Vox AD60VTH Valvetronix guitar amplifier - Vox Tonelab SE guitar amp modeller pedalboard

Last Update 07/08/2012

Once a tube snob, always a tube snob.

I've been a faithful Mesa-Boogie user for years. Owned a vintage Mark IIa amp head for years that was great at what is does. But when I wanted it to do other things, it was reluctant. Infidelity set in. Sound like a pretty bad letter to Ann Landers? Amp modellers had been around for some time, but when I played one my ears told me that something was missing. They all modeled the tube preamp - but none modeled the tube power amp. I learned the value of power tubes when I was experimenting with tubes in my Boogie at the tech shop. I swapped out preamp tube after preamp tube and was not happy with any of them. Then my buddy tech friend suggested swapping power tubes. The first set of power tubes I swapped out was an amazing difference. Was that ever an eye-opener!! As I was researching tube amp design, I gradually came to realize that the soul of a guitar amp is largely based around the tube power amp section, not just the tube preamp. As I was trying different amp modellers, I realized that none of them modelled the tube power amp despite the Marshalls and Fenders they claim to model. Most of my guitarist friends were none the wiser because they had never experienced many of these amps in person as I have.

I attended a summer festival and one of the performing bands there had an amp that sounded pretty good - my eyes spotted a combo amp with the Vox badge. A few weeks later a very respected guitar player was raving about this new amp he started using - he had just got the Vox AD60VTX Valvetronix combo amp. We were both well familiar with tube amplifiers and the popular Marshalls, Fenders, Vox, et al. I paid little attention to all the effects and gadgets his new toy could pull off, but when he talked about the fact that it modelled the tube power amp my ears were perked. Could this be the same amp I heard at that festival?

So the next time I was in a store I took my guitar to try one of these Valvetronix amps. And... wow. Did it ever sound good. The factory presets are no fair judgement as what this amp can do as the presets appeal to the teenagers that mob Guitar Center stores after school gets out (these stores should have NO "SWEET CHILD OF MINE" signs). I tweaked the panel to hear the raw amp models... and came away impressed. Not only could I dial in the Boogie sound, but I could dial in many other tones I was after. Now I'm a modular component guy (it's the practical pig character in me) and I decided that the head would be preferable to a combo amp because I was gigging without a cabinet - I used the Hughes & Kettner Red Box inline with a 70 watt 8 ohm resistor on the speaker output jack of the Boogie, and my intentions were the same with the Valvetronix. The great thing about the Red Box is it allows me to gig without a speaker cabinet and it keeps the stage volume reasonable. My primary instrument is keyboards, and I am proficient enough on guitar to play rhythm parts and some leads. The Red Box allows me to use one amp and speaker for both keyboard and guitar duties. I've had more than one lead guitar player tell me he liked my sound better!

The Valvetronix was offered in mono 60w 1x12 or stereo 120w 2x12 combo packages. There were also head versions with accompanying speaker cabinets. The only thing you will hear in stereo on the AD120 is the chorus so I opted for the mono package with my own stereo processing (and it's a lighter package).

And just as my luck would have it, the head version of that amp had just been discontinued. Story of my life - as soon as I find something I like, they quit making it. I asked Guitar Center to scour their national network of stores and they found one. Later I added the VC-12 pedal controller which is a must for any Valvetronix owner. The VC-12 includes three more banks of factory sounds, which have better variety than the stock sounds in the base Valvetronix unit. The VC-12 comes with two footcontrollers - one is volume, the other can function as a wah-wah pedal (and includes the toe-activated footswitch like the real thing). The footswitches allows you to change banks and patches quickly, and switch in pedals/modulated/delay/reverb effects. The tuner display has more resolution than the base unit which is great for fine tuning, there is a footswitch that lets you toggle back and forth between your two most recent patch recalls (handy for fast switching between rhythm and lead patches), and you can set the echo delay time via a "tap tempo".

I decided to add a speaker cabinet for recording so I opted for something with the famed Celestion G12 alnico "blue" speakers, which were stock in AC30s made during the 1960s. Used cabinets with the "blue" speakers are very rare and coveted by their owners. So I ordered a new 2x12 cabinet loaded with alnicos from Northcoast Music who makes replicas of Vox cabinets with the blessing of the Vox company. The Valvetronix combos are equipped with speaker(s) that is voiced specifically for this amp. Because I opted for the speakerless head, I was free to use the speaker(s) of choice. And the 2x12 alnicos sound pretty damn good with this amp. I also opted for the speaker stand, and I'm glad I did as this was a practical addition (practical pig character I am).

The team that developed these amps were obviously gigging performers - the front panel is logical and intuitive (especially for the majority of guitar players who are conservative and are reluctant to comprehend anything beyond volume and tone controls) and the FX are placed exactly where they need to be. To clarify the latter, stompbox effects are segregated where they are most effective in the audio chain of the amp - IE compressors and fuzzboxes are before the preamp, and modulation/delay effects are between the preamp and power amp. The choices of amp models (most of them models of vintage amps) gives you a pretty flexible palette of sounds, and if you're a tube amp snob you will find they are accurate (later I'll reveal a tip that really makes these amp sound authentic). Fans of "scooped mids" sounds in modern rock are not fans of the Valvetronix line, and they'll get no argument from me - this is an amp that is tailored to the classic genres. The front end preamp is the Korg REMS package, an early amp modeller in a tabletop format. Vox designed a power amp section that is centered around a real 12AX7 tube and is re-configurable to emulate the desired amp model, including phase splitter type, class configuration, feedback topology, and transformer speaker coupling (I'm an EE and know how these traits contribute to the sound of an amp). Speaker coupling is important because the reactance of the speaker alters the interaction of the tube and transformer, thus the Valvetronix includes this interaction. The 12AX7 comprises a half watt tube power stage which is applied to a solid state amplifier, and it sures sounds like a tube power amp to my ears. This was a selling feature for me. To round out the package, Vox threw in an effects loop and a power selector for switching between stage volume and 2am bedroom volume. This is a pretty complete package for the gigging musician.

A reading of the front panel reveals mysterious names for the amp models and effects. The reason is trademark protection - Vox cannot use the "Marshall" or "Fender" or "Boss" names to label the models - this includes the user manual. They are free to use "Vox" "AC15" "AC30" for obvious reasons. Well informed sources did identify the actual devices, so here is a table that solves those mysteries:

Amp Type	Actual	Pedal Type	Actual	Mod Type	Actual
Vox AC15	Vox AC15 vintage, channel 2	Comp	MXR Dyna-Comp	Chorus	Boss CE-2 Chorus Ensemble
Vox AC15TB	Vox AC15TBX 1990s, 'top boost' channel	Acoustic	?	Flanger	MXR M117 Flanger
Vox AC30	Vox AC30 vintage, 'normal' channel	Vox Wah	Vox V847	Phaser	MXR M101 Phase 90
Vox AC30TB	Vox AC30 Top Boost vintage, 'top boost' channel	Auto Wah	?	Tremolo	Fender Twin Reverb tremolo
UK Blues	Marshall 1960s JTM45, high treble channel	U-Vibe	Univox Univibe	Rotary	Leslie speaket
UK 70s	Marshall 1969 "Plexi" 100W, high treble channel	Octave	?
UK 80s	Marshall 1983 JCM800 100W	Treble Boost	based on AC30 top boost circuit
UK 90s	Marshall 1990 JCM900 100W, lead channel	Tube OD	Ibanez Tubescreamer TS808
UK Modern	Marshall JCM2000 DSL100 100W, high gain channel	Fat OD	Proco Rat
Recto	Mesa Boogie Dual Rectifier, modern high gain channel	Fuzz	Electro-Hamonix Big Muff
US Hi Gain	Soldano Super Lead Overdrive, high gain channel
Boutique OD	Dumble Overdrive Special, overdrive channel
Boutique Clean	Dumble Overdrive Special, clean channel
Black 2x12	Fender 1960s Twin Reverb Blackface, clean channel
Tweed 1x12	Fender 1958 Deluxe tweed "narrow panel"
Tweed 4x10	Fender 1959 Bassman tweed "narrow panel" 4x10

In my years of personal experience and working with guitar players, my ears have become intimately familiar with most of the amps in the list (I have a good aural memory and my ears pick up minute details of sound). I also know which amps were used on popular "classic rock" songs. Armed with that knowledge I would play any classic song that was associated with the amp and found that the model was very accurate. It is that good. Vox even went the distance by emulating the action of the tone controls - THAT'S dedication.

My one major beef with the AD60/120 amps - unless you are lucky to possess the optional VC-12 pedalboard, there is NO FACILITY - for a programmable amp - to backup your custom patches. In today's connected world, Vox couldn't be bothered to even put a set of MIDI jacks on the thing. I guess I don't fit the conservative guitarist mold. If you have the VC-12 in your possession, it comes with an empty bank for storing user patches (there is a power up key combination that puts the amp in backup/restore mode). If you don't - make sure you replace the backup battery in your Valvetronix on a regular basis because if the battery goes dead you will lose your patches!!! This beef does not apply to the Tonelab SE as it does have MIDI jacks.

To differentiate from the current and past Valvetronix models, these amps - AD60 and AD120 - came to be known in guitar player circles as the "blueface" Valvetronixs referring to the blue tinted grillcloth on the front of the cabinet that uniquely identifies them. The opinions regarding the blueface models is that they are superior to the later Valvetronix models and have the best sounding amp modellers to date. I've tried the newer "chrome faced" and "black faced" Valvetronix and Tonelab pedals and not only do they not sound as good as their predecessors but they are much more limiting in effects and models. Even the amp models that were retained from the "blueface" series don't sound as good.

There were two versions of the "blueface" Valvetronix. The VTX series fixed some reliability problems of the earlier VT series and used a better sounding speaker. They are differentiated by the gold "VTX" badge on the front of the amp. The AD120 models seem to have more reliability issues because they have double the power amps of the AD60, a sure sign of breakdown from accumulated heat (the dual power amps generate too much heat in that small package). If you experience the sound cutting in and out, try running a jumper cord between the SEND and RETURN jacks - Vox used cheap jacks that sometimes do not completely close the normal connection. Speaking of normalled jacks, the headphone jack has also been known to fail the normal connection which can cause the amp to cut out. And finally, the power selector switch on the rear panel should be changed with the power OFF because it is not rugged enough to handle the switching action while power is present.

If you're really anal about authenticity (like me!), you'll get the best emulations with model-correct speakers and cabinets. If you want a great Marshall sound, use a Marshall cabinet with Celestion ceramic speakers. If you want a great Fender sound, use a Fender cabinet loaded with Jensens or Webers. If you want a great Vox sound, use a cabinet loaded with Celestion G12 alnico speakers. This is the key to true authenticity. No single speaker or cabinet is going to sound right with all those models. Speaker cabinets have an inherent resonance that is a component of the sound of the model, as is the speaker itself is a component. In fact the Celestion ceramics - 25w, 30w, 65w, 70w, etc - all sound different. You need not restrict yourself to model-correct speaker and/or cabinets - you can discover various useful tones by experimenting with speakers and cabinets. This is how the professionals did it back then!

The Tonelab SE encompasses the same architecture minus the solid state power amp, but the tube power section is still intact. Since the Tonelab is designed to be used with another guitar amp or with a high fidelity sound reinforcement system, it adds speaker emulation of various Jensens/Celestions of varying sizes and ceramic/alnico magnet compositions. Handy additions are MIDI, assignable pedal control (you can use the pedal to control delay time, reverb mix, pitch bend, etc), an LCD display with patch naming, extensive rear panel I/O, and additional models of delays, choruses, reverbs, and phasers. There is also an A/B mode in which you can configure a "B" mode for lead work with different amp models and speakers - handy for quickly switching between rhythm and lead sounds. The effects have a broader range of controls than the AD series. The Tonelab also adds a noise gate which actually worked well on a high gain patch that I made. Like the AD series, the control system is quite intuitive once you read the manual. And this is a much better stereo unit than the AD series as you can configure stereo delays, phasers, flangers, and choruses. The reverbs are stereo to accomodate the stereo effects upstream. If you like heavily processed guitar then you'll like the Tonelab SE. Far more flexible than the AD series, but I keep the AD stuff around when I want live speakers and the flexibility of experimenting with speaker varieties. The speaker emulation is handy but not the same as a real cabinet moving air around a room.

The main reason I bought the Tonelab was for gigging. I didn't have a case for the Vox head or cabinet and had discovered that the tolex on the Vox head was easily torn, so I delegated them to studio work only. At the time I only had my compact car and a pedal format was a lot easier to transport. I also played keyboards and the pedal allowed me to play everything through one speaker.

One foible I found with the Tonelab is the footswitches. They are simply actuators for tactile switched underneath, and I had one tactile switch go bad so I replaced ALL of them with REAL switches. Carling makes a low profile momentary normal open switch that is a direct replacement with no modifications other than wiring.

And here's the secret I'll share with you: MASTER VOLUME MUST BE SIX OR HIGHER. When you crank the master volume, you're overdriving the power amp stage. That's how the original artists got "that sound". That is the sound that establishes the authenticity of the model. It is NOT enough to overdrive the preamp, you MUST overdrive the power amp stage. And if it's too loud, that's what the power selector on the rear panel is for!

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