I love old tube amps. If you dig them as much as I do, this blog is for you. Guitar, Hi Fi, recording gear, nothing beats the warmth and character of this antiquated technology. Shared here are tips to keep your much loved old amps in good shape, and tips how to improve your new gear. Have a comment or suggestion? Leave it here! Thanks for reading!
Just finished this one, a very rare Magnatone A-646 amp from about 1951. This one us a real gem and is visually striking as well.
I bought this amp by mistake on Reverb this winter. I put an offer on a Varsity that I wanted as a backup to my main one and the owner declined. It wasn't a bad price and I love those early Varsity amps and it was pretty enough that I was willing to pay his price anyway. This one came up in my feed and I was curious so I put an offer on it. The owner said he would think about it. First amp wound up coming through at my price so I bought it then.......so did this one!
This one arrived first. It was noisy, had some really poor tech work done to it so I got it going. I wasn't all that impressed with it though and even after re-capping the power supply it had a considerable amount of hum. I even added another filter stage. I knew there were other solutions, maybe filament, maybe ground loop but I shelved it. If it's mine I tend to just put it away and forget about it.
So today I did a better re-cap, with a nice expensive C.E. can, an additional filter stage and while it got better and was certainly tidier, still hummed at an unacceptable level. So I disconnected the center tap of the 6.3v filament and added a hum balance: 2x 100 ohm resistors, one on each side of the filament, the other sides both going to the cathode bias resistor on the 6V6 tube. Looks like this:
When I brought this up on my Variac I thought "dammit! I killed my amp! Time for more troubleshooting!" I just wanted to be done with it. But reality is, the amp is just so quiet now! Hum free with only a little bit of noise when it's turned all the way up.
This amp I believe is the precursor to the Varsity Deluxe I reviewed here. Similar circuit, 40's style box, single 6V6 and 5Y3 but driven by the darker more euphonic 6SL7 tube rather than the snappier 12Ax7. It has a single 8" Alnico 5 Jensen speaker.
More pics:
How does it sound? Like the early version of the Tweed Fender Princeton. It's a similar circuit, but this plays cleaner and more articulate. It has a big sound for such a small box, warm but not fuzzy. Ideal Wes Montgomery or Charlie Christian sound. I'm a big fan of the Magnatone amplifier, especially the early ones. They are a bargain. I may sell this one but not for cheap! I like it a little too much.
The only drawback is the 6SL7 tube can be microphonic. If you turn both the volume and tone all the way up it may sing a song. The 12AX7 is a better tube for guitar amps. You could simply use a 6SL7 to 12AX7 adapter available on EBay, or you can just roll a little bit of the tone control back and enjoy that big warm sound.
If you like something different, give one of these a try! They are lovely little amps!
JB
8/29. After tracking with a Les Paul all weekend I've decided this is my best sounding amp. Bigger tone than a tweed Champ, smoother top, goes to tape beautifully! It's a keeper! Do look out for one of these. I did some reading about the hum and one tech mentions he struggled with his as well. he resorted to installing a big ass choke and extra filter stage. That should do the trick but try the hum balance first along with adding one filter stage. Quite happy with the results here. JB
Here's my main guitar. I built it on my rooftop when I lived in Williamsburg Brooklyn 3 years ago:
Photo by Starina Catchitoorian:
Beach gig!
I started out a Jimi freak when I was 14 years old. So naturally I played a '69 Maple cap Stratocaster ($750 in 1990!) for years. Trouble with a Strat, something Dave Navarro said to me: "Trouble with a Strat is you wind up playing Strat things on it...." They do have a way of commanding you to play certain things. So during the grunge scare of '92 I bought my first Jazzmaster, a beat to death 1964 model(100% original, $750 in 1992!). I played that guitar for years. Best part was I didn't know how to play a Jazzmaster so I really feel like I started to find myself on that guitar. It wasn't until '99 at a guitar show in Portland that I bought my first Telecaster, a refinished black 1966 maple cap model ($750! Notice a trend??) that was light as a feather and trust me, I really didn't know how to play that guitar. I sold it in 2003 and doubled my money. It gets played in church now. I've bought and sold a lot of guitars over the years and that is the only one I regret selling. I had the bridge pickup rewound by Fralin to make it hot like an early 50's model. That was a great guitar. Rent and debt! Bah!
But the guitar I've always wanted is the Fender Esquire, namely ones made in the early 50's. They cost a lotta dough now. I have played some that were not to my liking at all and priced about $15k, and played some that if cost were no object I'd just pay whatever it takes.
To find one in Copper? There may not be any. There are only a handful of copper Telecasters in existence. I'm not too keen on the new Fender product, the relic or reissue series. Good stuff but I'm way too picky.
And really I'm totally happy with this one that I built. I have about $400 into it! It gets played every day.
The neck is just an Allparts V. They're great. I may upgrade to a Musikraft cause they are better and I can afford it now but like I said, this guitar keeps me really satisfied as is.
The body is pine, bought from Clearfork Designs on EBay. His EBay name is Ohlar. It's super light, about 3 pounds and a few ounces. I met the guy who makes them at the Dallas Guitar Expo. He's just a great guy. Super warm and friendly. You can tell when that kind of vibe goes into something one builds. I bought another body from him there that I am going to do something with next year. It's lightweight ash.
So I used Guitar Re-Ranch products to do the finish. Desert sand undercoat, copper then clear. They make great stuff. My only error was not doing a sanding sealer. Oops! Well, the grain shows through now. Fender wouldn't let that happen, but I'm not Leo!
After 3 years it's getting pretty worn!
No need for relic stuff, these are my scars and this is my story. I did the silly dowel holes as well, just details:
Finishing I did the lazy susan nail hole method Fender used to use. It's already developing that 'Fuller Tan' visible when you remove the control plate:
I went with Fender hardware and a Mojotone 50's pickup.
I really like Mojo pickups. This is the heart of the Esquire. That simple 1 pickup design forces me to play for real and extract what I want out of the guitar buy using my hands creatively. If I want mellow I need to find mellow. Gnarly is less of a challenge!
I used all CTS pots and CRL switch, the knobs are Daka Ware from the 40's, bakelite and oxblood colored. I like the way they look with the copper body. The switch tip is Daka Ware as well, oxblood too!
The pickguard is bakelite, did the whole lacquer paint circle thing cause I can! The decal I bought from some European vendor. It's pretty accurate!
So this is my baby now. My main guitar. I think it's the simplicity of the Esquire that I like the most. It forces me to find melody, be creative in my playing since I'm not fiddling with tremolo arms and pickups. I just play the thing!
A bit of the guitar in action in a 110 degree room!
And me and my friend Starina....she plays a copper Danelectro. These go together well!
So a client of mine has this amp for his office use. It's a Bad Cat 5R. Don't know much about them but have heard they are related somehow to Matchless. This is my first venture into a Bad Cat and having worked on many Matchless amps I can say they certainly are similar.
The job: Modify the crap out of this amp!
My client has recently become hooked on old amps, Marshall, Tweed Fender, Supro, 50's Gibson, Ampeg. This amp just isn't doing it for him any longer. It's stiff and rather dull.
Now, it's a very simple circuit with only 2 tubes. A 6V6 driven by (interesting choice that I like!) a 6SL7. There is only so much modifying one can do. When I fired it up the first thing I noticed was what a lack of distortion there was. I like my little amps, distortion (Gibson GA5 from the 50's) or no distortion (Magnatone Varsity) to have a warm singing quality to them. My client is into warmth more than over the top blast so the goal is to get it to do both. I found the amp to lack warmth.
I have a back to front approach with amps whether I'm trouble shooting or modifying. Example: first thing to look at with a dead or dull sounding amp is the speaker and/or the power supply. So I started there. First thing: Why use a Celestion Vintage 30 on a 5 watt amp? If you want to go for cleaner tones that's great and I'm not objecting their speaker choice, it's purely subjective. But for this project we went with a 20 watt Weber 12A125A the one that says "woody and reedy".
I love this speaker. My favorite amp that I built uses a 30 watt version. A bit on the darker/warmer side of the spectrum, nice smooth breakup.
The second thing is the power supply. Stock it uses 2 1N4007 diodes loading into a 100uf 450V capacitor. I decided if it's an easy fix to add a tube rectifier let's go for it. I like my little amps to compress! You can see diodes right under that blue power resistor.
So once I looked around I noticed 2 things right away that made me happy. Chassis is pre-punched for more octal sockets and there are 2 yellow wires coming off the power transformer. That means there is a 5 volt filament tap! YES! This job just got easier.
So I took out the plastic socket plug and installed a socket. Removed the 2 diodes, put the red wires to pins 4&6, the yellow to pins 2&8 and replaced the 100uf with a 47uf cap. Why replace that cap? The 5 volt filament line is at risk with anything too high. With diodes the sky is the limit, but with a tube rectifier you don't want to go too much above 50uf.
I opted to use a 5V4 for the rectifier. For squishiest results go with a 5Y3. I figured this would be a dramatic shift as is and didn't care to go too dramatic. Fun thing is, they are interchangeable and my client likes to fiddle with tubes.
The circuit itself:
I won't go too much into detail on the circuit mods cause I encourage you to use your own creativity. What I did start with was the cathode resistor on the output tube. It's a 270 ohm. I replaced it with a 500 ohm. It's just more loose. I also replaced all those horrible brick drop polypropylene caps with warmer sounding Mojo Dijon caps and any resistors in the signal path with carbon composition. Also the first gain stage cathode cap is a 6.8k. I just copied Fender and used a 1.5k bypassed by a 22uf cap. The whole amp seemed to come to life in a good vintage fun way.
So now this amp sings at any volume. It has a master volume which didn't really serve too much of a purpose before but now you can bring it down and blast the preamp. With my S.G. it's like a mini AC/DC concert.
I think these are good amps even stock. Very well made and built to last. The reverb is transistor driven but that doesn't offend me, it's quiet and sounds nice. But if you aren't opposed to making your Bad Cat a Badder Cat, try some of these fun mods, use your creativity and you can tailor it to suit your needs.
Disclaimer: if you are a novice, don't try this at home. Pay someone like me to do this kind of work. Tube amps are no joke inside, they can kill you with the amount of juice running around in there! So tell your favorite tech what you hear in your head and let the magician work his or her magic.
There was a time not long ago when a 'vintage' guitar was just called a 'used' guitar. When I was a teenager I played a blonde 1961 Stratocaster at Chuck Levins in Washington DC that was expensive, about $1200. This was around 1984. You could buy a new top model professional guitar for about the same price or buy this 'vintage' instrument.
That was a lot of money for me then, I was a kid throwing the Baltimore Sun newspaper on Sunday morning, cutting lawns for ten bucks and really, a later not fancy Fender could be had for half that or less. A re-painted one for even less. Point is you could buy the guitar of your dreams for an attainable price.
I got to enjoy a few over the years, refinished ones that could be had at a players price. There was a lot of them around then. They may have been modified by a good player to their liking, nobody cared then, these were just tools. Practice, learn, get a good instrument and join a band. If you could improve it for your needs all the better.
Prices went up and up and up then 2003 happened. A second war started, easy credit and an older generation that would pay anything to get some good memories back skyrocketed prices. The last 2 vintage Fenders I sold were my '61 Stratocaster (refinished) for $3500 and my refinished '66 Maple Cap Telecaster for $1500. I double my money on both of those and only owned them for about 5 years each. Today that Stratocaster would command $10k and the Tele around $5k. I can afford one now but have no interest in paying that kind of money. Fender guitars are the Lego of the guitar world, easy to fake parts and with all that relic jive going on, you need a sharp eye and a lot of experience to make an informed purchase. And I'm a musician. I want something I can carve up, change colors on and make my own should I choose without the 'vintage guitar' police telling me I'm an idiot for lowering the value.
Fender over the years has attempted to capture the spirit of the old guitars by making 'reissue' series and now 'custom shop' and 'relic' guitars. They've been getting better over time. The first series to me, completely missed the mark. Details.... the way the necks feel, the finish, the 'Fender Fender' saddles rather than the 'Fender Pat Pend' saddles, just weird enough pickguards. Little silly things like that. They just seemed to refuse to get it right.
So that drove other parts makers to get it right. You could buy 'Pat Pend' saddles on the black market, decals on the black market, better pickups, better necks and better bodies. Fender would often clamp down and you'd wait a year to find some other counterfeiter to sell you saddles that looked right.
Other builders got better, but the trend was 'relic'. I prefer to put my own dents in my guitar. My scratches=my story. And todays Custom Shop stuff, feels too perfect for me. A great Fender should be just janky enough and not one bit more.
So the goal for me since I like nice things but don't really play Stratocasters these days, is to build something that's as good or better than what other builders make, something as satisfying as the top flight instruments Fender makes with a budget of less than a grand. Something I can schlep to gigs and lessons, enjoy and not be worried about.
I've always liked Fenders made between '64 and '65. I like the transitional logo, the curved rosewood fingerboard, clay dots, green guard and lacquer finish. That's a sweet spot for the necks, not small but not huge.
I have a thing for black Fenders.
We live in a real renaissance period for parts. I like it. Just like the amps I've built, speakers and transformers have gotten so good I lost my lust for old amps.
About this build. The most expensive part was the neck. It was built by Musikraft. I think it cost me around $300. I ordered it unfinished with only a sealer, post '64 dot spacing, real clay dots and with a curved rather than slab fingerboard. I could buy the Allparts '62 neck for about a third of the price and been happy too, those are great. The buy I wanted those clay dots (even though a real old Fender never used clay!) and didn't want to go through the process of replacing those plastic ones. And I gotta say, Musikraft knocked it out of the park with this one. Great product, well worth it. There is something just a little extra special with the detail. The difference between a good guitar and a great one is often the person with a piece of sandpaper. I'll gladly buy another one and may even buy one for my beloved Esquire.
A word on the Fender Custom Shop. They've gotten better at their dots, the older 60's Custom shop models used dyed plastic. The more you played them the newer they got!
Only one company has mastered those mysterious dots and that is:
These guys do such a great reproduction I'd be afraid to buy a vintage one. Apparently they are closing shop. Do read about their dots! It's rather fascinating!
The body I found on Reverb.com. It's made of pine and built by Guitar Mill. I put an offer of around $250 and got it. No, I realize it's not proper alder, I just like pine. And it's about 3 1/2 pounds. My back prefers a light guitar. I also like Clearfork Designs. He lets you know the weight of each body. You want light, order it! Heavy, yes. You get to choose.
I did order an MJT body. Truly great craftsmanship. I just didn't want the checking and scratches. Plus I decided to just do my own finish. It's the most challenging part and I'm still buffing it. But it keeps getting better and it's starting to check naturally. Plus I could put those silly dowel holes in it and do the whole 'lazy Susan nail hole' method of finishing like they used to do. Now of course I didn't set up a spray booth, this was finished on my rooftop in Greenpoint!
Silly dowel holes:
In a few years this body will just look like an old body. The only difference may be in how we see it. Is it something special or not? Older I get the more I realize it's just a matter of perception.
For the finish I used real nitrocellulose lacquer from Guitar Re-ranch:
They have great products and if you follow their instructions patiently you'll have a world class finish. I'm not all that patient so mine is second class but, in a year it will just look worn. I did the 'desert sand' primer coat like they did in the old days, with black over that and high gloss over that. I got it so it's like a black mirror on most of it!
The hardware is mostly Fender. They have that great new 'True Vintage' series. Yes, they make my "Pat Pend" saddles finally and they cost about $30 for a set as opposed to up to $100 for black market ones.
I also used a Fender "True Vintage" tremolo block. I could have spent a lot more but why? I do like the Callaham stuff. I was a dealer a long time ago. Today I'm actually happy with what Fender is doing. It shows someone cares at the Fender company. That's all it really takes, someone to listen to their consumers and respond accordingly.
The pickguard was believe it or not, the next most expensive part:
It was made in Italy. I don't know if they make them any longer. What's so great about it? Why spend $150 rather than $39? Details. It's thick and like the old ones and flammable too! It's the right material and color. This guitar has been in service for all of 8 months now and it's starting to show signs of shrinkage. The old ones age organically, there is a beauty to them. The new PVC ones frankly look cheap to me. I simply can't tolerate cheap looking stuff!
The pickups........ugh. There are so many people making pickups today. I was a Fralin and Chandler dealer years ago, Great stuff. Never liked some of the bigger builders and definitely not crazy about the Fender product. I don't know why cause at the end of the day it's just some magnets with some wire wrapped around it.
I refuse to pay a lot for pickups...... Yeah, I'll pay a lot for a pickguard but that's cause I need to feed my vain streak!
So I like the number '59. I looked on EBay, punched in '59 Stratocaster pickups and up popped a few sets. I chose the one that was around $89 and bought them. I'm happy with them, they sound great!
I simply didn't want to think and do a bunch of research. That's a rabbit hole I don't have the time for. I'm a good player. I've played cheap crappy Strat copies and made them sound just like a Strat!
I used CTS potentiometers and a 3 way CRL switch. The tone cap is an Aerovox .1.
A word about tone capacitors. You can spend a fortune on one. Paper in Oil yadda yadda. It's jive. You're literally rolling off a little bit of highs to ground. The difference is the value. I know a lot of people beg to differ, but the power of suggestion has quite an effect on the brain.
I used a bone nut. I never really enjoy making nuts so I'm glad to say there are pre slotted ones available with perfect spacing. Just deepen them, cut it down to size and polish it out and you're done.
The decal I bought online from a dealer in Europe. Nice product. Not too pleased with how I did the head of my guitar so I may do it again. I've thought about doing a matching black headstock like the John Lennon '64.
And another parts maker is making decent serialized neck plates. Gotta to the L number!
The font is a bit weird but whatever! Like I said, Fender is the Lego of the guitar world.
Under the hood:
Nail holes!!!
So overall I have about $850 invested in this guitar. The more I play it the better it gets, it's starting to really warm up and it keeps getting better looking. I've gotten exactly what I wanted. It plays and feels like an old Stratocaster and is starting to show nice wear, not like a cartoonish 'relic' guitar.
So I encourage anyone to try this. It's fun and in the end you'll have an instrument that is every bit as good as any top flight guitar old or new. Resale value? I'm a music maker. I don't really care though I get the feeling I can sell it for more than I paid for it to the right buyer. But, not concerned about that, I'm just enjoying it now.
I love Magnatone amps. Just a great, warm sound all around. I've worked on dozens of Varsity amps, but not the Varsity Deluxe. Completely different circuit, more like an early tweed Princeton. I do own a Magnatone Model A646 that is similar to this amp circuit wise except it uses a 6SL7 rather than a 12AX7 for the preamp. This amp loses the Hawaiian theme, a move from the 40's to the 50's. Classic Jet Age style.
Typical single 6V6 tube with a 5Y3 rectifier and 12AX7 preamp. 5 watts, 8" speaker....
Grounded it, re-capped the power supply, fired it up for the first time in probably more than 2 decades (pulled from an old studio that had 100 amplifiers in various states of neglect 17 years ago!).
Sounded like crap.......
A little secret. The ceramic caps in these can sound terrible. Just change them. These amps aren't worth much so why have 'originality anxiety'? I replaced them with some Mallory 150 caps and the amp came to life. It sounds fantastic. Punchy, good volume, lots of warmth and harmonics. Great jazz tone with mild breakup. The earlier Varsity amps had great signal caps. If they are still working I leave them alone. The later ones use those lovely Ajax blue pill caps that Fender used. But these? Pure crap. Trash them and enjoy your amp! These can hold their own with any other small amp from the era. Transformers are excellent and the speaker is a nice little Jensen. Worth re-coning if it's fried.
Simply put, the Ampeg B15 is a legend of the studio. This plus a Fender Precision Bass plus massive amounts of talent and persistence equals the legendary Motown sound. But, any passive old school bass sounds great on one of these. I've had the pleasure of working on many of these. This week offered a nice journey into 3 versions of this lovely amp.
First a 1963 model:
This one came from MSR studios in New York City. Countless artist probably recorded through this amp including the Stones, Talking Heads, Roberta Flack.....
This was the best of the 3. It's an early cathode bias version. Probably in the 25 watt range. What do I like about it? Punchy, great low mids, clear sound with a nice bit of growl.
This particular amp was sitting neglected for over a decade. It was a hot mess when I got into it. Random wires clipped, some components flopping about and the tag board burnt through where the cathode resistor resides. Typical, that resistor gets hot. Something blew up in this amp and the power transformer was also fried. This is typical too. I replace power transformers in about one of these a year. This year it's been 2 so far. Weak part I suppose. I didn't need to replace any of the Cornel Dublier caps, they are almost always still good. Surprisingly the circuit is dead quiet with all of the original resistors as well. They didn't mess around with making things cheap back then.
After replacing the power transformer and re-capping the power supply it roared back to life. Glad to say it's making music again in another studio. I'm stunned anyone would let this one just sit unused for that long. The tone is simply perfect. Loud enough for a small combo live too. But best suited for studio tracking.
The next one is a 1966 model:
Similar cosmetics, the differences are it's now a printed circuit board rather than the old school tag board. Ampeg did these so well that it's still fun and easy to get around in. It's also fixed/grid bias rather than self/cathode bias. Result is more power, more headroom, more 'clinical' sound. Haven't dug into this one yet but will be re-capping the power supply.
It doesn't hum so why re-cap it? Isn't it best to leave it original?
Short answer: no way. Just do it. Why?
First is safety. This amp is 51 years old. Caps fail. You don't want this happening.
Second is sound. I can always tell and feel the difference. Stronger low end and more even across the range. My clients agree. Most of them spend years listening carefully in the studio and they say the same thing. Amp got 'bigger' sounding.
Right now the amp sounds good, but we're going for great.
Amplified Parts (CE Distribution/Antique electronic Supply) makes brilliant caps for these. The grid bias amps require a 525 volt can and they also have a beautifully made 25uf@800V "firecracker" cap for the first stage.
The firecracker cap saves a good amount of time on installation. I used to use the Sprague Blue Atom 20@600V cap, but you need to monkey around with stuff to make that work. These come with a wire tie and easy mounting. Takes a whopping 60 seconds to install.
Next photo is one I worked on last winter. It's a 1968 model. Similar 'drip edge' cosmetics to the Fender amps of that year. Pretty much the same amp as the '66 but with a new sexy look. Great amp.
I needed to replace the power transformer on this one as well. Full re-cap of the power supply. Powerful. Great live or studio rig.
The 3 amps above all have the original CTS speakers loaded into them. Still making music!
Last but not least is an early 70's model. These are great live amps and are a bargain:
This one also came from a studio that let it rot away. Didn't take much, power supply re-cap, new preamp tubes (6SL7) which were all dead. I left the signal caps alone in this one as well. 1/2 are the Cornel Dublier green pill types, the preamp is loaded with the turquoise little fish caps. 2 of the input jacks were opening up so with nothing plugged into the amp it squealed like a electric hog. I've seen people re-cap amps and go to all sorts of trouble when all that was needed was a good closed circuit Switchcraft 12 jack.
These late model amps have nice but not really necessary filter switches for 'ultra low' and 'ultra high'. These share the most similar sound to the SVT out of all of these, probably due to the preamp. More of an analytical sound than the amps above, less warm but still plenty of warmth. Not nearly as attractive, which is typical of the 70's designs over the 60's. But, this is the best live amp choice. Lots of power! This particular amp was loaded with an Eminence speaker and is now slated to be a live workhorse.
On all of the grid bias amps above, I installed a bias trimpot. Why not do this? They do tend to run quite hot. And hey, you may save the life of that very expensive power transformer:
So if you have a serious recording studio, don't go without a real flip top. Even the B12SB amp is a fine choice for your bass tracks. I wouldn't buy a new one, there are so many good old ones around and they can be had for not too much. A late model can sell for less than a grand, middle period between $1.5k-$2k. Early ones can be a lot more but if you have the dough, a good tech or some good skills on the bench, you will not regret it.
