(856) 292-3194
Cart | Wishlist | User Profile









SECURE SHOPPING Our site is tested by TWO services every day to protect your information.

McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams



GENUINE PRODUCTS
GUARANTEED



We are an authorized retailer for everything we sell - we do not use unathorized or "shady" sources.
   
Bookmark and Share

AMPLIFIERS: Learn How to Play Your Amp (Pt.II)
Recent News and Updates
Boom.
Adjustable Bridges Back in Stock!


Our long-running, time-tested adjustable bass bridges, which have been out of stock for some time, are finally back in stock! Ready to send out today, still with free shipping to all 50 states.

Recently Added Products
Bass Bomb - Feedback Fighting Resonance Reducer
Bass Bomb - Feedback Fighting Resonance Reducer
Feedback issues? This thing is da bomb. It'll solve ALL of your feedback problems. Okay, maybe not. But it's absolutely adorable, and might help a bit. And it's good for finger warmups, too.
Novelty Street Sign - Doublebass Place
Novelty Street Sign - Doublebass Place
Need some decor for your music room? Our aluminum "Doublebass Place" street sign is full sized (24" x 6") and can be used indoors or out.
Radial Engineering Tonebone AC Driver 1 Channel Preamplifier
Radial Engineering Tonebone AC Driver 1 Channel Preamplifier
Like to 'KISS' (Keep It Simple, Stupid)? This preamp just has the most crucial features in a small, portable box that is quiet, beautifully engineered, and practically bulletproof...
Learn How To Play Your Amp!! (Part 2)

Back to Part 1Forward to Part 3

In Part 1 of this series we talked about basic amp controls and specific methods for learning their effects. This article, Part 2 (of 3) covers the tools (and concepts) for managing preamp gain, as well as some of the features which can have an effect on preamp gain, like compression and alternate inputs.

Preamp (input gain) and Master Volume controls are two different controls entirely, and how you use them can have a big effect on your sound. This brings us to the important topic of...

Gain Staging
Instrument amplifiers have separate preamplifier and power amplifier circuits, and most have a volume (gain) knob to adjust the levels of each. The way these knobs are adjusted can help -- or hurt -- your sound. What the preamplifier and power amplifier do is pretty simple; they each multiply the bass signal.
  1. The Preamplifier takes the relatively low level signal of your instrument and preamplifies (multiplies) to a medium signal level that is at a high enough level to feed the power amp.
  2. The Amplifier then takes that stronger signal and multiplies it to an even higher level to power your speaker.
Generally speaking, if your instrument and/or preamp signals (volumes) are too low and your Master (power amplifier) level is too high, you're likely to have extra noise (usually "hiss" or "static.") This is because the percentage of good bass signal is low, so the preamp increases general background noise in the signal along with the bass. On the other hand, if your instrument level and/or preamp signal (volumes) are too high, they can cause distortion, and other ugly sounds, as they overwhelm the input capacity of the power amp.

The trick to setting these controls properly is to find the "window" where the incoming signal has sufficient level to provide adequate volume without excess noise, but not so "hot" that it overloads the input and causes distortion. Our friend on the left demonstrates the signal levels as you play bass; he's a 6'4" foot guy in an eight foot room. Just as you play notes, he jumps, but if you play a note that makes him jump higher than the amplifier's ceiling (maximum level)... well, it's bloody.

Some amplifiers provide assistance: Peak, Overload, or similarly labeled lights, or a meter, are designed to tell you when you have reached the preamp's or amp's design limit. There is no "standard" (or if there is, nobody abides by it), so experience or experimenting should tell you just how ugly things get if that light flashes too much or stays on. To set my amp's input gain/volume control,
The Straight Dope: if an amp has a power rating of 300 watts, even if you add more preamplification (gain) to try to make it louder -- well, that's like trying to put 400 gallons in a 300 gallon septic tank. The brown seeping over the 300 watt limit represents the brown sound; let's say it sounds like something brown.

The bottom line is that an amplifier cannot get louder than it is designed to get, at least not in a "pretty" way.
I will play my lowest note at the loudest instrument preamp and/or volume control level (play hard and continually) and adjust all the knobs to a point (all the way up on my bass guitar) and adjust the input gain control on my amp so that little light only flashes a tiny bit. That way you'll know you shouldn't distort, but still have a strong signal that will have a full sound. Listen carefully for distortion, because those lights and meters are calibrated differently depending on each amp's design, so you will know what works best for your particular amplifier.

Note: Depending on the amp, turning up any tone controls (bass, in particular) may also increase the effective preamp volume and can put you back into that distortion place, so compensate by reducing the amp's input volume/gain control if necessary. You can also use this to your benefit: if you are at the limit and still need more volume, roll off some bass and then turn up a little; lower notes take more amplifier power to reproduce than the highs and mids, and while you won't have quite the "bottom," it may increase your percieved overall volume.

High/Low and Passive/Active are just two examples of labels you may find next to input jacks. Usually, the two different jacks allow for two different fixed levels of gain (see above) - one for the higher level of output for instruments with active preamplifiers or other electronics, and the other for lower-gain "passive" pickup arrangements. Unfortunately, there are no industry standards, but you'll find when you plug into one of them your bass will be quieter. That is the jack to use if you use an external preamp, or if one is built into your bass, meaning it is "active." The other is for basses with passive (no preamp) instruments, so it is "louder", offering more gain (volume). It is important when considering Gain Staging, above, so that your preamped, and therefore usually louder, signal does not overload the preamp inside your amplifier. Some amplifiers have only one input jack but may have a switch or button to decrease the input sensitivity; like with the jacks, your ears should tell you which to use.

Drive, if included, is usually a knob alongside the input gain control. The design goal is to add character to the sound, such as a tube saturation or mild to wild intentional overdrive, which can add thickness and/or distortion to your bass sound. Some amps include preamp tubes (aka "valves") or tube emulators, and in that case a gentle dose of drive can add heft to your notes. Off is usually a good position for these controls if you want a pure upright bass tone, but as with these other controls, experimentation is worthwhile.

Compression, Limiter: An Upright Bass, when we pluck it enthusiastically, can put out a huge burst of sound. Compressors and Limiters soften and minimize that peak so it doesn't overload the amp and/or annoy your bandmates. A Compressor can usually do it more gracefully than a simple Limiter (depending on its design), but a compressor's primary role is to squeeze the dynamic range of the notes you play, so the quietest are a little louder, and the loudest are a little quieter. You'll notice compression being used when you watch a TV show -- where if the whispers were at their original, actual volume, they would be hard to hear, and an explosion in an action scene would make you jump out of your chair. Amp makers may include simple single knob compressors, or less often, a more comprehensive unit with up to four knobs for precise control. Compression is not something generally needed for upright bass gigs, except in special situations, such as for taming the impact of rockabilly slap. Using compression well would take up an entire article on its own -- so Study user manuals, and experiment extensively before using.  Rule #1: If you can "hear" the compressor working (a "pumping" sound) it isn't set right. Subtle = good.

A final word on Too Much Bass Disease: Yes, I know you are playing a bass, but don't automatically turn up the bass or push the deep switch! If you've read my other writings, you know this is a pet peeve of mine. This is due to the many upright and electric bass players I've heard, or tried to hear, only because they are so far down in the bassment that their all their cool musical activities are buried in rumble. And dammit, so many can't take the constructive criticism or objective advice from their band members or another bass player. "This is the way I play," or some similar justification makes for the ugly status quo. And yes, I am like one of those reformed smokers, because I remember my own past self-defeating leanings towards the Deep Dark Side.

So check out these features (if available) on your amplifiers, perhaps it's time to adjust these controls and carefully listen to the results, so you are familiar with the tools at your disposal. All of these are potential ingredients in creating your Reference Sound. It may be time to revisit Part 1 and go back to the drawing board for some tweaks.

Coming soon: Part 3 - Parametric EQ, Notch Filters and other useful features!


Back to Part 1Forward to Part 3







The Fine Print:

The information contained herein is based on what's in my brain — and/or my observations and opinions from my personal experiences (and those of Bob, before me) — as of this moment today, and is subject to change. I'm sure that a great deal more information and detail could be added — but the intent of these writings is to present easily understood, quick FAQs, to address common questions and improve the reader's general knowledge.

What's written here is by no means any kind of authoritative absolute answer, for I am not the world's greatest authority on bass (not even close), or on much of anything else, for that matter. So, by all means, get a second opinion, and know that all the information provided here is for general informational purposes only. I am not providing professional advice; be aware that, where applicable, any information acted upon is at your own risk.

I simply and sincerely hope the information and opinions here are helpful to you on your quest for knowledge about the bass and related subjects... that's the point!

I welcome email with dissenting and additional viewpoints/information/updates that help improve my personal awareness and these content pages. If you have a question that you think belongs here, please let me know.
Mark