Amps, speakers and Headroom...How does it work?

[streetknight]

I'm going to admit here that I don't know much about amps, that's why I'm asking lol.

 

I'm going to use my Peavey Classic 30 as the example here, but feel free to post about what you know.

 

Is headroom related to the pickup in the guitar, the wattage of the amp, speaker breakup, or what?

 

ie- I start getting a good breakup with my Les Paul with 57' Classics at around 4-5 on the clean channel of my Peavey. Is this the Speaker breaking up, preamp, or what?

 

Is there a way to get more headroom? ie- will a higher wattage speaker help?

 

Or do I just need a higher wattage amp?

 

thanks

[Ancient Mariner]

Headroom is related to amplifier design, although high output PUs can make it seem like there is less headroom too.

 

Some amplifiers are dsigned to stay cleaner, even when you push both the preamp and the power amp hard, others will dirty up really fast. On top of that you have, as you suggest, speakers that may also distort at low power levels or remain clear at quite high levels.

 

With your C30, if you want a louder clean (what I assume you mean by more headroom) then you should choose a more efficient speaker than the standard one. Something like a Celestion G12H30, Eminence Cannabis Rex, Red Fang or Wizard would be suitable.

[streetknight]

Thanks, that's what I was wanting to know.

 

Also, can you put too much speaker?

 

ie- Listening to the clips on the Eminence site, I really like the sound of the Swamp Thang, but it's like a 150 watt speaker. Would that matter?

[GCDEF]

 

Thanks, that's what I was wanting to know. Also, can you put too much speaker? ie- Listening to the clips on the Eminence site, I really like the sound of the Swamp Thang, but it's like a 150 watt speaker. Would that matter?

 

 

no

[cratz2]

It definitely won't hurt the speaker or the amp to have a speaker with a higher power rating than the amp puts out, but in general, speakers that handle more power have larger voice coils and usually speakers with larger voice coils are less responsive to nuances from the player.

 

The Swamp Thing is really known for being able to bust out some serious bottom end.

 

I've said it in other threads, but I cannot convey that almost any name brand speaker will be a significant upgrade over the stock Blue Marvel.

[Wyatt]

Ultimately the most important things for headroom are amplifier output and speaker efficiency.

 

Output is typically measured in "Watts RMS," which is the maximum output the amp can constantly maintain, for all practical purposes this is the maximum clean headroom, and when your push the power tubes to distort, you are actually pushing the amp beyond RMS, a tube amps' "Peak output" can actually be 50% to nearly 100% more than RMS. The is no industry standard for measuring output, so one companies 30-watt RMS amp may actually be putting out significantly less or more than another company's 30-watt RMS amp. There isn't much you can do about this, it's just the industry.

 

Now pickup output, preamp design and phase-inverter design can all affect this. The tubes in the preamp and PI are gain stages can be dialed in to clip earlier or later or too feed more or less signal strength to the next gain stage, etc. Well, let's just say dozens of factors can affect this...B+ voltages, tone stack (more midrange=less headroom), negative feedback, cathode followers,...etc., etc.

 

Another major factor is the speaker efficiency. This is typically printed in Db values, the higher the db number (I'm gonna skip the calculation, but these numbers are more uniform from company to company because there is an established way to measure) -- the more efficient and louder the speaker. On paper, a 3db increase in efficiency means twice the output (in reality, probably less, but it is a huge difference). What this means is if you pop a more efficient speaker in the Classic 30, you can get more overall output from the amp/speaker even though you still have to leave the Volume control on 3.

 

Guitar speakers generally range from around 89db to 102db in efficiency.

 

Speaker wattage doesn't affect speaker output. A 30-watt speaker can still be significantly more efficient than a 200-watt speaker, and vice-verse.