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Tube Safety Control and preventing an amp-related apocalypse


Back in the late ‘90s, one of Blog Of Tone’s esteemed writers once had the (mis)fortune to play an outdoor gig in front of a field of inebriated Harley-Davidson enthusiasts. Oversized motorcycles, beer and other related debauchery in abundance were the order of the day. Sounds like rock ‘n’ roll heaven, doesn’t it? Well, it would’ve been, had our man’s amp not exploded during sound check. If only he’d been able to call upon the magic of Tube Safety Control to save the day…

There’s one very special musical event that I can remember as if it happened yesterday; an experience so vivid it’s now hardwired into the circuitry that starts somewhere behind my eyeballs.

Allow me share it with you: my demurely named four-man band, 8Balls, had secured a coveted gig at one of Europe’s biggest Harley-Davidson get-togethers. It was much like any convention, except that its attendees were a horde of what seemed like 10,000 Visigoths on huge hogs, with an entourage of women whose only mission, apparently, was to look as stunning as possible.

The entertainment was appropriately rowdy: a rather raucous rock band of the pool-shooting persuasion (lest you think less of us), bad-ass Harley burnouts, a moped-throwing contest, a pole dancing extravaganza and more good clean fun were on the agenda.

The all-powerful Harley president, an Odin-like presence whose word was law, added a menacing dystopian touch to the chaotic drunken antics. Mountains of grilled meat and gallons of beer to wash it down with were on the menu, so this promised to be a night of epic debauchery.

With a nod to the event’s gravity, I schlepped my exorbitantly expensive, all-tube custom boutique amp and twin 4×12″ cabs on to the festival stage.

I knew these were serious bikers, and I believed I would need lots of raw power to match the roar of all those Harleys. It would be a showdown, 100 tube-driven watts versus oodles of hog-power.

One of the top secret testing machines at H&K HQ. If a new piece of gear makes it out of this big red box alive (and no, we're not telling you exactly what it does in there!) rest assured that it's good enough to rock your gig - even if you're playing to a field full of drunk bikers!

One of the top secret testing machines at H&K HQ. If a new piece of gear makes it out of this big red box alive (and no, we’re not telling you exactly what it does in there!) rest assured that it’s good enough to rock your gig – even if you’re playing to a field full of drunk bikers!

Let the games begin! Or not.

You see, the grounds were in the middle of nowhere, far from the comforts of civilization. There was no power supply, the nearest outlet being miles away.

This wasn’t a problem for the bikers, who borrowed diesel generators from nearby fire departments. Perhaps they were a sacrificial offering to keep the barbarians outside the gates of their fair towns.

I didn’t bother to take a meter to the power supply to gauge amperage and voltage.

Who does that anyway?

I should have, though. It was the fastest sound check we ever had, ending abruptly after five minutes or so. My cherished über-amp crackled loudly a few times, coughed, sputtered and thumped feebly one last time before passing on to the great beyond where only the good amps go.

All its vital signs had flatlined, and there was nothing I could to do to snatch my beloved baby from the cruel clutches of death.

Of course, no biker rolls with an amp strapped to his back; that seat’s reserved for his significant other.

What to do?

I jumped in a car and hauled booty to the nearest big town, which had a building with rehearsal spaces for rent, in the hopes of finding a kindred spirit who would bail me out. I was lucky; a fellow traveler on the minstrel’s trail loaned me his solid-state combo, and we somehow managed to get through the gig.

Another of those mysterious testing machines chez H&K. The crux of today's story is that in the years since our colleague's fateful gig, we've had time to develop systems that can prevent pre-gig disasters like that happening...

Another of those mysterious testing machines chez H&K. The crux of today’s story is that in the years since our colleague’s fateful gig, we’ve had time to develop systems that can prevent pre-gig disasters like that happening…

However, my personal experience had gone from epic to abysmal the moment my magnificent amp head went up in a puff of smoke.

The bikers, though, were far more interested in their bikes, their booze, their tattoos, and sometimes even their women, whom they either dispatched to fetch more beer or displayed proudly aloft, like Pictish priestesses being marched off to the shoulder wars astride Viking marauders.

The strains of secondhand Hendrix and Stevie Ray wafted through the alcohol-laden ether, unappreciated by these wild men and women.

Not to be melodramatic or anything, but that night in the company of many more than four riders gave me a foretaste of the apocalypse.

And the aftertaste was no less evocative: for weeks, all our gear reeked of burnt Harley-wheel rubber, reminding me that the fast lane is not the place to be when you’re on the Highway to Hell.

Back at home, the troubleshooting commenced the next day.

A friend who knows the business end of a soldering iron pinpointed the defect in a jiffy. He told me a power surge had slammed into a tube in my sensitive hand-wired amp head, which first blew that tube and shortly thereafter the fuse.

Replacing the fuse wouldn’t have fixed the problem because the defective tube was still plugged into the socket. Piling insult onto what was already a painful injury, my technician buddy said the tube would have soon failed in any case.

Now, I’m not a technician, and I would’ve stood a better chance of snuffing out the fires of Hades with a water pistol than figuring out what was wrong and finding a way to get my amp back up and running.

A tube was toasted, but that’s not something anyone without the gift of X-ray vision could see. The fuse had been blown; who would have thought to carry a spare?

I was a musician, not an electrician. If the grounds had been far more remote, the show most definitely wouldn’t have gone on.

In the past, a broken tube - hardly a rare or unlikely happening, given their unstable nature and the typical close proximity of clumsy drummers - would put your entire gig in jeopardy. These days, systems like TSC mean that the show can, and will, go on...

In the past, a broken tube – hardly a rare or unlikely happening, given their unstable nature and the typical close proximity of clumsy drummers – would put your entire gig in jeopardy. These days, systems like TSC mean that the show can, and will, go on…

These days, my tale of woe is just an anecdote that gets a few laughs when musicians swap war stories.

I don’t worry about that kind of stuff anymore since more tech-minded brains than mine have come up with surveillance systems such as Tube Safety Control (TSC for short). Tube failures are history thanks to this pioneering system.

It’s not just that TSC constantly monitors the tubes in its care. It also switches off any ailing or failing tube and its partner in a flash.

The only thing the guitarist notices is a slight dip in output power: if it’s a 100-watt amp, the output drops to 50 watts. The difference in loudness is perceptible, but at just a few decibels, negligible.

It’s the tiniest of prices to pay for the show to go on without the crowd noticing a thing.

If you own a TSC system, you don’t need a technician to bias your tubes. That means you can experiment with any power tube set – say KT88s, 6L6s, 6550s and the like – that fits the sockets, provided you always do what Noah would have done, popping them in in pairs.

If you wish, you can even A/B different types to tune your tone to taste. One of the more interesting tweaks for those who like their metal hefty is to replace the standard EL34s with a quartet of KT88s. This usually nails that raging American-style metal sound.

If the amp that died at the Harley huddle had been equipped with TSC, the defective tube and its twin would have been switched off automatically, the power tubes’ performance parameters adjusted accordingly, and the gig would have been hog heaven for me.

The TSC system did for tube-amp reliability what cloud backups did for computing. It took convenience up a dozen notches and gave serious users unprecedented peace of mind.

A TSC system in all its glory on the TriAmp Mark 3. Wonderfully simple and yet devastatingly effective, it's a tube doctor, gig saver and peace of mind giver all in one!

A TSC system in all its glory on the TriAmp Mark 3. Wonderfully simple and yet devastatingly effective, it’s a tube doctor, gig saver and peace of mind giver all in one!

Power tubes are exposed to huge temperature differences, and several of their parameters may change audibly over time.

This creeps up on you, but at some point what you’re hearing is no longer what you expect from your trusty sidekick.

And that’s just one of the factors that can cut a tube’s life short and mess up your tone.

There’s nothing more precious to the gigging guitarist than a reliable, wicked-sounding amp paired with a magical guitar; a combination that delivers to-die-for-tone, everywhere and every time.

If you’ve ever seen a middle-aged Oxfordshire man on hands and knees tending to his turf, trimming individual blades of grass with nail clippers, than you know how obsessive the English can be about their lawns.

Many of us guitarists are like those guys and gals going for Britain’s best greenery. We tend to our tone with equally fanatical devotion.

With systems like TSC leading the way, surveillance systems such as those found in today’s automobiles are making inroads into ostensibly old-school tube technology.

That’s good news indeed.

Because the better maintained, a better biased, better monitored, and better protected amp is bound to be – you guessed it – a better amp. TSC takes on all these tasks, and reliably at that.

We players should expect nothing less from today’s equipment, and if you’ve ever had an experience like mine at the biker bash, you’ll appreciate that kind of reliability all the more.

Have you ever experienced anything similar? Did an ominous change in sound, a weird whiff of something frying, or a sudden spike in temperature clue you into the fact that your equipment was on the brink of disaster?

Ever had to finish a gig with borrowed gear or improvise an on-the-fly rig to get yourself heard? What are your wildest tales of the road?

And, most importantly, do any of you ride a Harley?


First published: February 20 2015. Most recent update: October 02 2015.

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Leave a comment

Francois Lycke on February 11, 2017 Reply

Hello from Montreal Canada !
GM 36 problem ! I can’t switch power soak in global mode…GrandMeister 2.4 Windows
It’s work in library, i send this comand to the GM, buT dont work, …the GM is not in global mode..
Another thing, is the FX loop, i dont see anny global mode,
I don’t see global setting in the android app to..
Those feature are absolutely a must, i have a big rig, and a small one..
Last night i give a try to the GM in small show. with the fx inside it’s cool.
Arrive in place with the FSM, for the first time…nightmare…
All my 20 preset are with FX loop, ( big rig ) so i start to play….Nothing ! no sound !
i have to reprogramme everything with FX loop OFF !!! 20 prog !! Take me 15 min rushing, looking like a amateur with is gadget
Today back to the big rig, reprogram the 20 preset, with loop on ! It’s a real pains….
Same as the power soak, not global by default, whe use this feature to work at low volume with wharm sound….first.
The GM 36 are very dangerous about this option for you ears. Exemple :
We are in studio, the GM is on 1 watt output, for a nice warm rythm, playing by a guess, he said ” ok guys i will try another preset ” …but the powersoak Jump out to 36 wat !! So all people with headphone, look at him very bad, very bad !
This feature is very dangerous, don’t forget in 128 presets witch one is 1w 18 w 36w ??for the audition, i could beleive the techniciens never see this, it’s so Big. I can make a complaint to CSSC in Canada to dangerous tool, realy is not a joke.
Recording at midnight at 1 watt is great, i switching to my solo preset…..and BOUM !!! 36 Watt, and weakup everybody !
For me it’s bizzare, i have to write this, at a company making tube amp, top of the line.
The footswitch, i rent it, for now, is to big ! They must have alternate FS, a small one fit in the gigbag, this FS is big like the head amp ??
This drive me crazy….
I love the sound, is perfect with my big rig, 4 cable methode, in parralèlle with Guitar synth in JC120.
I need this global mode, maybe a good tech can make the powersoak manual….
Best regards Francois Lycke

Another terrible issue, about, no global setting.
One night a power tube burn, and make a big buzzy sound, but working ok in 18w…Cool ??? Not realy…..
All my 20 preset is at 36w, so when i switch the GM is go back to 36w with the big fuzzy sound.
The tube is bad but the powersoak don’t go in 18w mode, you have to push the 18w switch & store,
for every presets !!!!!
This is the worst configuration i never see,
I never lost control like that, on my rig in 35 year, i am sorry to tell this, but this is wath appen…
Best regards Francois lycke

    Hughes & Kettner Hughes & Kettner on February 15, 2017 Reply

    Hi Francois, and thanks for your feedback on here (we already replied to your similar feedback on our Facebook page, but we’ll do so here as well so the blog people can read it!).

    As we explained before, the GrandMeister 36 does not feature a global power soak mode – the GrandMeister Deluxe 40 does. This means that you simply need to program your power soak settings for each preset, and it’s the same principal with the FX Loop. The GrandMeister 36 comes with a selection of built-in presets when you buy it, and these feature numerous power soak modes. You simply need to program all your presets to the setting that you like, save them, and then use them like that. You can program two sets of identcial presets for practice and live use, for example – with all the settings the same, except with the power soak at 1 watt for practice and at the full 36 watts for the show.

    We had a lot of feedback about the global power soak with the 36, and this is wha the feature is built into the new GrandMeister Deluxe 40. We admit it’s a lot simpler now, and a lot easier. This is a big evolution for the Deluxe 40, and we’d recommend you try this amp too to see if you prefer it this way!

    About the footswitch, we made it suitable for live use, and it’s designed to fit the natural size of most people’s feet when they stomp on pedals! You can use other brands of footswitch too, of course, so if there’s a smaller one you prefer this should also work (although please check before you buy another, because a small minority of brands have switches that are NOT compatible with our amps!).

    Like we also did with Facebook, we’ve passed on your concerns to our engineers/R&D guys. We do take constructive criticism like this very seriously (which is why the new GM has a global power soak and the old didn’t, for example!) and we hope you have not suffered too much inconvenience here. Please let us know if there is anything else we can help with.

    All the best,

    Team H&K in Germany

jeff mercer on January 12, 2017 Reply

I couldn’t seem to find much information on which positions were the best for the tubes in pairs, if you were to go with say 2 kt88, and 2 el34’s at the same time. The web sight i came a crossed said you could put them both in the inner, or outer positions, but also said you could put them in the 1st, and 3rd, or 2nd, and 4th position. He recommended the inner position. This info i found was not specific to the H&K ampls though. Is there any recommendation from H&K that would be best to use?

I currently have them in the inner positions, and did turn it on, but did not flip standby on yet. I have the retainers, for the Kt88’s now in place.

jeff mercer on January 4, 2017 Reply

The Kt88’s base is quite a bit bigger then the spring that holds the EL34’s tube in. In order to put this bigger KT88 tube in I would have to remove the tube spring retainer right? I see online you can get some retainers for the KT88 tubes. My Coreblade isn’t currently sitting on the cabinet, and should be ok, and protected from any vibrations that would loosen the tube. Do you see any issues of taking off the tube spring retainer, and just putting the new tube in till i can get a KT88 tube spring retainer for it put on?

    Hughes & Kettner Hughes & Kettner on January 5, 2017 Reply

    You’re right Jeff. This is the case with the TriAmp Mark 3 too, if you want KT88s in there you have to dispense with the spring that holds the tubes in place from above. It all depends on how comfortable you are with doing this stuff yourself, and whether you think it’s safe to do so. If you’re in any doubt, ask a local tech to take a look for you (sorry if we keep repeating that, it’s something we have to say from a legal point of view!) and they’ll let you know.

    That all said, if there is another aftermarket retainer that would fit that you can use, and the delivery time is not too long, we’d be tempted to wait…

jeff mercer on December 24, 2016 Reply

Well I would hope it could handle a lot for the price. Having the capability to do more tubes then EL34, and 6l6?GC makes it more attractive. I was considering at one point on getting a 36 Grandmeister, for the small size, factor, and similar capabilities to the CoreBlade, but if the KT88’s and the other tube types that you meantioned it can handle, will possible make it a keeper.

I’m surprised the Tube list type’s isn’t in the manual. I got me some Preferred series KT88 coming so will see how it goes.

I wonder if mixing my current EL 34’s, and the KT88’s would be good sounding. Which sockets are the ones you need to make your you have the same type tubes in, if you mix 2 types, of different tubes?

jeff mercer on December 23, 2016 Reply

That is cool! Thanks I was looking into the KT88’s, and was interested in trying them out, but didn’t know if it could do them, or not. Don’t the KT88’s put out a lot more power then other tubes.

    Hughes & Kettner Hughes & Kettner on December 23, 2016 Reply

    No worries 🙂 You’re right, they do, but nothing an H&K amp can’t handle 😉 If you’re not sure about it though, take the amp to your local tech and have them test it out for you first! That’s a surefire way of nothing going wrong…

jeff mercer on November 27, 2016 Reply

Hi I have a Coreblade, and your article says TSC will support KT88, but according to the manual for the amp I have, it only mentions el34’s, and 6l6gc tubes. Will it support KT77’s as well?I was curious have you tried a KT88 tube in the Coreblade amp. I’ve read from some forums there is some major differences on how a amp needs to be set up for it to use a KT88.

    Hughes & Kettner Hughes & Kettner on November 28, 2016 Reply

    Hi Jeff! Hmm, the manual only mentions the most typical types, but with TSC, you can indeed fit any tube that’ll physically fit into the sockets. That means that KT88s and KT77s will fit, but of course the tones are something of taste. If you dig the sounds that tubes like these are famous for, could be worth a try for you 🙂