Harmony H303A

My amp is dated 1961 and is pretty straight forward with just a volume control. I modified the 3rd input and replaced it with an external speaker jack to run an 8 ohm cabinet. This amp is probably about 5 watts, but can keep up in small venues with a drummer when mic'd.

I use this amp as a studio practice amp and when driven through a 2X12 enclosure this amp has a large enough sound for a small venue. I play all styles from Blues to Rock to Jazz and this amp absoulutely nails them all! This amp is a tone monster and can give you SRV straight up or Hard-Rock with the use of a good distortion pedal (I use an old Ross distortion). My H303A breaks up with the volume at 7 with the bridge pickup on my strat and what a sweet sound it is!

I needed to replace all Filter Caps and tubes when I bought mine, and it has not given me a problem since. I would reccommend changing the electrical cord to three prong for grounding/safety issues. Changing all of these elements is common place for an amp that is 40+ years old.

I have been playing for 13 years and have owned Fender, Peavey, Mesa Boogie, and Orange amplifiers, this amp has a quality of sound all its own. A buddy of mine just bought a vintage Fender Champ and when he played through the Harmony, he said that the Harmony sounded better. No guess work here I knew that already! The only thing I wish it had would be a tone control,although the 1st and 2nd input do a good job of varying the tone pretty sufficiently (as well as the tone pot on my guitar).

Pretty basic 5 watt tube amp. Has one knob that is the on-off/volume. Has three in puts. One hi-z and two low-z.Bought it on ebay a few months ago. Near mint condition. Bought it for harp so I don't need any other features. This is for blues and it handles the job. Amp was made May 7th 1964. I did have a friend of mine install a 3-prong grounded power cord and a fuse. Otherwise it's just like it came from the factory.

This has a nice crunch tone that alot of harp players look for. I prefer a little more bass tone than this amp gives but with a 6" speaker I wasn't expecting alot of bass when I bought it. With the three inputs I have a choice of mics with very little if any feedback. This little amp is so quite that it's easy to forget it is on. And that is cranked up!

Well it's almost 44 yrs old and still going STRONG. I've only had it a few months and have only used it at home, but have given it a good work out. No problems.

Don't know if Harmony is still in existance.

I would definitly replace it with another H-303-A if it were lost or stolen. These are nice little tube amps that you can still get for very little $$$ Light weight and easy to haul around.

A blistering 8 watts with one on/off volume knob, and no tone knob. It does not need one as it has three input jacks set to different tones. It also has the original Jensen Spiecal edition speaker. There are three tubes, 12AU6 input pentode, 35W4 single rectifier, 50C5 class A output pentode. My transformer is marked 1963.

The amp has some noise but wiggling the tubes will quiet it down. I remember taking my original amp (I owned one in 1965) and spreading the pins on the tubes and making them set in more solid. I am afraid to try this as these tubes are no longer young and easy to buy.
But when I plug in my Gibson Bluewhawk, this little amp has a warm low sweet distortion.
For recording it is a better choice than either of my Marshalls.

When it came in, the top two chassis screws were missing and the weight of the transformer had ben ths chassis up a few inches. Since it is hand wired it was not damaged. It it had a pcboard it would of been trashed.
And if it does "break down" it is realitively an easy circuit to repair. And it comes with the schematic and parts list glued into the inside of the cabinet.

It is definately out of warranty...

I have been looking for a replacement of my original H303a for 40 years, so give this amp a super WOO-HOO rating.

Im not sure what year this little guy is,but i've had it since i was 15.Im 42 now,and i got it from a friend for either 10 or 20 bucks.That included a Harmony guitar also.I think he got the guitar back but i kept the amp.I had kind of a hard time finding tubes,which it never had,but found some at an old TV repair shop.I had this thing for about 5 years before i even knew if it was going to work or not.I also had to replace the speaker which I got at the local music shop.Im not sure how many watts it is but I would guess around 8.Its nice having only 1 volume,on/off knob,and three inputs.I wired the end input to be an output which opens the speaker circuit.I added a grounded plug in,and also replaced the cord.

I play an old Lotus guitar(Les Paul copy) which is in excellent shape,with an Ibanez pickup at the bridge. Let me tell you,this little guy can sing with it cranked it to 10 and my Zoom 505 behind it.The distortion comes on early and is a little muddy, but fine for 80's rock that I like to play.Stand close to it and you can get some cool harmonic feedback that will ring forever.This thing is acually pretty quiet.With it up all the way there is very little noise.It's not real good for clean sound unless you mic it, to where amp volume is low and you can crank it up through a mixer or whatever.

I've never had any problams except for I need to replace the speaker once again.I've abused this thing (not physically)by running the wrong impedance very many times and haven't changed a tube or had a bit of trouble with it thru out the years.Very well built and wired!!

I've been playing for 25 years on and off.I have a Marshall slant 4x12,and a straight 4x12 cab I built,plus 2 1x12 monitors I built.I have a bunch of stomp boxes,but like my Zoom 505,and Boss digital pitch shift and delay the best.I have a Boss drum machine I run thru a litte Yamaha practice amp, and power everything from a Peavey Rock Master head.I'm always trying different ways and things to get "THAT" sound,but like everone else,i still haven't got it.Playing thru my Harmony(miced)is one of the best sounds i've found so far.I wish the volume knob went to 20!!

One knob, volume with on/off in same control. I converted one of the three input jacks to a speaker out jack and put a phone plug on the stock 6" speaker so I could use an external speaker. Three tubes, 12AU6 input pentode, 35W4 single rectifier, 50C5 class A output pentode. I use this amp with an external stack, 6 X 10" Jensens, circa 1968 Montgomery Wards. It has probably 4 or 5 watts, but is plenty loud for a room in your house and can be heard clearly out in the street in front of the house. Not many features, but a most efficient design for such a small amp that can be pushed to several degrees of distortion. Without tone control the amp is slightly warm sounding. Perfect for a tube amp. I dial the amp to 10 and use the guitar's knobs to control volume, distortion and tone.

I use a 56 Fender Strat clone, Tokai TST-56(read Harmony reviews), with this amp and it doesn't have quite enough punch to distort the amp fully without a preamp . That is, you can get about 60% of available distortion without a preamp, 100% with. The amp goes off on it's own at about 80+% distortion and generates some of it's own sounds, very harmonic and very musical. Tube amps when distorted make pleasant musical sounds, "even" harmonics mostly. This amp makes sounds anywhere from clean warm tones to sizzling distortion just like Jimmy Hendricks, or Van Halen. The 3 inputs are slightly different gains, the 1st on the left is a mike or harmonica input, hi-Z, hi gain, and slightly noisy. The middle is good for guitar, med-Z, low gain, very low noise. The one next to the volume control is med-Z, med gain, low noise. If you plug into more than one input jack they all become med-z, low noise, so you should use an external mixer.
I've tried to use my Yamaha Compass South acoustic on this amp and it isn't clean enough to give the optimum sound with a mike equipped acoustic. Use a PA or acoustic amp instead.
I've also tried singing into the 303A amp, and using the 6X10 stack and a preamp, it sounds very good, no reverb needed, and not enough headroom to generate much feedback which is good, but undistorted sounds are held to about the same noise level as a very loud shout. I rarely sing louder than that with my old 6L6 amp due to feedback concerns. The 6L6 amp can make the windows and doors rattle all over the house without distortion!!
The stock 6" speaker breaks up and adds a nice crunchy sound to the distortion, but frankly it sounds better, (and louder), with a bigger or better speaker which won't break up. Then it sings.

When I bought it the tubes were all bad, broken filaments and worn out. I replaced them with assorted NOS tubes from EBay, added a fuse and converted the amp to 3 wire AC cord to lower noise and eliminate possible shock hazard. Also, I added two 20uf capacitors to the B+ circuit to cut the already low 60 cycle hum by 80%, now it's so low you could leave the amp on accidentally. Note: you can barely hear this hum in the stock speaker, so add caps only if you use more efficient external speakers. Three resistors had changed value due to heat and age, so I replaced them. I experimented with some of the resistor values to optimize the voltages on the preamp hoping to get more gain, but changed them back to stock where the sound was much better. The amp is quite well-designed as-is. It will wear out the tube rectifier faster due to the extra capacitors, but I expect at least 500 hours anyway. FYI, I tried a solid state rectifier and the sound was inferior when the amp was overdriven, so I went back to the tube. As you can tell, I'm an electronics tech and spent a few hours on the bench with it before leaving it basically alone.

Self-supported. First, the voltages in this amp will KILL you, it's not like a transistor amp. So if it needs service, hand it off to a tube certified serviceman, or if you are one, go to the internet for guitar tube amp general instructions.

I've been playing since I was in Viet Nam in 1968, some of every kind of music, constantly evolving my sound, currently learning R&B and finger-style, sometimes don't play for a year or othertimes play every day for 6 months. I also own a JMF Spectra 35 watt solid state guitar amp with reverb, in and out volume, effects loop and 3-way tone. And a 1968 Montgomery Wards 35 watt guitar amp with pushpull 6L6's and tremolo and reverb and 6X10 stack. A 1968 Fender Villager acoustic 12 string with vintage DeArmond pickup, and the above mentioned Tokai and Yamaha guitars. I used to have a 1968 Les Paul black and gold, wish I still did.
If it were lost or stolen, I would of course buy another one just like it. I'm currently designing a 6V6 amp, but while it may sound more "vintage", it won't have the distorted little soul this amp has.
This amp makes the best distorted sounds I've ever heard live, equal to the best studio sounds you hear from certain artists played thru expensive sound equipment. Most tube amps when overdriven sound somewhat muddy with loss of definition, this one sounds different, and even when driven with distortion effects pedals, still sounds like itself. That's what I love about it. It's perfect just as it comes, other than adding a 3 wire AC and an external speaker jack.

Late 50s early 60s model. I play metal and stoner rock. Played for 25 years. I wanted to see what the hubbub was all about with this and I lived in an apartment so I bought one off ebay.

It has one knob and really that's all it needs. Has good full sound. Just enough bass and treble so it doesn't need a tone knob.

My neighbor said she could still here it. She could hear my 1 watt amp too tho.

Mine is quiet. So quiet I forget and leave it on for days at a time and then finally here a hum and I get soo fn mad at myself.

It is so light and flimsy I can't beleive it made it through all these years. Especially the speaker. If it was a foam edge Jensen it would have died decades ago.

I use an 80s Ironbird custom with Super dist and a Seymour in the neck.

Effects sound great. Metalzone sounds alot better than I thought. Sounds like a quality full stack when miked.

Ain't bad all by itself. Distorts at about 2/3 volume.

Its still here and in one quiet peice. Non orig. tubes tho.

Hmm? Stick with the old tube stuff.

Worth every penny. No transisitor amp will copy it period. If it were lost or stolen I'd shite myself. It's my little buddy for life now.

I'm glad this doesn't have a tone knob. That would only let ppl screw it up. If I every change to playing the blues or slide or harmonica I'll be set.

I wonder what the 303 b and c models sound like?

I don't know the year, but the transformer say's Nov 1960
As mainly a blues harmonica player I don't need many features and I couldn't imagine having 2 knobs on this little tone monster! I can play this amp anywhere and it's light.
Tubes are 12au6, 50C5, 35W4

This amp really kicks out some nice horn-like honk. With the hotrodded crystal mic this amp really sends out a nasty breakup through the 6" Jensen. I can crank this amp all the way with no feedback at all. There's just a little hum at high volumes, but that's no big thing and it's not loud enough to bother me.

I have only had this amp for 1 week now and got it from a older man on e-bay who has had it for years and years, he can't even remember how long, but he did say it has never failed him.

I've been playing for 9 years and I'd buy another one even though I have a H305A being shipped as I type this. My other amp is a 95' Fender Blues Jr with internal tone voice modifications specifically for harmonica with a Weber P10R Alnico speaker. The H303A doesn't have the low end like the Jr, but I don't want that all the time anyway. The tone is so clean and crisp with nasty qualities all at the same time. I love everything about this little amp and hate nothing.
What a bargain!

I picked this up off eBay and it's very clean. This one had a lot of closet time. As for features - a single on/off/volume control. It is perfect for playing. It starts to break up and get the fat tone without having to wake up the neighbors.

I'm playing a strat through this. I bought this as a toy but haven't played through anything else since it came in (about a week ago). I had an old black face Champ when I was a kid and mitakenly sold it. This thing gives me that same great tone at low volume.

This one was in mint condition. I'm ordering some tubes for backup but I don't plan on touching them. The pots could stand cleaning but I'll not touch it unless I need to.

I love it...

my Harmony h303a amp was made during the early 60's. It is in almost mint condition and is all original. 3 inputs, 1 volume control which also acts as the on/off switch. There is not a pilot light, unless you want to count the glow from the tubes telling you it is in fact working. Obviously all-tube, has a 35w4,50c5,and a 12au6 tube. features a 6 ich jensen special design speaker, and the amps size is roughly that of a black/silverface fender champ. output is no more that3 or 4 watts.

To start off with, I have a very extensive collect of vintage and recent amps and guitars. everything from soldano,flot-o-tone,univox,marshall,laney,alamo,peavey,mesa,fender..you name it I have it. I play all types of guitars through it but mainly my 60's harmony rocket hollowbodies. amp sounds bigger than expected, tight and dark sounding with the harmonys. breaks up rather quickly without much headroom but crunches up nicely. great recording amp. not loud but that classic r&r tone. with a les paul, it breaks up amazingly. wow, not bad for an amp I bought at a guitar show for 80 bucks. I got this to match my earlier single cutaway rocket, while my mid 60's dual cutaway rocket is paired up with the h303a's bigger brother the h304a amp. looks almost indenticle but with a top mounted chassis 8 inch jensen and a 6v6. if you dig this amp, you'll dig the h304a.

no problems yet. may have some in future like most tube amps. tubes arent the easiest to find but when need be Ill locate them.

If youre thinking about buying this amp, please due. just because it doesnt say fender on it doesnt mean it doenst sound great. in fact, I like this more than my 65' champ and my 71' bronco, and.... it cost less than 1/2 of either of the fenders. these harmony amps, along with magnatone and silvertone, sound great and are underpriced and underrated. buy them now before they catch on, and believe me they will.. peace.

I just got this amp at a flea market for $10 mint condition with the instruction booklet,I use my Takamine accous/elec guitar thru it and I also run my Blues Blaster harp mic tru it as well I love this little amp and it really gives my music that down home blues sound

I use my Takamine accous/elec guitar thru it and I also run my Blues Blaster harp mic tru it as well

I love this little amp and it really gives my music that down home blues sound