Harmony H420 115 Combo

The Harmony H420 amp was originally advertised as a bass amp and marketed in 1965, I did find a copy of a 1965 Harmony mail order add. I obtained this amp when me and ole lady bought our new house 2 weeks ago. Going through this attic of this house that was only built 8 years ago here in CT, this jewel was a great find. Me being quite the collector of music and instruments, I was quite suprised. It has two inputs, one labeled Guitar/Bass, and the other labeled Microphone/Accordian. It has 3 knobs; Volume, Treble, and bass. NO BELLS and NO WHISTLES. When I plugged this jewel in, I've discovered it needs a lil work. I see it has 2 6L6GC (Realistic)tubes in the power section, and and 2 12ax7's in the preamp, but inbetween the 2 6l6's is a long tubular, silver thing with numbers extactly like this around it 303-53
303-53
85 C
2356525X
55 63
I am in the process of redoing the whole thing over as a total restoration project. The speaker is mint as well as the guts. tHe shell needs some attention. Once restored I plan to play me slide through it and maybe even my baritone guitar.

This amp is a true tube. Very basic and even thoughI haven't had it perform to its fullest, once I complete the tube swap and restoration I will post another stating whats going on with the sound. I play all styles of music, mainly hardcore & thrash, but I am true southerner and I love my bluegrass and especially my blues with slide.

I found this in my attic like I stated so I have only had it since 3/27/08. Who knows how long it's been in the attic; the original owner of the house built it 8 years ago, so who knows what and where he did to it or how long he ownd it. With some TLC this thing will be the site to see at our bi weekly blues jams.

I have found the internet to be the only source of info like this site, and the one here- http://harmony.demont.net/amps.php. I figured between myself and a buddy of mine who is awesome with electronics we should be able to cover it.

I have an extensive collection of equipment. I have been playing 26 years, and about 20 of them seriously. I've never sold anything I have ever bought and I always come across great deals. For blues I currently use a Fender HOt rod Deville 4x10 and play a Gibson Baritone guitar and a 75 SG. I have a couple of classic Fender guitars too. For my hardcore rig I actually use a Peavy Renown 2x12, it's 350 watts of solid state power and i use it to also push a peavy 4x12 cabinet. I use a Digitech Grunge Distortion with an MXR 10 band EQ and A Seymour Duncan SFX-03 Twin Tube Preamp for warmth. I also have a delay and Wah for kicks. I have a full PA and my bass rig too. I have aa total of 64 guiatrs in all and numerous amps. I have had ADT here for 2 days installing my home alarm. All my equipment is fully insured too.

Other reviews and catalog say '66, sounds about right to me from the graphics.
35 watts. Big 15" Jensen.
3 input jacks, not sure if there is any difference to them. One says "Accordion." Go figure -- it was made in Chicago. Two big tubes, 4 small diodes, see other reviews for specs.
I bought it for exactly what it had and so I've never wished it had any other features.
I have used and abused this amp for over 30 years. Gigs, practice, and miscellaneous. Got it as a bass amp but it has been used for guitar, keyboards, vocals. Lugged it all over the country. I have used it in music applications but also as a PA at rallies,etc. It has been pressed into duty as a stage monitor. It has been the sole amplification for Cub Scout and middle school variety shows, you name it.

Has mainly been used as a bass amp with first a cheapo Kingston bass then a nice '76 short-scale Rickenbacker. Lately I have learned to appreciate it as a blues-chuggin' guitar amp with a new Tele and a vintage Gretsch. No effects boxes.
It is pretty clean up through about halfway, then you start to get some nice "organic" breakup, good for bluesy rock, Creedence, ZZ Top etc. At top volumes it kind of honks, amp is insufficient for bass if your drummer or guitarist are at all loud, turning up = not a very clean bass sound, at full volume it records as kind of a bass fart. We used to call it "Dinosaurs in Heat." But not a bad GUITAR distortion at all.
You don't need to turn it up very far to project in a small room. Has some real nice low end and subsonics thanks to the Jensen.

30 years and never in the shop, depite complete neglect, so what do you think?
Even the cheap stuff 30 years ago was more dependable than the computerized crap they sell now that is programmed to die 12 minutes after warranty expires.

Sometimes the sound is a little shaky and you've gotta jimmy the diodes or the tubes to get a better connection, as other reviewers note the sockets seem sub-par.
You should always have a backup at a gig, but often I never did. When I finally got a bigger, louder, cleaner amp, this became my backup.

Never needed any customer support.

Here is my complete repair history:
Once an idiot guitarist kicked out a tube. This was before the Internet, I didn't even know where to get a replacement and I was broke, so I walked down the alley till I found a busted TV in the trash. I cannibalized a bunch of tubes from it, brought 'em back to my pad, and stuck 'em in the amp one at a time till I found one that fit. It glowed a weird violet radioactive sci-fi color but the amp cranked back up and we were back in business. That was 15 or so years ago, amp still chugs along. It seems indestructible. I cut the plug cord once to add another 10' and not have to use extension cords. That's it.

Been playing about as long as I've owned this amp (32 years). I have enough gear to outfit an entire small band. But no more than that. Mainly vintage gear.
If this were stolen or lost I'd be pissed and sad because it has been with me longer than my wife, my kids, my house, and every guitar but one. I might keep my eye out for another one. Probably buy the very same amp back on eBay :) Then sic the cops on the seller.
But I wouldn't go out of my way to replace it. Most of the ones you see out there no longer have their original Jensen. That was the beauty of this baby, and still is. Incredible, indestructible, magnet monster of a speaker.
Lately I am learning more about my gear and may fix this up. It WAS junk. Now it's "vintage 60s tube" sound. The original Tolex on the edges is gone. Might re-cover the thing in tweed, or pink naugahyde. Yeah I know, the anal purity collectors will scream. Too bad. Screw 'em. This is an amp for players. If you can find one for cheap, do it.

This amp was made in 1966 according to the other revieq posted. I play classic rock, 80's metal, alternative, grunge, new metal and blues. This amp has one channel with three input choices. Two are for guitar or bass. the other is for a microphone or an accordian. I wish it had reverb but I can add a pedal to get the effect I need. I use this amp in my apartment for practicing, but when the neighbors are gone I can crank it up and get a room full of sound with out the adjacent building hearing me. It is an all tube amp with 2 12AX7A's and two 6L6GC's. It uses diodes in the rectifier portion of this amp.

I use a strat, a 335 copy, a Jackson SL-1, and a BC Rich Rave. My Jackson and my 335 copy sound the best through this amp. It has a lot of low end and with my distortion pedal pushing it a little I can can get some really heavy sounds out of this mother. This amp would be great for playing or recording drop "D" stuff. or maybe even lower tuning configurations. Not a power house in any respect but the sound is very full. It has a 15 inch Jensen special design speaker that buzzes a little. I am gonna have it repaired because i love the sound it puts out. In the mean time I am using a 15 inch speaker out of a Kay 720 bass amp. Definitely not a good replacement but it gets me by for now. This amp has absolutley NO HUM!!! I can crank it up and I hear nothing but the sound of my guitar. A very very clean signal. I am going to try some 12" inch speakers in this puppy and see what i can make it do. Definitely a blues or rock amp. I suppose you could play country through it, if you're into that sorta thing. I do not play country so I can't tell you how that sounds. This ampdistorts at about 3 o'clock on the volume control. If you back the bass way down it distorts a little sooner. Distortion is kinda like FREE, early KISS, or just about any rock guitar group from the early 70's. But like I said add a distortion pedal and look out new millenium. Really comes alive.

I would definitely rely on this amp for a long time. The tubes sockets ar kinda flimsy, but over all the amp is built very well. The back cover comes off to reveal all of the point to point circuitry. Troubleshooting or repair would be a breeze. The cabinet is built well and stands about 30" tall.

Due to it's age I doubt any customer service is available. I am not sure if schematics are available on the net.

If you have an opportunity to pick one of these amps it's definitely worth it. After all it's, a tube amp and made in the USA. Plus they are cheap to come by. If someone stole it I would hunt them down and beat there ass. I doubt I could find another for the deal I got on this one. I like the fact that there are some reasonably priced vintage tube amps out there. Even if it's not a popular brand with the selling and buying communtiy, it's still a very good amp to own and play through.

I believe this amp was made around 1966. This amp would be good for playing just about any rock/country/blues song for that era. It has one channel with three (3) inputs. One marked guitar, another bass, and the third for microphone. I think I can make out the word accordian near the input jacks, too. Three knobs Volume, Treble, Bass. It has no external speaker Jack, reverb, or vibrato. The speaker plug in is the 2 prong type. this could be easily modified to adapt it for using a cabinet with this amp.
It has three (3) 12AX7A's in the preamp section and 2 6L6GC's in the power section. It uses four (4) diodes for the rectifier section. All point to point wiring. no circuit boards.
I am still getting used to the 6L6 sound so I can't elaborate much on sound. The sound fills my apartment at a modest 35 watts and I believe it would sound great at a small club or mic'd at a larger gig. The 15" Jensen is the best sounding speaker for this rig. I might try to stick a 12" n there for the hell of it to see how that sounds.

I play my Jackson SL-1 plugged into a distortion pedal to give it a little boost to get it to overdrive a little more. Has plenty of low end ass. I turned my distortion up on the pedal and I was playing some Godsmack through it and I must admit that drop "D" stuff sounds awesome on this amp. This also can be very clean. The 15 inch Jensen speaker sparkles with clean but not piercing highs. I am going to have the speaker repaired though, as it has developed a buzz (Damn!) I tried a speaker from a Kay Model 720 and it sounded pretty muddy. Not a good choice for a replacement but it will do until another speaker comes along or I repair the Jensen.
Absolutely NO HUM OR HISS!!!!! Solid state rectifier so no sag when pushed hard.

I would say it is moderately dependable and I think it could benefit from some better tube sockets. The sockets for the 6L6GC's aren't very snug. I might try to bend the pins a little. If I get ambitious I may replace them, but for now I just want to have fun playing it. RCA tubes sound the best in this amp.

Probably won't need to contact.

I will keep this one just because it's a tube amp and I got it so cheap. Plus it would be fun to do some recording with this amp and make people guess what I am playing through. I might try recording some drop "D" stuff and see if it will stand out. I am not ashamed to buy or play a cheap guitar amp or any othe equipmet as long as it sound good. Made in U.S.A. is another reason to keep it.

1966 Harmony Model H420 Bass Amp
From the 1966 catalog, the following description is word for word:

"This newly designed powerful 35 watt amplifier can also be used for
accordion, guitar, and voice amplification. Power amplification,
with clear reproduction of a wide sprectrum of tone with minimum distortion. 15 inch heavy duty Jensen Special Design Speaker permits use of deep bass with adequate volume. Two chassis. Power chassis has advanced design using 4 silicon diode rectifiers and 4 tubes (2 dual purpose) for performance equivalent to 7 tube circuit.
Equipped with polarity reversing line switch to reduce AC line hum;
neon pilot light; extractor type fuse. #instrument input jacks.
3 seperate controls, for volume, bass, treble. Housed in locked corner
wood cabinet, covered with black ostrich grained simulated leather,
mordern woven acoustical grill."

Mine of course, looked nothing like that.
This is 1 x 15" combo amp made by Valco. Two 6L6's and two 12AX7's that claim to add up to 35 watts. One channel, 3 inputs, Volume, Bass, Treble knobs and that's it. No effects, no line out, no headphone jack,no reverb, vibrato or any modern conveniences.
Extremely basic no frills vintage amp. But this junker is loud and very toneful in a narrow way, that is, if one has the controls dialed in just right.

I play harp through this amp. I'm just realizing I haven't tried any Microphone except a Shure Green Bullet with this amp in a couple of years because it sounded better than my other Mics, with this particular amplifier.
I'm not sure how it would be for guitar. Since I added the 15" WeberVST speaker, I have really liked the sound and tone of this amp. The bass knob needs to be fairly low at -| or 9:O'clock and the treble 180 degrees opposite,
at |- or 3:o'clock. Although the treble is effective anywhere between 12:O'clock and max/6:O'clock. The volume is usually set about 2:O'clock, but one can go up from there.
At these approximate settings this amp really roars a big, beautiful, honkin'/quackin', loud and ballsy sound. I don't know if it's distortion or compression, or something else, but it's just a great sound to my ears. I don't make this statement lightly either, since I own more than twenty mostly vintage amps. Lots of Fenders, a few Gibsons, several Silvertones, Harmonys', other Valcos. This has been one of my favorites the last 3 to 4 years.

The 15" Jensen was long gone when I acquired this amp, and a cheesy failing Magnavox was dying fast, so I replaced it with a 15" WeberVST
and it's been singing ever since. The Weber speaker is probably a key to the great tone as well. I also put 2new NOS Phillips 6L6WGB tubes and NOS 12AX7's. I liked this amp enough, that when I saw another one, cosmetically much nicer, but broke down and silent, I bought it also.
Seventeen dollars to replace a bad resistor, and I have a second Harmony H420. It came with the orginal Jensen, but I had to put a WeberVST 15" anyway.

Loud, gutsy and gritty, from a harp players perspective, with mild but nice distortion. As indicated elsewhere in this review, this amp is very limited, and has to be dialed in or tweaked carefully via the control knobs.

I'ts been very reliable, after initial minor repairs and re-tubing.
I've used it two to four times monthly over the last several years without problems. The amp is 36 years old, however, and components do fade.

None available from Harmony, obviously. But local techs seemed able to handle initial repairs.

I'm an amateur I'm sorry to say. Been playing harmonica about 37 years, been studying/practicing/learning and playing blues harp in clubs about 10 years, trying to get good.
Played blues piano in a few bands, and jams about 15 years, piano lessons 44 years ago. Also played guitar until accident disabled one arm.
I have about 23 other vintage amps, a couple of newer amps, and a Yamaha PF15 Electronic Keyboard. I'm a blues fanatic, as you may have deduced by now, record and CD collector, and I do a weekly blues radio
program on small local station, WWW.WQNA.ORG, on the inernet, while our dues are paid up.
If it were stolen, I'd use it's sister H420 amp, and If I lost the backup too, I try to get another.
Reverb would have been nice.
I think these are pretty fine harp amps, and I suspect they might be pretty good for guitar too. I'd always heard that 8" and 10" speakers were preferable for harp, but this 15" combo puts out a hell of a sound.