what is wrong with my amp?

[Thatupstateguy]

As for the original question in this thread,..... it could be lots of things, ...from loose solder connections to bad tubes,.....

For my two cents worth,...... start simple and work up,... meaning,...

start by jiggling parts,.... cords first, could be a jack,.... then switches,... volume, tone controls,... then jiggle,... or just move the tubes in their sockets,.... do not worry about fingerprints,.... not really an issue,....

if crackle gets worse, or changes with any of the above,... you found the part that needs work,.... if not,... then take it to a guitar amp tech,..... you have exhausted the non-tech methods of locating problems,.....

Touching the tubes with extreemly dirty hands, or grease,.. will indeed shorten their life,.... but since they last about 10,000 hours or more,.... under normal use,... that is if they are good quality to start with,....then shortening their life by a few hours is no big thing,...... unless you are talking about something like a 300B Western Electric or something like that,.... (they go for about $400 ea) and it is just a normal easily replacable, and available tube,... 6L6,12AX7 or some other common one,... don't sweat it,..... so you will lose a days use over 15 years ,....... if you touch it and leave a print,.....

I have changed tubes on hundreds of amps,./.. and never once used anything but bare hands,....

as for the crackle sound,.... I recently had an amp that did the same thing,..... it was loose soldering on the tube sockets,......

from trying out so many different tubes,......


Get new old stock if you can,.... old RCA, or Phillips,..... Mullards or Telefunken if you can afford the best...


GT is making some big strides in tube designs, and is also worth a look,....


Steve

 

[Outlaws]

so you will lose a days use over 15 years

ummmm.....you should play your guitar a bit more.





Or get a lower watt amp so you can crank it. My power tubes never last over a year.

 

[Thatupstateguy]

Ouylaws,.... I don't know what you have for an amp,.. or what it uses for power tubes,... but if you play thru it for 5 hrs a day for 10 years straight, you might wear out some decent quality tubes,..... they are meant to last at least that long,.....

I have pulled tubes from 30 year old amps that are stonger than new Groove tubes, or svetlanas,.....

Sovteks and some other 'new' tubes pale in comparison to say,.... Telefunken, or Brimer, or Amperex from Holland,.....or Mullards,.... that is precisly why they are sought after, and even used demand a higher price,... they are absolutely better tubes,...... VERY long life,... and even used are very often stronger, and sweeter sounding with booming lows, and crystal clear highs,.....than newly produced any brand.....

Russian,Chinese, or domestic simply cannot touch NOS for that very reason....


I think personally that if you are losing fidelity after only a few hundred hours of playing you have something other than weak tubes goin on,... heater voltage too high, plate voltage too low,.... or something,.... they absolutely should not wear out that quick.......



I have a couple of Siemans, EL84s that are used, and test very well,.... strictly a loaner for comparison purposes, I will send em to you so you can hear for yourself,....


that is ....of couse,.... assuming you are using an EL84 based amp


Steve

 

[Outlaws]

Well, most tubes are not meant to last when amps are cranked to 10 all the time.

I was under the assumption that power tubes are only supposed to last a year...maybe two. I know I have yet to need to replace a preamp tube, but power tubes seem to blow out on me. Maybe it was just my Blues Jr (which I already sold) but I just got a ProJunior and I am just expecting the same. If it was just my amp then that will be great. I want to buy some nice NOS tubes, but so far have yet to feel like they will last long enough.

I have a Super Reverb that I got a little over a year ago. I haven't had to replace those tubes yet, but I don't get to playout at full boar with it that much either. But those are the tubes I am really interested in swapping. I heard that the Mullard recifiers are some of the best around...but at $100 a pop, I don't want to go too far. That is my first amp with a tube recifier, so I am still clueless how long those tubes last.

Thanks for the offer to try out your tubes, but I couldn't do that.

 

[Thatupstateguy]

Outlaws,.... I have over 30 used old bottle shaped RCA 6L6s,.... and several of the same, rectifier tubes,..... so if you have an amp that uses those types,...(the rectifiers are 5U4s), just gimme your snailmail, and I will send you some to try,.... they are at least 40 years old,.... and test very strong,... so,....



As for your questioning the life of any tube,... they should ALL last for a lifetime basically,.... over 40 years for most,....


to 're-new' the average tube,.... just run it at double the heater voltage rating for about 3-6 minutes, and the excess coating of stuff is burned off,.... and Voila, you have renewed the tubes for another 10-15 years,....


all a tube does, is to emit electrons and collect them on another surface,.... that action, re-action is based on what the plates are made of,... how thin, or thick they are,... what the cathode is made of,... and how hot they are run,...... that is pretty much the story,.....


Pre-amp tubes can be changed without doing anything to your amp, other than powering down,....and back on,.... all of the 12--7 series will work as well as the military or european versions, IE:7025,5751,ECC81-82-83, etc....

When it comes to the power tubes tho,... some 'boutique' amps, and others are a bit more sensitive when it comes to swapping tubes,.....I would ask an amp techfirst,....

altho,..... my 50 watt 'Univox' , I have changed power tubes MANY times with no ill effects at all,....It is an older,(1969) 6L6 based amp....

most of the older designs can be that way,....very simple, basic designs,....

VERY little to worry about and no trouble with bias adjusting at all.....


let me know on the RCAs,... be happy to pass on the knowledge,...and ship you some if they will work in your amp..... and by the way,..... the tubes you swapped out of those amps are probably still good,.... just need to be re-newed via the method I have described above.....


Steve