ProSoundWeb Community
Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Mike Sokol on March 10, 2014, 07:59:55 AM
-
You're gonna love this. When one of my seminar students tried to get the guitar player at his church to turn down the volume on stage, here's the response he got.
Well, there's a "sweet spot" on the amp, you see. He CAN'T turn down the
amp because then it doesn't sound right. It HAS to be at THIS volume for it
to sound right. In fact, it'll TURN OFF due to low signal level if he turns
it any lower. (So he says.) Now what do I say to him? Just food for
thought for your next sound board class.
I've heard a lot of excuses for playing a guitar amp too loud on stage, but never that the amp would "TURN OFF" if it was played too softly. Who knew??? :o
-
Because some of the battery powered units might have a battery saver option and turn off for no activity. ???
Playing loud on stage is a symptom of him wanting to get feedback from the amp?? If he wants to have the guitar and amp to get into a feedback for the song than he will need to have a volume level and proximity of the guitar to the amp to get the feedback. Does he need to do this from across the stage ?? I hope not.
-
In fact, it'll TURN OFF due to low signal level if he turns
it any lower.
He clearly "understands" how under-powering damages loudspeakers. ::)
-
He clearly "understands" how under-powering damages loudspeakers. ::)
Seriously, some powered speakers (such as Mackie) have an auto power-off button that turns off the internal amplifier after several minutes of inactivity. Had a customer once call me for a service call that his speakers were turning off randomly. Of course, as soon as you send some music to them they come back on.
I'm pretty sure this guitar player has an old-school tube amp which he needs to distort for tonal qualities, and if the speaker is loud and close enough to his guitar then he'll get extra sustain and feedback. I just think it's funny he told the soundguy that his amp would "Turn Off" if played too softly.
-
Not to perpetuate any new myths, but there could be an oxidized switch or jack metal-on-metal contact, where the voltage from playing the amp louder punches through a thin oxide layer and conducts again. Generally after it punches through you can turn down the volume again, but it "could" happen that after sitting for some time (like a week), the amp needs to be turned up at first to pass audio.
JR
-
Not to perpetuate any new myths, but there could be an oxidized switch or jack metal-on-metal contact, where the voltage from playing the amp louder punches through a thin oxide layer and conducts again. Generally after it punches through you can turn down the volume again, but it "could" happen that after sitting for some time (like a week), the amp needs to be turned up at first to pass audio.
JR
I have seen that exact scenario more than a few times, especially on older mixing consoles with ribbon connectors between the channels. I had something like that happen on a missile guidance system back in 1979 with predictably bad results. But if I tell you about it I'll probably have to kill you... ::)
On a different tangent, I was doing a gig at a big church yesterday where they claimed that earlier in the morning a "power surge" caused their media computer and digital mixer to shut down and need to be restarted. They wondered why their SurgeX conditioner would let this "surge" through, but I told them it was more likely an AC power drop-out or brown-out and that a UPS was also needed. They somehow thought a SurgeX would protect them for ALL power conditions, including power outages and low-voltage conditions. Just one more thing their sound system installer left out of the mix. I would NEVER run a modern digital mixing board without a good UPS providing the AC power.
-
Seriously, some powered speakers (such as Mackie) have an auto power-off button that turns off the internal amplifier after several minutes of inactivity. Had a customer once call me for a service call that his speakers were turning off randomly. Of course, as soon as you send some music to them they come back on.
I will bet any amount of money you like that this is not the scenario. I am familiar with gated devices, and avoided buying the JBL PRX500 series boxes for this reason among others, but have never heard of a guitar amp with this function. Even if this did exist, it would certainly open at a level far lower than "face melting."
Either the guitarist is full of it (likely scenario), his equipment is damaged, or he is incompetent - he is using some kind of gate effect, but has his final level knob cranked, etc.
-
I have seen that exact scenario more than a few times, especially on older mixing consoles with ribbon connectors between the channels. I had something like that happen on a missile guidance system back in 1979 with predictably bad results. But if I tell you about it I'll probably have to kill you... ::)
The more likely culprit in consoles (in my experience) are the switch contacts bypassing insert jacks. These switch contacts over time can get dirty/oxidized and cause intermittent and level dependent signal drop outputs.
The same phenomenon can happen from cold solder joints, where the solder doesn't wet the connection and the physical metal to metal connection oxidizes and degrades. Faulty ribbon cables, where the gas-tight insulation displacement contact is not actually gas tight can cause similar symptoms, but there are a few bazillion good ribbon cables out there, and even more good solder joints.
JR
-
I will bet any amount of money you like that this is not the scenario.
I am positive your are correct. It's not a gate or auto-shutdown feature on the amp. It's an emotional shutdown of some type, for sure. ;D
-
I am positive your are correct. It's not a gate or auto-shutdown feature on the amp. It's an emotional shutdown of some type, for sure. ;D
:D
-
Either the guitarist is full of it (likely scenario), his equipment is damaged, or he is incompetent - he is using some kind of gate effect, but has his final level knob cranked, etc.
The guy needs a "toaster" - drive the amp as hard as he wants to get "the sound", but limit the power to the speaker.
I'm amazed more guitarists don't utilize of that kind of device - Don't know they exist? Don't know how to hook them up? I know, they can't dominate the band if they use one.
frank
-
I have seen that exact scenario more than a few times, especially on older mixing consoles with ribbon connectors between the channels.
I have modified just about every Peavey XR600/500/400 within 30 miles of me due to this problem. Hard wiring between the contacts solves it.
It's not the ribbon cable at fault though, it's a build up of oxidisation on the tin plating of the connector contacts.
One of my friends used to get his XR600 working by turning the channel and master volumes up full and shouting into a microphone with no speakers connected, then turn it all down and plug the speakers in!
Steve.
-
The guy needs a "toaster" - drive the amp as hard as he wants to get "the sound", but limit the power to the speaker.
I'm amazed more guitarists don't utilize of that kind of device - Don't know they exist? Don't know how to hook them up? I know, they can't dominate the band if they use one.
frank
I used to build these power-soaks back in the 70's using toaster heating elements (I worked for Corning Glass at the time) and it could tame a 100-watt Marshall down to 10 watts or whatever. But it's hard to convince some stage musicians that they're loud enough out front no matter how good it sounds on stage. IIRC before he was famous Eddie Van Halen used a VariAC on his Marshall amp in small clubs to reduce the voltage down to 90 volts or so. That way he could get output tube saturation at a lower stage volume.
Stage volume is not just a guitar problem, I went through this last month in Evans, GA with a Hammond B3 player and a Leslie. Yikes...
Here's a THD Hot-Plate which looks like a high quality power soak.
-
I have modified just about every Peavey XR600/500/400 within 30 miles of me due to this problem. Hard wiring between the contacts solves it.
It's not the ribbon cable at fault though, it's a build up of oxidisation on the tin plating of the connector contacts.
One of my friends used to get his XR600 working by turning the channel and master volumes up full and shouting into a microphone with no speakers connected, then turn it all down and plug the speakers in!
Steve.
I don't know about the smaller powered heads but yes, the larger ones use the same switching jack as gets used on typical console inserts between the mixer section and amp. One anecdote from a decade plus ago, when those products were under my responsibility. I discovered, after the fact that an engineer at the connector company had changed the plating spec on the switch contacts, in combination with a purchasing agent pursuing some small cost saving. IIRC the cost saving change was to silver plated vs tin plated (?), and while silver should be good, as we all know silver tarnishes and turn black over time. This was brought to my attention over the cosmetic concern that black jack contacts "looked" bad to QA inspectors in the factory, while they appeared to work OK there. When I learned of this I changed it back immediately (and kicked some purchasing a**). Even when optimally plated these switches can become problematic over time if not exercised. I do not suspect that you have any of the silver plated jacks, but even if you do they would be old enough to benefit from replacement.
Rather than jumper across them I would just replace any faulty jacks with new ones. Many millions of these switching jacks are used routinely with quite modest failure rates. Decades later stuff happens.
JR
-
It's not the ribbon cable at fault though, it's a build up of oxidisation on the tin plating of the connector contacts.
One of my friends used to get his XR600 working by turning the channel and master volumes up full and shouting into a microphone with no speakers connected, then turn it all down and plug the speakers in!
I have found that to be a common problem with a lot of equipment, especially if those jacks are rarely used. When they are used more frequently that tend to be self wiping and stay problem free for a much longer period.
Shouting into a channel to get it to turn on is usually some device in the channel that is on the verge of failing. I had a mixer that did this once. Yell into it and it worked just fine until you turned the mixer off. Turned out to be a bad IC.
-
and while silver should be good, as we all know silver tarnishes and turn black over time
Oxidised silver is still a good conductor though. In my boring day job, I deal with products which use screen printed silver inks to produce flexible circuits and medical products on polyester - so I know a bit about silver tarnishing!
When printed silver is exposed such as part of a connector to go into a ZIF socket, we often overprint it with carbon. This is largely a cosmetic thing to keep customers happy as they don't like to see tarnished silver no matter how many times we tell them it's ok!
Rather than jumper across them I would just replace any faulty jacks with new ones.
It's not the jacks I hard wired, it's the inter PCB connections which are on pins and crimp sockets (Molex? - or similar). Cut off the crimps and solder the wires straight to the pins and the problem goes away.
It makes it a bit trickier when something else needs repairing - but invariably, that would be done by me as well!
Steve.
-
I have found that to be a common problem with a lot of equipment, especially if those jacks are rarely used. When they are used more frequently that tend to be self wiping and stay problem free for a much longer period.
Unfortunately insert jacks can sit unused for the life of the product.
Shouting into a channel to get it to turn on is usually some device in the channel that is on the verge of failing. I had a mixer that did this once. Yell into it and it worked just fine until you turned the mixer off. Turned out to be a bad IC.
Sorry but I must disagree... Perhaps an IC pin making a bad connection in a socket, but semiconductor devices do not fail that way. The loud sound punching through is a purely mechanical metal to metal connection, with insulating oxidation layer.
JR
-
Sorry but I must disagree... Perhaps an IC pin making a bad connection in a socket, but semiconductor devices do not fail that way. The loud sound punching through is a purely mechanical metal to metal connection, with insulating oxidation layer.
JR
I agree with your disagreement. I remember something we called "thermal ratcheting" back in the 70's which allowed IC's to walk up out of their sockets due to temperature cycling. When it walked up onto an oxide pad, then you would have a high-resistance failure of some sort. Pushing the IC's back in the sockets would "wipe" the contacts and scrape through the oxide layer, so the circuit could work for another few months or so. This was in mini-computers (remember them?) so we left them on all the time to minimize the problem. The computers that were turned off daily would sometimes fail several times a year, but those that were left on all the time (and at a constant temp) could go for years without a high-resistance failure of this type. I even did a few meter tests on IC legs to confirm this high resistance hypothesis.
-
Either the guitarist is full of it (likely scenario), his equipment is damaged, or he is incompetent - he is using some kind of gate effect, but has his final level knob cranked, etc.
All the above, PLUS, the guy probably has an effects board the size of Ohio and 500 stomp boxes all fighting against each other. The best way to deal with players like this is to either embarrass them or just punch them in the fucking head.
-
All the above, PLUS, the guy probably has an effects board the size of Ohio and 500 stomp boxes all fighting against each other.
-
All the above, PLUS, the guy probably has an effects board the size of Ohio and 500 stomp boxes all fighting against each other. The best way to deal with players like this is to either embarrass them or just punch them in the fucking head.
Don't sugar coat it, Bob! I think your latter solution would be more effective in that most guitarists are way beyond embarrassment.
Per Mike Sokol's pedal-board:
Anyone else find the humor in the fact the center stomp-box is OCD?
frank
-
Anyone else find the humor in the fact the center stomp-box is OCD?
Yes.
From the guitarist whose guitar lead goes from his guitar straight to his amplifier (perhaps with a tape echo sitting on the amp). I have never been a fan of having stuff on the stage floor.
Steve.
-
Yes.
From the guitarist whose guitar lead goes from his guitar straight to his amplifier (perhaps with a tape echo sitting on the amp). I have never been a fan of having stuff on the stage floor.
Steve.
Even more OT, but what kind of tape echo? I recently rebuilt a Roland Space Echo and gave it to my guitar player as a present. Now I'm building him a 7/15 watt tube amp with triode/pentode switching and multiple gain stages and equalization paths. And I'm building in a tube-soak so he can practice in his home studio without disturbing family. Should be able to recreate the tonal and distortion characteristics of all the various amps he played over the last 40 years. But he doesn't need or want 100 watts anymore since small clubs (or churches) and high-powered tube amps don't get along very well. We figure that 7/15 watts and a great speaker/mic is the way to go.
-
But he doesn't need or want 100 watts anymore since small clubs (or churches) and high-powered tube amps don't get along very well. We figure that 7/15 watts and a great speaker/mic is the way to go.
Of the 3 great guitarists I work with regularly, two use Fender Princetons (12 watts), and the other uses a modeler and goes direct. If you play in arenas, you can have as much stage volume as you want. For everybody else, get with the program and choose gear that makes the gig better, rather than ruins it.
-
Even more OT, but what kind of tape echo?
I have a Watkins (WEM) valve (tube) copycat. It's not an old original one though, they brought out a 'retro' valve model in the 1990s.
This sits on top of my WEM 17 watt MkIII Dominator amplifier. Plenty of power for most pubs. If I need a bit more, I use a Line 6 Flextone (modelling amp - 65 watts).
Then for bigger gigs where everything goes through the PA, I go back to the 17 watt WEM.
I am known locally as the only guitarist who gets asked to turn up instead of down!
I also dabble in valve euipment building and have built a few amps but I have also made valve microphone preamps for recording and I made a nine channel all valve mixing desk for a friend a few years ago.
And back in the 1980s, we had a Roland Space Echo for delay in the hire PA system. Brian Setzer uses one too.
Steve.
-
All the above, PLUS, the guy probably has an effects board the size of Ohio and 500 stomp boxes all fighting against each other. The best way to deal with players like this is to either embarrass them or just punch them in the fucking head.
Is it legal to shoot "stoopid guitarists" in the USA? I think we could call it a mercy killing... mercy for us to not put up with such nonsense.
/satire, sarcasm
I love the instrument but find the wacky, voodoo priestess-required, psychiatrist-optional type of player sometimes really difficult to deal with. Not because they're batshit wacky, but because they have no sense of ensemble playing and must have "their tone" even if it sabotages the gig or deafens the rest of the band & audience.
And I've said this before, but guitarists can hear stuff that ain't there when they get all misty-eyed about "my tone." I've stood with string players who can readily demonstrate different tonal palettes, even the most nuanced are discernibly different, but some guitarists hear changes to "my tone" that simply don't exist.
My NYE gig featured a very skilled guitarist who had some awesome sounds... but mostly they didn't work in the arrangements of the songs being performed. Playing by himself, though, I loved what came out of his amp. Surely there can be a balance struck.
/rant
-
I also dabble in valve equipment building and have built a few amps but I have also made valve microphone preamps for recording and I made a nine channel all valve mixing desk for a friend a few years ago.
Veering VERY far OT, I'm threatening to build tube/valve active pickups for an experimental guitar. You can get miniature trioid and pentode tube about as big around as a pencil that were used in hearing aids during the 50's and 60's. The plates need 50 volts and the filaments run on 1.5 volts and they were designed to work from batteries in a pocket hearing aid. Now I can certainly build FET or op-amp pickup and tone circuits instead, but having a guitar with a clear plexi pick guard where you can see the little vacuum tubes glowing inside will be a real hoot. And I'm sure I can make them crunch/distort a bit as well.
-
Veering VERY far OT, I'm threatening to build tube/valve active pickups for an experimental guitar. You can get miniature trioid and pentode tube about as big around as a pencil that were used in hearing aids during the 50's and 60's. The plates need 50 volts
You could probably run them from 48v phantom then! (not the heater though).
Steve.
-
You could probably run them from 48v phantom then! (not the heater though).
Steve.
Yup, that's the plan. If I can make this work I'll publish the plans here for fun. The Brits made a lot of these tubes, as well as the Russians (for fighter jets with hardened electronics that could survive a nuclear EMT pulse). You can find NOS (New Old Stock) hearing aid tubes/valves on eBay for $5 each or so, but of course there's not a lot of practical uses for them. I think that tube-active guitar pickups are just the home for them.
-
Is it legal to shoot "stoopid guitarists" in the USA? I think we could call it a mercy killing... mercy for us to not put up with such nonsense.
/satire, sarcasm
I love the instrument but find the wacky, voodoo priestess-required, psychiatrist-optional type of player sometimes really difficult to deal with. Not because they're batshit wacky, but because they have no sense of ensemble playing and must have "their tone" even if it sabotages the gig or deafens the rest of the band & audience.
And I've said this before, but guitarists can hear stuff that ain't there when they get all misty-eyed about "my tone." I've stood with string players who can readily demonstrate different tonal palettes, even the most nuanced are discernibly different, but some guitarists hear changes to "my tone" that simply don't exist.
My NYE gig featured a very skilled guitarist who had some awesome sounds... but mostly they didn't work in the arrangements of the songs being performed. Playing by himself, though, I loved what came out of his amp. Surely there can be a balance struck.
/rant
It's called the guitar solo... :-)
JR
-
Yup, that's the plan. If I can make this work I'll publish the plans here for fun. The Brits made a lot of these tubes, as well as the Russians (for fighter jets with hardened electronics that could survive a nuclear EMT pulse). You can find NOS (New Old Stock) hearing aid tubes/valves on eBay for $5 each or so, but of course there's not a lot of practical uses for them. I think that tube-active guitar pickups are just the home for them.
I officially do not approve feeding the madness. Why not add a LED and tell them it's a tube. :-)
Back a couple decades ago I designed a "DIC" A direct injection cord, that was a phantom powered JFET buffer/preamp built into the barrel of a 1/4" guitar plug. This JFET front end was low noise and high impedance so we could get all the HF content and edge the guitar pickup was capable of, cleanly.
While I was able to get the guitar input clean and accurate, it generally sounded very thin, because the guitar interacts with the guitar amp significantly to develop it's full "sound".
JR
-
I officially do not approve feeding the madness. Why not add a LED and tell them it's a tube. :-)
JR
Like this Yamaha THR guitar amp with Orange-Glow LEDs and no actual tubes? ;)
-
Like this Yamaha THR guitar amp with Orange-Glow LEDs and no actual tubes? ;)
And Yamaha was not the first or only manufacturer to do that... Conversely at Peavey I recall having some actual tube products designed to be used with guitars that we couldn't give away.
One very nice simple 4 input tube mixer was intended for combining a few pedal effects between a guitar and amp, using an all tube path. I got involved when these became slow moving inventory that I had to figure out how to get rid of. ::)
They were too clean to sell as a tube sonic effect. I tried to dirty them up some by increasing the gain. No love for real tubes.
JR
-
Yup, that's the plan. If I can make this work I'll publish the plans here for fun. The Brits made a lot of these tubes, as well as the Russians (for fighter jets with hardened electronics that could survive a nuclear EMT pulse). You can find NOS (New Old Stock) hearing aid tubes/valves on eBay for $5 each or so, but of course there's not a lot of practical uses for them. I think that tube-active guitar pickups are just the home for them.
Not much different to the valves in Neumann (and other) microphones: http://www.saturn-sound.com/Curio's/what%20valve%20in%20what%20microphone.htm
Steve.