Members Fear My Potato Posted December 25, 2005 Members Share Posted December 25, 2005 I'm chopping an old electronic organ from the 1970s that should go relatively easily. But in order to conserve space and weight, I want to remove the twelve inch woofer, eight inch mid, and tweeter from the thing. Is it as simple as just disconnecting the speakers and leaving the wires capped, or will this cause issues with the poweramp? It has a dedicated 1/4 inch output that I plan on using...I should be able to remove the speakers and still use the 1/4 output no problems, right? Link to comment Share on other sites More sharing options...
Members bbach Posted December 26, 2005 Members Share Posted December 26, 2005 You won't have any problems as long as you make sure the wires are capped. The signal will go nowhere without a place to go, so no speakers = no signal path. The 1/4 out should not be affected. Link to comment Share on other sites More sharing options...
Members Fear My Potato Posted December 26, 2005 Author Members Share Posted December 26, 2005 Right on. I read this response and tried it...kept the organ plugged into an outboard amp and disconnected the speakers. Still works no problem. Just in case anyone was curious lol Link to comment Share on other sites More sharing options...
Members where02190 Posted December 26, 2005 Members Share Posted December 26, 2005 Leaving an amp with no load is a big no no, and you'll end up with at minimum a smoked amp in short time. Should it share a power source with the rest of the organs electronics, it could render it nonworking. remove the amp circuit as well, since you don't appear to be planning on using it. Link to comment Share on other sites More sharing options...
Members piano39 Posted December 26, 2005 Members Share Posted December 26, 2005 where02190 is right. Never run an amplifier without a load (speakers) attached. You can blow out the output transistors of the power amp. Some amplifiers have built in protection for this, but there is no way for you to know if yours does or not. If it's an old organ from the '70s, my hunch is that it does not have protection. Link to comment Share on other sites More sharing options...
Members the stranger Posted December 26, 2005 Members Share Posted December 26, 2005 What about a dummy load/power brake? Link to comment Share on other sites More sharing options...
Members where02190 Posted December 27, 2005 Members Share Posted December 27, 2005 Dummy load would be fine, but it's a whole lot cheaper and easier to simply disconnect the amp. Link to comment Share on other sites More sharing options...
Members bbach Posted December 27, 2005 Members Share Posted December 27, 2005 I don't think there's going to be a problem. I'm not so sure the amp in the organ operates like a guitar amp. In the electronic store I ran we frequently had amps running without speakers hooked up in order to use the headphone out jacks. I don't know if the 1/4 outs are run from the amp or pre-amp section. If you disconnect the amp, you may not get sound through the outs. I guess you can try it but the dummy load may be the way to go if blowing the amp is a concern. I decided to post a question to Miles at the MP forums and see what's up with this. Guess I've heard that damage can occur but never had a problem in ten years of running amps with no speakers. A Google search gave me nothing. Link to comment Share on other sites More sharing options...
Members where02190 Posted December 27, 2005 Members Share Posted December 27, 2005 Most all amps with hp amps have bypass circuitry so when you use the hp out you are NOT using the amp for the speakers, otherwise it would make using the headphones moot. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted December 27, 2005 Share Posted December 27, 2005 Originally posted by where02190 Most all amps with hp amps have bypass circuitry so when you use the hp out you are NOT using the amp for the speakers, otherwise it would make using the headphones moot. Yup. No resistance load is the same thing as a dead short, and the amp will fry under those circumstances. Either pull the amp or use a suitable dummy load with the proper ohm rating and of sufficient power handling capability to deal with the wattage of the amp in question. BTW SOME amps have a dummy load built into them. My THD Univalve does. But it's always safest to presume that the amp in question DOES NOT have one, unless you're absolutely certain (RT#M is usually the best way to find out ) that the amp is so equipped, and you've got it set up to use that feature properly. Link to comment Share on other sites More sharing options...
Moderators MrKnobs Posted December 27, 2005 Moderators Share Posted December 27, 2005 Solid state amps DO NOT need a load, period. Tube amps do. Terry D. Link to comment Share on other sites More sharing options...
Members bbach Posted December 27, 2005 Members Share Posted December 27, 2005 Originally posted by MrKnobs Solid state amps DO NOT need a load, period.Tube amps do.Terry D. There Terry, that's what I was seeking! Somewhere back in my memory banks on some dusty shelf was that very thought. This thread was annoying me because I could not get the information out of the closet. The thing that still troubles me is why is it a problem at all? I see electronics as a completed circuit. With the circuit interrupted, I don't see a load at all. Link to comment Share on other sites More sharing options...
Members bbach Posted December 27, 2005 Members Share Posted December 27, 2005 Originally posted by Phil O'Keefe No resistance load is the same thing as a dead short, and the amp will fry under those circumstances. I'm definately going to have to do some study on amplifiers, because I don't see a load as being any load at all without a completed circuit. Take house wiring for example. I can take out a light fixture and cap the wires and there is nothing that is going to blow, even if that fixture is the only load on that circuit. So, how do you create a no resistance load without a completed circuit, ie speakers? Link to comment Share on other sites More sharing options...
Members franknputer Posted December 27, 2005 Members Share Posted December 27, 2005 I did find a mention at Yorkville's site that says this:It would seem to follow that solid state amplifiers might be able to deliver more than their rated power if you connected them to very low impedances. But we all know that this is not the case - especially if we've had an amp shut down or, Heaven forbid, blow up because the speaker load was too low. What happens is, the amp actually tries to put out more power than it was designed to deliver. It overheats in the process and will self-destruct if it has no thermal protection circuitry to shut it down or otherwise limit its activity. Conversely, amps are not harmed when connected to high load impedances; their maximum output is simply reduced. And when a solid-state amplifier is connected to no speakers at all, in other words an infinitely high impedance, it won't put out any power at all, it just takes a holiday.[Tube amps are very different in this regard. They will self-destruct if run with no load connected]. http://www.yorkville.com/default.asp?p1=6&p2=17&p_id=25 So, assuming that it is not a tube amp (it wasn't specified in the original post - folks, you should be specific if you want good advice!) then it's probably OK. That said, remember that a) early 70s electronics probably do not have the same safeguards as modern ones, and b) running it with an active amp & wires in place still leaves a potential hazard - if one of the wires should ground, or they get crossed somehow, then you WILL have a problem, Houston. If you're simply not going to use it, the safest thing would be to disconnect the amp, if that's possible. Link to comment Share on other sites More sharing options...
Moderators MrKnobs Posted December 27, 2005 Moderators Share Posted December 27, 2005 Originally posted by bbach I'm definately going to have to do some study on amplifiers, because I don't see a load as being any load at all without a completed circuit. Take house wiring for example. I can take out a light fixture and cap the wires and there is nothing that is going to blow, even if that fixture is the only load on that circuit. So, how do you create a no resistance load without a completed circuit, ie speakers? No load is NOT the same thing as a short. Maybe what Phil was talking about was tube amps. Still not right, except in the sense that both are trouble. Tube amps need a load connected because they use an output transformer. Unless the secondary of the transformer is loaded high back EMFs can be generated that will compromise the insulation within the transformer, eventually. It's better for a tube amp to drive too low an impedance (within reason) than too high of one, the exact reverse of transistor amps. Terry D. P.S. One could, I suppose, make the case that running a solid state amp with an output transformer might not be a good idea for the same reason. However, it has been a very long time since I've seen a transformer in a solid state amp (other than for the power supply), much less an output transformer. Besides, tube amps run at much higher voltages than transistor amps, which makes the back EMF thing unimportant. Link to comment Share on other sites More sharing options...
Members bbach Posted December 31, 2005 Members Share Posted December 31, 2005 Keep the speakers connected. It is NOT the same as a light bulb. We are talking DC here, not AC, and once you take the amp out of standby or have B+ on the plates of the output tubes they are running whether there is input signal or not. They need a load and the load is the output transformer in a balance WITH the speaker. No speaker No balance - blown output transformer (maybe the most costly component in the amp). --------------------Myles S. Rose (posted on the mp forums - thank you Miles)bbach Link to comment Share on other sites More sharing options...
Moderators MrKnobs Posted December 31, 2005 Moderators Share Posted December 31, 2005 Originally posted by bbach Keep the speakers connected. It is NOT the same as a light bulb. We are talking DC here, not AC, and once you take the amp out of standby or have B+ on the plates of the output tubes they are running whether there is input signal or not. They need a load and the load is the output transformer in a balance WITH the speaker. No speaker No balance - blown output transformer (maybe the most costly component in the amp). -------------------- Myles S. Rose (posted on the mp forums - thank you Miles) bbach This only applies if he has a tube amp, not a solid state amp. My post also explains why a tube amp needs a load, and a solid state amp does not. So far as I can see above, he's never said whether the amp is tube or solid state? Terry D. Link to comment Share on other sites More sharing options...
Members bbach Posted December 31, 2005 Members Share Posted December 31, 2005 I'm with you Terry. I posted Miles response but see that you have offered pretty good info. I agree on the solid state issue. I've run many a solid state amp without speakers connected. Miles is a most excellent source for tube amp info. I have querried many a question his way. Great person also. Link to comment Share on other sites More sharing options...
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