50 vs 100 watts

[Rex Rocker]

I didn't know dB's = headroom necessarily

I thought it had more to do with power tube clipping. Full windings of a big Output Transformer mean more headroom no?

Yep. And power amp clipping happens when the amp reaches the ceiling of its headroom (meaning how loud it can go without distorting). Thus, 100W can go 3dB louder without clipping.

I'm oversimplifying, since tube amps don't behave like linear poweramps, but in general, headroom in a poweramp means how loud it can go without clipping. More or less.

 

[Racerxrated]

I didn't know dB's = headroom necessarily

I thought it had more to do with power tube clipping. Full windings of a big Output Transformer mean more headroom no?

If you look up an old Marshall owners manual(very quick reading lol) it will say that a 2203/1959 puts out 100w clean power; and something like 175w with clipping/distortion involved. Which is why boosting them will cause even more clipping and put out over 200 distorted watts...some claim even 300w.

https://www.manualslib.com/manual/556268/Marshall-Amplification-1987.html?page=8#manual

 

[311splawndude]

I get it guys, I think we are all saying the same thing. I was just trying to say that decibels and headroom (or watts) are not linear.

 

[easstudios]

Depends on the circuit being the same too, for instance a 2204 has less negative feedback than a 2203 so that contributes to them sounding different.

Another factor is transformers - powering a 50W amp is different to powering a 100W amp, and the output specs will need to be adjusted too.

Some 50W amps sound cool, especially when the circuit was originally designed around being a 50W amp rather than just being a scaled down compromised version of the 100W amp.

Generally though, I prefer the headroom of higher powered amps. You just have a wider sweet spot and more room before the tone starts falling apart

 

[7704A]

Which is why boosting them will cause even more clipping and put out over 200 distorted watts...some claim even 300w.

Dang. Might need two EV's for that. At that point might as well specify power by the size of mammal it'll take down. *slaps headshell* "this here is a two-bear amp."

 

[JackBootedThug]

I'm running a stereo rig....before I was running my tremoverb with a PV ultra + 60.....I picked up a PV windsor and it was a big difference when I switched out the ultra for the Windsor. The sound improved a good bit. At the time I was pretty shocked by how the sound improved. Take into consideration that I'm only using the power stage of the PV's...not the pre's....At first I thought it was because I went from 60 watts to 100 but now I'm thinking it's because I'm using an amp with el34's....plus the extra wattage helps also I'm sure. Personally I think the more power the better. And being honest I'm a home wanker so a lunchbox amp is more than enough....but I really think that the more power helps the sound. more headroom=better tone-dynamics-feel...all imo of course.....nah fuck that-it's SCIENCE...TRUST THE SCIENCE!!!!

 

[311splawndude]

^ good points Mr. Thug.

The iron used definitely makes a difference. I'm guessing that even in half power mode, with half the windings of the OT in use, that 'half' of the OT is still larger than a lot of 100w amps out there

I'm talking about amps with scaling available, like a lot of Mesa's, Splawns, etc. If there are any amp tech/builders/EE's here please correct me if I'm wrong. Not an expert here.

 

[Rex Rocker]

I get it guys, I think we are all saying the same thing. I was just trying to say that decibels and headroom (or watts) are not linear.

Yep, I was oversimplifying. There's certainly nothing linear about a tube poweramp. But the way you measure headroom is in dB.

 

[311splawndude]

But the way you measure headroom is in dB.

OK. Thanks for coming back and clarifying. I did not realize that headroom was measured in decibels.

I thought "headroom" was more of an abstract concept that varied upon lots of factors including decibels, watts, rectification, copper windings, quality of iron, speaker efficiency, boosts, humidity, , etc etc.

 

[Rex Rocker]

OK. Thanks for coming back and clarifying. I did not realize that headroom was measured in decibels.

I thought "headroom" was more of an abstract concept that varied upon lots of factors including decibels, watts, rectification, copper windings, quality of iron, speaker efficiency, boosts, humidity, , etc etc.

No, headroom is an audio term in general. It's sometimes abstractly used to refer to tube amps, because, like you said, you're rarely ever comparing apples to apples with those.

 

[CurlOfTheBurl]

Depends.

Just like most of your diapers.

 

[Rex Rocker]

Also, apples and oranges, but I used to have a Mode Four that was 350W. But it was solid state, and REALLY bassy. Bass frequencies take more power to be cleanly amplified.

And that makes sense. I didn't think feel that amp was any louder than your average 50W or below tube amp.

 

[311splawndude]

No, headroom is an audio term in general. It's sometimes abstractly used to refer to tube amps, because, like you said, you're rarely ever comparing apples to apples with those.

Thanks. So not to beat this to death

I realize it is an audio term but if you compare a 50w amp and a 100w amp, regardless of all the other factors I just mentioned, you are saying one can safely say that a 100w amp is EXACTLY 3 dB louder than a 50w amp. Regardless? Always? Exactly?

You know I respect you but that doesn't make sense to me.

I think maybe I'm being too pedantic My point of view is that yes, you generally get an extra 3 dBs just like the difference between a 2x12 and a 4x12. But that "headroom" is pretty arbitrary and variable based on lots of factors. For example, I'll be there are some 50w amps out there that have more "headroom" then some 100w amps. Watts does not = volume.

Last comment and I'll let it go

(I googled this and yes, I see lots of references to headroom being measured in dB's (including Sweetwater and other) so from that perspective I can let this go)

But the wikipedia definition fits more inline with what I was thinking:

"In digital and analog audio, headroom refers to the amount by which the signal-handling capabilities of an audio system can exceed a designated nominal level.[1] Headroom can be thought of as a safety zone allowing transient audio peaks to exceed the nominal level without damaging the system or the audio signal, e.g., via clipping. Standards bodies differ in their recommendations for nominal level and headroom."

Note the word "system"

 

[Rex Rocker]

I realize it is an audio term but if you compare a 50w amp and a 100w amp, regardless of all the other factors I just mentioned, you are saying one can safely say that a 100w amp is EXACTLY 3 dB louder than a 50w amp. Regardless? Always? Exactly?

No, I'm not saying that. Just nominally. Just like 100W and 50W amp power ratings are only nominal and vary based on bias and other stuff. I was agreeing with you in the fact that not all amps are made the same and that there is more at play with tube amps since they're not linear and they're all not the same. What I was saying is not that it's 3dB louder AND has more headroom. I was saying it has more headroom because it's 3dB louder or that it's louder because it has 3dB more headroom. It's not a separate thing. Of course, it's not 3dB exactly. It's just nominally.

And yes, that definition doesn't contradict what I was saying. The poweramp is a system. It's not a single element working alone. It's a bunch of stuff working together. However, regarding that definition, I don't think a 100W tube poweramp has more input headroom than a 50W poweramp. I think the headroom comes from somewhere else down its discrete chain where the signal-handling capabilities are (nominally) 3dB more because it has the potential to pump twice the power out.

I'm not disagreeing with you. I was saying that in a poweramp, headroom and output volume go hand in hand and are not completely separate things when speaking of a tube poweramp.

And about a 2x12 being quieter than a 4x12, speaker coupling in cabs only really happens in lower frequencies. In my experience, a 4x12 doesn't really feel louder than a 2x12. It just "feels bigger and fills the room better", which is a concept I hate because it falls into the whole YAH AMP M0J0 thing that I kinda dislike, LOL.

 

[311splawndude]

OK. Thanks. Then we are definitely on the same page. Hopefully, the dialog was helpful to others regardless.

Now, regarding the 4x12 vs 2x12 thing, all things being equal, the larger cab is definitely 3 dB louder

.....as well as bigger and fuller and occupying more space closer to your ears

 

[Rex Rocker]

OK. Thanks. Then we are definitely on the same page. Hopefully, the dialog was helpful to others regardless.

Now, regarding the 4x12 vs 2x12 thing, all things being equal, the larger cab is definitely 3 dB louder

.....as well as bigger and fuller and occupying more space closer to your ears

Only on the lower frequencies.

 

[Smash]

I get it guys, I think we are all saying the same thing. I was just trying to say that decibels and headroom (or watts) are not linear.

You are very correct. I dont just guess. My 50 watt mgl has "clean" master at 112+ dbs. My 100 watt wizard was 110 max before saturation. My avenger 100 watt was 115+ clean headroom, whereas the 50 watt avenger had around 109. Anything over 112 starts yo make my ears sting, so i dont stay there long.
Every amp i have tried, though, punch was greater the higher the wattage(with exception of wizard: 50 watt and 100 watt punched same; 150 watt was godlike). And the punch matters if you are running through 4x12s.
Front of house punches in its own way totally independent of how much or little punch your amp has.

I run through same cabinet for all my amps. If i ran through different cabinet woth different speakers, those numbers could fluctuate also.

 

[cobrahead1030]

Depends on the amp.

I've played 50w amps that were so loud and did their job so perfectly, I couldn't imagine what the bigger version is like.

 

[acceptance]

I saw Toxic Holocaust recently and their guitarists' 50w 5150 III El34 was underwhelming. It sounded okay but really lacked the punch I'd have wanted. Could have been the venue, his vol preferences or the general area I was standing, but I did move around a bit.

 

[ZEEGLER]

Always 100/120 watts