analogman Posted March 12, 2004 Share Posted March 12, 2004 Gentlemen, Will damage occur to a tube amp if it is powered up with no load on the taps and no input signal present?I am asking this in the context of doing so to burn in new circuitry,tubes etc.Even if there are better ways to do this would/could this practice cause damage or compromise components ie:output transformers? Thank You, Analogman Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 12, 2004 Share Posted March 12, 2004 That is a good question, I have HEARD that one should not operate an output transformer without a load somewhere in the very distant past. This of course is assuming some amplification is happening. However, your question is referring to an amp at idle with no signal. There is no reason that the amp would be bothered as long as it is not amplifying anything, and thus, no current through the xformer. But that being the case, what would you be accomplishing in the tubes themselves other than applying some hours to the heater elements. The other elements (grids, etc) will not be subject to "burn in" without a signal... at least not enough to make a difference, I would think... DM Quote Link to comment Share on other sites More sharing options...
analogman Posted March 12, 2004 Author Share Posted March 12, 2004 D-Man, Thank you for the response.Maybe it's a meaningless ritual but whenever I change anything I like to "put some heat on it" before I run a signal.With regard to your observation I'll expand the question;same scenario but using a signal,white noise,pink noise,test tone disc etc.It's probably obvious by now I've already done this in practice in the past.I'm just a "worrier king" and am looking for more insight than the cliche "sounds OK is OK".Thank you again for your time! Analogman Quote Link to comment Share on other sites More sharing options...
WMcD Posted March 12, 2004 Share Posted March 12, 2004 I would say there is no problem. The output, secondary, winding of the transformer only "sees" a load when there is an a.c. waveform input to the primary. Without that, the secondary coils are just sitting there; dumb, fat, and happy. Gil Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 12, 2004 Share Posted March 12, 2004 I have not really noticed a "burn in" type of improvement in my tube gear after changing out driver tubes. But that is not to say that there isn't one... I would not think that there is any harm to doing what you are thinking about. If it was me, I wouldn't turn the volume up very much, as the current has to go somewhere and I think it would be in the form of heat (in a no-load situation) from the xformer resulting from the lack of current flow on the secondary winding (the speaker side) which was what I originally heard long ago. I am not sure if it is really correct or not. DM Quote Link to comment Share on other sites More sharing options...
analogman Posted March 12, 2004 Author Share Posted March 12, 2004 Thanks again Analogman Quote Link to comment Share on other sites More sharing options...
WMcD Posted March 14, 2004 Share Posted March 14, 2004 Yes, I'm quite convinced that Ryan is correct. But his comments have given me pause; predicting horrors, and no horrors. When everything is quiesent, and with no load, there should not be a problem. But what about when the amp is turned on, or off, without a resistive load. Probably bad things could (could!) happen with the transients of turn on, and off. On the other hand, 35 years ago or more we were dealing with mostly tube amps. Some of us today too. At least then it was not uncommon to turn on an amp, no sound came out, and then we'd discover there was no load . . . for whatever reason. Typically the speaker wiring was wrong. From those days, I don't recall any warning that the output transformer or tubes would be fried. There is some chance that operation without a load on a repeated basis, eventually caused premature failures in the long run. If anyone has an operating manual for a tube amp, it would be interesting to learn what the manufacturers think. Nontheless, it just make sense to operate an amp with a load. But no load conditions do occur. It may not be necessary to break out in a sweat and check the prices of replacements on the first mishap. Gil Quote Link to comment Share on other sites More sharing options...
analogman Posted March 14, 2004 Author Share Posted March 14, 2004 Thank you, Analogman Quote Link to comment Share on other sites More sharing options...
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