Why 100 Watts?

[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.

[krash]

well this is interesting.

I have been considering building a low-watt amp with two parallel 12AU7s in push-pull (the equivalent of 4 output tubes). I wonder if it really will sound any better. It will certainly be louder

[Tonegeek]

Over the years I have heard countless comparisons of 4 tube output amps vs 2 tube amps and for whatever reason, my recollection is that most people prefer the sound of 4 tube amps (even if only slightly) over the 2 tube versions when it comes to tone, extra harmonic content, etc. I think I agree with this consensus as well after using all variety of 4 vs 2 output tube amps. For your ponderance: if Duane used 2 50 watters, isnt that the same as 1 100 watter in terms of harmonic interaction, etc. (assuming they were both on at the same time)? Even the Dumbles (which don't rely on an overdriven output section) seem to sound better with 4 outputs. Still, I agree with Krash that smaller wattage is the way to go. Don't know if 2 watters will catch on, but there are plenty of people with 30-40 watters out there and the market is big for these amps. Just look at what those go for on eBay vs what a 100 watt Twin sells for. The Twin is not selling at a premium. Let the amp get the tone and let the PA do the work. What good does it do to have a 100 watt non-master amp if you can't crank it up to get the output working? with a 100 watter, You are hauling around this extra weight, it will heat your house, and is more expensive to maintain. That teeny bit of extra 4 octal mojo just isn't worth it unless you got roadies and are playing on a large stage. It's not practical, but then again how many musicians are practical when it comes to tone? I think the 4 output low wattage idea is solid. One of my favorite amps is a Peavey Classic 30. Its a great sounding 4X EL-84 circuit and can be modded to sound even better (been there and beyond thanks to Steve Ahola). I believe this circuit with slight modifications, and if built by hand on an eyelet board, and in a good cab, and with a good speaker would hold its own with anything in its class (ok basically replace everything but the knobs!). Too bad Peavey chose to do it their normal, cheap as possible way. I digress. 4 outputs gets my vote on tone.

[krash]

Well just today I finished building a customer amp with a 1/2 power switch that turns off two of the power tubes (it's a 4xEL84 amp). The amp sounds almost identical in two-tube mode as it does with all four. I would say that if you didn't know the switch position, there's no way you could tell the difference. In fact the difference in volume level is only very very slight. Mostly it's a dynamic difference that I think is related primarily to power supply load.... the amp feels a little more compressed and "chewy" with all four tubes on.

I'll probably build myself a four-power-tube 12AU7 amp to play with but there is kind of a problem coming up with the right output transformer. I guess I could just use the one I am using into a 4-ohm load.

BTW I have worked extensively on a Classic 30 (it's my main prototype platform, test mule). The stock tone is dominated by the sound of the cathodyne phase inverter, and the boost switch. I really think the cathodyne PI is an under-utilized animal. But I don't think you are getting a lot of power stage distortion in these amps. They are biased pretty cold and have a real high plate voltage (like nearly 400V). But anyway, my mid-30s watt amps (Revelation 72) are remarkably loud. It's just that when they are loud, they are also distorting quite a bit. I think the only purpose in a 100W amp is if you need loud AND CLEAN.

[David Root]

Interesting idea, krash!

Why not try a Hammond 100 series OT, the one with multiple Zprim/Zsec combinations, in a suitable power rating. You can get some pretty off the wall Zpri with those. They don't cost big bucks, and if you want wider bandwidth than 40-15kHz you just go up one size.

[jaysg]

Well just today I finished building a customer amp with a 1/2 power switch that turns off two of the power tubes (it's a 4xEL84 amp). The amp sounds almost identical in two-tube mode as it does with all four. I would say that if you didn't know the switch position, there's no way you could tell the difference. In fact the difference in volume level is only very very slight.

I bet it 'throws' better in a club -- noticeably louder at the back wall.

[vibratoking]

I have several amps with 1/2 power switches. I can't hear or feel the difference. Since they are all too loud for me, I remove the two unused tubes and save money by not running or replacing them.

[Structo]

I have noticed with the EL84 amps that having four of them compared to running two is not as dramatic as with the large octal power tubes.
Not sure if this has to do with plate area or what.

[UR12]

A 1/2 power switch actually removes two tube from the amp
so there is no need to physically remove the tubes. If you use the
feature a lot you might want to swap the pairs around so they
all wear the same.

[selloutrr]

Hey Gang,

I'd like to get the opinions of guitar players on 100 watt amps. First, let me say that I am not a guitar player. I'm a geek who has become consumed by how guitar amps work and I have a past in the recording business (only as a hobby nowadays). What quailties can be found in a 100 watt amp that can't be found in lower power amps? The 50 watt amp I built can produce in excess of 124 dBA, plenty to wreck my ears. As a guitar player, why would you pick a 100 watter over something lower powered? Like I say, I don't play myself, and this has been something I've been curious about for awhile.

Ted

the 100 watt + amp came about out of necesity to play larger venues in the 60's - 70's when PA systems were under powered and pieced together. so volume mattered in the sense that without it you wouldn't be heard. the 80's were more about looks and much like hair who had the most or biggest stack. Now with advances in PA systems the wattage is more of a hastle then anything else. Needing to turn up to 8 to get the "tone" and being to loud for the room. leading to iso cabs and power breaks.
In the studio it's 50/50 some 100 watt amps do exibit a sense of "air" or more open top end then a 50 watt model. but if you are after a hi gain or full out tone you're sure not going to want to be in the same room. making lower wattage amps a prime pick to drive hard and track Preamp and output tube compression.. this has led to the boom in small 5 watt and under amps like the valve jr, blackheart, etc.
I guess a benefit to any 100 watt 4 tube amp is that you can remove 2 tubes and cut the ohm load in half and you have a 50 watt model.

[martin manning]

I guess a benefit to any 100 watt 4 tube amp is that you can remove 2 tubes and cut the ohm load in half and you have a 50 watt model.

You mean double the load... but with the same speaker impedance you'd move the selector to half of normal.

[Ken Moon]

Since you guys are digressing. Back in the day in the late 60s and early seventies we didn't have 100kilowatt PA systems to mike everthing up. Those 100 Watt amps were standing on their own. The only things through the PA were vocals. Now days you can easily use a 15 watt amp cranked , miked and amplified by the sound system. If you can't hear it on stage they can put you in your own monitor mix. I can remember that is was nothing to use a Crown DC300 or D150 for the whole PA.

Here is a pic of the band I was playing with in 1974. (I'm the drummer in the right ) It's a wonder I can still hear.

Hey Dana, you're old

Here's me in '74 - I only had a Dual Showman Reverb with 2-15s - I don't know how the audience even heard me

[IMG740]http://i514.photobucket.com/albums/t346 ... 80_jpg.jpg[/img]

[Travst]

I don't use high-watt amps now, but back in the day I loved my Orange Hustler 125 combo at 120 watts through 2x12s. With a '70 335, it had the biggest, fattest sound I'd ever found. I played a Dual Showman into a Sunn 410 until that time. There is some magic to some high-watters, but it's not just the watts. I've played a few very sterile 90+ watt rigs.

[iknowjohnny]

uh.....................because it's 50 more, innit?

[Reeltarded]

Woohoo Dana, double stacks!!!!

To my ears, 4 power tubes have a different sound than 2. Maybe the slight imbalance adds harmonics.

A Marshall 50 breaks up early, and has a slightly grittier sound than a similar Marshall 100. You can't get the same grit with the 100, and you can't get the same lowend with the 50.

I like 100s with a Rat as a lvl boost. (dist near 0, tone straight up, dimed output) I can like a 50 without boost. Basically same amp.