[sammy weller]

I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

I bought the amp new in 1988 and had never changed any of the tubes
before. I figured that it was time, even though I've never had any
problems with the original tubes or the amp's performance and sound.
It's been a great eighteen years of playing.

So, my new tubes arrived, (2 6L6 power tubes; 2 EL34 power tubes and 5
12AX7 pre's - plus a spare 12AX7, just in case) and I put them all in
the amp and then powered the thing up with great expectations.

Instead of the sound coming up gradually, as the tubes warmed up, it
came on after a pause with a sudden bang. But then it sounded terrific,
better than I could ever remember it sounding - lots of clear tone.
Heavenly! I played for about an hour and then shut it down.

The next day I went to play through the amp again, turned it on, no
sound at first and then nothing but nasty static. The manual said to
replace the "V1", or the first 12AX7 tube, which I did and it sounded
great again, I played for an hour or so.

The next day, same thing, turned it on, noise again, replaced the first
tube with one of the old ones (I used the one new spare the day
before), still noisy and I replaced the second, or "V2" tube with one
of the old ones and it sounded okay. I played for a while, now getting
very nervous about this daily tube changing routine. The owner's manual
advised that the first tube, the "V1" would usually be the culprit,
possibly the "V2".

I've been using it that way since - about a week - with the old,
original 12AX7's in the critical "V1" and "V2" spots. Normally I don't
push it to extremes, I tend to like a clear, clean sound, but I do
crank up the gain and use the distorted sound some of the time.

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure? The
guy at Mesa said that these (Sovtek Chinese-made) tubes were the ones
they were using in the current production amplifiers.

I'm kind of spooked at this point and worried to use the amp for any
serious gigs and I'm worried about a life of replacing $15 12AX7's
every day or so.

I'd love to hear some advice from anyone who is more learned on the
subject.

Many thanks!

[Bob H.]

Sounds like Mesa Boogie is possibly sending out marginal tubes. Maybe
the amp runs them at max voltage, or whatever, and you're quality
testing the tubes for them.
I'd at least get some contact cleaner and clean the tube sockets (with
the power off and sitting for at least 10 minutes, and then unplugged).
Just spray some contact cleaner on a tube's pins, and insert it a few
times to get the contacts cleaned in each tube socket.

If tubes continue to blow, someone will have to check voltages and bias
currents to detirmine if a component is failing.

re/
Bob Hedberg


sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

I bought the amp new in 1988 and had never changed any of the tubes
before. I figured that it was time, even though I've never had any
problems with the original tubes or the amp's performance and sound.
It's been a great eighteen years of playing.

So, my new tubes arrived, (2 6L6 power tubes; 2 EL34 power tubes and 5
12AX7 pre's - plus a spare 12AX7, just in case) and I put them all in
the amp and then powered the thing up with great expectations.

Instead of the sound coming up gradually, as the tubes warmed up, it
came on after a pause with a sudden bang. But then it sounded terrific,
better than I could ever remember it sounding - lots of clear tone.
Heavenly! I played for about an hour and then shut it down.

The next day I went to play through the amp again, turned it on, no
sound at first and then nothing but nasty static. The manual said to
replace the "V1", or the first 12AX7 tube, which I did and it sounded
great again, I played for an hour or so.

The next day, same thing, turned it on, noise again, replaced the first
tube with one of the old ones (I used the one new spare the day
before), still noisy and I replaced the second, or "V2" tube with one
of the old ones and it sounded okay. I played for a while, now getting
very nervous about this daily tube changing routine. The owner's manual
advised that the first tube, the "V1" would usually be the culprit,
possibly the "V2".

I've been using it that way since - about a week - with the old,
original 12AX7's in the critical "V1" and "V2" spots. Normally I don't
push it to extremes, I tend to like a clear, clean sound, but I do
crank up the gain and use the distorted sound some of the time.

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure? The
guy at Mesa said that these (Sovtek Chinese-made) tubes were the ones
they were using in the current production amplifiers.

I'm kind of spooked at this point and worried to use the amp for any
serious gigs and I'm worried about a life of replacing $15 12AX7's
every day or so.

I'd love to hear some advice from anyone who is more learned on the
subject.

Many thanks!

[[email protected]]

sammy weller wrote:

I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.


I'd love to hear some advice from anyone who is more learned on the
subject.

Many thanks!

Hi RATs!

Nothing was wrong, so you just decided to fix it, anyway

The fixes made it worse, huh?

Almost like you wasted all that money fixin' nothing?

They are sending you more new tubes. Do yourself a favor, don't change
anything until something stops working.

I change parts on perfectly good systems for the joy of discovery. I
often discover I have conquered all functionality. I put it back like
it was and sometimes that fixes it.

I am a crazy old man desperate for ear thrills ... what is your excuse?

Happy Ears!
Al

PS Univac used tubes in the early computers ... some died in service,
but, some of the originals were still working when they took the
computer out of service several decades later ... some tubes fail, some
don't. Changing working tubes is a good way to find some which will
fail ... the Army had its techs test tubes every few months. It really
shortened the Mean Time Between Failure. The military is not a good
place to look for intelligent ideas

[[email protected]]

sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

Why is it that without exception, those I know who have purchased Mesa
Boogie branded tubes have been disappointed?

That aside, a couple of questions:

1. Does your amplifier have adjustable bias? If so, did you adjust it?
And did you continue to adjust it during the tube burn-in process? That
you are possibly using both 6L6 and 6CA7 tubes in the same socket at
least suggests that the bias may be adjusted.

2. Do you have the means to test tubes on receipt (and the ones you
pulled)? I ask this because it would be quite useful to understand the
actual condition of the old tubes prior to replacement.

3. Were these by any chance Chinese tubes? It is my *opinion* that
Chinese tubes are fit only as floats on miniature fishing nets, and not
for the reproduction of sound at any level.

At this point, you need to do some general maintenance of the entire
amp. Do this with the understanding that there are lethal voltages
inside that amp, so much of what you do should be done with the power
off and the amp unplugged. Also in very good light.

1. Clean all the controls, switches, tube sockets, jacks and any
connectors. Use a non-residue contact-cleaner designed for the purpose.
DO NOT USE any automotive produce (such as CRC 'Lectra-Sol or similar)
as they will chew through many plastics and dry out many connectors
(make them brittle).
2. If you are so-inclined and know enough to do it, check all the
solder joints, circuit boards (if so-equipped) and such for loose or
cracked connections, or cracked circuit-board traces. This does not
sound like the problem here, but that sudden onset is suggestive.
3. Check (and adjust) the bias if the amp is so-equipped. This is a
*MUST* for the life of the tubes.

BTW, that sudden onset really sounds like one of the output tubes has a
cold-short internally. I have seen quite a number of 6L6 tubes used in
stressful situations (theater amps, sound-reinforcement amps) that
display that behavior. As the filament heats, the short clears, hence
the thump at turn-on. And this is where even a simple tube-tester can
be your best friend... put it in "test" mode as soon as you plug the
tube into it. Watch the needle climb. If there is a sharp jump, you
have found your culprit.

Good luck with it. Find a better brand of tubes, really.


Peter Wieck
Wyncote, PA

[Sander deWaal]

" said:


1. Does your amplifier have adjustable bias? If so, did you adjust it?
And did you continue to adjust it during the tube burn-in process? That
you are possibly using both 6L6 and 6CA7 tubes in the same socket at
least suggests that the bias may be adjusted.


There's another catch he EL34 has its supressor grid and cathode
separated, meaning pins 1 and 8 have to be connected together at the
tube socket.
American tubes like 6L6GC, 6550, 7027 and the like have an internal
connection between g3 and cathode, so most likely, the connection
between 1 and 8 won't be there in the amp.

That said, get your tubes from a reputable seller who knows of what he
speaks.
In this regard, I would suggest calling Lord Valve at NBS in Denver.
NBS ELECTRONICS
230 SOUTH BROADWAY
DENVER, CO 80209-1510

303-778-1156 - ask for LORD VALVE.


The guy's an ass, but he knows his tubes ;-)

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Chris Richmond - MD6-FDC ~]

In article ,
Sander DeWaal writes:
In this regard, I would suggest calling Lord Valve at NBS in Denver.
---snip
The guy's an ass, but he knows his tubes ;-)

LV, How's that for an endorsement?

Sander, you should copyright that. It's funny.

Chris

--
Chris Richmond | I don't speak for Intel & vise versa

[Jim]

sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

I bought the amp new in 1988 and had never changed any of the tubes
before. I figured that it was time, even though I've never had any
problems with the original tubes or the amp's performance and sound.
It's been a great eighteen years of playing.

So, my new tubes arrived, (2 6L6 power tubes; 2 EL34 power tubes and 5
12AX7 pre's - plus a spare 12AX7, just in case) and I put them all in
the amp and then powered the thing up with great expectations.

Instead of the sound coming up gradually, as the tubes warmed up, it
came on after a pause with a sudden bang. But then it sounded terrific,
better than I could ever remember it sounding - lots of clear tone.
Heavenly! I played for about an hour and then shut it down.

The next day I went to play through the amp again, turned it on, no
sound at first and then nothing but nasty static. The manual said to
replace the "V1", or the first 12AX7 tube, which I did and it sounded
great again, I played for an hour or so.

The next day, same thing, turned it on, noise again, replaced the first
tube with one of the old ones (I used the one new spare the day
before), still noisy and I replaced the second, or "V2" tube with one
of the old ones and it sounded okay. I played for a while, now getting
very nervous about this daily tube changing routine. The owner's manual
advised that the first tube, the "V1" would usually be the culprit,
possibly the "V2".

I've been using it that way since - about a week - with the old,
original 12AX7's in the critical "V1" and "V2" spots. Normally I don't
push it to extremes, I tend to like a clear, clean sound, but I do
crank up the gain and use the distorted sound some of the time.

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure? The
guy at Mesa said that these (Sovtek Chinese-made)

That's mutually exclusive. Sovtek are Russian, not Chinese. The Mesa
preamp tubes that I have are a few years old, and Chinese.

tubes were the ones
they were using in the current production amplifiers.

I'm kind of spooked at this point and worried to use the amp for any
serious gigs and I'm worried about a life of replacing $15 12AX7's
every day or so.

I'd love to hear some advice from anyone who is more learned on the
subject.

Many thanks!

FWIW, I own a Mark III and have run various tubes in it for
experimentation (your basic "tone quest"). I have NEVER had a failure,
but I use quality tubes. It came loaded with EH, but they sounded a bit
bright uneventful, so they were promptly replaced. I tried Telefunkens
with success, but decided on Mullards. I'm running Sylvania 6L6GC,
since Mesa told me that's what they designed the amp around (I think
they also used Sylvania preamp tubes, which I have yet to try, but have
on hand).

My schematic is tough to read, but I don't see excessive plate voltages
or other explanations for failure. Could it be that there's a reason
some people call current production tubes "polished turds"?

[juju]

Hi Bob!

Thank you so much for your reply.

I just don't know what to think about these tubes. Like I mentioned
before, I had NO problems with the originals.

So, what is a good brand of contact cleaner and where would I find it?

Where I live, it's all big box stores, no small businesses, like
electronics supply or tv & radio repairmen.


In article . com, Bob
H. wrote:

Sounds like Mesa Boogie is possibly sending out marginal tubes. Maybe
the amp runs them at max voltage, or whatever, and you're quality
testing the tubes for them.
I'd at least get some contact cleaner and clean the tube sockets (with
the power off and sitting for at least 10 minutes, and then unplugged).
Just spray some contact cleaner on a tube's pins, and insert it a few
times to get the contacts cleaned in each tube socket.

If tubes continue to blow, someone will have to check voltages and bias
currents to detirmine if a component is failing.

re/
Bob Hedberg


sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

I bought the amp new in 1988 and had never changed any of the tubes
before. I figured that it was time, even though I've never had any
problems with the original tubes or the amp's performance and sound.
It's been a great eighteen years of playing.

So, my new tubes arrived, (2 6L6 power tubes; 2 EL34 power tubes and 5
12AX7 pre's - plus a spare 12AX7, just in case) and I put them all in
the amp and then powered the thing up with great expectations.

Instead of the sound coming up gradually, as the tubes warmed up, it
came on after a pause with a sudden bang. But then it sounded terrific,
better than I could ever remember it sounding - lots of clear tone.
Heavenly! I played for about an hour and then shut it down.

The next day I went to play through the amp again, turned it on, no
sound at first and then nothing but nasty static. The manual said to
replace the "V1", or the first 12AX7 tube, which I did and it sounded
great again, I played for an hour or so.

The next day, same thing, turned it on, noise again, replaced the first
tube with one of the old ones (I used the one new spare the day
before), still noisy and I replaced the second, or "V2" tube with one
of the old ones and it sounded okay. I played for a while, now getting
very nervous about this daily tube changing routine. The owner's manual
advised that the first tube, the "V1" would usually be the culprit,
possibly the "V2".

I've been using it that way since - about a week - with the old,
original 12AX7's in the critical "V1" and "V2" spots. Normally I don't
push it to extremes, I tend to like a clear, clean sound, but I do
crank up the gain and use the distorted sound some of the time.

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure? The
guy at Mesa said that these (Sovtek Chinese-made) tubes were the ones
they were using in the current production amplifiers.

I'm kind of spooked at this point and worried to use the amp for any
serious gigs and I'm worried about a life of replacing $15 12AX7's
every day or so.

I'd love to hear some advice from anyone who is more learned on the
subject.

Many thanks!

[[email protected]]

Sander DeWaal wrote:

There's another catch he EL34 has its supressor grid and cathode
separated, meaning pins 1 and 8 have to be connected together at the
tube socket.
American tubes like 6L6GC, 6550, 7027 and the like have an internal
connection between g3 and cathode, so most likely, the connection
between 1 and 8 won't be there in the amp.

Sander:

For whatever reasons, most (but not all) American designs will accept
either tube in the same socket. That the OP ordered both tubes
certainly also suggests that this is the case with the Mesa amp. But
you are absolutely correct that such a connection should be checked.

Peter Wieck
Wyncote, PA

[Jim]

wrote:

Sander DeWaal wrote:


There's another catch he EL34 has its supressor grid and cathode
separated, meaning pins 1 and 8 have to be connected together at the
tube socket.
American tubes like 6L6GC, 6550, 7027 and the like have an internal
connection between g3 and cathode, so most likely, the connection
between 1 and 8 won't be there in the amp.


Sander:

For whatever reasons, most (but not all) American designs will accept
either tube in the same socket. That the OP ordered both tubes
certainly also suggests that this is the case with the Mesa amp.

I suspect that the amp in question is a "Simu-Class" Mesa Boogie. It is
DESIGNED for two EL34 and two 6L6GC.

My Mark III is the 60W two tube 6L6GC version.





But
you are absolutely correct that such a connection should be checked.

Peter Wieck
Wyncote, PA

[Fuck Spam]

"sammy weller" wrote in message ...
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

I bought the amp new in 1988 and had never changed any of the tubes
before. I figured that it was time, even though I've never had any
problems with the original tubes or the amp's performance and sound.
It's been a great eighteen years of playing.

So, my new tubes arrived, (2 6L6 power tubes; 2 EL34 power tubes and 5
12AX7 pre's - plus a spare 12AX7, just in case) and I put them all in
the amp and then powered the thing up with great expectations.

Instead of the sound coming up gradually, as the tubes warmed up, it
came on after a pause with a sudden bang. But then it sounded terrific,
better than I could ever remember it sounding - lots of clear tone.
Heavenly! I played for about an hour and then shut it down.

The next day I went to play through the amp again, turned it on, no
sound at first and then nothing but nasty static. The manual said to
replace the "V1", or the first 12AX7 tube, which I did and it sounded
great again, I played for an hour or so.

The next day, same thing, turned it on, noise again, replaced the first
tube with one of the old ones (I used the one new spare the day
before), still noisy and I replaced the second, or "V2" tube with one
of the old ones and it sounded okay. I played for a while, now getting
very nervous about this daily tube changing routine. The owner's manual
advised that the first tube, the "V1" would usually be the culprit,
possibly the "V2".

I've been using it that way since - about a week - with the old,
original 12AX7's in the critical "V1" and "V2" spots. Normally I don't
push it to extremes, I tend to like a clear, clean sound, but I do
crank up the gain and use the distorted sound some of the time.

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure? The
guy at Mesa said that these (Sovtek Chinese-made) tubes were the ones
they were using in the current production amplifiers.

I'm kind of spooked at this point and worried to use the amp for any
serious gigs and I'm worried about a life of replacing $15 12AX7's
every day or so.

I'd love to hear some advice from anyone who is more learned on the
subject.

Many thanks!


Hey Sammy,

Many Mesa Mk 3's & Mk 4's were built with bus wire instead of grid stop
resistors on two of the four output tube grid pins (ain't bean counters
wonderful?). They tend to go crazy when you switch the B+ on with all
4 output tubes engaged, but come up just fine when you're only using 2
output tubes. Solution: install the missing grid stop resistors (I forget the
value, but it's the same as the grid stop resistors on the two tubes that
have them, and it's on the schematics).

I got this from a Mesa factory tech, and it's solved turn-on problems in
several Mesa amps I've fixed that worked just fine until the original tubes
got changed out.

Regards, Fred

[Ned Carlson]

sammy weller wrote:

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure?

No. First thing I would do is get some contact cleaner and clean the
sockets. You can get the stuff at Rat Shack or auto parts stores, make
sure it's the kind that doesn't damage plastic. Read the fine print.

Instead of the sound coming up gradually, as the tubes warmed up, it
came on after a pause with a sudden bang.

That's a sure indication that there's contact problem.
Possibly the new tubes have slightly thinner pins than what
was in there. If the sockets are really distended you might
need a couple of new sockets.

---
Ned Carlson
SW side of Chicago, USA
www.tubezone.net

[Ned Carlson]

wrote:
sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

Why is it that without exception, those I know who have purchased Mesa
Boogie branded tubes have been disappointed?

Golly, I can only imagine. Didn't used to be like that.


That aside, a couple of questions:

1. Does your amplifier have adjustable bias? If so, did you adjust it?

It's a freakin' Boogie, there's no adjustment. Nothing's been done to
the amp since 1988 so we know that. Boogie (Randall Smith) writes
web pages full of rationalizations as to why they don't put bias
controls in their amps. Look 'em up.


Sometimes people add bias adjustments to Boogies. Typically, there will
be a note written in the amp to indicate that's been added, usually,
something like "F**K YOU, RANDALL SMITH, LOVE, WILLIE"



And did you continue to adjust it during the tube burn-in process? That
you are possibly using both 6L6 and 6CA7 tubes in the same socket at
least suggests that the bias may be adjusted.

What could that possibly have to do with an intermittent?


2. Do you have the means to test tubes on receipt (and the ones you
pulled)?

Yes, he has an amplifier. That's a pretty good test.


Supposedly Boogie is sending him some free tubes, if that and a good
socket cleaning doesn't solve his problem, it's time for him to drag it
into the shop for some new sockets and a checkout. After all, it's been
running 18 years, which is a lot longer than you'd run a TV or VCR
before it gets tossed, and people usually don't drag TV's and
VCR's back and forth to music gigs. I think he's had a pretty good
run without needing major repairs, and from what I can tell, the
worst he needs is a couple of $3 tube sockets. I hate to give any
credit to Randall Smith, but not much new transistor gear can last that
long and only need a new set of active parts and a couple of sockets.





--
Ned Carlson
SW side of Chicago, USA
www.tubezone.net

[f.leghorn]

......And lastly, since no-one has mentioned it, I suggest you have the
filter caps replaced, as this amp is 18 years old and it sounds like
this has not yet been done. And check all the non-electrolytic caps for
DC leakage, it only takes one to screw things up.

[Jim]

Ned Carlson wrote:

sammy weller wrote:

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure?


No. First thing I would do is get some contact cleaner and clean the
sockets. You can get the stuff at Rat Shack or auto parts stores, make
sure it's the kind that doesn't damage plastic. Read the fine print.

I've got a Caig product that looks like a magic marker. I think it's
Pro Gold XL, or something like that. You paint the pins on the tube,
insert and remove. Insert again, and as long as the socket is tight,
you're good to go.

I've used a sharp dental tool to re-tension socket connections, but do
NOT do this unless you understand how to discharge the caps and have
basic knowledge of how you can get BIT (intended for OP, not Ned).
SOMETIMES you can re-tension without replacing. ...and whatever you can
do to avoid disassembling a Mesa Mark... DO IT!




Instead of the sound coming up gradually, as the tubes warmed up, it
came on after a pause with a sudden bang.


That's a sure indication that there's contact problem.
Possibly the new tubes have slightly thinner pins than what
was in there. If the sockets are really distended you might
need a couple of new sockets.

---
Ned Carlson
SW side of Chicago, USA
www.tubezone.net

[sammy weller]

Thank you, and while I'm at it, I thank everyone for their input, ideas
and advice.

1. No, this amp definitely does not have adjustable bias. This amp is
what they call their "simul class" amp. It has two EL 34 power tubes
that are always on, and 2 6L6 power tubes that are user selectable. I
can use it as a "Class A" amp (2 EL 34's only), or in "Simul Class"
mode (with all four power tubes running - 2 EL 34's and 2 6L6's).

2. I don't have a tube tester, nor do I have any way of testing them
aside from plugging them into the amp chassis and testing them in
action. The drug store up the street had a tube tester, but they've
gone out of business and it's now a CVS.

I will say that when I put all the new tubes in initially the amp
sounded better than I could remember it sounding in a long while. When
I put the two old 12AX7's back in to the first two critical spots
(because they were all I had to use at that point), it definitely lost
some high freq. and clarity. The tone wasn't as nice. But it works.

3. The 12AX7's are marked "Chinese 1", the order form says "Sovtek",
the web page from which I clicked to add the tube to my shopping cart
says "Chinese". I don't know what to say - I don't know if Mesa
switched the "Sovtek" brand for the Chinese, or if Sovtek actually
farms out manufacture to the Chinese, like everyone else seems to do
these days. But, screen printed onto the tube's glass is definitely the
word "Chinese".

I'm not really comfortable going inside the chassis and checking solder
joints, etc. Since the amp was working just fine before I put in the
new tubes I was really hoping that the tubes themselves, or possibly
the sockets, were the culprit.

Since reverting to two of the old 12AX7's (all other tubes are the new
ones), the amp behaves exactly as it did before - including the volume
coming up gradually. I don't know if I described it well, but that
condition was not a "bang" as in a loud pop or something, it was just
that the sound came on at once after an initial pause. So, I'm hoping
that there is no damage to the sockets. I'm hoping that a cleaning of
the pin sockets and maybe some tubes that don't suck will solve my
problems.

From the sound of it, you guys, who sound pretty knowledgeable, don't
think too highly of Mesa. As a musician, they have always known them to
have a good reputation for high quality products. So, I'm not sure
where to go to find better tubes.

For your reading pleasure, I copied this from Mesa's web site:

"If you play at moderate levels 10-15 hours a week

Power Tubes will generally last 1 - 1.5 years.
Preamp Tubes will generally last 2 - 3 years.

Signs of Wear

Power Tubes:
€ Low end response is not as clear and distorts earlier.
€ You turn your amp¹s master volume up to hear the level that
you are used to hearing.
€ Eventually you will hear 'crackling' 'popping' sounds, often
accompanied by:
€ 'Swelling' volume levels.
€ Buzzing.

Preamp Tubes:
€ Hissing, 'shooshing'.
€ Sputtering, 'grumbling'.
€ Microphonic squealing (feedback type sound).
€ Loss in signal in one or more modes of the amp (channel, reverb,
fx-loop)."

Thanks again to everyone.



In article . com,
" wrote:

sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

Why is it that without exception, those I know who have purchased Mesa
Boogie branded tubes have been disappointed?

That aside, a couple of questions:

1. Does your amplifier have adjustable bias? If so, did you adjust it?
And did you continue to adjust it during the tube burn-in process? That
you are possibly using both 6L6 and 6CA7 tubes in the same socket at
least suggests that the bias may be adjusted.

2. Do you have the means to test tubes on receipt (and the ones you
pulled)? I ask this because it would be quite useful to understand the
actual condition of the old tubes prior to replacement.

3. Were these by any chance Chinese tubes? It is my *opinion* that
Chinese tubes are fit only as floats on miniature fishing nets, and not
for the reproduction of sound at any level.

At this point, you need to do some general maintenance of the entire
amp. Do this with the understanding that there are lethal voltages
inside that amp, so much of what you do should be done with the power
off and the amp unplugged. Also in very good light.

1. Clean all the controls, switches, tube sockets, jacks and any
connectors. Use a non-residue contact-cleaner designed for the purpose.
DO NOT USE any automotive produce (such as CRC 'Lectra-Sol or similar)
as they will chew through many plastics and dry out many connectors
(make them brittle).
2. If you are so-inclined and know enough to do it, check all the
solder joints, circuit boards (if so-equipped) and such for loose or
cracked connections, or cracked circuit-board traces. This does not
sound like the problem here, but that sudden onset is suggestive.
3. Check (and adjust) the bias if the amp is so-equipped. This is a
*MUST* for the life of the tubes.

BTW, that sudden onset really sounds like one of the output tubes has a
cold-short internally. I have seen quite a number of 6L6 tubes used in
stressful situations (theater amps, sound-reinforcement amps) that
display that behavior. As the filament heats, the short clears, hence
the thump at turn-on. And this is where even a simple tube-tester can
be your best friend... put it in "test" mode as soon as you plug the
tube into it. Watch the needle climb. If there is a sharp jump, you
have found your culprit.

Good luck with it. Find a better brand of tubes, really.


Peter Wieck
Wyncote, PA

[sammy weller]

In article , Stuart Krivis
wrote:

On 15 Aug 2006 04:03:17 -0700, " wrote:


sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

Why is it that without exception, those I know who have purchased Mesa
Boogie branded tubes have been disappointed?

On the other hand, I know guitarists that won't use anything but Mesa
tubes in their Mesa Boogie amps...

They make a big fuss about their tubes being the best, and using other
brands voiding warranties. There are not a lot of choices presented to
musicians as far as tube selection goes, and (with my non-technical
understanding) I thought that if I bought them from Mesa that I'd be
getting the best tubes for their amps. I'd love to know what the best
tubes REALLY are for my amp (even if they're not Mesa-branded).


3. Were these by any chance Chinese tubes? It is my *opinion* that
Chinese tubes are fit only as floats on miniature fishing nets, and not
for the reproduction of sound at any level.

He's not using them for the reproduction of sound. He's using them for
the _production_ of sound. :-)

That is exactly the point of a guitar amplifier - it is very much a
part of the production of sound, as much as is the choice of guitar.

Since it sounds as though most of you all are guys who build audio
amplifiers and radios, etc. that are designed to faithfully reproduce
sound, is the guitar amplifier - that relies on tubes clipping and
distorting by design - something I should be asking you all about?

[sammy weller]

Yes, this is the Mark III "Simul Class" amp and Mesa explicitly
recommends the EL 34's and the 6L6's, each in their specified sockets.
They don't recommend switching them around or substituting one for the
other. This is the configuration the amp came with when I bought it.

In article , Jim
wrote:

wrote:

Sander DeWaal wrote:


There's another catch he EL34 has its supressor grid and cathode
separated, meaning pins 1 and 8 have to be connected together at the
tube socket.
American tubes like 6L6GC, 6550, 7027 and the like have an internal
connection between g3 and cathode, so most likely, the connection
between 1 and 8 won't be there in the amp.


Sander:

For whatever reasons, most (but not all) American designs will accept
either tube in the same socket. That the OP ordered both tubes
certainly also suggests that this is the case with the Mesa amp.

I suspect that the amp in question is a "Simu-Class" Mesa Boogie. It is
DESIGNED for two EL34 and two 6L6GC.

My Mark III is the 60W two tube 6L6GC version.





But
you are absolutely correct that such a connection should be checked.

Peter Wieck
Wyncote, PA

[sammy weller]

In article , Ned
Carlson wrote:

wrote:
sammy weller wrote:
I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

Why is it that without exception, those I know who have purchased Mesa
Boogie branded tubes have been disappointed?

Golly, I can only imagine. Didn't used to be like that.


That aside, a couple of questions:

1. Does your amplifier have adjustable bias? If so, did you adjust it?

It's a freakin' Boogie, there's no adjustment. Nothing's been done to
the amp since 1988 so we know that. Boogie (Randall Smith) writes
web pages full of rationalizations as to why they don't put bias
controls in their amps. Look 'em up.

Sometimes people add bias adjustments to Boogies. Typically, there will
be a note written in the amp to indicate that's been added, usually,
something like "F**K YOU, RANDALL SMITH, LOVE, WILLIE"

I'd love to know what you all REALLY think of Randall Smith! It sounds
as though the Mesa Boogie cachet is over-trumpeted? not deserved? To
musicians a Boogie has always been considered a really nice amplifier.

And did you continue to adjust it during the tube burn-in process? That
you are possibly using both 6L6 and 6CA7 tubes in the same socket at
least suggests that the bias may be adjusted.

Do I need to do some kind of burn-in when I install new tubes? What
should that burn-in process be exactly?


What could that possibly have to do with an intermittent?


2. Do you have the means to test tubes on receipt (and the ones you
pulled)?

Yes, he has an amplifier. That's a pretty good test.


Supposedly Boogie is sending him some free tubes, if that and a good
socket cleaning doesn't solve his problem, it's time for him to drag it
into the shop for some new sockets and a checkout. After all, it's been
running 18 years, which is a lot longer than you'd run a TV or VCR
before it gets tossed, and people usually don't drag TV's and
VCR's back and forth to music gigs. I think he's had a pretty good
run without needing major repairs, and from what I can tell, the
worst he needs is a couple of $3 tube sockets. I hate to give any
credit to Randall Smith, but not much new transistor gear can last that
long and only need a new set of active parts and a couple of sockets.

They are sending me three replacement 12AX7's, and all of these tubes
are supposedly guaranteed for six months, full replacement, no
questions.

I've had the amp for 18 years, schlepped it to a lot of gigs, in and
out of taxi cabs in NYC or even in the back of a pick up truck; kept it
in a rather drafty barn for a time (rehearsal space) that was one mile
from the beach that was probably not the most friendly environment for
it and it has never given me any trouble at all. I think that's pretty
good service. I was just looking to freshen up the sound since the
tubes had lived long past Mesa's recommended life span. I seem to have
opened a can of worms instead.

[sammy weller]

I called Mesa and they said, "that's tubes - you never know", but
doesn't it sound strange that three tubes in a row went bad after such
a short time of service? They're sending me three new ones under
warranty, which is nice, but at this point I don't have a lot of
confidence in them. Does this sound like a normal rate of failure? The
guy at Mesa said that these (Sovtek Chinese-made)

That's mutually exclusive. Sovtek are Russian, not Chinese. The Mesa
preamp tubes that I have are a few years old, and Chinese.

Screen printed on the glass of the tubes is the word "Chinese". On
their online store's web page it says clearly "12AX7 ECC83 Chinese",
but the order form says "Sovtek". Maybe they have switched to Chinese
tubes without updating all of the web pages?


FWIW, I own a Mark III and have run various tubes in it for
experimentation (your basic "tone quest"). I have NEVER had a failure,
but I use quality tubes. It came loaded with EH, but they sounded a bit
bright uneventful, so they were promptly replaced. I tried Telefunkens
with success, but decided on Mullards. I'm running Sylvania 6L6GC,
since Mesa told me that's what they designed the amp around (I think
they also used Sylvania preamp tubes, which I have yet to try, but have
on hand).

My schematic is tough to read, but I don't see excessive plate voltages
or other explanations for failure. Could it be that there's a reason
some people call current production tubes "polished turds"?

My amp originally had Sylvania tubes.

I also have a Powermatic 66 table saw, also purchased in 1988.
Interestingly, that was the last year of the iron castings being made
in the USA. Now it's all done in China (and the new 66's are really
huge polished turds). I definitely rue that decision to send all of our
manufacturing overseas, I see so many poor quality products that used
to be made so well in the USA, but that's a topic for another
discussion.

[sammy weller]

No, nothing was broken, but the tone has gotten a little flat over
time. Before the new 12AX7's started crapping out on me, the amp
sounded so much better than it had sounded in years.




In article .com,
" wrote:

sammy weller wrote:

I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.


I'd love to hear some advice from anyone who is more learned on the
subject.

Many thanks!

Hi RATs!

Nothing was wrong, so you just decided to fix it, anyway

The fixes made it worse, huh?

Almost like you wasted all that money fixin' nothing?

They are sending you more new tubes. Do yourself a favor, don't change
anything until something stops working.

I change parts on perfectly good systems for the joy of discovery. I
often discover I have conquered all functionality. I put it back like
it was and sometimes that fixes it.

I am a crazy old man desperate for ear thrills ... what is your excuse?

Happy Ears!
Al

PS Univac used tubes in the early computers ... some died in service,
but, some of the originals were still working when they took the
computer out of service several decades later ... some tubes fail, some
don't. Changing working tubes is a good way to find some which will
fail ... the Army had its techs test tubes every few months. It really
shortened the Mean Time Between Failure. The military is not a good
place to look for intelligent ideas

[Ned Carlson]

Jim wrote:

I've got a Caig product that looks like a magic marker. I think it's
Pro Gold XL, or something like that. You paint the pins on the tube,
insert and remove. Insert again, and as long as the socket is tight,
you're good to go.

That's a good idea. If I were a gigging musician or sound guy,
that'd be a useful thing to carry in the gig bag to clean connectors,
too.


I've used a sharp dental tool to re-tension socket connections, but do
NOT do this unless you understand how to discharge the caps and have
basic knowledge of how you can get BIT (intended for OP, not Ned).
SOMETIMES you can re-tension without replacing. ...and whatever you can
do to avoid disassembling a Mesa Mark... DO IT!

Oh, mais oui.


--
Ned Carlson
SW side of Chicago, USA
www.tubezone.net

[Ned Carlson]

Sammy Weller wrote:

Do I need to do some kind of burn-in when I install new tubes?

Not in this case. The tubes might sound a bit better after they've
run awhile. IIRC, Mesa is supposed to burn-in the power tubes,
if for no other reason, because there's no adjustment in the amp to take
up any slack if the bias drifts a bit in the first few hours of
operation.

I've had the amp for 18 years, schlepped it to a lot of gigs, in and
out of taxi cabs in NYC or even in the back of a pick up truck; kept it
in a rather drafty barn for a time (rehearsal space) that was one mile
from the beach that was probably not the most friendly environment for
it and it has never given me any trouble at all. I think that's pretty
good service. I was just looking to freshen up the sound since the
tubes had lived long past Mesa's recommended life span. I seem to have
opened a can of worms instead.

Naw, you just found a intermittent connection.


--
Ned Carlson
SW side of Chicago, USA
www.tubezone.net

[Jim]

Sammy Weller wrote:

In article , Stuart Krivis
wrote:


On 15 Aug 2006 04:03:17 -0700, " wrote:


sammy weller wrote:

I recently bought all new tubes for my Mesa Boogie Mk III guitar
amplifier.

Why is it that without exception, those I know who have purchased Mesa
Boogie branded tubes have been disappointed?

On the other hand, I know guitarists that won't use anything but Mesa
tubes in their Mesa Boogie amps...


They make a big fuss about their tubes being the best, and using other
brands voiding warranties.

I wonder if they do any testing before silk screening their name?
Obviously, they test the power tubes to assign the different values for
bias matching, but do they test the preamp tubes?

There are not a lot of choices presented to
musicians as far as tube selection goes, and (with my non-technical
understanding) I thought that if I bought them from Mesa that I'd be
getting the best tubes for their amps.

The "best" tubes for my Mesa Boogie Mark III are Sylvania's. That's
what they told me that they used when designing the amp. But they are
not available in numbers that Mesa could market at a profit.

I'd love to know what the best
tubes REALLY are for my amp (even if they're not Mesa-branded).

Sylvania, especially for the power tubes. For the preamp, I'm very
happy with Mullards, but I have yet to try sylvania.



3. Were these by any chance Chinese tubes? It is my *opinion* that
Chinese tubes are fit only as floats on miniature fishing nets, and not
for the reproduction of sound at any level.

He's not using them for the reproduction of sound. He's using them for
the _production_ of sound. :-)


That is exactly the point of a guitar amplifier - it is very much a
part of the production of sound, as much as is the choice of guitar.

Since it sounds as though most of you all are guys who build audio
amplifiers and radios, etc. that are designed to faithfully reproduce
sound, is the guitar amplifier - that relies on tubes clipping and
distorting by design - something I should be asking you all about?

There are also guitar amp savvy people in this forum.

[Sander deWaal]

(Chris Richmond - MD6-FDC ~) said:


In this regard, I would suggest calling Lord Valve at NBS in Denver.
---snip
The guy's an ass, but he knows his tubes ;-)


LV, How's that for an endorsement?

Sander, you should copyright that. It's funny.


LV hardly needs (or *wants*) my support, but I do my best ;-)

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Dominique Michel]

3. Were these by any chance Chinese tubes? It is my *opinion* that
Chinese tubes are fit only as floats on miniature fishing nets, and
not
for the reproduction of sound at any level.


It depend. With the cheaper chinese tubes, you must buy 10 pieces to get
1 or 2 "good enough" tubes, 1 or 2 that doesn't even work, and the
other are "usable" and you can resell them if you are lucky.

But tubes as the Golden Dragon are among the best tubes you can find on
the market. Sure, they are expensive too, as all that is very good.
http://www.pmcomponents.com/

Not all the Golden Dragon are coming from China, other come from Russia
& Yugoslavia, and they are manufactured to meat the exact standard set
by PM ValveLabs, and it is very high standard.

Ciao,
Dominique

[[email protected]]

Dominique Michel wrote:
stuff on Golden Lion tubes...

Dominique:

To-date, I have been able to live off my store of NOS US and Euro
tubes, with no need even for Russian versions for personal use. But
at-present, I am working with a pair of Chinese-made single-ended
guitar amps that quite apart from needing the power-supply to be
entirely rebuilt kept eating the Chinese 6BQ5 amplifier tubes at the
rate of about one per 20 hours, or so. Just to help out the owner, I
put in a pair of used Zenith-branded (Sylvania) tubes (one per amp).
It's been about 40 hours, they are still going fine. Time will tell,
but if it goes over 100 hours, it is the tubes.

I have come across several situations where Chinese 5AR4s have caused
all sorts of mayhem with internal melt-downs, and generally find their
tubes to be quite short-lived relative to others. So, for now I will
continue to stay away from them even for others. For the relatively
tiny difference in price between them and the Russian/EU versions, why
take the chance.

Peter Wieck
Wyncote, PA