Comparing Tube and SS amp ratings

[b0b]

Based on that, I'd "hazard a guess" that the N112 is roughly equivalent to a 25 watt tube amp.

So, a 50 or 60 watt tube amp would simply blow away a N112?? Thanks, that answers my first question. Now, if someone had a 50 watt tube amp and plugged into the speaker of the N112 wouldn't they effectively have a 50 watt tube amp and 2 speakers (the one on the tube amp and the one on the N112)???

Output power increases as you decrease the impedance (ohms) of the speaker system, which is what happens when you wire speakers in parallel. This makes the amp run hotter. If your impedance falls below a certain point (varies by amp design) you run the risk of overheating the power amp and blowing it up.

The formula for calculating the impedance of two speakers wired in parallel is (AxB)/(A+B). Two 8 ohm speakers gives you (8x8)/(8+8) = 64/16 = 4 ohms. I don't know of any tube amp that would have a problem with a 4 ohm load and yes, it would be a little bit louder.

If you're carrying the N112 around anyway, why not use both amps instead of just using the speaker of the N112? Two amps would give you a louder, richer tone that one amp with two speakers.

[Dan Tyack]

I've had similar experiences, David. My main amp is a THD BiValve, which like yours is a dual tube class A (parallel single ended) amp with massive power transformers. It's easily loud enough at 30 watts max to hang with any on stage volume I deal with.

That said, I would imagine that our tolerence (preference) for tube distortion is different than 99% of the pedal steel players out there. I know that while I love the sound, Donny Hinson probably wouldn't be happy with the amp sound I get when I'm keeping up with a guitar player playing through a Marshall Plexi. To play really clean at loud volumes I add an additional power amp (currently the Crate powerblock) driving an additional cab.

[Richard Sinkler]

JUST preamp distortion can sound weenie,
hence the many real tube pedals that don't
make you a guitar god just by pluggin them in.

But if they are used to push over the distortion edge
of the power amp section, then it is a cool sound indeed

David D.,

I use a Damage Control Liquid Blues stomp box with 2 12AX7 tubes. Using your statement above, would it be possible or advisable to run this pedal in between the preamp out and power amp in of a Nashville 400? Currently my signal chain is guitar-BoBro pedal-Liquid Blues pedal-Goodrich LDR2 vol ped-Nashville 400.

[Dan Tyack]

I think David was talking about the preamp tubes pushing the distortion characteristics of the tube power amp. Since the Nashville 400 is all transistor, you wouldn't want to push the power amp (not a pretty sound), so using it as a line level effect wouldn't be advised.

I've heard that the Damage Control boxes are good sounding, how have you found it?

[Richard Sinkler]

Hi Dan. Thanks for the info.

The Liquid Blues sounds pretty good. A guitar player I play with that uses a Mesa amp (with great overdrive) loves my pedal, although he doesn't need it with his Mesa. As far as how it sounds against other stomp boxes, I can only compare it to the Digitech Distortion Factory modeling pedal I was using. There were some good models in the Digitech, but this pedal blows it away. I get more noticable string seperation when using the Liquid Blues as opposed to any of the overdrive models in the Digitech. And when you hit the "Nuclear" switch on the Liquid Blues, the pedal really screams.

Interesting tidbit of info: Damage Control is in the Peavey family of brands.

[Don Poland]

Thanks guys, I really appreciate all of the input. This gives me food for thought.

[David L. Donald]

Dan is correct,
I was refering to the small 12**7 type tubes
pushing the output tubes into distortion
with a touch of their own Odd + Even distortion
in the mix.

12ax7's are two stage so the 'real tube' pedals are
taking the signal adding gain in stage 1 and then
sending hotter gain into stage two,
and then out to your amp.Be it SS or tubes.

Some boxes have two tubes and add some eq
and possible another gain stage or two.
Several small stages of controled distortion gain feeding
each other is getting to the Marshal sound,
odd/even adding onto odd/even and building multiple layers.

I know someone who has just built a 5, 12AX7 tube preamp
5 gain stages all tweaked for a bit more and a bit more,
cumulatively adding different levels of odd and even
from harmonics each stage.

But all that STILL sounds better hitting
a pair of (or one) output tube choosen to give
a bit of break up at levels, happy with the band in question.

No, putting the pedal into the preamp in/out of the NV400
and would be no better than putting it right after the Blackbox.
Getting your steel into a Black box and then into
a multi stage tube pedal will give a pretty good sound.

But nothing like Dan's Univalve output scaled
to match the band and cranking from stem to stern.
If you like distorted sound,
he gets one of the best I have heard on this forum.
Smooth but gritty, and as tube heads say "Creamy".
Hard to explain that one, but it IS an amp design goal....

I have looked at this amp as a theroy excercise,
and it is a pretty darned cool unit.
I want one, but will have to build something close instead.

[Dan Tyack]

Thanks, David!

The Seymore Duncan Twin Tube stomp box (no longer made) is the best box I've heard. I believe it's magic is due to the use of tiny output style tubes (NOS from the 60's, apparently for use in satellites).

I actually like my ZenDrive stomp box (100 transistor) better than any tube driven preamp. But then I mainly use it with my clean tube amp (a sweet 1965 Showman). It makes that puppy sound like a Dumble when cranked.

[David L. Donald]

I will be doing a twin tube stomp box at some point.

I like those mini tubes too.
There are some TINY amps built with them
but with suprisingly big sound.

Small tubes: How small?


What can you do with them?



A Mini Fender Deluxe amp.
Class AB push pull sub-miniature guitar amp





Class A Single Ended subminiature guitar amp
A mini Fender Champ amp.



Scale is the knobs from a Fender Precision bass...

[Dan Tyack]

Beautiful, David!

I'm going to have to get one of those to go along with my lightweight steel for fly gigs (I like the idea of an amp I can put in my pocket).

[David Doggett]

On Dan's advice I got a Seymour Duncan Twin Tube, and it is by far my favorite. I run it in front of my volume pedal, and there it is pick sensitive in a way I have never found in another stomp box. I guess because of the tubes it is very amp-like. I've also tried the Zen Drive II, which has a tube. It does get that thick Dumble sound. But it is more like a fuzz box in that it is always on. I can't get it to be pick sensitive.

I have a Fender silver-face Pro Reverb with a 15" JBL D130F reconed to 4 ohms. It had some black-face changes made on it. It's a pretty good blues amp, but that ruined it for traditional clean steel. Unless I am going to carry two amps around, I think I am better off with a clean silver-face amp with the Seymour Duncan for pick-sensitive grit.

[Donny Hinson]

So, a 50 or 60 watt tube amp would simply blow away a N112??

No, not really.

If you're happy with distorted, or "warm overdriven" tones, then yes. But when you're talking CLEAN tones (those with no distortion), "tube watts" are EXACTLY the same as solid-state watts.

(When a speaker gets 1 watt of electrical power, it doesn't know what's supplying it, tubes or transistors.)

The thing some people here seem to be overlooking/ignoring is that a (rated) 40 watt tube amp will actually put out far more than 40 watts when driven into overdrive, maybe even twice that! Whereas, a (rated) 40 watt solid-state amp, with protective (limiting) circuitry, will only put out 40 watts.

It's got nothing to do whatever with "tube watts vs. transistor watts", but with the way their respective circuitry is designed - tube amps don't need (and seldom have) "protective circuitry".

When tubes overheat, they'll sometimes actually work better. But when solid-state stuff overheats...it usually just melts.

[David L. Donald]

I have seen REALLY great work referred to as "Amp Porn".
This little babies sure fit that.
What great works of art, AND working units.

I just ebay'd 4 of those little long wired tubes
next to the Duracell. Originally for hearing aids,
and space travel...
Yep Nasa specs. Almost up to rock n roll specs.

Each one is a twin triode, like a mini 12AX7,
so a total of 8 possible gain stages
I will design a little stomp box,
that gets thick like a Soldano,
but can bypass some stages if I want
and have a bit of EQ in there too
maybe BnT in one stage, a mid on another
and a different mid on a third
With gain controls between EVERY stage.

A little somthing to put in front of the
'59 bassman, that's next on the list.

[Dave Mudgett]

OK, Dan and David - I just ordered a Duncan Twin-Tube Classic Pedal SFX-03 from AMS (B-stock at $180 including everything, there are 2 left for anybody that is looking for one of these a bit cheaper). All the major outlets are still showing them in-stock, BTW. But I don't want to wait until they're gone before I decide I want one. I have to admit that I'm one of the world's biggest skeptics about overdrive/distortion pedals. Replace my old Fender/Gibson/Maggie amps? I doubt it. But this sounds like it might be cool.

On the subject - power ratings - I think watts are watts, but agree that one can reasonably push most tube amps well over rating before the output is unusable, and that isn't the case for the classic bipolar transistor power amp section.

But another point is that an overdriven tube amp sometimes seems louder because of the increased compression/sustain effect where the volume stays high as the input signal envelope comes down.

To that last point - I think modern solid-state amps have achieved some of this with limiter/compressor circuitry like the DDT system Peavey uses. This allows one to push, let's say, a NV 112 harder without blowing it up and achieve a clean version of that compression/sustain effect. I think that's a big part of why I like these new pedal steel amps - and like them I do, even though I'm really a seriously old-school, tube-amp guitar player.

I had a chance to use a Zen Drive on a recording and gig over Xmas last year - he handed me the thing and said "try it on this track". I admit it was pretty durned good (too much for the track, we redid it clean), but I still preferred my THD Flexi 50 for something close to a David Lindley-style Dumble tone. Still - there are a lot of situations where that trick would come in handy in a tiny little box, so I guess I need to get on the list. Or maybe this Duncan will do it too. We'll see.

Not that I'm doing many major-travelling gigs, but I also like the idea of being able to put my "amp tone" into a small package I can conveniently carry around, and then plug that into a very linear power amp system supplied by "the house". I guess that's why I spent so much time fiddling with my Pod 2 getting what I wanted for guitar out of it. Yeah, they're not perfect, but to my mind, much better than any preamp I've tried yet for this purpose, and it makes rapid steel/guitar switches easy.

I think if a modeler gives enough real degrees of freedom and one takes enough time to really dial it in, one can do a lot with them. I realize that may be sacrilege to many, but I think that one can get "the sound" early in the chain and amplify it, or have "the sound" happen later in the chain (like in the power/speaker section of a tube amp). In fact, I think this was part of the major mindset change in the 80s when guitarists went from carrying around huge stacks of amps and getting most of their sound from the backline to simply micing a smaller amp that had "the sound". This thinking is gradually extending and I believe a new and useful paradigm will eventually emerge.

To me - the issue for tube amp modeling is to really understand what is producing "the sound". It's very complicated, but I think it's a matter of time before this gets sussed out in yet better ways.

[David L. Donald]

Yeah that's a cool little box.
I can't order one,
they only ship to Canada and Puerto Rico.
No respect for yanks abroad.

But I have those tubes coming,
so just build one myself
with MORE gaine stages. 2 tubes for each channel
and gang both channels ooh ooh!

I wonder what tubes they used in Sputnik?

We have Frying pans
we should play them through Baking pans...

'Cephus' built this unit.




Of course some guys just can decide Marshal or Fender.
But how about TWO speed fast and slow tremelos
Leslie like, in a Marshal and Fender combo.....

Sort of Stevie Ray meets Steve Stevens.

So 'Phsyconoodler' built this one recently;



Like a Limosine.



But some like to RIDE!!! into the night.
So from Fryingpan to baking pan to Panhead.



Of COURSE 'Panhead' built this for a biker amp customer.

[Dan Tyack]

I'm going to restrict my review of the Zen Drive pedal.

On my 60s Showman head, which was modified by Andy Marshall (of THD Electronics fame) to 'blonde' specifications (actually to more of a Dumpble tone stack)), if I use the Zen Drive pedal *after the volume pedal*, I get a killer, killer, Dumble like tone as long as the gain of the amp is at least 3 (in other words, really, really loud).


My experience with other amps hasn't been as positive.

[Dan Tyack]

So, a 50 or 60 watt tube amp would simply blow away a N112??

No, not really.

If you're happy with distorted, or "warm overdriven" tones, then yes. But when you're talking CLEAN tones (those with no distortion), "tube watts" are EXACTLY the same as solid-state watts.

(When a speaker gets 1 watt of electrical power, it doesn't know what's supplying it, tubes or transistors.)

The thing some people here seem to be overlooking/ignoring is that a (rated) 40 watt tube amp will actually put out far more than 40 watts when driven into overdrive, maybe even twice that! Whereas, a (rated) 40 watt solid-state amp, with protective (limiting) circuitry, will only put out 40 watts.

It's got nothing to do whatever with "tube watts vs. transistor watts", but with the way their respective circuitry is designed - tube amps don't need (and seldom have) "protective circuitry".

When tubes overheat, they'll sometimes actually work better. But when solid-state stuff overheats...it usually just melts.

I agree with most of what Donny says. However, in terms of what most steel players would percieve as being 'clean', I'd say that the ratio between tube and transistor amps is somewhere between 2X1. As Donny mentions, when tube amps overheat, they sound pretty good. When transistor amps overheat (get close to rated output) they sound like crap.

[Eric Jaeger]

Just to complicate things, I daresay no one here runs their amp at flat-out "10" (or for that matter "11" )

That being the case, we really have no idea how much power you're putting out without slapping a meter on the outputs, and *that* won't tell you anything without knowing the efficiency of the speaker. And as Jim points out, doubling the amp's power gives you only 3db more output (barely noticeable).

It would be really interesting to know where you all set the volume knob on your various amps. Do people run their NV1000's at "6" and their tubes at "9"?

-eric

hmmm, a graph of volme knob settings vs SPL?

[David Doggett]

I try to bring the smallest amp that will fit the venue. So, yes, I frequently play with the amp flat out on 10. But of course I'll be attacking notes with the volume pedal backed off over halfway - the rest is for sustain. This is why it is so difficult to explain my big amp to guitar players and soundmen. It's not for volume. It's for clean sustain.

In loud rock club gigs where the guitar amps are not miked, I have played pedal steel with a NV400 on 10, or with a Twin on 10. They seemed to have about the same amount of volume/sustain. So Dan's rule of thumb of a 2:1 ratio seems about right to me. I have also played in some situations where neither of the above could keep up (my volume pedal was bumping on long notes and I was running out of sustain). A Super Twin (180 tube watts) on 10 gave me the sustain I needed.

A young punk rocker once blew his Orange head. I loaned him my Super Twin head for the rest of his set. I set the Master volume on 3 and told him not to touch it under any circumstances. He took the channel volume up about halfway and had all the volume he needed. I sat out most of his set outside to save my hearing.

[Dan Tyack]

I've played with a VHT 2-90-2 tube power amp (90 watts per side) through a couple of speaker cabinets that was louder and cleaner than the pair of Session 400 amps ( 200 watts a side) that I used to use with Asleep at the Wheel.

[David L. Donald]

The amp I just built clocks in at 10 watts,
and I am being told to turn down, WITH drums.
It has a LOT to do with the speaker efficiency.

Now of course the MOST efficient speaker
may not have your sound.

[Eric Jaeger]

In loud rock club gigs where the guitar amps are not miked, I have played pedal steel with a NV400 on 10, or with a Twin on 10. They seemed to have about the same amount of volume/sustain. So Dan's rule of thumb of a 2:1 ratio seems about right to me. I have also played in some situations where neither of the above could keep up (my volume pedal was bumping on long notes and I was running out of sustain). A Super Twin (180 tube watts) on 10 gave me the sustain I needed.

Ouch!

-eric

[Dan Tyack]

I hear you, Eric.

When I played with the VHT power amp anywhere near flat out, it was painful.

I'm a lot happier with my 30 watt THD amp. Although I just played the NW Steel jam with my 80 watt blackface Fender Showman. Which I must say was as loud and clean as any amp there (mostly high powered transistor steel amps). I had headroom to spare.

[David L. Donald]

And on into tube absurdities.
Ear V20
TEN 12AX7 tubes in push pull per channel.

Push-pull stereo integrated amplifier operating in enhanced triode mode. 24 wpc into 4, 8, or 16 ohms. Uses 12AX7 output tubes (10 per channel). Self-biasing. Six line inputs and one tape output.


A very clean 24w a channel.
48w is not bad for a clean tube amp.

Might not be bad with a Revelation preamp....with
stereo reverb and maybe a touch of stereo chorusing too.

[Dan Tyack]

Bring on the amp porn!