My guitar amplifier is loud. It’s a Fender Deluxe Reverb. It’s only 22 watts and it’s only a single 12 inch speaker, but the volume… Good lord, does it get loud. The average threshold of pain for human ears is about 110 decibels. My amp spent some quality time at around 110 decibels today.
I was doing an experiment. I’ve spent the last couple of years watching a lot of guitar-related how-to videos on youtube. A common topic is tube amp compression. The idea is simple. With a tube amp, like a Fender Deluxe Reverb, as you turn up the volume, starting at zero, the volume goes up for a while, but eventually you hit a point of saturation. At that point the volume stops increasing and the signal starts to compress. A side effect of the compression is that the sound starts to distort. That distortion is better known as tube overdrive and it’s pretty much the basic building block of blues, and by extension rock, guitar.
Another little tidbit I’ve learned in youtube viewing is that a lot of guitar players who live in a world where it is possible to play loud enough to let their tube amps overdrive will use a boost pedal, or an overdrive pedal with the gain all the way down and the volume all the way up, to increase the amount of signal going into the amplifier. What that does is give the amp more signal to compress, which leads to more distortion and more overdrive. You can get a heavier sound that way. It’s something I never even considered prior to about two years ago, but it looks like it’s common practice among pedal users. Assuming, of course that you are in a situation where you don’t have to worry about being too loud.
Today, after all of that research, I actually put this into practice, just because I wanted to see it all with my own eyes. I was using my new Gibson SG into my new Wampler Tumnus overdrive pedal, into my deluxe reverb. The overdrive pedal was in the signal chain, but it was turned off to start with. I also had a decibel meter app on my iPhone.
I started with the amp’s volume on one, which is where I set it when I’m at home noodling. I turned it up to three. That is a touch louder than where I set it when we play gigs at Rack’s. It was loud. Loud enough that if my band was playing along they would be complaining. That’s really loud, but no overdrive yet. It was still a nice clean sound. I turned it up to five and it was much, much louder. It was beginning to get uncomfortable. Awesome. Still no overdrive yet. I bumped the volume up to six and the magic started happening. It was still louder than five, but not too much louder. There was also a little bit of overdrive. I had to really strum hard to clearly distort, but it was there.
Then I turned up to seven. That was officially the sweet spot. If I picked lightly the sound was clean, if I strummed normally it was a little compressed, and if I slammed the strings it was noticeably distorted. I checked the decibel app. Assuming it is accurate, and it’s a free app so who knows, I was hitting around 110 decibels.
Right, so now we’re into the area of interest. What happens to the sound if I now crank up the amp all the way to 10? Can you guess? The sound was much more distorted. Not like a metal band, but more like a mid-60’s blues band. I had a ton of sustain, surprisingly little feedback, a bit of farting out in the low end. I usually keep the bass knob on around eight but when I dropped it to 5.5 or so it sounded fine. How about the volume? I had just turned up the the volume three notches, what happened? As expected, the decibel level stayed at about 110 decibels. A huge increase in signal, no increase in volume. All of those youtube lessons are confirmed.
One more question left. What happens when I add a boost? I had the Tumnus with the gain all the way down and the level all the way up. The treble knob was a hair above noon, for those who are curious. With this setting, the overdrive pedal is not directly contributing the level of gain, but it is increasing the signal strength a ton. The result was as expected. The volume level did not change. I was still sitting at about 110 decibels. The overdrive level increased quite a bit. I still wouldn’t be confused with a metal guitarist by any stretch, but we were definitely into rock and roll territory.
So what was the inspiration for all of this? Two things. First, I was home alone and thought it would be fun to turn my favorite amplifier up to full blast. Second, the same thing that inspires everything I do in the first 8-10 weeks of each new year, the RPM Challenge. In my fantasy world, I want to record my rhythm guitar parts with the Deluxe Reverb at least up to seven and the Tumnus boosting the holy hell out of everything. Leads, ideally, would be the same thing only with the amp at 10. Unfortunately, I highly doubt I’ll be able to stick to this plan because it is amazingly loud, threshold of pain level, and I would only be able to record when no one is home. There just aren’t enough days in the month or hours in the day for that to happen. I hope to use it for at least some of the recording though and I wanted to hear everything fresh before I start banking on it.
RPM starts in 10 days.
Inside the Red Head's Head 