximum power rating all the time - that only happens during extreme peaks. In most cases, you might be sucking up 1 or 2 watts, for a small amp, up to maybe 5 watts for a large amp pushing several speakers at once. And at that, I mean to say, you're definitely louder than comfortable here.  The discussion of all this is extremely dense with math and theory, yet it is also academic - you want an amp that does what you want it to, not what is says it can do. Simple as pie, right? Well, yes and no. If you go by ratings (published or rumored), you have a good starting point, but not much else. Only your ear will be able to give you the definitive answer as to what works best for you. (And your wallets gets its two cents in, too.  But for the most part, one should get close when pairing up speakers and amplifier power ratings. You don't need to "push" a speaker to near its rating in order to prevent mistreating it, but I'm pointing out that just as you don't want to hang a single Craptone 8" speaker from a Fender Princeton onto a 200 watt Marshall Major head, you also don't want to saddle a Valve jr. with two 4x12" cabs for any length of time at high volumes. (The reason for that was explained in my previous post, above.) Both routes have their pitfalls, so buyer beware. sumgai |
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Post by dunkelfalke on Feb 14, 2007 7:16:07 GMT -5
the upper frequencies tend to distort before you can hear any problems. This effect is greater above the hearing range of most humans, and virtually all guitar players. (You know I'm right, don't try to deny it. ) i do deny it - have had a ear test two weeks ago and have attested 100% hearing ;D hmm, i have read, that the output transformer in almost all guitar tube amps would eat frequencies that high anyway. |
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Post by ChrisK on Feb 14, 2007 13:11:01 GMT -5
Yeah, but load impedance is load impedance, whether in the 8" Eminence in the Valve Jr or a 4 x 12" cab. It ain't much of a saddle, more like a small horse blanket.  Yeah, there are often ultrasonic osculations (inadvertent internal feedback) in amps that do heat up the loads (and the plate(s)). You'll oft see plate-to-plate or plate-to-common bypass caps in tube amps to suppress this. |
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Post by vonFrenchie on Feb 14, 2007 17:39:19 GMT -5
I was thinking of having two hooked up to a 2x12 cab for some cool stereo sounds in the studio and during smaller jams. I really dont plan on cranking any of my amps up to the max for more than 5 minutes.
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Post by ChrisK on Feb 14, 2007 20:52:03 GMT -5
Well, having both speakers in the same cab will diminish the channel separation both from acoustic coupling and point source distance.
If it's a closed back cab, it will acoustically couple the channels fairly tightly, especially at lower frequencies.
There aren't many guitar speakers over 8" in diameter that CAN be damaged by 5 watts. Remember, 5 watts is about as much heat as a candelabra base night light bulb develops.
Most humans sneeze harder than that. (1/150 of a horsepower)
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Post by sumgai on Feb 14, 2007 21:25:18 GMT -5
Chris, I claim Bojer! You're comparing electromotive force to kinetic motion, or IOW, apples to oranges. Engineering standards notwithstanding, conversions are for generalities, not specifics like this case. But more importantly, I wanna know just what your interest was that you sought out the kinesthesic power value of a human's sneeze! ;D sumgai |
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Post by sumgai on Feb 14, 2007 21:27:23 GMT -5
Yeah, but load impedance is load impedance, whether in the 8" Eminence in the Valve Jr or a 4 x 12" cab.
It ain't much of a saddle, more like a small horse blanket.
Yeah, there are often ultrasonic osculations (inadvertent internal feedback) in amps that do heat up the loads (and the plate(s)). You'll oft see plate-to-plate or plate-to-common bypass caps in tube amps to suppress this.Properly matched impedance was assumed..... Frenchie is a big boy now, I'm sure we can trust him to get that part correct. ;D sumgai |
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Post by sumgai on Feb 14, 2007 21:49:43 GMT -5
hmm, i have read, that the output transformer in almost all guitar tube amps would eat frequencies that high anyway.[/size][/quote] .....
Yeah, there are often ultrasonic osculations (inadvertent internal feedback) in amps that do heat up the loads (and the plate(s)). You'll oft see plate-to-plate or plate-to-common bypass caps in tube amps to suppress this. Nope on both accounts. I'm not speaking to HF oscillations, those are a product of tube capacitance, and Chris has illustrated quite correctly how they are handled. I'm speaking of raw harmonics. If enough power is used to amplify a signal that is even slightly distorted, then there will be enough HF harmonics that will get through the output transformer. While coils in general tend to suppress higher frequencies, they are not perfect in their execution of this - some amount will still get through. sumgai |
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Post by sumgai on Feb 14, 2007 21:53:27 GMT -5
.......
There aren't many guitar speakers over 8" in diameter that CAN be damaged by 5 watts. Size won't matter as to whether or not a speaker can be damaged. In point of fact, the larger it is, the less likely the cone can respond quickly enough. After all, Mass is. In turn, the unyielding cone fails to heed the voice coil's attempt to move it. Said VC will suffer the consequences, and heat is the result. Don't ask me how many speakers I've replaced, repaired, or even reconed, I've seen just about all of it.  sumgai |
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Post by vonFrenchie on Feb 15, 2007 18:12:47 GMT -5
I really dont mind if the channels end up blending together. The sounds made from them will be different enough to gain the effect I want. I just dont want any damage to my speakers, cab, or amp heads.
Oh Sumgai, about that "on average 5 watts or so from the amp" thing. If my amp puts out 5 watts per speaker each speaker would be pushing roughly 108 to 109 dB. Thats loud enough... not for Manowar (which my speakers happen to be named after... coincidence I think not)
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Post by sumgai on Feb 16, 2007 1:51:25 GMT -5
...... 5 watts per speaker each speaker would be pushing roughly 108 to 109 dB. Thats loud enough. Oh yeah, it definitely is loud enough! Taken in context with: ..... And at that, I mean to say, you're definitely louder than comfortable here. I'd say that 108 to 109 dB definitely qualifies for The Uncomfortable Zone. ;D But I'm curious, could you please cite your references (or sources) where you got the 5w = 108dB figures? Thanks. sumgai |
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Post by sumgai on Feb 16, 2007 1:54:09 GMT -5
I really dont mind if the channels end up blending together. The sounds made from them will be different enough to gain the effect I want. And of course, you can always mic the individual speakers, running them to two different PA channels, one panned to each side. Or, you could build the cabinent with a divided front board, the two halves angled away from straight ahead. sumgai |
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Post by sumgai on Feb 16, 2007 2:00:30 GMT -5
......
I dont plan on turning a single head past 12 oclock. These are conflicting statements! And of course, the best laid plans of mice and men, and all that...... Trust me, you will suffer from Crank Syndrome, until you turn it up, all the way to 11! sumgai |
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Post by vonFrenchie on Feb 16, 2007 13:40:38 GMT -5
Well... Ive only turned my peavey amp up to about 2 oclock ONCE. It was WAY to loud. I think that when the cab moves across the floor... its too loud... way too loud.
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Post by sumgai on Feb 16, 2007 14:06:07 GMT -5
Frenchie,
It only moved on its own accord? That's all? Hell's bells, my amp can fluff the pillows
.........
.........
.........
.........
over at the neighbor's house!
sumgai
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Post by vonFrenchie on Feb 16, 2007 15:06:37 GMT -5
Well the cab moved... the stuff in the fridge (ten feet away) rattled around. My and my dvds fell off the shelf. Also my dog was freaking out for 20 minutes... so were the neighbors dogs. Our neighbors probably would have called the cops if i went anywhere near full volume. Thats a different adventure.
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Post by sumgai on Feb 16, 2007 15:10:52 GMT -5
Well the cab moved... the stuff in the fridge (ten feet away) rattled around. My and my dvds fell off the shelf. Also my dog was freaking out for 20 minutes... so were the neighbors dogs. Our neighbors probably would have called the cops if i went anywhere near full volume. Thats a different adventure. Never invite the cops to a party, it always ends in tears! sumgai |
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Post by vonFrenchie on Feb 16, 2007 16:30:30 GMT -5
I wouldnt be so sure of that. My brother-in-law is a cop. Im sure he wouldnt mind if I blasted The Ocean. Now my sister would, shes an audiologist.
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Post by UnklMickey on Feb 16, 2007 18:48:41 GMT -5
what does how loud you play, have to do with the study of German automobiles?
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Post by vonFrenchie on Feb 17, 2007 1:10:41 GMT -5
nice.. it took me a while to get it... but nice. An AUDI-ologist.. haha. apparently Audis and ears have alot in common.
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popjinx
Rookie Solder Flinger
Posts: 3
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Post by popjinx on Jul 16, 2007 13:59:29 GMT -5
I purchased a valve junior head for the chassis. I put a new turret board (turretboards.com) and Mercury Magnetics transformers. I mounted a new Alnico blue speaker in a old Peavy 1-12 cabinet. It keeps up with a loud drummer at what I believe is only 5 watts. It distorts pretty early (around 10 o'clock). You can mod one much cheaper than I did using the existing circuit board and a Hammond 12DSE output transformer. The above source can even sell components to do the cheap mod ($50+/-). Good choice for getting some good old school tone. One knob... simple! It can get a neighbors attention (positive or negative) played loudly at the wrong time of the day. I think this subject might have had something to do with 18watt.com shutting down  Thanks, Mike |
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Post by sumgai on Jul 16, 2007 16:25:07 GMT -5
popjinx, 18watt.com is now back up and running, give 'em another go. sumgai |
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Post by sumgai on Jul 16, 2007 16:25:55 GMT -5
nice.. it took me a while to get it... but nice. An AUDI-ologist.. haha. apparently Audis and ears have alot in common. The were orginally called that because you could hear them coming a kilometer away! ;D |
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)
But for the most part, one should get close when pairing up speakers and amplifier power ratings. You don't need to "push" a speaker to near its rating in order to prevent mistreating it, but I'm pointing out that just as you don't want to hang a single Craptone 8" speaker from a Fender Princeton onto a 200 watt Marshall Major head, you also don't want to saddle a Valve jr. with two 4x12" cabs for any length of time at high volumes. (The reason for that was explained in my previous post, above.)
