Question for Mesa Strategy 8:88 owners - does yours pop when you power up?

[DeathSlanger]

I've had this awesome head for about 5 or 6 years, got it used. I had no problems until I dropped it on its face. After that, two KT88s had to be replaced, and possibly a resistor.

The tech has been a Mesa authorized tech for decades, and when he called Mesa about this amp, they recommended a mod to reduce the wear on the KT88s by swapping the 12AX7 with a 12AT7, and also a change of coupling resistor (or something). After buying two KT88s, I was all for that mod. Those tubes are pricey!

I got the head back and it's great, the sound is identical to before but I have to turn it up more. BUT - it now pops when powered up. The pops last a few minutes and then go away. It never popped before the mod. The tech called Mesa back and they said it was NORMAL - what?!! They recommended keeping the standby switch on for 5 minutes after powering up. No way. There is NO way this is normal! Unless it's a bad design, which I really don't think it is.

So now I must ask here, in hopes that someone else has this amp and can tell me about it. Did you get that recommended mod to a 12AT7? Does it pop? Did it before?

Thank you!

 

[agedhorse]

Is this an audio pop or a mechanical ping?

With large tubes like the KT-88 and 6550 (to a lesser degree), things move around inside the tube as it heats up and the structures expand. Different noises can be generated by this movement until the temperatures stabilize.

 

[DeathSlanger]

Wow Aged Horse! Dang, thanks for the reply! It's loud pops that blasts the speakers, when I forget to turn down the master vol. It's not pings. It almost sounds like weird cap noise but it's too consistent. Every time upon power up, it randomely pops for a few minutes.

What you say makes perfect sense, except why is it happening now? If I really have a hard time believing I was "just lucky" before!

 

[agedhorse]

It may be the new tubes.

Something else may have gotten damaged. Impossible to say for sure.

 

[coreyfyfe]

Wow Aged Horse! Dang, thanks for the reply! It's loud pops that blasts the speakers, when I forget to turn down the master vol. It's not pings. It almost sounds like weird cap noise but it's too consistent. Every time upon power up, it randomely pops for a few minutes.

What you say makes perfect sense, except why is it happening now? If I really have a hard time believing I was "just lucky" before!

So you don't hear them if you turn down the master?

 

[agedhorse]

It could also occur earlier in the amp, but the power tubes are a common issue.

 

[GMSweet]

The right man for the job (Agedhorse) is already involved, but the startup procedure is included in the manual.

Strategy Manual

NOTE: COLD START PROCEDURE: When powering up your STRATEGY from cold, ALWAYS follow this Start Up Procedure: We
have found the currently available KT-88s require substantially more time than 6L6s or EL34s to warm up to full operating temperature. If you hit them with high voltage with the STANDBY sooner than three minutes, you may hear some crackling as well as a slow
volume increase as they get up to full temperature. This subsides once they are fully warm, and while it might not hurt the tubes per
se, it is better to warm them up for at least three minutes (or longer) whenever you can.

NOTE: IMPORTANT!—Do Not flip the STANDBY SWITCH in and out of STANDBY mode (on and off) while the amplifier is being
played or with any type of signal being amplified. The large amount of current involved in this scenario can damage the STANDBY
SWITCH.

1. Begin with STANDBY in the STANDBY Position.
2. Switch POWER to ON and WAIT at least three minutes or longer for the tubes to "warm up". (With STANDBY OFF and POWER
ON, the tubes internal components are allowed to warm up slowly before hitting them with the high voltage controlled by the
STANDBY being switched to ON).
3. Flip STANDBY to ON.
4. PLAY!
Following this startup procedure will lengthen the musical life of your power tubes and decrease the chances of untimely power tube
failures

Disclaimer: I have no experience with your amp. I only chimed in because I have a solid state amplifier (SWR California Blonde) that has a note in the manual that a pop may occur at power on and I turn off the internal speaker before powering on and off. And I "love me a good manual!"

 

[cfortner]

I own a Strategy with all mods done and following the start procedure (waiting at least 3 min before switching Stand By), there are no pops through the speakers.

 

[DeathSlanger]

So you don't hear them if you turn down the master?

Yep.

1. Begin with STANDBY in the STANDBY Position.
2. Switch POWER to ON and WAIT at least three minutes or longer for the tubes to "warm up". (With STANDBY OFF and POWER
ON, the tubes internal components are allowed to warm up slowly before hitting them with the high voltage controlled by the
STANDBY being switched to ON).
3. Flip STANDBY to ON.
4. PLAY!

This is interesting, but I never needed to wait before. I just powered up, and a few seconds later I could play. I guess I'm leaning towards "I was just lucky" now.

I own a Strategy with all mods done and following the start procedure (waiting at least 3 min before switching Stand By), there are no pops through the speakers.

Thanks for replying! So you're saying you wait 3 minutes, switch the standby to play, and there are no pops? Could you try and see if you power up without standby on, are there pops? I guess I am trying to see if my pops are unique, or that's just the design of the amp.

I've got a spare variac and I was thinking I'll use that to power up. I am anti-standby switch, but if that's the best way to protect the power tubes I guess I could start doing that.

It may be the new tubes.

Something else may have gotten damaged. Impossible to say for sure.

With what I paid for them, that sucks! Maybe I should see about exchanging them. Do you think it's possible that they'll quiet down after some good use?

 

[cfortner]

My Strategy isn't in use in the moment, sorry.

 

[coreyfyfe]

Yep.

This is interesting, but I never needed to wait before. I just powered up, and a few seconds later I could play. I guess I'm leaning towards "I was just lucky" now.

Thanks for replying! So you're saying you wait 3 minutes, switch the standby to play, and there are no pops? Could you try and see if you power up without standby on, are there pops? I guess I am trying to see if my pops are unique, or that's just the design of the amp.

I've got a spare variac and I was thinking I'll use that to power up. I am anti-standby switch, but if that's the best way to protect the power tubes I guess I could start doing that.

With what I paid for them, that sucks! Maybe I should see about exchanging them. Do you think it's possible that they'll quiet down after some good use?

If you don't hear it with the master volume down I wouldn't necessarily suspect its an issue with the KT88s. More likely something in the preamp or related to the 12AT7 mod, but Andy would know the circuit much better than I. If you follow the standby procedure and that solves the issue that's good, but if you can also solve it by keeping the master volume down I might start there until you can have it double checked by an authorized tech.

 

[Wasnex]

I have several tube amps, including a Strategy that produces a few soft pops after switching from standby to operate. AFAIK, it's normal but not every amp does it. I assume it's related to the tubes warming up.

I have not played my Strategy for awhile, but from what I remember it produces something like 3 or 4 random little pops and then settles down. Mine does not have all of the reliability updates, so it's not running the 12AT7.

 

[TeaTime]

KT-88 today aren't the same as the ones made 5+ years ago. It even acknowledges that in the device manual posted above. Let go of what happened before and deal with what's happening now - run the amp the way it's meant to be. "Anti standby switch" is a odd frame of mind. Maybe it's time for you to move to a tubeless amp?

 

[DeathSlanger]

KT-88 today aren't the same as the ones made 5+ years ago. It even acknowledges that in the device manual posted above. Let go of what happened before and deal with what's happening now - run the amp the way it's meant to be. "Anti standby switch" is a odd frame of mind. Maybe it's time for you to move to a tubeless amp?

Thank you for your candor. shag solid state, by the way. I'm thinking the original tubes are from 2014, so these new ones could be the culprits.

If you don't hear it with the master volume down I wouldn't necessarily suspect its an issue with the KT88s. More likely something in the preamp or related to the 12AT7 mod, but Andy would know the circuit much better than I. If you follow the standby procedure and that solves the issue that's good, but if you can also solve it by keeping the master volume down I might start there until you can have it double checked by an authorized tech.

Thank you for your thoughts. The tech is the only authorized Mesa tech in my state. He thought the same thing, that it was related to the mod. I can control it by keeping the master volume down, I just have to remember to turn it down!

I'm not really trying to troubleshoot or diagnose, I'm just trying to find out if pops are normal. I have a hard time believing they are. I have about 18 tube amps and none of them pop like this, nor have they ever.

 

[agedhorse]

Yep.

This is interesting, but I never needed to wait before. I just powered up, and a few seconds later I could play. I guess I'm leaning towards "I was just lucky" now.

Thanks for replying! So you're saying you wait 3 minutes, switch the standby to play, and there are no pops? Could you try and see if you power up without standby on, are there pops? I guess I am trying to see if my pops are unique, or that's just the design of the amp.

I've got a spare variac and I was thinking I'll use that to power up. I am anti-standby switch, but if that's the best way to protect the power tubes I guess I could start doing that.

With what I paid for them, that sucks! Maybe I should see about exchanging them. Do you think it's possible that they'll quiet down after some good use?

Don't screw around with a Variac, just follow the instructions in the owners manual. That's why we provide owners manuals!

The noises are characteristic with some of these tubes, it's not a defect. If your new tubes are otherwise working properly, leave them alone. They may quiet down some, but they may not.

The 12AT7 modification improves the grid control and stability of the power circuit, again its recommended that you leave it alone. Because if the tighter grid control, any warmup noises in the power circuit (including PI/driver and power tubes) may become more apparent. The modification also extends the life of the power tubes.

Thank you for your candor. shag solid state, by the way. I'm thinking the original tubes are from 2014, so these new ones could be the culprits.

Your comment about solid state amplifiers is uncalled for and is disrespectful to those players here who prefer solid state amps.

 

[DeathSlanger]

Don't screw around with a Variac, just follow the instructions in the owners manual. That's why we provide owners manuals!

The noises are characteristic with some of these tubes, it's not a defect. If your new tubes are otherwise working properly, leave them alone. They may quiet down some, but they may not.

The 12AT7 modification improves the grid control and stability of the power circuit, again its recommended that you leave it alone.



Your comment about solid state amplifiers is uncalled for and is disrespectful to those players here who prefer solid state amps.

Thank you. I apologize for the comment about solid state amps. It wasn't meant to be disrespectful, just to illustrate my feelings about it. That user insulted me by telling me to consider giving up tube amps, so I guess I got a little triggered.

I guess I was just lucky before, and going forward I will simply have to deal with the pups.

 

[NitroBobby]

what does it mean to be "anti-standby switch"?

 

[logdrum]

I am anti-standby switch

That's really only good for low powered guitar amps - and it is a myth that's propagated in the guitar forums Why push a lot of voltage and current to power tubes that are not up to operating temperature yet. You need to follow the procedure on these amps. I had the smaller version the 4:88. It will pop when started cold . I also have a Mesa Hifi Stereo amp as well. My version came with a special switch that prevents you from starting the amp bypassing the standby mode. @Wasnex currently owns the same amp. He can chime in.

 

[agedhorse]

The standby function helps extend the fine of these power tubes by allowing the mechanical structure to heat up more slowly and stabilize before applying the high voltage.

 

[RedWire75]

That's really only good for low powered guitar amps - and it is a myth that's propagated in the guitar forums Why push a lot of voltage and current to power tubes that are not up to operating temperature yet. You need to follow the procedure on these amps. I had the smaller version the 4:88. It will pop when started cold . I also have a Mesa Hifi Stereo amp as well. My version came with a special switch that prevents you from starting the amp bypassing the standby mode. @Wasnex currently owns the same amp. He can chime in.

It's not a myth… for certain amps. Korg Vox AC30s can blow their rectifier when the standby switch is used. I've got a Matchless Lighting that doesn't even have a standby switch.