is this a sign of tubes getting ready to need changin' ?

tone4days

tone4days

Heel Whacker
i generally like the tone of my modded BluesJr - i dont *love* it as the end all and be all of tone, but it is quite versatile and satisfying enough with both my EJ strat and my PRS SC245 ... but when gigging (i.e. louder than rehearsals) i notice that my tone becomes really unpleasing in the late 2nd and 3rd sets (i do not turn it off beween sets) ... like it is straining and grinding and choked ... low mids and bass fading away ... and all sustain is gone to hell ... even with the zendrive pedal in front, it just doesnt get it done ... but when i turn it on at the beginning of the next gig (say, a few weeks later) it is right back to its former self respondig the way i want it to

so my obvious thought is that it is heat related and as the night wears on it gets hotter and tone goes south ... we dont play that loud (in fact, i think we are kinda wimpy) so the amp is not full up cooking at all ...

so is this an intrinsic sign of the amp needing new tubes - and if so, power, pre, or all? ... or is it something deeper in the amp that is suspect?

thoughts?

thanks
t4d
 
Re: is this a sign of tubes getting ready to need changin' ?

Do you wear any hearing protection? I thought i was having the same problem with my VK a while back. we would practice for several hours and the sound became very raspy, piercing feeling and sounding. I started recording practices when i listened to the to playback and it was consistent all the way through. no real change in the amp. My thought is hearing fatigue. Some Hearo's helped my situation. Not saying that is what your issue is. It may be when the board in the amp heats up there may be some expansion/contraction issues with the material in the amp.
 
Re: is this a sign of tubes getting ready to need changin' ?

I am not sure but I think if your hearing is being affected, you would lose the high end mostly?
 
Re: is this a sign of tubes getting ready to need changin' ?

That sounds exactly like aging tubes.

To be fair, an amp's tone changing over the course of a night is par for the course. But if it's changing from good to bad, then it's time for a retube.
 
Re: is this a sign of tubes getting ready to need changin' ?

after a concert, if you don't wear protection don't you get that high pitch ringing in your ear? We all loose the high end in our hearing, that happens with age no matter what. I feel safe saying the fatigue because i've been there and wish i'd worn ear buds earlier in life. The prolonged exposure to loud music now created a sound in my right ear the sounds like a clipping speaker. this only happens at certain volumes and at certain low frequencies. It's rare but i'd like the preserve what i have left.
 
Re: is this a sign of tubes getting ready to need changin' ?

i do wear hearing protection and have for years - grateful to not have tinnitus symptoms at all .. of course, we dont play very loud (hazard of being in a band with old guys :D )

i dont think this is hearing fatigue because i 'feel' it in my playing .. the notes dont sing out and the crunchy chords just kinda die

so hunter, full retube? pre's only? powers only?

whatcha think?
 
Re: is this a sign of tubes getting ready to need changin' ?

I had this problem a while back and new power tubes solved it.
 
Re: is this a sign of tubes getting ready to need changin' ?

I think if it was pre or power tubes, you'd notice a change for the worse as soon as the amp tubes heated up. Im going to say you might take a look at a filter cap.
 
Re: is this a sign of tubes getting ready to need changin' ?

I would start by changing the tubes in the pre amp, if that's not the cause then I would think about the power ones, 'cause the re biasing it's always a drag, I usually have new tubes saved up, I'm gonna use them some time so it's not a waste of money, it's like having backup strings for the guitar
 
Re: is this a sign of tubes getting ready to need changin' ?

Bill.....try changing the power tubes and try a 12AT7 in V1...it made my modded JR. sound so good that I have been leaving the Boogie at home.
 
Re: is this a sign of tubes getting ready to need changin' ?

thanks Joe - will do .. where do you recommend getting tubes from? anywhere special? any particular brand you recommend most?
 
Re: is this a sign of tubes getting ready to need changin' ?

I use an ancient GE in v1. As far as power tubes, I have good luck with JJ's.
 
Re: is this a sign of tubes getting ready to need changin' ?

Preamp tubes almost never go bad unless they're subjected to physical violence while hot or there's another problem in the circuit. I seriously doubt there's anything wrong with your preamp tubes.

The Blues Jr. eats power tubes. They're biased really hot.

For new tubes, I usually go to www.dougstubes.com. I see that he has Ei EL-84s in stock right now. Those sounded far and away the best in my Blues Jr. Clear bell-like high end without the ice-pick highs of some others I tried. JJs were too dark & muddy for me, but other guys love 'em so they can't be all bad! :wink:

If you want to play around with preamp tubes, V1 is the most important spot in terms of tubes & tone IME. Doug also has Penta 12AX7s - they've all sounded good for me and one is a standout gem. Honestly, buying a couple of Shuguangs and a couple of Tung Sols might be the best bang for the buck if you want to experiment. Every tube is different - even the same batch of the same brand. Oh, and IMHO don't buy into the "matched triode" b.s. Makes sense for hi fi but not a guitar amp. Your phase inverter isn't perfectly balanced anyway, and even if it were you don't necessarily want perfection in the power amp anyway.

For NOS tubes, I go to either tubesandmore.com (untested & random luck but cheap) or KCA NOS Tubes for the good stuff. Seriously, the guy at KCA (Mike?) really knows tubes and has a good selection of well-tested old goodies. Not all tube testers are the same, electronic or human, and you really do get what you pay for. Also, I'd never get an "almost new old stock" power tube, but I've had good luck with ANOS preamp tubes and you can save a lot of $$$ going that way.

BTW a 5751 probably is a better choice for V1 experiments than a 12AT7, at least in theory. A 5751 is very similar to a 12AX7 but with only about 70% of the gain. A 12AT7 is more of a current amplifier and it uses a lot more current. Also biases a lot different - but that could be why bungalowbill likes it.

Good luck!

Chip
 
Re: is this a sign of tubes getting ready to need changin' ?

tone4days said:
so hunter, full retube? pre's only? powers only?

whatcha think?
Click to expand...

Honestly, I don't know. I am a sort of a "completist," when it comes to repairing things - I like to "paint with a wide brush" to eliminate X-factor, for example "I know it'll work if I replace all the tubes."

And it will work / sound better if you replace all the tubes.

Coincidentally, my only experience with re-tubing amps is replacing all the tubes at once.

I say do 'em all, then rest easy. It's only an EL84 amp, the cost difference between a full retube and a partial is negligible, really. If it were a Mesa Triple Rectifyin' Road Master Stiletto King Ace-dyne with 27 tubes, I'd be more interested in figuring out which tubes are causing the problem, but it's just an old Fender with what, 5 tubes?
 
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Re: is this a sign of tubes getting ready to need changin' ?

Gigged a blues jr almost every weekend for over a year and played it hard! It did go through the tubes! I probably re-tubed it 4 times!

It did exactly as you're describing when it was time...btw...i always retubed the whole thing...that thing runs hot...so you might as well!

Also...i dug the JJ's.
 
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Re: is this a sign of tubes getting ready to need changin' ?

thanks guys - great stuff
i'll report back my results
t4d
 
Re: is this a sign of tubes getting ready to need changin' ?

Fresh_Start said:
Preamp tubes almost never go bad unless they're subjected to physical violence while hot or there's another problem in the circuit. I seriously doubt there's anything wrong with your preamp tubes.

The Blues Jr. eats power tubes. They're biased really hot.

For new tubes, I usually go to www.dougstubes.com. I see that he has Ei EL-84s in stock right now. Those sounded far and away the best in my Blues Jr. Clear bell-like high end without the ice-pick highs of some others I tried. JJs were too dark & muddy for me, but other guys love 'em so they can't be all bad! :wink:

If you want to play around with preamp tubes, V1 is the most important spot in terms of tubes & tone IME. Doug also has Penta 12AX7s - they've all sounded good for me and one is a standout gem. Honestly, buying a couple of Shuguangs and a couple of Tung Sols might be the best bang for the buck if you want to experiment. Every tube is different - even the same batch of the same brand. Oh, and IMHO don't buy into the "matched triode" b.s. Makes sense for hi fi but not a guitar amp. Your phase inverter isn't perfectly balanced anyway, and even if it were you don't necessarily want perfection in the power amp anyway.

For NOS tubes, I go to either tubesandmore.com (untested & random luck but cheap) or KCA NOS Tubes for the good stuff. Seriously, the guy at KCA (Mike?) really knows tubes and has a good selection of well-tested old goodies. Not all tube testers are the same, electronic or human, and you really do get what you pay for. Also, I'd never get an "almost new old stock" power tube, but I've had good luck with ANOS preamp tubes and you can save a lot of $$$ going that way.

BTW a 5751 probably is a better choice for V1 experiments than a 12AT7, at least in theory. A 5751 is very similar to a 12AX7 but with only about 70% of the gain. A 12AT7 is more of a current amplifier and it uses a lot more current. Also biases a lot different - but that could be why bungalowbill likes it.

Good luck!

Chip
Click to expand...

A lot of good info bro. I can't explain why the 12At7 works well....I am not a physics major or an EE...I do know it makes my JR sound like a bigger amp...maybe more headroom and clarity.
 
Re: is this a sign of tubes getting ready to need changin' ?

Mattr4president said:
after a concert, if you don't wear protection don't you get that high pitch ringing in your ear? We all loose the high end in our hearing, that happens with age no matter what. I feel safe saying the fatigue because i've been there and wish i'd worn ear buds earlier in life. The prolonged exposure to loud music now created a sound in my right ear the sounds like a clipping speaker. this only happens at certain volumes and at certain low frequencies. It's rare but i'd like the preserve what i have left.
Click to expand...

weird i thought i was the only one who got the clipping amp effect in my right ear. especially when the drummer hits a crash. it sucks
 
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