strange voltage ??

missing_dave · June 16th, 2007, 01:09 PM

bear with me on this one..what would the effect be on a tube amp when your plugged into a circuit (wall) with too many amps etc.( the breaker doesnt blow) but it seems like its drawing "to much" i notice once and awhile my super reverb sounds "different" and not cause of the room...we try to split up stuff on different circuits but sometimes ya just cant..anyone notice there amp sounding just "off" ?? almost like the more i dig in /add a boost etc it gets a "sag" ?? also i run it clean so its not amp breakup and usually within the same volume # on the amp range.
sorry for the lack of terms etc. but been really bugging me.. thanks for reading

Schnauzer · June 16th, 2007, 04:53 PM

Missing Dave:

After 21 years of doing casuals in every kind of situation you can think of from a nudist colony to cattle drives, homes, clubs, dives, theaters, indoors, outdoors, secluded island with generator power.....you get the picture. The changes you describe happened to me many times and often changed throughout a performance. I noticed a dramatic change at a job one night and traced it to two very large coffee makers that had been turned on at 1am. Voltage drop or variation may be your culpret (sp)

I began using a Fuhrman power conditioner on the pa rack and for my amp. Helped a lot. I found that if we were in a situation where there was variation in voltage that the dynamics of my amp went away. Amplification of low frequencies takes more power. My theory is that we are less able to hear the differences in the lows though and find that the highs suffer. At least we hear it that way. Voltage fluxuations can be very hard and even distructive to digital gear.

I am reporting my experiences but am not an expert on AC. I am certain there are people here on the TDPRI that can and will add some technical expertise to this subject. Perhaps you could start by measuring voltages with a digital meter prior to setting up and then again when you notice the changes. Would be good place to start. You would then know if there was a drop once everyone got up and running.

Hope this helps a little.

Jim

EMan · June 16th, 2007, 07:13 PM

Certainly, the line voltage effects te amp. Potentially, the more critical is the filament voltage that heats the tube's cathodes. Colder or hotter cathodes alters their 'thermionic emission' characteristics, and most likely, the sound.

I used a UL Twin for most of my stage days, and they aren't really affected by anything...but I have noticed, as mentioned above, the same type changes in most every other amp at various times.

missing_dave · June 17th, 2007, 07:24 PM

thanks Schnauzer really both of you..i will start measuring the voltage..maybe a used furman with the readout? i wasnt sure if i was thinking something weird here?? its hard with a tube amp to know . i almost couldnt tell if it could be tube related. its funny cause after posting this and playing two more shows this week it was "weird " at both places so maybe (although they were just changed and tuned up by my amp guy) one could be beat down ?????not that the voltage issue doesnt happen...

if you dont mind me hijacking my own thread

what kind of issue could this be:
loss of sustain
"tone" seems to degrade in quality after amp has been on for awhile

like i said its been retubed tuned up..sounded amazing to me then just went downhill ?? FYI its been recapped etc. very reputable amp guy..just tryin g to figure a bit on my own after all it just came from the shop..im broke
thanks sorry im all over the place on this stuff

June 16th, 2007, 01:09 PM	#1 (permalink)
missing_dave Tele-Meister Join Date: Dec 2005 Location: Boston, MA Posts: 127	strange voltage ?? bear with me on this one..what would the effect be on a tube amp when your plugged into a circuit (wall) with too many amps etc.( the breaker doesnt blow) but it seems like its drawing "to much" i notice once and awhile my super reverb sounds "different" and not cause of the room...we try to split up stuff on different circuits but sometimes ya just cant..anyone notice there amp sounding just "off" ?? almost like the more i dig in /add a boost etc it gets a "sag" ?? also i run it clean so its not amp breakup and usually within the same volume # on the amp range. sorry for the lack of terms etc. but been really bugging me.. thanks for reading

June 16th, 2007, 04:53 PM	#2 (permalink)
Schnauzer Tele-Meister Join Date: Apr 2005 Location: Coeur d'Alene Idaho Age: 61 Posts: 158	Amp Changes Missing Dave: After 21 years of doing casuals in every kind of situation you can think of from a nudist colony to cattle drives, homes, clubs, dives, theaters, indoors, outdoors, secluded island with generator power.....you get the picture. The changes you describe happened to me many times and often changed throughout a performance. I noticed a dramatic change at a job one night and traced it to two very large coffee makers that had been turned on at 1am. Voltage drop or variation may be your culpret (sp) I began using a Fuhrman power conditioner on the pa rack and for my amp. Helped a lot. I found that if we were in a situation where there was variation in voltage that the dynamics of my amp went away. Amplification of low frequencies takes more power. My theory is that we are less able to hear the differences in the lows though and find that the highs suffer. At least we hear it that way. Voltage fluxuations can be very hard and even distructive to digital gear. I am reporting my experiences but am not an expert on AC. I am certain there are people here on the TDPRI that can and will add some technical expertise to this subject. Perhaps you could start by measuring voltages with a digital meter prior to setting up and then again when you notice the changes. Would be good place to start. You would then know if there was a drop once everyone got up and running. Hope this helps a little. Jim __________________ Jim - "You boys doesn't play none of that narcotic music do ya?" The Clayton Club 1984

June 16th, 2007, 07:13 PM	#3 (permalink)
EMan Tele-Holic Join Date: Apr 2003 Location: Dallas, Texas Posts: 939	Certainly, the line voltage effects te amp. Potentially, the more critical is the filament voltage that heats the tube's cathodes. Colder or hotter cathodes alters their 'thermionic emission' characteristics, and most likely, the sound. I used a UL Twin for most of my stage days, and they aren't really affected by anything...but I have noticed, as mentioned above, the same type changes in most every other amp at various times.

June 17th, 2007, 07:24 PM	#4 (permalink)
missing_dave Tele-Meister Join Date: Dec 2005 Location: Boston, MA Posts: 127	thanks Schnauzer really both of you..i will start measuring the voltage..maybe a used furman with the readout? i wasnt sure if i was thinking something weird here?? its hard with a tube amp to know . i almost couldnt tell if it could be tube related. its funny cause after posting this and playing two more shows this week it was "weird " at both places so maybe (although they were just changed and tuned up by my amp guy) one could be beat down ?????not that the voltage issue doesnt happen... if you dont mind me hijacking my own thread what kind of issue could this be: loss of sustain "tone" seems to degrade in quality after amp has been on for awhile like i said its been retubed tuned up..sounded amazing to me then just went downhill ?? FYI its been recapped etc. very reputable amp guy..just tryin g to figure a bit on my own after all it just came from the shop..im broke thanks sorry im all over the place on this stuff