Monday, October 31, 2016

Silvertone 1434 2x12" combo. Tedious to work on but well worth the effort!

Don't have any proper photos of this one as I only have the chassis to work on. Decided to leave the cabinet elsewhere. It's a big amp and I have little room!

I've worked on many of these. I quite like the sound of them. Big and trashy!

They are a bit tedious to work on. One needs the proper approach to get them right. In this case the amp didn't work at all. That part was easy (6EU7 tube in place of what should be a 12AX7!). The rest isn't difficult at all, you just need to be patient and re-cap the thing.

When I say re-cap I usually mean change those dried up electrolytic capacitors. That part is obvious and on one of these amps quite easy. But for these amps you'll need to change EVERY CAPACITOR along with every load resistor. They are noisy. Every Sanagamo cap was leaking or dead. The tremolo was completely dead. That entailed replacing an open 330k resistor along with all the tremolo circuit caps. Also need to replace the load resistors. The 6AU6 tube was good, they usually are.

Tremolo circuit:

The 330k 'feed' resistor I'll be replacing with a 25k trim pot. Once I got the tremolo to work it was simply weak. I reduced that resistor to 50k and it's way better, but it can be great so let's go for that.

More shots inside the chassis:

Phase inverter/driver circuit:

One of the peculiarities of these amps is the filament arrangement for the 12AX7 tubes. Those are D.C. and powered from the cathode resistor on the 6L6 power tubes. They are wired in series with about 28 volts going across both tubes. The nice part about this was I have 2 modern Tung Sol 12AX7 tubes that hummed under any normal arrangement. I couldn't sell them. But in this amp with the DC filaments they run nice and quiet.

Bloody modern tubes! Got a set of modern Tung Sol 5881 tubes I dropped in this amp. One is bad....

I couldn't find a schematic so here is one that has some similarities:

Tremolo circuit is 90% identical along with the preamp....

Amp runs pretty quiet now. These will never be as quiet as a good Fender but don't let that stop you from considering one. If you get one don't bother trying to trouble shoot the issues, just bank on spending a few hours replacing every cap and every load resistor in the house. No sense in playing whack a mole with your valuable time! And please don't buy into that "but the original sound" bullshit! You can buy carbon composition resistors all over the place now thankfully, and I like those Mojo Dijon capacitors for my signal path. Get in there, get your hands dirty and get it right! Worth the effort!

I can say the same with every other Silvertone amp I've worked on. They were pretty crappy amps to begin with but that is their charm. They used the cheapest parts available so 55 years later......


1968 Ampeg B-15

Here's a lovely beast. A 1968 Ampeg B-15 with that super sexy drip edge styling you only see that year. These are rare. Most are the more classic blue tolex earlier style, this is the classic bell bottom zodiac bling jam.

This one was bought from the original owner. He took great care of it. It showed up at my place with a blown fuse. Amp was turned on, fuse fried. Like many Ampeg B15 amps, the power transformer simply died!

Fortunately Ampeg or someone else makes a suitable replacement. They even got the paint super close. And if you scratch it during installation, it simply matches the rest of your 50 year old amp better.

Pretty easy to install. You do need to get around the p.c. board a bit, takes some creative thinking and action to do so but no biggie....

I also always make sure I put the little cardboard piece with the date and part codes. The new part is better than the old I hope. I replace one of these about every year and a half on average! So if this goes 48 years from now, maybe that tech will think it's lasted 96 years??

Notice the micro fiber cloth under this transformer. I did all I could to install it scratch free! I also replaced the electrolytic caps as well. I never want to see a 50 year old can in one of these.

Amp is back to making music again and yeah, sounds lovely. These make cool guitar amps as well as the worlds greatest studio bass amp....

If you can find it, Jimi's first appearance on the Dick Cavett show, he plays "Hear my Train A Comin'" through one of these with the Dick Cavett studio band. He sounds, exactly like Jimi.....


Wednesday, October 26, 2016

Gibson GA-5 Les Paul Jr amp. My 2nd favorite small amp! And about "too big to care!"

This arrived in the mail today. An early 60's Gibson GA-5 Skylark. I love these amps. It's to me, a Champ killer. The Fender stuff is built much better but some of the late 50's to early 60's Gibson amps just have such a great thing going on.

Typical 3 tube 5 watt design: Single 12AX7, 6V6, and 5Y3 rectifier. This one came loaded with a nice RCA 6V6 and 5Y3 and a great nasty sounding GE 12AX7. It was also 100% original. I changed the electrolytic caps and installed a grounded power cable for safety.

I've bought a few of these as fixer uppers and flip them like a burger. They are easy for me to sell cause they are just that good. A bit wider and more open sounding than a tweed Champ and much less dough. I may keep this one, my last one I was bummed about selling.

Now, in the pictures. Notice how filthy this amp looks. Fresh from the barn. When I turned it on it crackled and popped, the pot was filthy. Not sellable in my opinion. I would have bought it at the asking price, no problem but that's cause I can fix it good and proper. If I was just a guy who didn't have those skills I would have turned away. I bought this from the worlds largest guitar store online. Won't mention the name but you know who I am talking about. I did a stint with said company and was baffled by their treatment of vintage gear, good vintage gear like this. No effort made to clean or improve. I suppose somewhere corporate sees that extra effort hurts that bottom line. I like to make money. I like to make as much as I can. It doesn't take much effort to clean something up. People like it when they don't need to worry and don't have to do anything except negotiate a price and be done with it.

But that's the nature of some big ass companies. Too big to care. It's okay to get big, but never give up the caring part! There's money to be made there and more importantly, there are people make happy.

And here's the schematic for you tech heads. Ultra simple signal path. LESS IS MORE!

So what do I like about these over a Tweed Champ? Well, first, I ain't gonna lie. The price! Tweed Champs to me are simply overpriced. No fun for me. Second? I just got back from playing this at my practice space for 2 hours. These amps tend to not fuzz out as much. The notes articulate better for me. Pick soft and you get a lovely clean sound, punch it and it sings, nasty distortion but....clear. I can hear all of the notes in each chord. It really sounds like a cranked Marshall in that respect.

This particular amp has the original .022 famous Bumble Bee Sprague capacitors. Yeah, they are leaking. Can tell by the fact that the volume pot scratches slightly from top to bottom. A little DC on that, and also by the way the notes decay. I may change them and sell those to a rabid Les Paul fanatic. But for now I don't care to change anything else. There is something I like about the slight trashiness.

So what is the difference between a GA-5 Les Paul Jr. amp and a GA-5 Skylark? Electrically, there is no difference. Same great Jensen 8" speaker too. The cabinet is slightly different and the Skylark says "Skylark" on it. The Les Paul Jr amp is a bit earlier, the Skylark was made in the early 60's.

Here's a Skylark I sold 2 years ago:

And the earlier Les Paul Jr amp:

If these amps were mint you would see that dapper Gibson logo on the front. The Skylark had it on the grill cloth, the Les Paul Jr amp has that lip across the top of the cabinet where the logo went.

 If you are considering one of those sad GA-5 Reissues, don't bother. You may find one of these for about the same money and these are simply better amps. And if you find a dead one cheap, they are so simple it won't cost much to get it going again. Even the higher priced ones are worth it as a tool. Nothing beats one of these in the studio. Pure, simple, direct and awesome sound.


Tuesday, October 25, 2016

1976 Fender Super Reverb, end of the good ones.

This came in last week, belongs to a recording studio. The complaint? Harsh distortion at any volume.

First note, just a low E revealed this to be true. I felt annoyed. Sounded like bad voice coils. I did not wish to box up another four speakers and send them to California, not after the last 4x10" amp ('67 Marshall Bluesbreaker combo) had four bad voice coils. Made that telltale "THWACK" sound. Ruh Roh.....

But after opening the amp up I could see one electrical problem. The screen grid resistors were fried. I believe they were 1 watt resistors. Never use less than 2 watt.

After installing them I checked the bias. Each of the Sovtek 5881 WXT tubes were drawing about 4 milliamps. So, I re-biased for 35ma and the amp came to life.

This amp was rebuilt by someone years ago, new caps etc. They also did the black panel Fender mod which is pretty extensive. Worth doing. These amps have nothing really special about them so why keep a rather mushy sounding amp 'original' when it can sound great, and this amp does sound great. It's one of the last of the 45 watt models. They went to 70 watts about a year later. I really don't like those! The 70 watt amps are heavier (these are plenty heavy!) have an ultra linear transformer which I'm not fond of, lacks the power supply choke and no tube rectifier. The result is a harder sounding amp. Okay for country music if you need to play really loud. But for me? I prefer the softer compression a 5U4 or 5AR4 rectifier tube offers. These earlier models just have nice color to the sound, more warmth and more compression when you hit a note at high volume. Amps from this era can be a bargain. Still hand wired, still very high quality and easily modded to be close to the coveted 60's black models.

One more problem was noise. The reverb recovery tube was bad and the 2nd channel preamp tube for volume and tone had a good hum. That part was easy. The first channel had a good amount of snap crackle pop going on. And to make matters worse after replacing the load resistors and cathode cap, it didn't go away, it just became intermittent. Ugh. Some 70's Fender amps I've found the wire to oxidize and go noisy. I really hoped it wasn't that. Not up to replacing wires but if you do find this, start with the anode wires going to pin 1 and 6 on the 12AX7.

Fortunately it wasn't this. I found when it was in full crackle mode if I turned the channel all the way down it was gone (duh!) but also found if I turned the channel all the way up is went away. It only crackled in the middle. So I threw in a brand new CTS 1meg volume pot. Let it play for 2 hours and no noise. It's rare I get a volume pot that does this but I remembered my man Steve at Angela Instruments telling me this back in 1990 or so. Worthy of a try and it worked.

This amp has the original master volume and distortion circuit accessible through a pull switch. If I did the mods I would pull that bullshit out of there! The master volume never really gets dirty enough to justify having it in there, the distortion is comically bad sounding and the extra wires running around add a bit of hum. But like I said, this amp sounds great so if it ain't broke.....

For some ideas on Super Reverb prices, click here:

The 1967-1969 ones are some of my favorites once converted. But even the 1967 black panel amps aren't awfully expensive! You can spend way more on a boutique amp. Heck, I even built one for a client that set him back $1800 initially. He had every ultra expensive component mapped out for the thing. Top of the line Weber speakers, big ass Mercury Magnetics output transformer, every cap and resistor mapped out from years of "research" on internet forums. The result was the only amp I ever built that I didn't like. It was anemic. Another $1000 later it was exactly as I would have built it. Run of the mill Sozo caps, carbon comp resistors, cheap Weber Chicago series speakers, and the amp sounded like an old Super. Really great! And I was was baffled as to why anyone would go to the expense when an original is just not as expensive! Though, I sure appreciated the business, and he was a great client. Learned a lot about cap differences through his OCD tendencies. Literally, he would have me change one cap due to some jive he read on the web, but that one cap did make a difference....

I remember the first Super Reverb I ever heard. It was a Berklee Professor named Jim Kelly who had one and I saw him on a gig. I was floored by his tone. The second was my man David Lyons who now owns Sonic Circus ( in Vermont. After playing his my "new amp" phase abruptly ended. He had such a lovely sound. I no longer really play gigs big enough to justify using one of these but if I did, these are excellent workhorses. Tough as nails and really cut nicely.

Let's see. One these plus that Bluesbreaker equals 8 ten inch speakers....... Yeah, that's the ticket....


Tuesday, October 18, 2016

1967 Marshall JMP "Bluesbreaker" 4x10" combo. One of the greatest amps of all time!

This was a fun project, and the 2nd most valuable amp I've ever worked on, the first being a Howard Dumble that belonged to a famous guitarist (not all that impressed with that amp, I would sell it and buy 5-10 of these!).

I've always wanted one of these. They are quite rare. I don't think any amp has surpassed the early 'plexi' Marshall era in terms of sound and style. Looks do matter and these amps are quite beautiful to look at. And of course, they have a special sound as well. Nothing quite like them. Clear, warm and beautiful overdriven sound when pushed. This amp is essentially a Tweed Bassman with tremolo circuit wise but with a much more present mid range.

When I received this amp it was quite a mess. It had been badly damaged in shipping. Poor packing? Maybe. Marshall combos are tricky to pack properly. These amps can command up to $15k so in my opinion it's best to ship the chassis separately. That is a weak part of these amps, how they are mounted.

It's heartbreaking when this happens. Fortunately, everything was fixable and my client decided not to send it back. The company he bought it from are good people and they payed the bill right away. No insurance battle for my client....

So this amp required quite a bit of gluing and clamping. Plenty of doweling as well. A couple filter cans were damaged and some components became unsoldered. The lovely Mullard 5AR4 tube was destroyed so I found a good deal on a NOS one. We're not going to load up a Rolls Royce like this with cheap new glass. No sir, not gonna happen!

Now the crux of this article. The unreasonable fear of 'originality' and 'collectibility' and what that does to a technician.......

Once I got into this amp, and it was gone through by what I assume is a good tech, I found a few issues. First, the Russian tubes were biased hot. 95ma each. These early models don't have a trim pot for bias. My opinion? Screw your 'originality' and put a trim pot in there! Running this amp this hot could kill the output transformer and possibly the power transformer! I was alarmed at seeing this but I've seen this many times before. The fear to alter something to make it ACTUALLY WORK properly. So I added a 22k trim pot. Took 5 minutes to install. Do it. If your customer freaks out about a change like this, you don't need to sell your amp to that person. He/she is unreasonable.

Had a private audience with George Gruhn last month. His words: "If it's old it's been worked on. Even a Stradivarius has a new fingerboard if it' been played." Enough said! My job is to keep important parts like your priceless transformers safe. In this amp the transformers and speakers are original and that is a miracle at 49 years.

Now the next problem. The speakers. At low volume you could hear this bzzzzzzzt as the note decayed. All 4 speakers were bad. One was not moving at all due to a frozen voice coil, the others were all rubbing. At higher volume one would think "oh this rocks". Inspect each speaker. It's important to do this! And it's worth having these re-coned. I had these done at Speaker Repair Pros in Los Angeles. I don't know of anyone here in New York that I trust to do these. One place I called after the third time the man on the phone said "you can just buy new ones cheaper" I finally said "you just don't get it, thank you for your time...." So off they went to Los Angeles. They did a fantastic job as usual!

So why was this amp sold with 4 bad speakers? I don't know. I attribute that to the same fear I wrote about above. In fact, in all honesty I refused to hear it myself. I was a bit afraid to tell my client he needed to get the speakers rebuilt cause I've dealt with many unreasonable clients who are so afraid their amp will lose all of its value. Bollocks to that! And fortunately my client knows better. He want's an amp that kicks it good, not one that will just be looked at!

I love the old logo on these speakers. Classy as can be.

Link to Speaker Repair Pros. They rock!

So next was the output tubes. We went for Siemens EL34. This amp was built in the first year Marshall switched to EL34 tubes. My favorite year for the old Marshalls!

Biased this pair at 35ma each. Good safe place to run this amp. I also added a pair of 1k 5 watt resistors for the screen grid. The early Marshall amps didn't have them though curiously enough the JTM-45 loaded with 5881 or KT66 tubes had a 470 ohm resistor in this place. Trouble is when you blast this amp without those resistors in place the tubes draw a lot of current and you can pop a tube. You lose a negligible bit of tone by installing them but, it's worth it for the extended tube life. I think it was fine at one point when you had 800 volt Mullard El34 tubes available, but even the Siemens tubes should have those resistors in place.

The Siemens EL34 is by far my personal favorite EL34. Smooth and creamy, no harsh overtones like modern tubes. They were original equipment in 80's 800 Marshall amps and I've seen them go for over a decade being gigged with on a regular basis. And, amps back then were far more brutal on their gear......

Preamp tubes survived, and they are all Mullard long plate 12AX7. The finest for this amp!

One thing about the old Marshall amps the younger folks don't get is, they are 2 channel low gain amps. They evolved into the metal monsters we know and love or hate. These early ones are just as suitable for a jazz gig. In fact, they sound absolutely beautiful for those who want a nice clean tone. Jim Marshall supposedly hated his tremolo circuit but I found it to sound really nice.

These amps are probably the most guitar friendly versatile amps I know. A Tele, Strat, 335, Les Paul, big old Epiphone Jazz box, all sound great through one of these. The first Marshall I ever bought was a '77 JMP 2 input head. Got it for $200. Back in those days we didn't really have all this "true bypass' goodness. Pedals robbed your tone. But with that amp I didn't miss much. There was so much tone there I could stand to lose some. I was sold. My Fender Super Reverb was sold too. That amp was tough as could be. I wonder who has it now?

Amp sounds nice and tight now and is being loved in a happy home.


Tuesday, October 11, 2016

And one of my own "B" amplifiers.....dedicated to Michael Carothers.

Well here's one of my main amps. I built this one around 2008. I sold around a dozen of these and kept this one cause it was the best and, well, I was working hard and I deserved to keep something.

It's been on a lot of gigs with me. The stain in the cabinet is from a wedding I did years ago, it's cake man, cake! There's no tax for cake in NYC. Actually, I think it's Cake from the Cake Shop on Ludlow. I just can't figure out how to get it out.

A bit of how this amp sounds:
Push here!^^^^^^^^^^^^^^^^^^^^

And with a Jazz Box.....

Push here!^^^^^^^^

I had the cabinet made in white. I think I was trying to get my man Michael Carothers to buy it. White and black, he's got this salt and pepper thing going on. He didn't bite. And I'm glad. He owns one of my amps, a green sorta Marshall 18 watter I built for Jim Lowenherz in Portland with EF86 preamp tubes. That one was a beast.

About this amp: It's kind of a Tweed Deluxe. Where it differs is I prefer the low end to hold up. First stage filter cap is a 47uf. The cathode bias cap is 100uf rather than 25uf. Also I added a 3.3meg resistor between the last B+ stage and pin 7 on the phase inverter. I can't actually tell you the science of this move, I just discovered somewhere that the amp focuses better with this little mod.

You would simply connect it between the 16uf 450V cap on the right of the power supply to the 1 meg resistor that goes to pin 7 of your phase inverter tube.

You can see it here:

The speaker is a Weber 12" alnico. Just their standard one the recommend for a Tweed Deluxe. Caps are Sozo and a couple CDE Black Cats for the preamp. Power transformer is Heyboer, output is Mercury. Now the wire. It's all Mogami. I have no idea how to get this any longer. I bought it years ago from BTX or Bi-Tronics. It's lovely to work with and it's also 99% pure oxygen free copper. There's no dispute for me, it sounds more clear and defined. Quiet too. More builders should use this. I got Brian Sours of Soursound in Portland hooked on this hook up wire for his own tube preamps and guitar amps. It wasn't all that expensive either. I had to special order it from Japan though and don't know where to get it any longer. If someone knows, please share! Little tricks like this can make your amps go from good to great. I like great. This amp upset some guys who have expensive Tweed Fenders! Kinda blew them away.

The trick to building a great amp is to use good components, but don't go overboard. A real vintage amp has some pretty crap components in them. Hence things like the Black Cat caps. They are valuable, and they aren't all that good compared to what you can buy for the same price. But that crappiness is a part of the mojo, part of the sound.

For tubes I've had the same glass since I built it. A pair of matched GE black plate 6V6 tubes and a pair of Telefunken 12AX7 tubes with an RCA 5Y3. All of these came from my used bin. None were new when I installed them and I probably spent almost nothing on this glass at Hamfest or surplus stores when those were still around. And, they still work great, still sound great and are still quiet. No, they will NEVER make glass this well ever again.

The knobs are old Bakelite big ass Disco knobs from the Swing era:

It's little touches like that that make your amp special. There are tons of parts like this about so why settle for boring reproduction chicken head knobs???? It's parts like this that draw attention to the object!

Last photo is taken at a wedding on the beach in the Hamptons...... No, I'm not a wedding musician. I only do that kind of thing for folks that are special to me! And my amp survived the sand here and no more cake stains happened!

Now where did that first cake come from? Where was I? I remember cake.....not much else!


1951 Fender Pro.... terrible looking, sounds like gold!

This was a fun and interesting project. Came from Division Street Guitars in Peekskill, a great lil' shop run by my good friend Paul Decourcey. When it came to me it was, well, truly a barn find. Translation: absolutely disgusting. Barns are no places for instruments and definitely not a place to store an amplifier. This amp was badly water damaged on the bottom with plenty of mud to prove it. Some of the plywood had separated so much gluing and clamping was needed. Very time consuming and rather educational. I never realized how many layers of stuff are between the wood and the tweed exterior. More than I thought! And I also know, I'm not the man to do a re-cover job. Used a lotta Simple Green on this one.

He bought it on Reverb from a store in the midwest as a project amp. At least 2 other very good techs turned down working on it. I don't blame them either. If I wasn't a little nutty myself, I may have made the same choice. Amp was full of dead egg sacs from some unknown bugs and some of the wires had been chewed by mice. First order of business was to use a couple cans of compressed air outside just to get the nasties out. Next was the black mold. That and the mud is where I used a lot of Simple Green and a lot of towels, old toothbrushes.....gross man.

It also came with a replacement output transformer that was nice, but the wrong type. This amp had the transformer mounted to the speaker originally, but that old Jensen was long gone. So since this amp is so ugly and we're not re-tweeding it, we decided to just make it player friendly. I replaced the output transformer with a Heyboer tweed 8 ohm Bandmaster transformer availble through Mojo Musical Supply. Not terribly expensive and they are fantastic sounding transformers. I believe Mercury makes the proper '51 Pro part but it's much more expensive and we want to keep this amp affordable for re-sale. And truthfully, I like the Heyboer Iron I've used a bit better though my own amps are loaded with Mercury.

Power transformer was the original Triad. Bakelite fuse holder was broken in half and the power cable and switch were done. Replaced all that and grounded the poor thing!

No tubes came with it. Had to buy 3 6SC7 tubes. A word about those: at this stage of the game, they are risky to purchase. Most of the remaining tubes suck. A decade ago when I was really doing this I could buy a dozen for $60, reject 1/2 of them and still make my money of the remaining ones. Now they set me back at least $18 a bottle. Most I come across are microphonic or have a good hum going on. This one 2 outta 3 were passable, the third I used as the phase inverter. RING! It works but I advised Paul to get another one or buy a 6SC7 to 12AX7 converter on EBay. Other octal preamp tubes are plentiful, like the 6SL7 or 6SN7. For some old Gibson amps 6SJ7 tubes are cheap and plentiful. But, I'm not rewiring this amp for those.

The filter caps were all leaking. They had to go. Don't even bother turning an amp on with those old caps still in it. Throw them away right away. All the electrolytic caps had exploded in this amp. Also the original signal caps were all leaking, badly. I use polyester Orange Drop Spragues in the phase inverter and my favorite Mojo Dijon caps in the preamp. The input caps I left alone. No DC on those so why bother. I'm sure they leaked when they were new but that's a part of the sound so, leave them be!

Also replaced the power resistors with 10k 5 watt wire wound types and the load resistors with carbon composition like the originals. Amp was making those telltale spitting sounds. It's dead quiet now.

When he got the amp it had one of those ugly ass 70's Disco square magnet heavy 15" CTS speakers that belong in an Ampeg cabinet. Nope! Not for a tweed amp! Paul fortunately had this beautiful sounding and great looking Jensen from a 60's rather useless Epiphone amp that lives in his window. He bought the thing for the "someday I may need this speaker" factor. That someday is today and this amps just gives up a beautiful tone now....

It really needs a Telecaster. That is what this amp was built for. My '58 Jazzmaster loves this amp as well. That's a combination from heaven. Big, warm with lots of bite.

Nice and simple 2 channel amp with a single tone control. One channel is nice and dark and is set up for a microphone, the other has plenty of bite. Whenever I get a chance to show a Mesa Channel Switch reared youngster one of these amps I take it. They usually plug in and wonder where the 27 other knobs are but when they start playing something always happens: they start playing better. More grit? Turn the tone knob up and play harder. More clean, back off that pick.

I wound up bolting the new output transformer to the chassis and adding a 1/4" Switchcraft jack so you can plug this amp into any 8 ohm cabinet of your choosing. Also this amp is cathode/self biasing. You can simply drop in any matched pair of 5881, 6L6 or KT66 tubes of your choice and jam out. That's the fun/madness of these early tweed amps. Endless choices! You can make decisions about your tone on the fly. New amps they pretty much make the choices for you. No thanks. But ya know, those new amps are good for getting you there. A real amp like this is good for the one who has already arrived dig?

                                                         Mandatory photo with a Tele:

So if you want to see this amp, hang ten and make the drive to Division Street Guitars in Peekskill NY. Great shop and Paul may even sell it to you!