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For about 10 months, I've had a Hughs amp; Kettner ATS Sixty combo amp that my cousin has lent me (permanently). It has a ECC83 tube in the pre-amp with a solid state power section. I find the tone to be very pleasing and warm considering it's a cheap hybrid amp. It's supposed to sound heaps better than any Valvestate Marshall has made, although I haven't had much experience with the VS line to make such a comparison.

Anyways, I'm pretty sure in it's 13 year life it's pre-amp tube has never been changed. I'm wondering if I replaced it with a new one could it possibly improve the sound of it? Or is it just a waste of time and money?

I want to have a look inside the amp to check out the tube but it has a warning on the back panel saying quot;Do not open case, no user servicable parts inside, refer to qualified service personnel.quot; Is this just a just general warning so that idiots arn't poking round in there and electrocuting themselves or is it to be taken seriously?

Not that it probably makes a difference but a picture of the circuit with it's tube can be seen at this current ebay auction for same amp model:

from : localhost/cgi.ebay.com.au/ws/eBayISAPI....309425946amp;rd=1

It would help the tone a lot if you replaced the old tube with something newer. Old tubes often give off a lot of hiss and excess noise. I'm sure the back panel is to keep ignorant people away from touching the insides (avoiding lawsuits).

When it comes to opening up an amp, it MUST be taken seriously! Make sure to never touch capacitors, as those store up energy and can deal it out in dosages lethal enough to kill. It seems like switching out the tube is easy enough, it's just getting to it that might be a pain. If you do decide to do it, make sure to exercise extreme caution.

I usually replaced mine (when i had a Valvestate) every 8 months or so when it wore out. I used the od1 channel a lot and it leaned on that tube for distortion. I found the tonal difference to be negligible but i did use fairly good tubes.

I'd knwo when it wore out cuz the amp would sound like a transistor radio and as soon as a replaced the tube the prob went away!

I just switched out the one tube in my Marshall AVT50 combo and it made quite a difference in both tone and volume. I replaced the factory tube with a Groove Tubes Gold Series 12AX7C. I also was worried when I saw the quot;no user serviceable partsquot; notice, but really needed to change the tube so I went ahead and changed it. It was a pain in the a$$ getting to the tube. I pretty much had to take apart the whole amp, which was annoying. I hope I didn't set myself up for a future electrical shock. I just didn't want to take it or send it in somewhere to change it. Anyone know if I could be in any danger of getting a shock since I opened it up?

Tube amplifiers use some pretty high voltages...like 300-600 volts. There are these quot;big round thingsquot; inside called capacitors. They basicly store energy. The catch is that a capacitor will retain it's quot;chargequot; for a certain time after unplugged from the wall. So you can get zapped if you're not careful and the design of the amp allows fingers to come into contact with the business end of things.


Originally Posted by SlyFoxxTube amplifiers use some pretty high voltages...like 300-600 volts. There are these quot;big round thingsquot; inside called capacitors. They basicly store energy. The catch is that a capacitor will retain it's quot;chargequot; for a certain time after unplugged from the wall. So you can get zapped if you're not careful and the design of the amp allows fingers to come into contact with the business end of things.

Exactly. That's pretty much what I was getting at above, but you went into greater detail


Originally Posted by SlyFoxxTube amplifiers use some pretty high voltages...like 300-600 volts. There are these quot;big round thingsquot; inside called capacitors. They basicly store energy. The catch is that a capacitor will retain it's quot;chargequot; for a certain time after unplugged from the wall. So you can get zapped if you're not careful and the design of the amp allows fingers to come into contact with the business end of things.Originally Posted by the_ChrisExactly. That's pretty much what I was getting at above, but you went into greater detail

Guys, while this is true and legit, it doesn´t apply here, because we´re talking about a Solid State amp (in all stated cases) with a single tube in the preamp to warm up the tone. No big scary capacitors or huge transformers, just nice light Silicon and Fiberglass

Switching out the preamp tube usually doesn´t cause much of a tonal effect in these amps in my experience, but Others have told me that they find the difference huge.....On my Attax and earlier my Valvestate I didn´t notice much if anything, but then again I only switched tubes to have a better reference pooint for future swaps, may very well have been a nearly identical tube. It also depends on what you use to replace what, if the original was very dark and the new one is very bright, I´m pretty sure there will be a difference.

What wonders me a bit is B2Ds experience, because preamp tubes usually don´t quot;wear outquot; like power tubes do, especially not in a short period like 8 months......You sure that amp was healthy?

BTW, how is the ATS? As stated I often use an old Attax at home, and it´s definitely a thousand times quot;betterquot; and more versatile than the Valvestates

Good point Zerb. I just assumed that because it had a tube in it, there had to have been some sort of a capacitor somewhere in the circuit.

If you have access to several tubes of different make, it definately makes a difference on this model HK amp and the 100 watt version. It's a fiddle to open and you must be careful as the other guys say, but it isn't that hard to access the amp and try the tubes out one by one. you should be patient and give them a while to warm up before caning it.


Originally Posted by Zerberus
What wonders me a bit is B2Ds experience, because preamp tubes usually don´t quot;wear outquot; like power tubes do, especially not in a short period like 8 months......You sure that amp was healthy?Me too... Even a cheesy Sovtek should last a couple years.

Incidently I cant remember the exact voltage but I know valvestates run the tubes waaaay under 350v its something closer to like 90. (I know some hybrids run them as low as 18v) Being they are run at so low voltages they theoretically should last alot longer than they would in an all tube amp. This is the reason why they say there are no user serviceable parts inside and they are siliconed inplace. The only times I tried replacing them was to see if I could change the tone. It was never a drastic change. Going from a 7 dollar chinese tube to a 100 dollar Telefunken was hardly noticeable


Originally Posted by the_ChrisGood point Zerb. I just assumed that because it had a tube in it, there had to have been some sort of a capacitor somewhere in the circuit.

There is, the entire layout and electrical setup of any amplifier requires the use of capacitors. Just not necessarily the huge, ominous filter Caps we use in Tube amps


Originally Posted by ZerberusJust not necessarily the huge, ominous filter Caps we use in Tube amps

I love your word choice there...quot;ominous.quot; I always feel like I'm disarming a bomb every time I discharge the filter caps.

Changing the tube would help with any noise issues coming from an older, worn tube, but I doubt it would improve tone. If you do change it, don't get a really expensive tube, go for something with low noise, like an Electro Harmonix or JJ.

The low voltages that most hybrid amps run the tube at means they usually have awesome tube life. There is another side though . . . the tube not being run at real voltages doesn't behave like a tube run at real voltage. It isn't being pushed to any amount of drive to improve your sound. That's why Riff Guy's amp had the tube impossibly buried. It's not really tube, and under normal conditions, that tube will pretty much never fry in that amp's likely lifetime. The catch is that running the tube at low voltage means the tube doesn't actually, well, do much of anything.

That was a long way of saying, if you don't have noise issues (radio coming through, pops, crackles, ringing sounds), then I wouldn't bother changing it.


Originally Posted by ZerberusBTW, how is the ATS? As stated I often use an old Attax at home, and it´s definitely a thousand times quot;betterquot; and more versatile than the Valvestates

For what it is, I think it's a great amp for something that was originally designed for the semi-budget/beginner market. Even though the clean channel runs enitirely through a transitor circuit, it has a pretty lush and warm sound.

Now the tube overdrive channel can pull off classic rock tones very easily. This is a bright amp and it probably does the old-school marshall sound better than most solid state amps out. Since I prefer a more even type of sound I usually always turn down the quot;voicequot; and quot;bitequot; knobs on the OD channel below 11' o'clock. With my alder guitar it can become club-med for shrill if I don't ease off on these two tone controls.

The heaviest tone I can currently get with the ATS is a AC/DC tone, and it does that sound very well. The problem is that I would like to be able to get a 'chuga-chuga' tone. After recently getting a SH-6 installed in my bridge position of my Jackson, it helped a little bit to get closer that sound, but there is still a lot of body to be desired for such an agressive thump to come out of the speaker.

This lack of gain can most likely be attributed to the fact the actual gain knob had broken off before my cousin had given it to me. Since the little holder that holds the knob has broken off also, it's impossible to adjust the gain level. I think it's stuck about just over halfway and I'm dying know to how much heavier the tone can get. I'm thinking about getting it fixed by a tech. Doesn't seem like big job.

The amp packs a lot of punch. It can get very loud if you want it to. Loud enough for jamming, rehearsal or possibly even for small gigs (i don't know yet). Being a hybrid amp the advantage is also that you don't have to turn it up loud to get a good sound. I would definitely recommend this amp for people who are on a budget and want a more tube like sound. They're cheap as chips second-hand if you find them in the right place.

So yeh, it can pull off rock and blues great. Don't think it would work for Jazz. Might possibly work for metal, I'll find that out soon enough once I've got the gain knob issue fixed.

Sounds 100 times more 3-dimensional and smoother than my 100-watt solid state VR-3000 amp and my little Peavey 158. Much more believable than my Yamaha DG-stomp digital pre-amp stomp box, which packs good sounds inside but doesn't sound quot;therequot;.

With all this, I'm curious about changing the pre-amp tube considering it's so damn old. I'll probably get an inexpensive electro-hamornix one. Is it possible to get a bassier/more high-gain sound sound just by changing the brand/make of the ECC-83 tube?

I think it makes a slight difference. I guess it's worth doing if you play the amp every day, and you don't mind popping a high quality tube in there. On my Valvetronix, I yanked out the Sovtek WA and replaced it with a Sovtek LPS. I can hear that the amp sounds slightly better, but not the dramatic difference it would have made if it had an all tube preamp section, and I replaced all three pre tubes with expensive tubes, from cheap ones.

As far as the tube wearing out... I always thought that was a bit strange and it was the same with my friend's valvestate too. Every 8-9 months the tube stopped glowing and the amp was crippled until the tube got replaced.

So as you can imagine the 1st time i heard tales of tubes lasting YEARS I was rather astounded LOL.