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Frequently Asked Questions

Forget everything you thought you knew about harp amps!



Who are you, and what are your credentials?

My name is Robert Reynolds.  I'm not going to tell you that I have a recording contract and an electrical engineering degree.  I'm just a weird guy who likes machines, music, vegetable gardening, raising chickens, and a lot of other things.  The main credentials I have are a diploma and an aircraft mechanic's license from the FAA. 

I play some blues harp and saxophone, and I know what sounds good.  So I read an old electronics textbook from 1960 and taught myself to build tube amps.  I think I got the old Little Walter tone figured out pretty well if I say so myself.  Try one of the amps yourself and you tell me if I'm right or wrong.

Other than that, my family and I are building an organic farm about 100 miles south of Kansas City.  I grow organic vegetables, I operate (and do a lot of repairs on) my own heavy equipment, I'm building a home for my family, and I'm enjoying country life.

I know these details aren't important to the average musician, but I just wanted to let you know that I'm not some con artist trying to convince you that I'm smarter than you.  I'm just a guy who likes to build things.  Check out my other websites:  www.balsaworkbench.com  , www.jensendealer.com and  www.reynoldsacres.com


Are Fat Dog amplifiers guaranteed?

Yes, parts and workmanship are guaranteed for one year.



What if I buy one but I don't like it?

The last thing I need is an unhappy customer telling everybody about a bad experience.  If you don't like the amp, I'm not going to make you keep it.  Send it back and I'll give your money back.  You have to take some of the responsibility, so you pay for the shipping.  I'm trying to be fair, so don't abuse my trust.



Do these amps make good guitar amps?

Probably not, but it's all a matter of taste, of course.  Most modern guitar players tend to like an amp that does screaming leads and gets loud enough to blow your head off.  Fat Dog amps were not designed specifically to make guitar players happy, but maybe you would like it if you're trying to sound like the guitar players on the old Chess Records classics from the 1950s.
What kind of microphones work best with Fat Dog amplifiers?

So far the amps sound good with every microphone that's been tried, although they all sound different and you need to pick the right microphone for your individual playing style.  If you're looking for classic Chicago crunch, you'll be happier with a high output microphone.  My favorite is the Shure controlled magnetic.  It's a classic for a reason.  But every controlled magnetic element sounds just a little bit different from every other one so you'll have to test them to find just the right one for your taste. 

Fat Dog preamps are wired for a nice dose of compression and just the right amount of crunch to add expression and body to your playing.  A hot microphone will turn this into a growling machine.  If you like cleaner playing, you can use a more mild microphone, or try this idea.  Use a hot microphone with a volume control, and turn it down a bit, and turn the amp up!  Then you can get both sounds from one song to the next without switching equipment.

Just for the record, I really like these amps with an RE-10.  It has a lot of guts.  The modern Blues Blaster is too wimpy, and the modern Green Bullet sounds too metallic for my taste, but I recorded the amps with a Green Bullet just to make the comparison.  Honestly it isn't half bad, but you can do better.  Get a good microphone.


What other specific equipment do you recommend to use with Fat Dogs?

There are two things that I recommend to anybody who asks. 

The first is the ElectroHarmonix Holy Grail Reverb.  I don't build the amps with reverb because not everybody wants it.  There's no good reason to make the amp more expensive for everybody just so a few guys can have built in reverb.  Get the Holy Grail and you'll find two settings (spring and hall) to give you just what you're looking for, and a knob that sets the reverb signal anywhere from zero to ridiculous. 

The other item I recommend is an EQ pedal for feedback control, tailoring your sound, and setting your overdrive level.  Use the equalizer pedal to dial down the mids a fair amount and turn down the highs just a little bit, and you'll cut your feedback tremendously.  An even neater trick is to buy an equalizer pedal with a master level control plus or minus a few dB.  Dial the entire signal up a few dB, and presto, you've turned your lame microphone into a hot microphone, and suddenly your amp has more growl and more crunch.


Why do you use Jensen Speakers?  Isn't there a better choice out there?

I tested a lot of different speakers, and I'm convinced that Jensen is the best choice.  They really sound great, but there's one catch.  You have to BREAK THEM IN.  A lot of people go nuts over Weber speakers, and I'll agree that they sound very good.  However, careful playing and listening tests showed that Jensen sounds as good and even better than Weber, AFTER THE JENSENS ARE BROKEN IN!  This process will take about 10 to 20 hours of playing, and then you'll really start to notice the  magic happening. 

While I'm on the subject, here's an interesting story about Jensen and Weber speakers, and a clever but misleading marketing trick used by Weber.  Once upon a time, Mr. Jensen invented the loudspeaker.  Later, in the 1940s and 1950s, Jensen speakers were used as original equipment in guitar amps.  They sounded great, as most people today will agree.  A few decades later, the Jensen factory in Chicago closed down.  Sica Speakers in Italy bought the rights to manufacture replicas of the Jensen guitar speakers and use the original model numbers and names.  That's what you get today when you buy a new Jensen speaker. 

Here's the part about Weber's clever trick.  On the Weber website you will notice that Weber claims to build replicas of the original Chicago Jensen speakers, NOT the newer speakers made in Italy.  That's funny, because that's exactly what Sica is doing.  They build replicas of the original Chicago speakers, too.  So what's the difference between their copy and Weber's copy?  They're both copying the same thing!  Unfortunately, a lot of people have been convinced that there is a huge quality difference between these two speaker makers. 

That's a very interesting story, but here's the important point to consider.  If you put a speaker in your amp, do you like the sound or not?  I tried a lot of different speakers and I know which ones I like.  Weber has one clear advantage in the battle for the best speaker.  A Weber speaker sounds broken in when it's brand new.  I don't know how they do that, but they sound great from the start.  Jensen speakers sound a little stiff to start, and then they gradually break in over a period of weeks, depending on how frequently you play.  After a while, they sound even BETTER than their best rivals, with richer tones and better overdrive. 

They're my favorite speakers, so that's why I use them.
How loud are these amps?

The larger models are not as loud as the famously loud Bassman, but they are plenty loud for a club gig with a tasteful band, which is what they were designed for.  The 1A is loud for a small amp.  It will give you more volume than a Blues Jr., but I wouldn't use it at a theater gig. 


Why don't you build an amp as loud as a Bassman?

That's a good question with a good answer.  Fat Dogs are cathode biased, which has a fair amount to do with how they sound and how they interact with your playing.  Using fixed bias would allow a greater overall volume, but it would come at the expense of great tone.  These amplifiers are as loud as I can make them and still have that great cathode biased sound.  They are plenty loud for a normal club gig with a reasonable band, but if you play with an unreasonable band then I'm not sure I can help you.  Either turn down the ego knob on the entire band or get a Bassman or one of its boutique-built clones that are extremely loud (but sound about as cool as playing through the PA). 

The question of volume is a tricky one, and it's hard to answer.  Honestly, I don't like listening to bands that play super loud.  As a music fan I'd like to tell everybody out there that the louder it is, the less you can hear.  I don't want to contribute to the way-too-loud problem by building another stupid 50 watt 4x10 brain damage box.  On the other hand, my amps are loud enough to get the attention of everybody in the room if the band is doing its job correctly.  They get pretty darned loud....but everything is subjective.  If you find yourself in a battle with a Ted Nugent wanna-be, use a guitar cable to plug the line-out into the PA.


How many watts?

The power output is low enough to surprise you.  That nasty blues harp tone sounds the best when it comes from a low power amp with plenty of speaker area to fill up the room.  It really doesn't take a lot of watts to get the job done.

When you plug a hot microphone into a Bassman you can't turn the volume up past 2 or 3 anyway, so how many of the 50 watts are you using?  Then you swap the preamp tubes for less powerful ones and turn up to 5, but now how many watts are you really using?  What difference does it make?  As long as you turn it up just below the feedback threshold, you're getting all the volume you can use.  The major difference is that 50 watt fixed bias amps have more PUNCH when you hit a note.  A Fat Dog has more CRUNCH when you hit a note. 



How about tube swaps?  Can you switch tubes in a Fat Dog to customize the sound?

First a few smart remarks about tube swapping.  There are only two reasons to do it:  1) you are trying to get a good sound out of your stupid amplifier, or 2) you are an incurable tinkerer.  The Fat Dog preamp is set up with the right tubes to make it sound good in the first place, so that rules out group #1.  If you belong to group #2, here's the answer to the question:

You can't do  a lot of tube swapping in Fat Dog amps, but there are a few exceptions.  The preamp lineup in all three amplifiers includes a 6SJ7.  If you have a shoebox with ten 6SJ7 and you try all of them, you will get ten different sounds.  There are also a few other substitutes that have different frequency response and overdrive characteristics.  You can use a half worn out 6SK7 out of an old radio and get a slightly different tone if you want to.  Send me an email and I'll tell you what other types you can try.  I always enjoy chatting about tubes.

The 6SN7 shouldn't be swapped.  The only tube with a comparable configuration is a 6SL7, which has way too much gain to work right in this circuit.

The power tubes in the different amps can be swapped if you want to.  In the Model 4A you don't have much choice.  You can trade one or two of the 6V6 power tubes for 6F6 to get a little bit thicker sound by mixing types.  This will also reduce your total volume somewhat.  Don't use more than two of them because the filaments draw more current than 6V6 filaments and you may burn up the power transformer.  Also, in my experience the four 6V6s provide a very thick sound already, and if you mix tube types it can become a little bit too thick for some people's taste.  (I like it that way, but not everybody is the same...)

The Model 2A gives you the greatest tube swapping options.  This amp can use a variety of power tubes including 6L6, 5881, EL34, etc, or you can even mix two different types of power tubes. 


Which Fat Dog amplifier is the low-end model and which one is the best?

There really isn't a beginner model and a pro model.  They share most of their parts in common, but there are some differences between the models that affect the sound and playing characteristics.  You should pick the one that best suits the size of the room you're playing, or the volume of your band, or how heavy of a cabinet you want to carry. 


Why don't Fat Dog amplifiers cost an arm and a leg, like a good harp amp is supposed to?

What a lot of people don't know is that good circuits can be built with reasonably priced, off-the-shelf components stocked by major dealers, which is where I get my parts.  The crazy 200 dollar transformers used in a lot of fancy amps aren't necessarily better, they're just different, and a lot more expensive. 

I ordered normal parts out of the Mouser catalog and from other common suppliers to build my test amps, and they sounded super-cool to my blues-loving ears.  These are normal electronic components built in normal factories, with specifications and tolerances good enough for a tube amp, printed right on the parts or on the data sheets available from the manufacturer.  I didn't see any reason to switch over to expensive parts built by magical elves in the moonlight for my production amps.

Of course the simple answer to why Fat Dog amps are so affordable is that I actually want to sell amps to normal musicians.  I know it's revolutionary, but it makes sense when you think about it!


Hey, where's the tweed?

Tweed is for old Fenders, and Fat Dog amplifiers are not Fender clones.  Each amp was designed from scratch, from an original idea, for harmonicas, not guitars.  You won't find a bastardized Bassman or a de-tuned Deluxe in the Fat Dog lineup.   So why should they be covered with tweed?  Not only that, but tweed drives up the price of the amp, and I'm sure you'd rather spend that money on a microphone or new harps.  The cabinets are coated with a roll-on called Dura-Tex.  It looks just like black Tolex, and your cat won't want to scratch on it.


So if it's not like a Fender, then what is it like?

You know the old department store amps from the 50s and 60s that sound so great as harp amps?  They had funny names such as Lectrolab and Valco.  Trying a friend's Lectrolab is what started me on the path to building my own amps. 


How come there are only two knobs on this thing?

Why complicate things unnecessarily?  There's no such thing as a "sound good" knob.  You could buy an amp with a three band tone control setup, but that isn't always better.  The great thing about a simple tone control is that it doesn't destroy the signal the way that complicated tone stacks sometimes do. The Fat Dog tone circuit is of the treble-cut variety, meaning that your bass is always there, and the knob controls how much treble there is. 



Need more info?   Contact Robert Reynolds:  417-646-8090
 fatdogamps@harmonicagear.com