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Maven Peal: Zeeta amp with variable wattage

Maven Peal Zeeta combo at Chapin Guitars - $3950 - "Winner of Guitar Player magazine's coveted editors pick award, this 15 combo brings new level of meaning to the term OVERBUILT. 10 guage (that's roughly 1/8 inch thick) steel chassis,Large torroidal transformer for the power supply, Massive transformer given it's power rating and all hi-fi grade componets.It even comes Stock with a Flight case. A resonant all pine cabinet is built to fine furniture specs. 12" Celestion Alnico blue speaker. Amazing Sag circuit manipulates the sound and FEEL of different types of amps while making this baby simply SING with sustain (really, I mean mondo sustain).Wattage control varies from the full tilt 15 down to 2 watts keeping the tone all the way. Granted it is pretty pricey. but monster tone at small club to bedroom/studio volumes and INSANE build quality you have to expect it doesn't come cheap. Is it Overkill? You have to make that call yourself. Sound samples due around Mid August...Stay Tuned."

http://www.delphion.com/details?pn=US05909145 -- patent

Variable-SPL amp from Maven Peal

An amplifier without the Sag Circuit is like a car with only one gear.

The Zeeta Amplifier

The Zeeta is an unprecedented 15 watt 1x12 combo. This maverick amp beautifully showcases 1960 Deluxe circuitry alongside the modern Sag Circuit design, introducing two new knobs, Sag control and Wattage control.

Sag Control allows you to control voltage sag, or power amp distortion. Lower amounts of sag give the amp a harder feel and brighter sound, while higher amounts of sag fatten up the sound and make the amp very responsive to your touch. In essence, you are getting a range of different amps all rolled into one very versatile package. This is the only amplifier that makes these claims from power amp, not from the preamp. The difference is organic and well, phenomenal.

Wattage control allows you to control the number of watts the power amp is capable of producing. This knob allows you to overdrive the power amp at whatever volume level is appropriate for the venue you are in. The Wattage control also allows you to adjust the mix between the level of power amp distortion and the level of speaker distortion.

This control is not a Master Volume control or any other preamp gimmick--but actual control over the power amp. Wattage control also allows you to adjust the mix between the level of power amp distortion and the level of speaker distortion. [this could very well be a built-in conventional power attenuator, after the output transformer -- or an approach like London Power's Power Scaling - Michael]

Additional Zeeta benefits include:

Infinite sustain, even at 2 watts

No power supply hum (essential for recording sessions and just plain easier on the ears). Freedom from varying wall voltages

High gain that cleans up nicely by backing off on guitar volume (and/or touch)

Alongside the Sag and Wattage controls, you'll find a signal path similar to a three knob tweed Deluxe with two inputs, two volume controls and one tone control.

This amp boasts the following production features:

Celestion Blue Alnico speaker (rated #1 in the August 1999 issue of Guitar Player)

$3,950 includes flight case

news release at Harmony Central

newsgroup postings about zeeta

Lord Valve's review from AGA NG:

Lord Valve Speaketh:

I finally found time to sit down with Dave Zimmerman's Maven Peal "Zeeta" amp today. Most of the regulars here know Dave as the designer of the Maven Peal Sag Circuit, a sandy little number that emulates rectifier tube sag (and then some) as well as provides power scaling for the output stage of a tube amp. An interesting side effect is that it makes for a *totally* hum-free DC supply. (I consider this to be more useful than the "sag" feature, but WTF do *I* know...I'm an organist. ;-) This article is going to deal mainly with the construction, circuitry, and physical appearance of the amp, rather than the tone and playability. I'll do a post on how it sounds later, when I can get opinions from five or six local guitar pickers, one of whom is my assistant technician. (Scooter Barnes, who, as soon as he figures out he ain't gettin' paid by the note, will be one of the finest pickers on the planet.)

The Zeeta comes with its own high-quality roadcase; it was delivered (upside-down, I might add...you'd figure the fact that the handles will kill the shit outta your hands in this position mighta given the delivery driver *some* kind of a clue) by FedEx in early December. I was swamped with the usual Christmas retail crap, so, after we played it for 5 minutes to make sure it wasn't DOA, we just put it back into the case and let it rot until today. When we gave it the initial checkout, we discovered that the mike input was *way* noisy...probably a bad tube, I thought. I called Dave up and gave him the low-down, and he said he was sending us an upgraded mil-spec ceramic-body IC to install in place of the consumer-grade part that was currently in the power supply. (He knew I was going to take his baby apart and lick all the pieces, so why not upgrade...right?) At any rate, the Zeeta impressed us (me and Scooter and Lady Valve) as a really solid-looking piece of gear. Pretty, too.

Absolutely gorgeous. You don't see joinery like this every day. The wood is cabinet-grade clear pine; the cabinet is covered with a lightly textured maroon Tolex. One thing I noticed about the amp right away was the care with which the Tolex was applied...it looked like it was done by someone who was not only really damn good at it, but enjoyed the hell out of doing it. (This was confirmed in a call I made to Dave tonight...he said the dude who does the covering only does Ferraris and Lotuses. And the Zeeta, evidently.) All the joints on the Tolex are dead solid perfect. Better than anything I've seen before by an order of magnitude. Really. The box itself is radiused throughout; the back panels are *thick* wood...5/8" at least, radiused, and and even the ends (which you cannot see without removing the backs) are Tolexed perfectly. Never seen anything like it. All the fasteners are stainless steel. Speaking of stainless steel, the chassis straps on top of the amp (like a Fender has) are machined from solid stainless steel, 3/16" thick. An inch wide, they weigh nearly a POUND each! The chassis bolts are Phillips-drive stainless 1/4-20; if this amp falls on its face, they are *not* going to bend, period. The grille cloth is maroon also, with tasty white piping around the edge. The handle is a black English leather type from Penn Fabrication referred to as a "dog-bone". On the bottom are a set of *huge* rubber feet. Regulation Fender-type corners, two-legged with turned-in lips. The corners appear to be the only hardware on the amp that's not custom built. The speaker is a blue- basket Celestion Alnico 12" "bulldog" type. It's hooked to the amp with a piece of 12-gauge audiowanker OFC speaker cable (why not?) that has been covered with a piece of sky-blue heatshrink. The plug is an old-fashioned squarish Switchcraft plastic-backed right-angle type; I'd have preferred to see the more modern (and considerably more rugged) part #228 from the same company. The inside of the top part of the cabinet is covered with overlapping strips of copper shielding tape which, according to Dave, are stuck to each other (and to the cabinet) with conductive adhesive. The shielding goes down the sides of the cabinet as well as covering the inside of the top; this is because the chassis, which is bent from a single piece metal, is open at the ends.

I took the chassis out; no surprises, it slid right out without binding on anything. I couldn't believe what I was looking at. The damn thing is *literally* built like a tank. The chassis is bent from a single piece of *very* stout aluminum...a full *eighth* of an inch thick! It makes a BF Fender chassis look like tin-foil. I could just barely flex it, and I had to strain like hell to produce even the slight flex I was able to achieve. (I ain't exactly small, and I *do* eat my Wheaties.) The control surface is slanted like a BF Fender...my favorite design. Looks cool, and makes the controls easy to see and adjust. It's black (anodized, I suppose, although I really didn't look at the finish that closely) with white lettering. Black chicken-heads on the pots. Two inputs, one for a mike and one for an instrument. Power switch, standby switch, and a Fender-type red pilot light. The circuit is nearly identical to a Tweed Deluxe. (With the exception of the power supply, of course.) Mike vol, Instrument vol, Tone, Sag, and Power are the controls. The "sag" control lets you dial in the amount of power-supply sag you like, while the "power" control lets you adjust the actual output power of the amp between one and fifteen watts. Inside the chassis was the single best set of parts I have ever seen, period. Central to and dominating the audio-circuitry layout is the cathode bypass cap for the output tubes. (2 X JJ/Tesla EL-84.) It's a *monsterous* 270uF/250V poly cap, the size of a soup can. A little larger than a soup can, in fact. The bypass caps for the preamp are huge, too...24uF/250V, same type, from the same French manufacturer. The coupling and tone caps are all audiowanker types. The preamp plate load resistors are three-watt metal composition parts. Are you starting to get the impression that the Zeeta is overbuilt? Read on... The audio portion of the Zeeta is all handwired, point-to-point. The resistors and caps and whatnot are mounted on a custom-built L-shaped turret board, made of mil-spec fiberglass an eighth of an inch thick. Numerous support points are provided for this board, to keep it stiff. Every bolt or machine screw that needs a nut on it has an aircraft-style nylon insert vibration-proof type installed. The power tranny is a large toroid type, mechanically isolated from the chassis to reduce mechanical hum. The OPT is mounted on 1/4" standoffs; I asked Dave about this, since I wasn't sure what good that would do (if any) and the answer was "Because it looks cool." It does, in fact, look cool. Jacks are the ReAn or Cliff's nylon type, with gold-plated contacts. The audio pots are from CTS, while the Sag and Power controls are Clarostat RV-4 conductive plastic types. All the internal wiring (with the exception of the transformer leads and the shielded cables that go to the first preamp tube) is Teflon-insulated sliverplated OFC. Good stuff; my own personal favorite, in fact. (Sorry, I think cloth-covered wire is crap. Sue me.) Tube sockets are ceramic. The two 12AX7 preamp tubes are the LP variety from Sovtek; Dave and I discussed trying the new EH variety (no, they are *not* the same thing as the LPS, although they were for awhile...see my description of the new 12AX7EH on another thread) when my batch of 250 shows up and I get done tossing out the clunkers. The Zeeta runs DC heaters, even for the power tubes. Well-regulated, too. The power tubes have their filaments wired in series (the DC filament supply is 12.6 volts) so that if one dies, the other shuts off too. A word about the soldering in this particualr unit...it was crummy. I reamed Dave about this on the phone; he told me that chassis was a prototype, wired by someone who no longer works for him, and modified and updated multiple times. (The serial number is 0010.) I found the tip shunt ground wire on the mike input jack was not soldered at all, and I also redid some of the connections on the tube sockets. (One nice thing about Teflon wire is that you can resolder it a jillion times and it still looks brand new.) I also had to re-solder and re-dress the shielded leads to the #1 preamp socket, as they were done completely wrong. (Whoever did 'em neglected to remove the conductive plastic electrostatic shielding from the center conductors, causing several high-impedance shorts both on the socket and under the turret board at their other ends.) Dave assures me that the currently-produced Zeetas are much neater inside. I should hope so. On to the power supply...LOTS of sand here, all over the place. Mosfets, ICs, regulators, you know...SAND. All topnotch, too. The Molex connectors used for the various inputs/outputs to and from the board were of a type I haven't seen before...special high-voltage connectors, which are insulated all the way to the bottom of each individual pin. Tight-fitting, too... three or four cuts above the cheapshit ones you see inside most MI gear. If I ever get around to building some of my amps, I'm gonna use those for sure. The power board is a conventional SS-type PCB, also very thick (but not as thick as the turret board in the preamp) mil-spec fiberglass, double-sided and plated-through-hole. I can't comment on how it works, because I don't know. (No schematic...Dave?) Dave's patents are somewhere online, I think.

Once I was done eyeballing all the guts, I gave the chassis my Hammer Test. I take a 2-pound Stanley shot-filled Deadblow hammer and whack the crap out of 'em; if anything is rattly, it's gonna show up when I do this. I couldn't believe it... it was like whacking a piece of concrete. No rattle at all... nothing. Nil point zippity-shit. The only thing I could hear on first whack was the cage nuts rattling in their clips; I put bolts in them and tightened them all the way down (like they would be when the chassis was in the cabinet) and after that it was like whacking a piece of lead. The Zeeta is the single most rattle-free combo amp I have ever encountered. (Contrast this with, say, the Mesa Heartbreaker, which rattles like a beer can fulla buckshot.) All combo amps should be built like this, and would, if it wasn't for...

Egad, FOUR GRAND! That's a *lotta* scratch. I know why it's so much, though, after eyeballing the parts. The output stage cathode bypass cap costs a hundred bucks by itself. OUCH! There are a lot of hand-machined parts in the Zeeta; some of them wouldn't be much cheaper even in production quantities. The amp does come with a top-quality roadcase, too. (I've had cases like that made for some of my customers, and they run in the $500-$600 range.) Once I figured out the approximate cost of all the stuff that goes into a Zeeta, it was apparent that Mr. Zimmerman ain't gettin' rich off em, at least, not in a hurry. This amp is a Rolls Royce, and there are certainly people who will pay for this type of construction. (Neil Young bought one, for instance.) I can't wait to hear some smokin' guitarists put it through its paces...stay tuned. Dr. Nuketopia gets this amp next; we'll see if his take on it mirrors mine. Mine is: it's the best-built guitar amp I've ever seen...and rumor has it that I've seen more than a few. ;-)

Lord Valve

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[end of LV's review from AGA]

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