KT120s?

[fiaj]

Okay.
My Rockerverb was replaced in December so the tubes are pretty fresh, all stock but i'm enjouying the Ruby el34s for now. But i want to buy my next tubes soon so they're there if anything terrible happens.
But, i definitely want to use something else when they've lost their vibrance a bit, and i wanted to use something with fatter lower end without sacrificing any high end definition so i always had KT88s in mind.
But, i went mad in December while i temporarily had a load of cash and bought i really nice Icon Audio stereo amp, all valve, and i opted to have the then newish Tung Sol KT120s in the power section because for some stupid reason i thought i'd need 75w per channel and it would have been 60w with KT88 or 50 with EL34s.
Comparing the 120s and 88s in these amps i could hear next to no difference other then ever so slightly more presence in the low mids with the 120s. Anyway, apparently they;re set-up to run as KT88s in this thing, which Icon tell me is a bonus because they are working well within there limits and should last years.
So i was thinking maybe these could have their benefits in a guitar amp, and i assume that they'd work well in a Rockerverbs if set up as 88s. Of course, with a 100w amp i barely get a chance to really saturate these tubes, and if i had these KT120s i guess even at top volume i may now get them to hot up the sound.
I'm pretty new to how this all works, just know what my ears like, so could someone with more knowledge give me their opinions on whether or not these may be worth a try, and how they'd affect the sound in a guitar amp.
Or better yet, anyone used these monsters yet?

[Randy Bass]

Although different power tubes are technically capable of higher output than EL34s, the limiting factor is almost always the particular transformers in the amp. You probably wouldn't notice a big difference in output unless they put transformers that are way over spec in your amp for no apparent reason. The benefit of types like the KT88 would mainly be a bit more bass and treble and a bit less midrange. Just don't expect an "instant power boost" or anything.

[a.hun]

The KT120 is a 'new' type I have never heard of. I say 'new' because chance is it is indeed just a variant on what has gone before. Which would probably explain why you didn't hear much difference yourself...

Sorry. Can't really advise on this. Insufficient data - can not compute...


Andy.

[a.hun]

Although different power tubes are technically capable of higher output than EL34s, the limiting factor is almost always the particular transformers in the amp. You probably wouldn't notice a big difference in output unless they put transformers that are way over spec in your amp for no apparent reason. The benefit of types like the KT88 would mainly be a bit more bass and treble and a bit less midrange. Just don't expect an "instant power boost" or anything.

Probably dead right. The ouput transformers will certainly limit potential power output, and there will be other factors too.

There may well also be a power transformer issue with using them too. The heater current (low voltage = 6.3V, but very high current - nothing to do with the bias or HT voltages!) is apparently 100 to 300mA higher with the KT120s. That being per valve of course. So you may well need a heater supply from the power transformer which can put out up to 1.2A more than KT88s would draw. That is quite a lot and I'd really suggest checking with Orange before trying them!


Andy.

[fiaj]

Thanks very much to both of you, i'm pretty clueless in this as you can tell.
I was just playing with the idea, maybe i'll phone the workshop and see if they have anything to say. I wasn't really into the idea for a power boost, more just that i want the KT88 sound or similar and thought the bonus may just be similar tone, longer tube life.
I'll look into it further, i'm in no mad rush to make a decision.
Thanks again!

[bassdrop]

I was also curious about this tube type and when I posted a thread on it a few months ago it got no responses. The KT120 is a completely new tube type with 60W plate dissipation so a push-pull pair can put out up to 150W. Although the pinout is the same as a 6550 or KT88, the biggest differences that might make this impossible is as Andy said they draw up to 300ma more filament current than a KT88 and they are 1/2" taller. So they may not even physically fit. The only guitar or bass amp that uses them that I know of is the Verellen Meatsmoke.

[bassdrop]

Here's a size comparison between a 6550 and KT120- methinks it shan't be fitting

[Randy Bass]

I've never seen one that big .

[a.hun]

I've never seen one that big .

This one is bigger...
http://forum.orangeamps.com/viewtopic.p ... 4&p=107091" onclick="window.open(this.href);return false;


Andy.

[bassdrop]

nice dig on the old thread! sweet! Phil Jones still hold the trophy for biggest tubes in a bass head. Quartet of 811's = 600 watts RMS. Reportedly only 2 were made, though. Ampeg also made a 600 watt SVT with all 6550's and a matching 32x10:)

[ironlung40]

Although different power tubes are technically capable of higher output than EL34s, the limiting factor is almost always the particular transformers in the amp. You probably wouldn't notice a big difference in output unless they put transformers that are way over spec in your amp for no apparent reason. The benefit of types like the KT88 would mainly be a bit more bass and treble and a bit less midrange. Just don't expect an "instant power boost" or anything.

Probably dead right. The ouput transformers will certainly limit potential power output, and there will be other factors too.

There may well also be a power transformer issue with using them too. The heater current (low voltage = 6.3V, but very high current - nothing to do with the bias or HT voltages!) is apparently 100 to 300mA higher with the KT120s. That being per valve of course. So you may well need a heater supply from the power transformer which can put out up to 1.2A more than KT88s would draw. That is quite a lot and I'd really suggest checking with Orange before trying them!


Andy.

I had a reputable tech explain it this way...........(for reference the amp was a 2203 marshall with 6550's) "Basically they were designed for EL34 tubes but many ended up shipping with 6550's. Trouble is due to the design of the transformers around an EL34 tube, they really weren't spec'd to run 6550's. As a result, the amp doesn't push the 6550's to their optimum level and you don't get optimum performance from them, so you're probably better off sticking with an EL34 tube type. However, this is not to say that the amp won't sound good with 6550's as many 80's guys loved the 6550 configuration."

So, the transformers and amp design do play an important role, as we all would probably deduce on our own anyway if we thought about it long enough. I'm guessing with Orange's offerings that run both, the trannies are powerful enough for both types though.

BTW, OP, is that an overdrive atop bass cabs in your sig pic? If so, how is it for bass particularly at a gig level?

[a.hun]

BTW, OP, is that an overdrive atop bass cabs in your sig pic? If so, how is it for bass particularly at a gig level?

Dont think it is - knobs are all wrong.

They are rubbish for bass anyway. No tone, no guts!
(Yeah, right...)

The tones for bass are fantastic. The main problem is simply that you run out of clean headroom REALLY FAST with these amps. For 100+ watters the clean headroom for bass really is pretty pitiful. Never stopped me using mine of course, but it does mean you need to use really good efficient bass cabs if you want to stay anywhere near clean(ish) at gig levels.

Now that I have other clean bass amp solutions my own Overdrive is allowed to live up to its name. Best bass 'Overdrive' unit I know of!


Andy.

[ironlung40]

BTW, OP, is that an overdrive atop bass cabs in your sig pic? If so, how is it for bass particularly at a gig level?

Dont think it is - knobs are all wrong.

They are rubbish for bass anyway. No tone, no guts!
(Yeah, right...)

The tones for bass are fantastic. The main problem is simply that you run out of clean headroom REALLY FAST with these amps. For 100+ watters the clean headroom for bass really is pretty pitiful. Never stopped me using mine of course, but it does mean you need to use really good efficient bass cabs if you want to stay anywhere near clean(ish) at gig levels.

Now that I have other clean bass amp solutions my own Overdrive is allowed to live up to its name. Best bass 'Overdrive' unit I know of!


Andy.

I've got to get a good bass cabinet. Currently, I'm not in a band, but have all sorts of song ideas floating around, but have no bass setup for home recording.


I believe you'll make a bass amp out of anything, Andy!

Seriously, does that rocker 30 sound that good for bass?

[a.hun]

I believe you'll make a bass amp out of anything, Andy!

Seriously, does that rocker 30 sound that good for bass?

Totally OT, so apologies to fiaj - but what the 'L'...

Yep - damn right. It is like an illness - I'll try bass through most things. Thats exactly how I got into Orange in the first place!

When I started out playing bass I first grabbed a 15W WEM Dominator Mk.III valve guitar combo. I'd heard that valve amps were best you see, and it had a 12" speaker. Well this one wasn't any bleedin' good for bass, no power, just instant overdrive - burble burble burble.
So I sold it and got a 60W HH Studio Bass combo. It was rubbish too - no guts at all.

Decided I needed me something with more guts and more power. One day when scowering the shops looking for something to make my bass sound like a bass I spotted this bright orange lump which even said 'Orange' in big cheery letters. Hmmm...
"Does it work for bass?" I asked. "Well lets try it and see!" said the shop guy, rubbing his hands with glee. That was back in 1980, and clearly it did - clearly still does it for me too!

About 15 years later (having worked through a couple of crappy bass cabs and found one which worked, my old 4x10 Peavey), I got the chance to stay at a friends commercial recording / rehearsal studio. I ended up living there for about 7 years. That was great!!!

By that point I had started mucking about playing and recording guitar and had a second amp - my Peavey Classic 30. That sounded okay for bass too but I soon learned that they shake up their EL84s which go microphonic, especially with bass. So I stick to guitar with that one.

But living there gave me the chance to try out a lot of different amps and speakers, and I soon found out what worked for bass too. If it had a small speaker I wouldn't expect too much, but I'd still hook it up to a bigger cab anyway to try. (Not always a bass cab either.) Still do that a lot. Thing is you'll never do any harm to a healthy amp itself by putting bass through it. Yes you do have to be a bit careful of guitar speakers, but at low / medium volumes its never a problem. Sometimes I've pushed them pretty hard too. Carefully enough though that I've never yet blown a speaker playing bass. (I have blown the odd speaker but thats another story!)

Bass amps usually have much stronger EQ circuits than guitar amps which usually work at different frequencies. But most good guitar amps, ones with a decent basic clean sound anyway, can be made to sound good for bass. If the EQ doesn't really work for getting great bass sounds then I'll cheat and use something external with some sort of EQ. My 4 band fully parametric EQ is really versatile - you can do about anything with it. Parametrics are fiddly though - easy to go boosting and cutting the same frequencies. For simple effectiveness my current favourite is the Tech 21 VT Bass DI. That has simple but powerful tone (and gain) controls with very tweakable mids as the 'Character' knob mainly changes the midrange character (and gain). Great box. Tweaking the mids are where it is at for bass and it lets me do exactly that.
I've also used their 'Bass Driver DI' at times but don't own one. Being a 'Sansamp', ('sans' = 'without'), an amp really is optional. You can run them direct to tape or PA and get great sounds very simply. Pro kit for pro bass sounds. Recommended!

Anyway... being stuck on Orange for so long I didn't feel the need to buy any more bass amps until 2005. But I've played plenty and I've seen things go full circle on design. Bass amps got more and more complicated, often with really complicated EQ's. Separate standard rotary EQ sections with a switchable multi band graphic EQ became almost standard. (And various other effects, low octave generators, loops, 'enhancers', separate compressors - somtimes dual low / high band ones, and of course the posh ones would have a token valve bunged in somewhere too!) They were very tweakable, but that didn't guarantee great sounds.
Some did sound fantastic, especially when you leared how to use them properly, but no guarantees. A real favourite amp when living at the studio was a '70s Peavey Series 400 bass head. That thing had a standard 3 band rotary EQ plus this 6 band EQ...

...which could be set and blended in to taste. Brilliant sounding amp!

But now things seem to have gone back full circle towards simplicity, which I like. I grabbed my second bass amp in '05, my 100W Ampeg B-100R combo. It has a straight 4 band EQ plus 3 simple push button tone tweak switches for bass / treble boost, mid cut. Simple, effective, versatile and a great sounding combo.

You'll see plenty really high end bass amps again with just a simple 3 band EQ. (AD200B! ) Often thats enough. It certainly is with no.3...
My Hiwatt DR103 has 3 bands (plus presence) and is really no.1 now - flat out the best bass sounds I've ever had with a straight bass --> amp --> speaker rig. For starters it does very loud clean, which the Orange doesn't - it is really a dirty amp. And the EQ is way more powerful and effective than on most other amps. You can put ANYTHING half decent through a Hiwatt and it'll sound fantastic!
No.4, a recent Genz Benz Streamliner 900 also just has a 3 band EQ, though there are 3 freqency range settings selectable for the mids. Again a tremendous sounding amp, tons of power (500W @ 8 ohms, 900W @ 4 ohms), and oceans of smooth rich bass, and smooth top end too. The bass and treble are a modified passive Baxandall stack, and the midrange is a separate active control. More power in reserve than I'll ever actually use - way more than a big all valve Ampeg SVT - and it weighs all of 3kg. Impressive amp.


Main point though is that only two of my 4 bass amps are dedicated bass amps at all. So, guitar amps for bass? Hell, yeah!

Fender Twin Reverbs sound fantastic, even through their own speakers. I've done a lot of recordings with them.
Big old Music Man amps, with their solid state pre's and valve power sections, are wonderful amps for guitar or bass.
Old Marshalls often had good bass and can make good bass amps. Modern ones don't and (IMO) don't.
Got some of the nicest bass sounds I've ever had from a friends old 20 - 25W EL84 Traynor combo. Through its own 12" speaker.
My old Top Boost AC30 head is (by pure chance) a 'B' for 'bass' version. It has more bass than the 'Normal' or Treble' variants and is usable but frankly not that fantastic for bass.
My wee 10W TOA valve PA sounds good though - at low volumes it even stays clean. With external EQ it is a wee winner, a real recording special. The overdrive is fabulously smooth too - great for rocking drive sounds with something like my Dano Longhorn reissue.

Basically if a guitar amp has a good full core sound (and the speaker is up to it or you put it through something which is) it'll probably work well enough for bass - at moderate volumes anyway. It is always worth trying.

And yes, the Rocker 30 sounds great for bass. The V.30 in the combo isn't ideal (bass is pretty tight and not that deep), but with a whack of (external) bass boost and maybe some midrange tweaking it is fine. Through a bass cab it really does sound nice, and very distinctive. Very like the tones I'm used to from my OR120 in fact!


Andy.

[bassdrop]

I thought I would resurrect this old thread because I recently talked to someone at Orange USA HQ. While they confirmed that the Tung Sol KT120 would most likely function in the AD200, that they have not tested compatibility and do not support installation of the KT120 in the AD200. The only tubes supported will be 6550s or KT88s. This would be especially helpful to any AD200 owners who still have warranty left on their amps since using KT120s may well void the warranty. Me, I'll be sticking to good 'ol 6550s.