Strange observation & question...

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Corium_AZ

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Ok, so I often play my RM100 thru my 'silent rig' - amp output to THD hotplate (used as loadbox) direct out to audio interface, to reaper & cab IR's. I monitor on headphones... In any case, I noticed tonight while re-amping some previously recorded DI tracks, that I could hear a faint output of the amp, behind the amp, eminating from around the RM's preamp tubes (V1, PI & FX loop 12ax7's). By this I mean, while the track was playing thru the amp (and subsequently being recorded), it sounded like there was a tiny speaker inside my amp enclosure playing a faint reproduction of what the amp was actually outputting. Also of note, the volume of this little 'speaker' did go up and down along with changes to the master volume. I swapped out all my preamp & power tubes to ensure it wasn't a microphonic tube acting as a 'speaker', this changed nothing. Anyone else ever experience this? Obviously I'd have never heard it if I were actually playing the guitar at the same time as the sound is so faint. Very strange... Should I be concerned at all or is this somehow normal? And if it's normal (or not I suppose), can someone please explain to me why it does this? Curious now....
 
Also, you can actually get sound reproduced by the output transformer.
Get a "mechanic's stethoscope" or a real one, and probe around.
You can also use a long screwdriver and touch the tip of the screwdriver to what you think is making the sound and put your ear on the end of the handle.
 
Corium_AZ said:
Ok, so I often play my RM100 thru my 'silent rig' - amp output to THD hotplate (used as loadbox) direct out to audio interface, to reaper & cab IR's. I monitor on headphones... In any case, I noticed tonight while re-amping some previously recorded DI tracks, that I could hear a faint output of the amp, behind the amp, eminating from around the RM's preamp tubes (V1, PI & FX loop 12ax7's). By this I mean, while the track was playing thru the amp (and subsequently being recorded), it sounded like there was a tiny speaker inside my amp enclosure playing a faint reproduction of what the amp was actually outputting. Also of note, the volume of this little 'speaker' did go up and down along with changes to the master volume. I swapped out all my preamp & power tubes to ensure it wasn't a microphonic tube acting as a 'speaker', this changed nothing. Anyone else ever experience this? Obviously I'd have never heard it if I were actually playing the guitar at the same time as the sound is so faint. Very strange... Should I be concerned at all or is this somehow normal? And if it's normal (or not I suppose), can someone please explain to me why it does this? Curious now....
That's so weird. This literally just started happening to my amp two nights ago. Same type of setup and everything. :?
 
For the benefit of those searching for this in the future, or those currently inquiring, I pm'd rob about this, and here is his RE:

Believe it or not, that's 100% normal. All output transformers will do that to some degree and it takes a special set of circumstances to ever hear it, as the speakers typically drown it out. It happens more with a resistive load like your hotplate than with an inductive one. If the transformers aren't getting hotter than normal all is well.

Once again, thanks rob! Your the man.
 
kc2eeb said:
Should I just stop posting?

No man, lol, rob replied right away, I just didn't get round to posting his RE for a couple days. I didn't see that anyone had answered until I already posted it... You got it though!
 
Thanks! I needed that. Reason I mentioned the reverb spring box is that you can hear the sound in the springs when a signal is going through.
 
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