Sunday, December 25, 2016

1954 Fender Princeton 5C2 amp. Lovely warm jazzy sound.

Here's an interesting amp. A 1954 5C2 Wide Panel tweed Fender Princeton.

This was an internet purchase what was serviced by the previous owner. I didn't take any before pictures but, the amp worked fine but the work was comically sloppy. I get a lot of work cleaning up poor jobs.

The other bits: this is a really great amp. It was loaded with a cheap Electro Harmonix 4 ohm speaker and a cheap Triode Electronics output transformer. Not bad stuff, but to my ears, it was rather flat and uninteresting. It was also loaded with Sprague Orange Drop 715 caps. No, no, no. Filter caps were decent quality but sloppily installed.

So I loaded it with Mojo Dijon caps, a 60's 8 ohm Jensen C8R (I effing love these speakers!) and a Mercury Magnetics '55 8 ohm tweed Princeton transformer.

C8R: Brown is Beautiful!!!

I come across these speakers on EBay all the time. Best lil' secret though I suppose if I get more readers everyone will want one. Not useful for Champs, these are 8 ohms. But for my GA-5 and old Magnatone Varsity, it's a match made in heaven. They were often used in organs as midrange drivers so they are usually in great shape. People played polka and church music through these babies, not blues and rock n roll!

Yes I know it's not an alnico speaker. I do love a good alnico but as someone who plays out live on tiny amps, I like the way these project and hold together. I like the clarity I get. Try one! Couldn't hurt!!!

Better interior though not final:

I replaced the original 250k 2 watt load resistors which were noisy with new carbon composition 2 watters. Also replaced the cathode bias resistor and power resistors, typically they drift far out over time and these were no exception.

This particular amp has one transitional feature. They were loaded with a 6SC7 tube, then a 6SL7. In this amp the socket had an adapter to put in a 9 pin miniature socket so it could be loaded with the more modern 12AX7. This was factory. And not unusual is the tube chart simply has the 6SL7 tube crossed out with a ball point pen and 12AX7 written in. Leo Fender liked to use whatever parts he had left over till they were gone. Very much in line with his practical sensibilities.

I took out the "meh" output transformer and loaded it with a classy Mercury Magnetics FTPO-55-8. From my research on these amps, they were 8 ohms. Better to not be lazy and use your off the shelf 4 ohm Champ transformer if you are going to get this right. Just my opinion. More expensive, yes, but totally worth it. The amp came to life after installing this and the Jensen speaker. Big, warm and round. I fell in love with it right away. With a Les Paul or a big Jazz Box it's heaven.

The Mercury transformer is bigger than what was in there, and I suspect the original may have been mounted to the speaker. But the good thing, there are some factory 'mystery' holes in the chassis that mounted diagonally the transformer mounted perfectly.

These are quite different than the more sought after late 50's 5F2 model. This one is a 5C2.

The preamp arrangement is radically different than a 5F2 or 5E2. Between the first and second stage in the preamp you have a 250k resistor connected to a 75k resistor that is going to ground. It's a bit like having a potentiometer in that spot and it's set to 1/4 volume. Just for fun I tried opening this up to see if I could get more gain. The amp simply became unstable and started motorboating. BUMP BUMP BUMP BUMP.......  I put the resistors back the way they were. Looking at the schematic this may work with an additional stage to the power supply, this sound typically happens when you have a bad filter cap or too little filtering. Could go to all that trouble or...simply accept this is the way this amp is and what it is is not a later one. Why not have an amp that plays cleaner? It has such a beautiful tone. For my style, it's perfect and I kind of want to build one just for me.

You can see the evolution in this amp going from the old 6SJ7 circuit, which has little gain, to the later rock n roll nasty later 50's 12AX7 version. It sits right in the middle of that evolution. The tone is more relaxed than a later version, but has a bit more punch than the earlier version. Right now the owner claims it's his favorite. I can see having one and feeling the same way. Great little rare gem!


Saturday, November 5, 2016

Sprague Vitamin Q capacitors. Old school paper in oil magic for your hi fi!

Hello there tube amp heads.....

This is a little post about the legendary Sprague Vitamin Q paper in oil capacitors. I used to have dozens of these and at one point used to swap caps in and out of my hi fi amps when I had that kind of time. I was never all that impressed with the Vitamin Q caps in the past myself but decided to give them a go again now that I only have one system that I know quite well.

These arrived yesterday and I threw them in to my lovely single ended 45 tube amp.

When you have such a simple circuit like this, every little change makes a difference. For instance, the 6SJ7 driver tubes pictured lived in this amp for a day. They are Sylvania. Really nice tubes. I prefer my 5693 RCA Red series tubes by far so they went back in the box! The Sylvania version I love in a guitar amp. Big, open sound but for my hi fi I found them a bit harsh.

The signal caps were Sprague polyester PS type, .1@600V. I hate the 715P series that has been so popular for the last 30 years. The 716 is better but if I gotta use Orange Drops they gotta be PS types. I find them to be smooth, detailed and musical. Plus they are warm which I need and they don't sound harsh like the beloved 715.

Now the 715 in a mushy old amp? That can work. Not saying they are trash, remember, everything is a relationship so they work for some amps just great.

So when I audition a new cap, tube or transformer, the first thing I do is pick a record I've been listening to for many years of my life, preferably something with vocals. In this case it was "Rastaman Vibration" by Bob Marley. First question is how does Bobs voice sound? Can I make out the words clearly? Second is how does Aston "Family Man" Barrett sound? Does his bass sound natural.

First listen is terrible. No definition, crap bass. But, the amp had also been on a mere 3 minutes. When auditioning a cap let it burn at least an hour. When you rebuild an amp, you must give it time!

So I went about my business and came back to it after a few hours. Liquid.... That's the word I use. Bobs voice sounds clear and natural and the bass is big and fat. The bass however, does have a bit of flab I didn't notice before. These are bigger caps than what I had in there (.15 rather than .1) and I could go down to .05 and get my bass needs met. But I will continue to listen to records and see if it works itself out. As I recall, these Vitamin Q caps got better with weeks of use.

So the jury is still out. Do I spend $30 a cap on Jensen Paper in Oil? Are those worth it? (the answer is YES in my opinion. Those sound beautiful.) Or do I keep on keeping on with these surplus store gems? Time will tell and I will tell you later. For now I dig them about 85%.

And on a final note. Are paper in oil caps worth it in your guitar for tone caps? No.... Those merely bleed a little high end to the copper pipes in your walls. You can get a 50 cent ceramic to do that job. That's all marketing ladies and gentlemen......


And instant update....That was fast!

Listening to my favorite Coltrane record, "Crescent". Side 2..... I wore out my first copy ,I love this side that much.

Jazz has a wonderful way of mixing itself. At least in a quartet fashion. The bass and low drums are the lows, the piano and sax are the mids and the ride cymbal are the highs. Coltrane sounds like he's hanging out in my little apartment playing. How the hell did he get that sound is beyond me! So warm and beautiful on this record. Jimmy Garrisons bass has authority and clarity and McCoy Tyner....crystal clear. The second song on side 2 is called "The Drum Thing". All about Elvin. Such a beautiful, dark drum sound. That piece moved me to change the way I make music. Oh yeah, this is about some caps.....they've been burning in all night. I'm in love.......

Wednesday, November 2, 2016

1973 Fender Twin Reverb with rare JBL speakers

I played a Twin through high school. They're big, heavy and torture to take around. I'll never forget loading mine up in the back of my dads station wagon one night and he drove me to band practice (a Go Go band called Currency back in 1985!) and we took a corner and heard a crash. I was worried about my precious tubes. In Actuality it took out a window and the amp was just fine.....

About this amp. It's a nice one. This was a custom order one loaded with original JBL speakers and has the original foot switch.....

I'd never choose these speakers myself but when I do hear them I understand why someone would. Clean, big and bright. I actually like them in a black/silver panel Fender amp.

The complaint on this one was muddy sound, noisy intermittent reverb. It had some bad caps, needed a good cleaning, fresh output tubes and a NOS 12AT7 reverb driver tube. Never use a new 12AT7 in this position. They don't last and there are plenty of cheap 12AT7 tubes about....Sylvania, RCA, Telefunken, GE, anything but JJ or Sovtek!

This amp was also literally 7 resistors and 1 capacitor away from the original black panel circuit. I converted it. That's a part of that muddy tone one heard with these early 70's amps. It's worth it. The amp plays with a more open sound. Also re-wire the bias circuit so you can actually bias the amp. Get rid of that 'balance' arrangement.

Silver panel schematic:

Look at the phase inverter. That's where the "silverness" happens. Change it up to:

You may also change the 2 resistors in the power supply, but I prefer to leave those alone. A hair warmer in my experience.

You don't see many of these about here in NYC. Most of us prefer Deluxe Reverbs or Princeton Reverbs for these tiny clubs. So the prices are largely dependent on region. Some places you can get one for a bargain. You can buy one of these hand made amps for the price or less than a new reissue! Leaves me to wonder what the point is in those reissue amps. They are nice, but not quite as nice as one of these. Something to consider......

Idea on value:

One like this with JBL speakers can command a high price, the rest, great amp for the money!


Update on this: Client wanted a fresh set of preamp tubes as well. I'm a "if it ain't broke don't fix it" kind of guy but complied. When you change an entire set of tubes sometimes problems can arise. In this case one did. The tremolo started going 'tick tick tick tick'. No biggie. Simply put a .1 600V capacitor across the neon bulb tremolo 'bug' from the 10 Meg resistor to ground. I have little idea why this works, I'm just glad Jeff Bober showed me this trick 25 years ago! Saved me a lot of time over the years. I watched another tech painfully decline this and his customers Twin just kept coming back to solve the problem. The situation got tense. I told him this but he saw no logic in it understandably but he wouldn't even try it. I wasn't the tech at this shop and knew by suggesting this I was merely causing tension so I backed off. The customer backed off too and went elsewhere.....

Amp sounds great. Those JBL speakers have a richness to them. That's why they work so well for me. Clean but good, complex clean.

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!