Author Options:

Can a solid state amplifier be reconstructed/reconfigured as a tube amp? Answered

All guitarists seem to prefer the sound of a tube amp over solid state. Amp manufacturers, after committing to the solid state format, hook, line, and heat sinker, must have been appalled when guitarists began to demand availability of the old school tube amps, and scrambled to replicate the distinctive tube sound by means of additional effects and eventually modelling features. But, the big boys doggedly refused to admit the error of their ways, which, as it turns out, was a good thing as new amp manufacturers began to spring up to fill the void. Finally after sitting around their boardrooms, no doubt sipping their Coke new recipes while watching their market shares dwindle, they decided to reissue some of their most popular tube amps...at six times the initial price of course. I can't afford a new tube amp. I can't afford a used tube amp. Ebay and craigslist are rife with inexpensive, (relatively), solid state amps. My question then is, could a solid state amp be retrofitted with a tube chassis and perhaps still utilize some of the solid state attributes and parts? My instinct tells me yes. However, my knowledge of electronics and theory being nil, I really haven't the foggiest idea of what might be involved with such an undertaking. To say that a schematic is Greek to me is a gross understatement. Therefore, I appeal to the genius of the Instructable contributers to comment, or even better, start a project build. (C'mon gmoon, you know you want to!) Thanks Sycan


hey im starting a project of making my living room into a healing energizer room, im going to interface my detox box with my receiver and have it broadcasted into a percise spot, then amplify the output,, get a light tube hook it up to a disco ball add some aroma lavinder and pass the water around..Then im gona offer magnesium back massages and call it the new wine clinic! So who wants to come and build it for me?

You want the sound of a tube amp without paying for the tubes?


I understand that the tubes would have to be purchased separately along with the sockets, etc, and that some sort of chassis would have to be fabricated. I'm not sure what might be reusable from the ss amp. Even if it were only the speakers, cabinet, controls, and perhaps some of the onboard effects, I've got to think that you'd be ahead of the game compared to building a tube amp from scratch. Sycan

Tubes need high voltage supplies and work a bit differently to silicon. You can't just swap them for transistors. In real terms you'd have to build the amp from scratch, but the speakers, cabinet, controls, and perhaps some of the onboard effects* could still be used.


*depending upon what they are.

Thanks Lemonie. I accept that as a yes..er, maybe. Positive nonetheless. :) BTW. What are your thoughts on making a reverb unit from an old toaster? Sycan

You made me laugh! - Please do make a reverb unit from a toaster - that would be so good to see.


Makes me laugh too. Crazy thing is, I think it might work. I got the idea after taking apart an old Silvertone amp many years ago. Those had a thunderous reverb in them that when punched, kicked, or otherwise jostled, produced a sound similar to a nuclear detonation. The reverb chamber itself wasn't much more than an aluminium housing about 10 - 12 inches long that contained a spring, bringing to mind, (my mind anyway), a toaster element. Come to think of it an electric heater with a coil element may work even better. :) Sycan

That sounds like the oddball "piezo" element reverb tanks that Silvertone and Danelectro used for a while in the 60's...you either loved 'em or you hated them. A grungy "garage band" sound that's enjoying a real resurgence right now...

You might be able to replicate the tank using the cheap piezo disks you can find in old hand-held video games and toys. Or piezo mic or even phonograph elements...

Are solid state amps bad? A lot of metal players insist on SS amps. Harsh, third-order harmonic distortion works just fine for that sound.

But personally, I agree with you.

Anyway, it's always been about economics. It's way cheaper to build SS amps, and they have other advantages too--a cheap, modern SS can take much more physical abuse than any tube amp. Transistors don't need to be replaced every year or two, and a transistor power stage can be designed with a low enough output impedance to eliminate an output transformer.

In short, manufacturers love SS technology, whether we like it or not. It is rather cool that tube tech won't go away, despite what the manufacturers do or say...

Sure, you can use some of the parts from a SS amp in a tube project. And you can build SS / tube hybrids. It's all been done.

But not every pure tube amp sounds good, and many hybrids sound flat out crappy. Technical problems (hybridizing) can be overcome, but you might not like the monster you create...

I'm not sure I agree that you cannot afford a tube amp--keep checking craigslist and Ebay. A year or so ago Crate sold all their remaining V18 amps online for ~$150.

Two days ago I bought a 60's Kalamazoo Bass 30 amp for well under 100 bucks from Ebay. It's not strictly a guitar amp, but it's from the era when bass amps (like the fender bassman) sounded good with guitar, too. The cab is rough, but I'm a player, not a collector.

And the amp is sans-speakers, and I don't have any 10" speakers, so I'm running it through an external cab (and $#,&$ I have lots of 12" speakers :-P .) Anyhow, it sounds real nice. Not bad for an amp that cost less than a set of replacement tubes. At this point I'll see if a single 12" speaker will fit--if not, I'll invest in a couple Weber 10" speaker for $80-90.

Here's a tip--refine your ebay search by distance. The Kalamazoo was a "local pickup only," which is why no one else bid on it...

...Ya never should have let the Silvertone go...

(I do have another DIY tube amp build in the works, which might show up here some day...)

Yeah I know. I should have never sold my 66 ES-335, my 60 something Tele w/bigsby, my SG, my Polaris 200w head w/2-15" jbls, (used to play bass), my 100w Polaris combo w/4-10s, (think super reverb minus the reverb), on and on. The fact that this was 30 years ago does little to diminish my remorse.

Funny that you mention the Kalamazoo Bass 30. That was my very first amp, which I bought with a Lyle single cutaway hollowbody bass. It didn't last me long. I upgraded to the Bass 50. After maybe 6 months, when something went wrong with it, my mom, God bless her, decided that this playing guitar in a rock band, wasn't something that I was going to give up and sprung for the Polaris amp, $1145 and a brand new Gibson EB-3 bass, $485. A considerable investment for us in 1967. I went on to play in bands on and off for the next 15 years or so. Along the way there were many guitars and amps that came and went. Who knew?

Several years ago I realized that the Gibsons and Fenders of my past were out of my reach pricewise. I remembered how good, (and cool), some of the 60s Japanese guitars were and I found a beauty in an Oregon pawn shop for $95. It was a double florentine cutaway, electric hollowbody with a beautiful sunburst finish, and the coolest pearloid headstock, and switch cover that you've ever seen. It had several problems, none of which were insurmountable. Besides, I had plans.

Since the headstock emblem was missing, it took me some time to discover that it most likely was a Univox, anywhere from mid 60s to early 70s vintage. I have since seen this model described as a Trini Lopez and even a Barney Kessell model. Whatever. The whammy bar, and pickguard, and selector switch knob were missing, and one of the pickup rings was cracked. I didn't care, I had a pair of humbuckers gathering dust. I was dying to rebuild this guitar.

A couple of years past, and all I managed to accomplish was to put a small agate cabachon knob on the selector switch, and make a new bridge piece.

Those were turbulent times for me, and between jobs, and homes, I left the guitar in a friends storage unit, the contents of which were auctioned when she failed to pay the rent. Lost a real pearl in the rough there. Your green guitar reminds me of it.

Heres the kicker. A couple of months ago while perusing the web, guess what I found? Want to see it? http://www.univox.org/pics/guitars/335divot_red_sharp.jpg]

Pretty much exactly as it was the last time I saw it, I have no idea how it got where it is. All I know is that I'm back to square one..looking for another guitar treasure, and bemoaning what might have been.

Don't even get me started on my cars!

:) Sycan

*choke* . . . Yep, I foolishly sold some of my instruments, but not a 60's 335 and a Tele... A black, hollowbody double-cutaway Vox bass, for one. A Gibson Melodymaker for another.

I had a buddy years back who bought and sold so much gear, he'd could have retired on what it's worth today...

I managed to hang on to the Gibson Les Paul Custom I bought in high school ('74, it was used and a couple years old then.) And an old Ampeg Gemini II I've been gradually getting back into order.

Your Mom was awesome, that was a chunk of change back then.

That's wild about Univox. What are the odds you'd find a pic on the net... You gotta look for another one, they still aren't very expensive. Those MIJ thin-line hollowbodies are like candy; I've picked up three over the last few years: the green-burst Sekova, a Kingston and a Maxitone (still a project.)

I keep a list of MIJ names, like Cameo, Crestline, Domino, Kawai, Hondo, Vantage, Zimgar, etc. ;-)

The Maxitone is the closest to your lost Uni, it's larger--more like a "real" guitar and has a real nice tone (had, anyway, before I started working on it.)

I don't know if it's cheapness or just pure stubbornness, but I also tend to avoid collecting Gibsons or Fenders (they do call me a contrarian.) You can't fixup or modify them anyway without ruining the collector value, and where's the fun in that? (I did find one prize recenty...check out my orange board.)

Your Duo is waaay cool ! What do you know about it ? I sent you a message loaded with questions and speculation with regards to your treasure but I'm pretty sure that it got lost in private message limbo. I won't rehash that communique, only to say congrats, and keep me posted. I can't wait to see what you do with it.

Yeah, I never got the PM.

There is a cool back story:
I bought the Duolian from a 60-something woman who said the guitar had been her father's. He was a machinist who died at age 55. The guitar had last been played when she was in high school, probably sometime in the 1960s. It was kept in a case under the bed for all those years ( I have the case, too.) The neck is perfectly straight--a good thing since it's not adjustable.

The steel body was painted silver; she didn't know if he did that, or if he bought it that way. I stripped the overpaint with rubbing alcohol. That took 3 or 4 weeks of attention, usually while watching TV in the evenings. Very little of what remains of the original "Duco" paint was damaged in the process.

I've done some work on the bridge, but I'll probably have a luthier cut a new bridge for me. This is one guitar I don't mind having a pro setup for me...if I could find someone local who knows vintage Nationals, that is.

Relative to what it's worth, I paid very little for the guitar. I think she sold it to me simply because I offered her a little over the asking price. And of the TONS of emails she received, I was the only person who did offer more (maybe there's a lesson there, maybe not.) And I was honest with her when we met: I told her I thought it was worth more. But I guess she wanted it to go to someone who would play it...

I was afraid that you were going to tell me that you found it in a dumpster, which, of course would have meant that I'd spend the rest of my life smelling like garbage. I see nothing in your photos that would prevent you from restoring the instrument to pristine if not mint condition. Unless 'mint' meant perfect-unrestored. I'm not an expert , but trust me there are many out there. Duolian collectors are particularly fanatical. One guy is offering to buy any,.. sight unseen! I believe your Duo is either a '34 or a '35 . After seeing yours, I googled duolian and found a wealth of devoted websites, many with just incredible photos. There is also a serial # to year of manufacture database. Who knows where tracking that serial number may lead you. Where it was sold. Perhaps to whom. Okay, that might be a reach. But you never know. I can imagine it being toted around the delta by some obscure, itinerate bluesman. Or you may not find out anything. Thats ok too, because all the really good treasures deserve a little mystery.

Yeah, I've already IDed it as a '35 Duolian based on the serial number.

It's also a little unusual. I was told on a resonator forum that most 1935+ "14 fret models" (14 frets at the body) have a solid, not a slotted pedhead. so it seems to represent a transition from the 12 fretters to the 14 fretters, and has characteristics of both...

I also know the previous owner's father grew up in Pennsylvania, so it's likely the guitar was purchased there. I don't believe he was the original owner, however. The sell said her dad didn't play much, but it was definitely played.

He probably painted it though. I sort of liked the "trailer park mojo" paint job, but it was 3 or 4 coats and effected the resonance negatively...

Other than setup, I'm not sure much more needs to be done. The wear pattern cannot be reversed...and shouldn't be. Totally "cherry" Nationals fetch a bit more, but collectors don't seem to mind natural wear. Maybe there's a bit more "roadhouse cred" to them.

Other than a couple screws in the tuning machines, it's original. Down to the resonator cone.

Sweeeet! The larger pics really allow seeing the original finish, which I hadn't realized is gold. Is that finish referred to as 'crystalline' ? I've heard the term before somewhere. Some of the examples I've seen appear to have many, many coats of clear applied. Seems as if that would dampen resonance somewhat. Maybe that's the difference between a collectors guitar and a players.

Not certain about the clearcoat, I don't think the original Nationals had that. But the "crystalline" effect was called the "Duco" finish. Some of the new Nationals, and maybe the "Michael Messer" resonators try to replicate it, but it's a lost art. They produce something similar, but not quite as nice, IMHO.

. Try searching for something like
 tube +transistor +amp +hybrid tube +transistor +amp +retrofit

Thanks NM. Search thread has steered me onto the right track. I have much research ahead. Hopefully, studying hybrid schematics will provide some answers. Sycan