Big Boy 330


The Big Boy 330 is a Bass tube amplifier with high quality custom wound transformers.
Simplicity in design and function creates the purest and most musical bass tones made available yet.

The Big Boy has silky smooth big warm lively tube sound packing a powerful tight punch.
The overdrive tone and crunch is rich with even-order musical harmonics.

Six KT120 or KT150 power tubes in ultra-linear operation with Gain, 5-band EQ and Master Volume controls plus parallel FX loop and Preamp output and Power amp input.
External bias and balance feature allows for easy adjusting and monitoring of the output tubes for ideal performance and sound quality.

Handwired point to point terminal wiring

330 Watt ultra-linear output with even-order harmonic break-up

Versatile, interactive 5-band EQ

True bypass Master Volume

External class AB bias & balance adjust

Unique no-compromise Custom Transformers
by Mercury Magnetics

Parallel FX loop with Preamp and Power amp access

Highest quality NOS components

Super quiet without any hum or noise

6x KT120 300 Watts UL class AB or
6x KT150 330 Watts UL class AB
EF86, 2x 12DW7, 12AT7 preamp tubes
5-band EQ
Parallel FX loop
True-bypass Master Volume
Paper/oil tone capacitors
Carbon composition resistors
F&T filter capacitors
Point to point terminal cloth wiring
NOS tube sockets
Powder coated Aluminum chassis 12 ga.

100,120,220,240VAC 50/60Hz
Handmade in USA

25-1/2 x 9-1/2 x 11 ; 82 lbs.

The EF86 pentode preamp tube is known for its big warm tone and punchy high gain.
Only select non-microphonic and no-noise tubes are used for this amp.

The 12DW7 is a specialty dual triode with 12AX7 and 12AU7 sections driving the 5-band EQ with sufficient gain and low-loss signal transfer.
EQ band ranges: 50, 160, 500, 1600 and 5000 Hz with 6 dB/octave roll-off between peaks and flat below 50 and above 5000.

The 12AT7 phase inverter tube drives the power tubes without overloading their input while providing low-loss signal transfer.
Another 12DW7 is used for the parallel FX loop with low impedance driver for the Send output and sufficient gain at the Return input.

An optional DI transformer balanced output is also available.

The Preamp output can be selected with EQ and FX loop or bypassed, as needed for recording or FOH mixer inputs.
The Power amp input turns off the preamp for connecting of another preamp.

The output stage of this amplifier uses a no-compromise custom high quality transformer that is in the top 1% of the best transformers ever made.
Its even-order harmonic break-up gives a musical sound quality not made available before with bass amplifiers.

The matched KT120 or KT150 tubes can easily handle the voltages provided by this amp and with proper biasing these tubes will last for a long time.

Power tubes are thoroughly burned in and matched using Apex Tube Matching giving beautifully matched and stable tubes.

Available with optional illuminated front panel

Low noise high efficiency cooling fan

Panel Controls:

Front: High/Low Impedance switch, Input, Gain, Sub, Bass, Mid, High, Bright, Master, Standby Switch, Power Switch

Rear: IEC power socket, Mains and HT fuses, 1/4" and Speakon 2-4 ohm outputs, Bias and Balance, Power amp input, Preamp output with EQ/FX or bypass switch,
FX Mix, Return, Send, Level , DI output

click to enlarge

Custom solid ash cabinet with half-blind dovetail joints and custom stainless grill

Your choice of vinyl covered cabinet with custom tolex and grill options or solid-wood cabinet.
Covered cabinets are individually custom made to order from finger-jointed baltic birch-ply.
Ask for samples of available covering and grill cloth.

Solid wood cabinets are individually custom made to order from hand selected solid wood with oil finish.

With added blue LED strips inside the cabinets and KW ULTRA-Bass Cabinet

Big Boy 330 with KT150 tubes in oxidized Walnut cabinet

Every Big Boy amp comes with a 12 AWG 10ft Super-Duty Copper-Tone power cord by Mercury Magnetics

User Feedback:

Hi Chris. It's Sooo Awesome! I love love love it. With my passive Fender Jazz there is a little buzz. With my active Sadowsky it's absolutely silent.
So far it's got that vintage tube, warm, tone perfect sound. I turned up the gain a little to get that grunge, distortion, angry sound & blew through Entwistle's "The Real Me"
Whhoooooooo! Looking forward to trying it live.


So, I've got about 20 hours of rehearsal time into the Big Boy 300.
I have never heard or played anything quite like it. It is so warm, so powerful, so many tones, so much detail, so full, no dead spots;
the super lows, the lows, the mids, the highs, I simply have not found an area on my fret board that is mute or retarded. It is ALL there.

I have never really been a big fan of 15 inch bass drivers. I find them too mushy, too tonally limited, too much lost detail. Well, I'm starting to change my mind.
The Big Boy drives the 15 inch driver in my KW cab like it's never been driven before. It is tight & detailed, there is no mush or loss of detail.
It is crisp and moves in & out with such authority & punch. Also if I stand in front of it, it moves so much air!

I love, love love it!

We gig out this Friday. Looking forward to see what it will do in a big hall.


The Big Boy 300 had its live debut. We had a full house with around 400 guests. Standing room only. Your amp performed flawlessly. It put out way more than enough sound.
Clean, Crisp, Full, & Warm. I was amazed at how much power I had. A bass player whom I didn't know came up on stage afterwards and asked, "What The Hell Are You Playing Through?"
He laid his hands on the Bog Boy and caressed the ash & felt her heat. He then placed his hands on the KW Cab and did the same. He told me he loved the sound & the power.
He looked through the handle holes and back & admired the fire & glass. He couldn't believe how big the transformers were.


We recently did a five band outdoor concert. I was with the opening band and after hearing my Bass on the Big Boy 300 and my KW ultra-bass cab. The bass players from the second, third, and fourth band all asked if they could play through my rig.
They said it sounded incredible and wanted to try it. I of course obliged. Just thought you would like to know.


Hi Chris,

I have had a few good rehearsals with the Big Boy 330 and wanted to give you an update.
This amp is simply stunning!!!!!!!!!

It gives back to you what you put in. I have tried 5 basses now.
A fodera monarch, Rickenbacker 4003, Fender Jazz Active, Fender roscoe Beck and a mim jazz with darkstar pickups.
The Big Boy sounds fantastic with each one. From the nuances of the fodera to the treble bite of the Ric.

The EQ points are perfect. Absolutely perfect.

The volume is mind blowing. And completely clean to well above any scenario I could ever imagine needing it.
I have another tube amp that is rated at 435 watts but the Big Boy 330 stays cleaner much much longer.

The output and EQ from string to string is flawless. Notes don't jump out or duck on you. My drummer didn't realize until after rehearsal today that I had a new amp. He was commenting on the balance and note clarity.
He said he could hear every note and every run perfectly.

I couldn't be happier with this amp and want to thank you. Not only is it beautiful to look at it, but it sounds fantastic.

I will give you an update on the DI after our next gig or recording session as I haven't had a chance to try that out yet.

The amp is beyond my expectations!!!!


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