Why 100 Watts?

[Firestorm]

It's technically possible (or at least almost possible) to build a 4-output tube amp that sounds the same as a 2-output tube amp (only louder), but it requires more circuit modifications than manufacturers typically want to do. Obviously the power supply has to provide more juice, the output transformer has to handle more juice and the OT has to be wound for half the primary impedance. That's about as far as anyone goes.

But to really make a 100-watt version of a 50-watt amp, you've got to increase the capacitance on the output tube grids, reduce the value of the grid return resistors, redesign the PI to compensate for the frequency shift caused by the higher input capacitance, and redesign the feedback loop for the higher transconsuctance of the paralleled output tubes.

That's a lot of work just to make an amp that will seem only slightly louder than the 50-watt version. Especially considering that if the guitarist needs to be heard over a loud drummer, he or she can usually get there by buying another 4 x 12 cabinet.

[krash]

The issues Firestorm just posted are precisely why (in inverse) many small amps sound small, or entirely different.

You have to scale everything if you want it to work right. And then you have to tweak it some.

And FWIW as a builder of small (sub-2watt) amps and also bigger amps, I can say unequivocally that even though for most guitarists today, especially home recording guys and the like, a sub-2watt amp is going to be far more useful and more enjoyable, I still sell a LOT more of the big (35W+) amps.

Mostly it's a matter of economics. If a 30W amp costs $1800, then a 2W amp should cost 1/15 that much right? less than $200? Nope. Very few of the parts in a 2W amp are less expensive than those in a 30W amp. Yeah the power transformer is about 1/2 the price. The OT is about 2/3 the price. There're fewer tubes and tube sockets. But other than that, the rest of the amp is basically identical. Same chassis, pots, board, capacitors, resistors, hardware, cabinet, etc. So it costs nearly as much to make a 2W amp as it does to make a 30W or 50W or 100W amp with the same features.

Anyway that's the idea behind the "standard line" of amps I am trying to market... low-watt amps with the real tone and boutique build quality and parts, but at a much lower price... but I'm still not getting any traction selling them. Nobody wants to shell out $500 for a 2W amp.

Maybe if I market it as a 100W amp modeler, 100% analog tube based, it will sell. put a headphone jack on it.

[Johnhenry]

BobI, do you know who modded the Champ's that Duane and Eric used on the Layla session's ?
Johnhenry

[Robert Rowe]

Hello.

My first post.

I am not an amplifier-builder ... but, a user (a player). Also, I've "been around" ... saw Jimi before he was "Jimi" ... (Jimmy James and the Flames, at the Cafe Wha? in the Village). First live Rock-'n-Roll act I saw was Link Wray (stood 4 ft in front of him) ... etc., etc., etc.... Lotsa "war stories". But, another time for all that.

Just want to establish some credibility ("bona fides", if I remember my Latin). I've seen a lot of live acts ... many of the "big names". I always tried to check-out the equipment. I play guitar / bass / mando / Trumpet / Fluegelhorn.

Anyhow ... back to the post-topic ....

It occurred to me that two identical 50-watters used together always seem like a better set-up than one 100-watter. Many years ago, I acquired an early Hiwatt 100-watt stack. Was not pleased ... sold the rig, and bought a couple early (Reeves-era) 50-watt Hiwatt's (still have 'em). I am very pleased with the flexibility.

I go for stable headroom ("clean"). My "main-squeeze" is a vintage Ibanez GB-200 small-bodied jazz-box ... but, I am not a straight-ahead "Jazz-Bo". More rock-a-billy (and some "psycho-billy"; ... think Brian Setzer meets The Clash). I use a "hybrid"-picking style (pick + 3 fingers of right-hand).

With the Ibanez GB (using Pyramid Gold roundwound 12's ... or Thomastik Infeld flatwound 13's), I need very efficient speakers for clean headroom. JBL D-130's, EVM's, etc.

I find that higher-powered amps deliver tight pedal-tones, at ppp or fff volume-levels ... (with the above efficient speakers). Low-wattage amps do not provide enough "texture". I play in a duo or a trio, with no bass-player. I need this "texture" for a substitute for a bass. Clean headroom is essential. High-powered amps are necessary to achieve this.

Most of you probably don't want to hear this, but I often use a vintage Sunn or Acoustic solid-state amp (very high wattage). Germanium transistors provide great "clean" with "warmth". Tone remains the same at "1" (volume pot) as it does at "10" ... my studio, or Shea Stadium. Same sound / tone. Also, totally reliable.

Please -- no gnashing of teeth / wearing sack-cloth / plucking your beard / beating your breasts. I'm kinda bored with high-gain tones. Everything begins to sound compressed and muddy.

I have about 50 vintage, "high-end" amps (almost all are tube) ... some, you've probably never heard about. I still use those solid-state amps, occasionally.

BTW -- I've got a couple Jim Kelley amps (four 6V6's ....). I don't think (?) any other amplifier uses that tube complement ... (correct me if I am wrong). Amazing headroom ... and amazing modest-gain tones with harmonics all over the place. Ken Fischer tipped me off about these (and also, the Sundowns). They do require alternate speaker configurations to maximize tonal possibilities. (More on that, another time).

Anyhow, I'll have to put my "vote" in on the higher-wattage set-ups ... particularly, in light of my choice of axe, and my style-of-playing. I don't have to play loud. I do appreciate the string-to-string articulation and the fine tonal-palette, at any volume. Better dynamics with the higher-wattage amplifiers.

[Andy Le Blanc]

the difference in tone between 50 and 100 watts is because of the effects of paralleling of the out put tubes
the output impedance is divided and the out put is multiplied by the number of tubes
lower output impedance permits the use a trannie with a lower primary impedance
the lower impedance means a broader bandwidth
also the driving stage sees a differnt capacitance
one can probably make a 50 ( or a 5) that sounds like a 100 if the tube selection
and circuit conciderations reflect these differances

[6G6]

The biggest difference in tone is from the 100 watter having more headroom.
Very few people can dime a 100 W amp for long without somebody getting bent out of shape.
I also agree that four octals will sound different than two.
No matter how well matched those tubes may be, they cvan never be absoluely identical.
Back in the day, I can remember finding that a Dual Showman wasn't quite as loud as a Sunn 200S, even tough the Sunn was "only" rated at 60W.
That is one example of a four tube amp compared to a two tube amp.
I think that, ratings aside, they both put out about 85-90 W, but sound very different. More than just different tube types.
Part of the Sunn's extra cleaness is the lack of extra harminics from another pair of tubes, reacting slightly differently from each other.

[roberto]

IMHO a big difference is done by power supply and trafo out. The first makes the amp more dynamic at low volume setting, the latter is well explained by AndyLeBlanc (also more iron than 50w OT).

[dobbhill]

FWIW: the Sunn was an Ultralinear OT rated for 120 watts run at over 500v B+ using tubes with a plate dissipation rated for 42 watts each. Not really an "apples to apples" comparison to the Twin.....
D

[CaseyJones]

I think y'all are comparin' apples to oranges.

For the sake of good science try plugging a small amp into the same speaker setup as a big amp some time. Traditionally the difference has been that little amps use cheap speakers, little amps use cheap speakers because the guys who build them want to save some bucks and by the same token the guys who buy them want to save some bucks. Traditionally little amps use cheap speakers and they use less of 'em.

Plug your 100 watter into a sterile soundin' setup like a single EV 12". Then plug it into 4 x 12". Then plug it into a mixed setup of 4 x 12", say a Greenback, a Blue, maybe an old D120... whatever you have, mix 'em up.

Then plug your small amp into the same setup. If it sounds weak start lookin' at why, if it has an itty-bitty cheapo junker tiny OT that might be your culprit right there.

A 100 watt stack is just the easy way to get thick tone and perhaps the only way to get ear splitting volume onstage. Trust me, you can crank up a little ankle biter of an amp, shove an SM57 right up against the speaker grille and it's gonna sound ten feet wide in the mix.

[krash]

true about miking the amp.

anyway I'm going to keep building low watt amps even if i have to keep them all for myself. with typical huge installed sound systems, in-ear monitoring and that kind of thing, the days of needing a big amp are soon to be over IMHO. my low-watt amps have fantastic clean tone. it's just not very loud. once you mic it, it's plenty loud.

[roberto]

I was talking about same cab configuration, same preamp, only supply and trafos changed. I think also other people mean the same.
I don't need to crank a 100w to hear my guitar onstage. My 2channel 11W SE head is enought, and cuts the mix very well, but the 100w is wider and fuller, and sometimes I need it.

[Structo]

So what I gather from the preceding diatribe is that 100w amps just simply have more balls than smaller amps.
Have a bigger "feel" when playing and push a hell of a lot more air.

But to get to the sweet spot where the power tubes are cooking, you are talking about pretty big SPL's as well unless you put a brake on it.

For me, 40-50 watts on a couple 6L6's is plenty.

[6G6]

My original point was about two tubes compared to four.
The Showman/Twin compared to a Sunn 200S is apples to oranges, but I couldn't think of another two tube amp that had about the same power as a well known four tube amp.
There might be some point in building a four 6V6 amp, with big iron, to get a big sound and only mostly ear splitting volume.

In my case, I'm a bass player, so I expect my amp to be able to make my pants flap around.

[Firestorm]

In my case, I'm a bass player, so I expect my amp to be able to make my pants flap around.

Ahah -- then what you need is 4 x KT88!

[Stanz]

I had a theory recently as to why a four tube power section sounded better than a two tube power section.

With synths, to build your sounds, you stacked "voices" (sound sources) and detuning each slightly would add a fullness and richness to the sound.

Seeing as how each power tube will be putting out a slightly different version of the signal, I would imagine using four power tubes adds a richer mix of tones.