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Amplifying a Diatonic Harmonica
by
John Watts

This was written in response to the following email:
"Hello John, 
I need your help. Here is my question for you. I want to know what type of amp and mic does an aspiring blues harp player need in order to get the "Little Walter" sound. Some refer to as the  deep "fat" sound.  I think  that you know what I mean. I have asked a number of  people this question  and have gotten a variety of answers. Any help would be greatly appreciated. Thank you, Charles"

I'm glad to give you some ideas, but as you have found out there are a wide variety of opinions on how to get there.  It is my opinion that there is no "Holy Grail Rig" that will produce "that tone", but a combination of factors working together.

First and foremost you need to have good acoustic tone, because if you don't you'll just be amplifying your weak tone and it will not sound like you want it to. No amp or mic will give you that. Once you have decent tone the amp and mic can make some difference in your overall sound. However you will find that many of the old pros played and still play with whatever mic is at hand through whatever amp is at hand or just through the PA and still have their own distinctive great sound. This is because they first have great acoustic tone, so the equipment does not make as much difference for them. 

For just starting off I don't think you can go wrong with a Legendary Pignose amp and a Shaker Dynamic microphone. Both tend to be on the "dirty" side, so they tend toward the sound you are seeking already.   The combination is a good one to learn to hold and work the mic and to see how the amp responds to different techniques. The rig is small, portable, and about as bullet proof as you can get. This makes it good for hauling around and practicing at odd moments. It is also not too loud for playing in your house or basement. Your controls on the amp are limited, so you can work on getting the tone you want from you and not feel like you constantly have to tweak the amp. If you want to add a little more depth to your sound a Danecho or BLT echo effect are good additions to this (or any) harp rig. Even though this rig is small and low powered you can use it for playing in a venue other than your bedroom if it is mic'ed properly through a PA system. There is also a line out jack for connecting directly to a PA or a larger amp, so you'll never outgrow this set up. 

Here are a couple of tips for helping to get the most from any amplified setup: 

1. Cup the mic and harmonica tightly! I don't mean squeeze them to death, but to work on getting your cup around the mic and the harmonica as air tight as possible. This will "drive" the mic element harder and cause it to distort, which is what you are after. When you have a good airtight cup you'll see a remarkable difference between the sound you get that way versus when you loosen the cup or open your hands entirely. Since the Shaker mic is small and light it is easier to handle while trying to develop a good tight cup than a larger and heavier bullet mic.

2. Open up yourself inside as much as possible to create a large sound chamber. The air in your lungs, throat, and head cavities should all be open to the harmonica. This is also key to good acoustic tone. If you play with just the air in your mouth, your tone will always be thin, weak, and tinny - which you may want for particular effects, but not as a rule. 

Of course anyone who wants to develop "that Little Walter sound" eventually tries to duplicate the type of equipment he used - the small tube amp and the crystal bullet microphone. A good portion of the desired sound comes from the smooth distortion provided by the tubes and the microphone element when overdriven, which is easier to obtain with smaller amps. Modern solid state amps usually tend to play cleaner to a higher volume and tend to sound harsh compared to tubes when they finally do begin to distort. 

The Astatic JT30 is the industry standard when it comes to harmonica microphones. The Hohner Blues Blaster is the same microphone, produced by the same company, but relabeled for Hohner. The mic comes with a crystal element and it can be changed to a ceramic element later if you want.  Astatic makes both types, but as far as I know only sells the assembled mics with the crystal element installed. Another popular bullet mic is the Shure Green Bullet, but this has a dynamic element, not a crystal element. It's a little larger and heavier than the Astatic, but it's also more rugged than the Astatic due to the dynamic element. Dropping a crystal mic or exposing it to extremes of heat or cold can ruin the element. 

For small tube amplifiers (under 20 watts) there are many choices. Many people shop the pawn shops and yard sales looking for old tube amps and great deals can be found at those places. They're often available on the Internet at places like eBay as well. An old or used amp should be gone over by a technician to make sure it is operating properly, and possibly adding a modern grounded plug for safety, before you use it seriously. I don't recommend poking around inside of tube amps yourself unless you have training because they can contain lethal voltages even if they are unplugged. You could die! 

For new small tube amps there are quite a few choices. A couple of the more popular ones are the Crate VC508 (5 watts) and the Fender Blues Junior (15 watts). Both of these can sound wonderful as a harmonica amp. On the Crate the pre-amp tube needs to be changed to a lower gain tube like a 12AU7 to give you more control over the amp without excessive feedback. I'm not experienced with the Blues Junior, but the pre-amp tubes may need to be swapped out as well. The Blues Junior has a built in reverb, but it can get to be way too much unless you use it sparingly. A better way to go in my opinion is to use a Danecho or a BLT effect pedal to add some echo to your sound if you want the reverb effect. Echo just sounds better with harp than reverb does to my ear (and many others as well). These smaller amps may have enough power to play a small room and still be heard depending on the conditions, but they can also be mic'ed to the PA like the small Pignose if they are not loud enough to cut through on a gig. 

For more power and larger rooms many harp players use larger tube amps, sometimes as much as 100 watts or more. In a large venue this can be fine, but to properly distort the tubes the more powerful amps must usually be run at high volumes - so it's not something you'd want to get for primarily playing in your house or apartment. There are many brands available new such as Pignose, Fender, Peavy, Crate, and others. The same thing I said above for the smaller used tube amps and sources applies to these. The tube amps by Pignose and both can be fine harmonica amps with plenty of power - the G60VR and the G40V. The G60VR works well as a harp amp right out of the box because it has a high/low gain switch that allows you to play a variety of mics without feedback. It also has a built in reverb, but I like the Danecho better with it as I mentioned before. The G40V needs to have the pre-amp tubes changed out to lower gain tubes before it is usable with a microphone, there is just too much gain with the stock tubes making feedback near impossible to control. This is an easy job though, just like for the smaller amps. 

Just remember - develop your acoustic tone first! It is popularly said that your tone comes 80% from you, and 20% from the equipment. That said, 20% is still 20%, so it's worth exploring the equipment once your acoustic techniques are solid.  Below are a couple of posts by "Ironman" Mike Curtis that have appeared on HarpTalk that also speak to the "how to get that tone" issue.

From:  "IronMan Mike Curtis" <ironman@ironmancurtis.com>
Date: Mon Aug 7, 2000 11:40am
Subject: Microphones and technique

First, I'll give some mic advice. But the "lecture" following is the MOST important part. If you don't get THAT tone from EVERY mic you try, study it carefully, because your tone is lacking, and can be vastly improved. I may save you a lot of heartache - AND MONEY - seeking *that* elusive tone.

I'm not a big vintage mic fan. Not that they're not good - often they are - but they're WAYYYYYYY overrated (and overpriced) as tools of the trade.  My current favorite harp mic is the Astatic JT-30 and variants. It "blooms" into a really nice, fat "natural overdrive" when tightly cupped and played loudly. I have big, strong hands and can tightly cup the large mic.   I also like the (older) Green Bullet (haven't yet tried the new one), but not nearly as much. The JT-30 has a natural distortion and is more resistant to feedback. My one gripe is that it doesn't use a standard cable, so you really need to carry a spare.

The Shaker Dynamic is a one dimensional mic that does a great job of overdriven harp but is virtually useless as a clean mic. If you have a good tube amp (i.e. Champ or other smaller amp) and *always* overdrive it, this mic will make you happy. It's small, weighs nothing, and can be tightly cupped by folks with the smallest hands. Joe tells me the crystal is better for clean, but I've never tried a crystal Shaker.

There are a lot of inexpensive microphones that do a great job of amplified harmonica. If your acoustic tone is good, you'll find that most mics will deliver great sound. If your tone is weak (usually the case), there is no mic that will deliver "that" tone.  The fact that the distortion of these mics and amplifiers _appears_to_mask_ tonal deficiencies is an illusion. If your acoustic tone is weak, your distorted sound will also be weak. 99% of all amplified harmonica players have weak tone.

A lot of folks have poured enormous amounts of money down the drain seeking that magical "Little Walter" tone. In fact, LW had great acoustic tone, and just used the cheap gear available in his day. His big "secret" was tight cupping the mic.  If you play amplified and have problems with your tone, one area you're probably lacking in is tight cupping the mic. You literally need an air tight seal. Yes this is fatiguing, and your hands will cramp, but that's what you need so get used to it. Do hand exercises. And get a mic you can more easily cup. Check into a small lavolier type mic. Cheap lavoliers work wonderfully well. I have a tie clip mic (Numark) I paid $35 for that sounds great, cups like a dream, and has impressed pro harpers with thousands of dollars worth of expensive vintage mics.

Still, keep working on improving your tone and resonance. I sit in a lot with other harpers - many who are doggone good. In most cases (by far), the first thing I have to do is turn their amp DOWN. I've measured my acoustic harp output, and it's anywhere from +10 to +20 dB louder than most other harmonica players. +10 dB is TEN TIMES the power, and +20 dB is a HUNDRED TIMES the power (it's a logarithmic scale). It's like (@ +10 dB) trading your five watt amp for a fifty, or (@20 dB) one watt amp for a hundred watter! And yes I was shocked, but instruments don't lie.If you sit in and DON'T have to turn down most of the time, your tone could be much better. Work on it, and when it gets "there", you'll find that ALL mics are good harmonica mics.

So - how do I know? Simple - can you bend reeds with windsavers (AKA valves) on them, i.e. chromatics? If not, then you are not resonant. Plain, simple, and absolute. The easiest way I know to learn resonance is by playing a valved harp. It won't lie to you. If you can't bend the valved notes, then you're not resonant.  Like anything, there are degrees of resonance, and it can be improved in a number of ways. Having a large opening from the harp to your mouth is one. A little tiny hole permits little tiny sound. Having a wide open throat and large mouth volume is another. It allows more air to be vibrated. And if you ply with cupped hands, you can add resonance by cupping them just right so it makes your sound mellow and fat, so it sounds almost like it's coming from inside your head.

The principles are simple. Applying them effectively takes a lot of work.


IronMan Mike Curtis one man blues/jazz band http://mp3.com/ironmancurtis8/11/18 9p HT Grill 1710 S.Catalina/Redondo 9/2 7pm Riverbottom/4201 W 
Olive/Burbank; TU 8p Pro Jam/Starboard Attitude 202 The Pier/Redondo
SA 1pm Yesteryears/235 W. 2nd/Pomona Buy IronMans CD http://Got.To/bumpNgrind

How To: Modification for Amplified Harmonica Players (op amp)
by
IronMan Mike Curtis

OK - here's the basic circuit. It's called a Voltage Follower or Unity Gain amplifier.  This will work with ANY hi-Z mic (especially crystals), into ANY device, including tube amplifiers, and will improve the sound.  The difference in sound with crystal microphones into anything is dramatic. On some things, it improves quite noticeably. On others, it's totally night and day - unbelievable improvement. Even with my wireless (1 meg input impedance), it gives quite a bit more volume and beefs up the low end tone.

EXPERIENCED BUILDERS, SKIP THIS PARAGRAPH - SOLDERING INSTRUCTIONS This is actually an excellent "first time" electronics project. Use a small (25-35 watt) soldering iron with a fine tip, 60/40 rosin core solder (63/37 is better, but it costs a lot more). You'll need some basic tools, like wire strippers, dikes, needle nose pliers, and normal hand tools. Cleanliness may be close to godliness, but when it comes to soldering irons, cleanliness is just plain ol' necessary. Keep the tip of the soldering iron CLEAN. Electronic stores have special little sponges for this. Wet the sponge (soaking wet), and every few minutes wipe the tip. It should be shiny. Use only enough heat to make the solder flow. Apply the iron to the junction to be soldered, wait a second or two, apply the solder to the parts (not the iron), and it should flow. Don't move it until the solder has cooled. Otherwise it makes a "grainy" looking junction (a cold solder joint), and has to be reheated. 

OK - IT'S SAFE TO START READING AGAIN... This is a simple, easy to build, and foolproof circuit. The 741 op amp (operational amplifier - originally designed to do mathematical operations in stone age analog computers, but the circuit obviously has other uses) is ancient, proven, cheap, and stupid simple. It also has poor high frequency response, which is desirable for harp mic applications. For example, it won't oscillate at some weird radio frequency if you're a little sloppy with your wiring. Use two regular 9 volt batteries in series. The mic ground and output ground go to the connection between the two batteries. Off/on switch can break the connection between the two batteries. The op amp symbol is a triangle (yeah, I know, mine isn't exactly perfect, but you'll recognize it). 

The package the op amp comes in will identify the pins (or drop me a note if yours doesn't - I'm too lazy to get out the book :-) It's in an 8 pin DIP (dual inline package) (which means it has 4 pins per side). I recommend using a socket and doing your wiring in advance. Pin 1 on the 741 has a dot over it. The numbers go in a "U" shape. 1 thru 4, and then starting at the end opposite pin 1, 5 thru 8 - so pin 8 is directly opposite pin 1. Pins 1 and 8 are power + and -, if I remember correctly. check the package and make sure. The op amp output is shorted to the inverting input. This feeds power back into the input eliminating losses and making it infinite impedance, which your mic will like a lot! Gain is clamped at 1 (unity), so it will neither increase nor decrease your mics signal. However, if you build it into the mic shell, you may notice more highs. this is because the cable capacitance acts as a "tone control" and bleeds off highs. It also skews phase, so you may notice that your mic sounds "more precise". 

Use Courier or other proportional font to view. And drop me a note if you have questions. 

           o--------------o 
           |              | 
           |   |\         | 
           o---|  \       |
               |   >--||--o Output   
Mic hot --||---|  / 
               |/

The ---||--- is a tantalum capacitor. You'll need two. Value is around 10 uF, any voltage. The polarity doesn't matter. Build the board, and after checking all connections, then install the IC into the socket. Make sure you don't accidentally bend any of the pins under the op amp. Insert it firmly and all the way. If you build this into the mic, the output goes to the cord center conductor. If you build this into a box, plug the mic into INPUT (use a 1/4" jack, or whatever), and your amp input to the OUTPUT (ditto 1/4" jack). Make sure you mark the box as to which is input and output. Not that it'll hurt anything, but it'll save you grief at gigs.