Epiphone 75th Ann. Electar Century Amp for Jazz

[ruger9]

NICE!!! That is BY FAR the best tone I have yet heard coming out of a new Century amp.... and the only "demo" I have seen that would make me want to check one out.

Is it noisy? I've read buyers' complaints of buzzing or humming that is louder/more than normal with these amps...?

[anothersixstringer]

Thanks a lot ruger9! Much appreciated
Regarding your question, yes the amp is noisy, but manageable.
What I do is to roll the tone knob depending on the situation. Silent room practice, roll to 0 (or go unamplified!) which produces a nice warm tone (guitar tone open).
Noisy gigs, I go up to 5ish on the amp tone depending on noise level, so that the amp can cut through the mix.
Btw, I posted an open question to Gibson on their amp forum about this: possible solutions for the noise are a) change tubes b) reroute heat wires c) reduce bias
So far no answer :/

Just for fun, here is another video of the same session

[Dennis D]

The initial impressions & reviews weren't the greatest, but someone discovered a boost function on the volume switch. Some testers had found the hum they were hearing went away when they adjusted the volume switch to normal.

Interesting idea for my living room, and sure like the look!

[BeBob]

They sure look nice.

If I could confirm that the amp could stay clean with a nice clean tone at decent volume then I'd buy one for the living room too. The problem is that I have no idea what kind of speaker they use. Unfortunately, the manufacturers tend to use crappy no-name speakers on the cheap limited edition amps. Another problem is that I have no idea how loud they can get while staying clean. I'm not looking for a Twin Reverb, but I've never been able to hear one played loudly and cleanly ... every youtube demo that I've seen has a yayhoo playing them dimed, so they sound like ass. Obviously, the manufacturer is marketing the amp to that demographic. I doubt that they have jazz players in mind.

It's too bad that the factory demos don't reveal how loud the amp can get while staying clean. I've looked for a schematic, to get a better feel for what's inside of the box, and I've come up empty handed. For similar cheapo limited edition amps like the Excelsior, Fender does make schematics available, and the schematic says "Not to be Serviced in the Field" on it. In other words, if the amp needs to be repaired under warranty then the prescribed service procedure is destroy it and replace it. I'm worried that this amp may be treated similarly by Epiphone.

With that said, I've thought about buying one just for the box, gutting it if the tone isn't satisfying, and putting a different circuit inside. My biggest reservation is that the knobs are on the back, which is a rather useless location to me.

[zephyrregent]

I have an Epiphone Century amp also. Most people including myself have experienced a noticeable hum from the amp that is caused by improper heater wiring. There is a schematic and instructions on how to fix the problem on the Epiphone website under the description of the amp and on Harmony. Some have experienced more hum than others. I adjust the volume and tone controls to get rid of the hum and haven't had it repaired yet. It can get loud and stay clean. It sounds like an old small tube amp. The bass never gets boomy. Maybe the sound could be described as flat or boxy. I use it at low volume for a practice amp and it gets a clean jazz tone. For comparison, the Roland Blues Cube Hot that I recently purchased sounds fuller and has more tonal range. I just plug into the dark channel and set the controls for volume and tone then make tone adjustments from the guitar so having the controls on the back hasn't been a problem.

[Drifter]

I bought one of them. It sounded absolutely awful and hummed like a beehive. A local tube amp expert pulled out the guts, designed a new amp for the chassis using all quality parts and installed a Weber AlNiCo speaker.

It does sound decent now, has a nice warmth as the old style 6SC7 are glorious sounding tubes in my opinion. So it is a nice living room amp but all in all it still sounds too boxy for the ingredients used. Bottom line is, even the cab is designed just for visual beauty but not for good tone.

[Dennis D]

..as far as the knobs on the back, that's similar to other period amps....the amp faced the crowd - in front of the player - so the player would've had an easier time on stage adjusting the settings w/ the knobs facing him......

[BeBob]

Thank you, Gentlemen, for those very informative posts.

I had already been to the amp's page on the Epiphone site during my search for the schematic but I failed to find it, because Epiphone doesn't bother to provide any links to technical data for the amp. The schematic was posted as an attachment to a blog post by a 3rd party user. I never would have found it without knowing to look in the blog posts, because I don't read blog posts.

Thanks for the tip on where to find the schematic. Here it is in case anyone needs it:

[BeBob]

......and sorry but don't really know what 'octal' or 'Valco' means

"octal" refers to the tube having 8 pins.

"Valco" was an amp manufacturer.

[neatomic]

dd- just for info

octal is a type of tube...used before the fender era...they are big toned and slightly rough (odd harmonically)..think charlie christian.and most pre early 50's electric guitar tones

valco was a huge amp and guitar manufacturer from 1940-1967..they were rebranded by many companies

the cab on the epi 75th is just cheap ply...


2 companies- trillium & mergili amps makes some fine wood beauties

here's a trillium



cheers

[campusfive]

You know, I've been tempted to pick up one of the Epi amps, because I've seen them on clearance for super cheap at some Guitar Center locations, but why bother? It would only because it looked cool, and it would have mediocre sound and ZERO resale value.

For anybody into the sounds implied by the visual aesthetic of such an Epi amp, you should be really be looking at Vintage '47 on the less expensive side, or Nocturne's Moonshine '39 or Blondeshell Betty on the higher end.

I've played several different Vintage '47 models and really dig them, and often take out my VA-185G for gigs instead of my EH-185, and even the very little time I've spent with the Nocturne Moonshine tells me it's awesome too.

Don't buy mediocre stuff because it looks cool!

[BeBob]

Yes, the really old-school amps from the 30s-40s all used octal preamp tubes because the miniature noval preamp tubes hadn't been invented yet.

But all of the early Tweed Fenders, like the TV-front and wide panel amps, used octal preamp tubes. Everything from the Champs up to the Bassman and Twins. That's because in the mid 1950s octal tubes where what was available. The miniaturized tubes with 12V heaters didn't become commonly used until the late 1950s.

I'm not quite sure what was meant by "odd harmonics". The harmonic content of a valve amplifier's output stage is largely determined by the topology of the output tubes. When clipping, single ended setups are full of both odd order and even order harmonics, while a push pull configuration cancels out the odd order harmonics, leaving mostly even order harmonic content in the output.

Many people who prefer octal preamp tubes seem to favor them because of a sweeter, less gainy sound. The same thing can be done with modern miniaturized noval tubes, provided the circuit is designed properly; the problem seems to be that most of today's designers don't adequately tame the gain stages, because they're catering to a different market. I think that the biggest difference in the sound of the amplifiers is attributable to the design objectives of the era in which they were designed, rather than the tubes themselves. Just as much of the tone of a guitar comes from your fingers as well as from the guitar, much of the tone in an amp comes from the circuit design, as well as from the tubes themselves.

[BeBob]

You know, I've been tempted to pick up one of the Epi amps, because I've seen them on clearance for super cheap at some Guitar Center locations, but why bother? It would only because it looked cool, and it would have mediocre sound and ZERO resale value.

Why bother? Because I can use that ZERO resale value to my advantage. My plan is to buy one on the cheap because it has a nice cabinet, gut the innards, and build an EH-185 in the empty shell.

BTW, I absolutely *LOVE* your YouTube videos. I was pleasantly surprised to find you here.

[BeBob]

the Epi box does have some visual appeal. I've always liked the old Epi scrolled grillework and veneer.

I have a complete wood shop and a complete electronics shop. I've been designing tube circuits and building my own amps from scratch since the 1960s, long before the internet explosion and the spread of information that resulted in proliferation of DIY building. Building square hardwood slab cabs isn't at all challenging. Today it seems that everyone and his brother has an amp business that is based on simple carpentry and leveraging someone else's electronics designs.

Instead of engaging my time in the tedium of bending veneer and standing over a scrollsaw to reproduce the old-school grillework, I'm thinking about taking advantage of third-world labor costs and just buying the Epi cabinet as a finished product. It has visual appeal, and if I can get the shell for the right price then it's worth a shot to start with something pre-made. If that works out it would spare me from committing to another cabinetry project.

I can understand why some people like the Epi amp based solely upon it's looks, while others are wise enough to avoid it. I think there's some middle ground though, where the amp could be reworked into something far more useful than it's native factory embodiment.

[Greentone]

Great looking amp, but it would seem that Epiphone really rolled craps on this one. Read on the 'net and you find that everyone ended up with a blown amp. Must be some kind of design flaw.

[BeBob]

I'm going to step out on a limb for a minute...

Looking at the schematic, there's nothing wrong with the design of the amp on-paper. Granted, there are some funny things in the circuit ( like the fixed value FMV tone stack that feeds into a second treble-cut filter ) but the basic design of the circuit is conventional -- nothing out of the accepted design standards. The guy who designed the circuit put more effort into safeguarding the amp against user error than most circuit designers -- that's evident by the appearance of protection diodes on the 6V6 plates to protect the tubes from an over-voltage spike that might occur when a numbskull cranks the amp up without a speaker attached, which will blow an OT. As far as the amp goes, it looks just fine on paper.

Looking at the inside tells a different story. If you go to the blog comments on the amp's page at Epiphone.com, you'll see some gut shots of the amp which I find troubling. Although the amp was designed well on paper, it's build quality is not very good. Sure, the paper design is fine, and the circuit board seems to be of decent quality, but the lead dress is just awful. It's plainly evident that someone spent a lot of time designing the circuit and the circuit board so that it could be made in China by a contract manufacturer. What looks like the weak link in this case is the abysmal quality of the assembly in the Chinese plant. It's no wonder that these amps hum badly, the heater windings are textbook examples of what should not be done.

I think that the weakest link in this case is that the amp was manufactured in China by people who don't know anything about assembling a tube amp. The techniques of interior wiring and lead dress are important. These are areas that can't be done carelessly, and the gut-shot photos of the amp show that the wiring was done very carelessly. It would appear that getting the wires corrected to the right terminals so that the circuit would function is all that the assembler considered to be important. In all likelihood the assembler doesn't know anything about theory, or how an amp should be wired to avoid hum. Or maybe they do know, but they just don't care because they aren't allowed enough time to do things properly on the assembly line. Either way, it's no surprise then that someone hired by Epiphone did a decent job of designing the circuit, but the whole thing fell apart when a Chinese low-bid ghost manufacturer was entrusted to build the amp. The result ended up being a turdsickle.

Another problem is that with "limited edition" amps like these, the production run isn't long enough for anyone to really care about working out the bugs so that future production amps are bug-free. The initial production run is just built and then the model is abandoned. There's not much effort on the assembler's part to get it right the first time, and getting it right the second time isn't even an afterthought.

Another reason that circuits that look good on paper tend to fail in service is due to low-quality components. Back in the old days radios, amps and TVs were built with quality in mind and they were designed to last forever. Sure, they needed regular service and routine PM, but it's not at all uncommon to see 70-year-old vintage equipment that's still in service.

Today everything is considered to be disposable and is not meant to be serviced. Warranty work is centered around replacement rather than service. When an electronics item fails it is intended to be discarded and the consumer is expected to re-purchase the item rather than servicing it. With this sort of attitude, it comes as no surprise that the core components are no longer designed to be highest quality items that will last forever. At best, today the components are good-enough quality that is intended to last through the warranty period and die shortly thereafter.

I can't tell you how many recent production electronics gadgets I've seen fail as soon as they go out of warranty. This is by design. A particular trouble area is the low quality no-name Chinese capacitors in circuits that you'll find in a power supply. they are designed well enough to last through the warranty period and no longer. Nobody cares that they eventually fail, that's actually part of the design. Once they've got your money, the Chinese manufacturers are happy. If the product fails right after the warranty expires they're even happier because you get to buy again. These are some of the reasons that I prefer to build my own amps and restore vintage gear rather than buying modern Chinese electronics.

I know this is getting long-winded, so suffice it to say that I don't think that the amp was designed badly, it actually looks good on paper. But it sure looks like it was assembled badly based on the photos I've seen. I'm going to keep my eye out for one of the blown-up ones, just to get hold of the shell.

[Esko]

I have one these Electars, and I changed the 12axV1 preamp tube to 5751. Now turning the tone over 5 is posible without to much gain, also gain in the boost is greatly reduced.

Now it sound's "rounder and softer", if that makes any sense.

I am total newbie with amps so... YMMV

[BeBob]

I'm wondering ... did you try a 12AY7 in the V1 position, or did you stop with the 5751?
The 12AY7 would be taking you one step farther in the direction you've already headed.
JJ also makes a medium gain version of the 12AX7S. I think they call it a 12AX7S-MG, or an ECC83-MG or something like that. I have not tried it.

One of my main disagreements with the amp is it's contrived frequency response contour. I mentioned in another post (and posted a frequency response plot) that the amp had several additional high-pass and low-pass filters added to it's basic circuit in order to shape it's overall response as a midrange bandpass filter. Granted, that might be exactly what some people are looking for if they want the sound of a field-coil speaker with a thin cone, and and amp that has very weak bass response, a lot of treble rolloff, and a rounded but peaky midrange. The price that you have to pay for getting the tonal response that way is that the amp has a huge insertion loss. In other words, it doesn't make very much power/volume for it's tube compliment and power supply.

To me that contrived frequency response curve makes the amp very much of a one-trick pony. that's good or bad, depending on your point of view. but that shaping also results in a greatly diminished ability to project loud/clean tone. For the people who are after that character in the amp, I think that a bigger amp is needed. The way they designed the amp tone profile definitely limits how loud the amp can get while staying clean. The result IMO is that they neutered the amp to get that clean sound, and they neutered it enough that there isn't very much of it. It's OK for a living room, but I wouldn't take it on stage.

I found the amp to be a good design, but one that was executed poorly by it's assemblers. The amp is far more noisy than it should be, and that's due to it's layout and construction methods. As an example, the heater supplies are poorly wired and have "lazy loops" around the tubes. Rewiring them isn't the complete answer, because the amp's input board lies right up against the heaters, which results in coupling of noise into the signal. After doing the re-wiring I had to pursue more "heroic" techniques to get rid of the AC hum. My mods included completely re-wiring the heaters and using shielded signal lines, but that wasn't enough. The input board itself needed shielding. That made the amp quiet, but I'm still not satisfied with the tone, and the gain boost circuit is too extreme for my needs. So I'll be taking it apart again when I have more free time.

[Esko]

Hi Bob,

no I havent tried the 12ay7 since 5751 changed the sound enough for me, for this time.

I agree with you it is a one trick- pony and the looks of it are one the reason's I still have it as my bedroom amp.



The way I see it, if I want BF or Tweed sound, I will get one. I don't have knowledge or the skill's to make this amp to sound anything else what it is.

[GNAPPI]

Aside from the fact that makers use crappy speakers, it's the easiest one to remedy.

I have two little Fender practice amps with ginormous EV 10" speakers. Sure the speakers cost more than the amps, BUT, rather than wait for innard mods or worse still dumping a crap amp, I think a speaker upgrade to an already decent amp is a golden approach... IMO that is.

[Dennis D]

This amp is intriguing to me because I really like the look. It just occurred to me I may be able to make this work - I have an electronics repair place that could do the fixes / upgrades.

For sure I'd be swapping a tube or two, right ?

Then what ? The repair guy I know has repaired my vintage stereo's and turntables, so he's capable, just not ' an amp guy '.

If I had to buy one new and still take it to this guy, what would the budget ( for repairs ) end up being ? Could I safely assume I'd end up with a capable practice amp ? This would never leave my living room, and always be used at low volume.

[Esko]

Just a thought, how about fitting amp and speaker from Cube inside the Epi cabinet ?

Cube is allready designed to be small and closed back.

Just a thought ...

[BeBob]

Dennis -- I think that c5 hit the nail on the head with what he said about the amp. I would echo that if you are your own amp guy and you know what you are doing, then this amp could be a suitable starting point if you like to design your own circuits. OTOH if you have to pay someone else to do the work then stay away. In that context I think you're better off with a different amp as this one would end up being a money sink.

There is very much that is right about the circuit as it was designed by epiphone, but there is just so much that is wrong about the physical layout and the way it was manufactured that I can't even speculate as to what it would cost to make it something you would like. I've put more hours into my amp just trying to make it quiet than the amp is worth. IMO it would be an OK project for a DIY guy who's time is free, but I wouldn't recommend it if you have to pay anyone else to do the work. If you have to go that route maybe you should just use the cabinet and throw away the rest, like Drifter seems to have done.

[Little Jay]

Aren't the internal volume in cubic inches and dimensions of the cab just too small to ever produce big and strong bass tones?

I have a Bluesbaby 22 in a small DIY solid pine cab (Blues Jr sized) with a rather thin plywood baffle and a Fender Blues Deluxe (ply cab with thick particle board baffle and about 1.5 times the dimensions of the Bluesbaby). I have Jensen Neo 12-100 speakers in both, but the Blues Deluxe has so much more 'oomph': bigger bass and a more solid feel to it. I thought it was the amp as they differ a lot (tube vs solid state) but to my surprise I found that playing the Bluesbaby thru the Blues Deluxe's cab mad that sound nearly identical to it!

[Little Jay]

Btw, I don't think the construction of the cab of a modern on differs that much of that of a vintage one:

Vintage: