VOX AC30CC2X Details
The late 1950’s saw the launch of the VOX AC15 shortly followed by the AC30; remarkable then and legendary today. Right from the start, VOX valve amplifiers were adopted by some of the world’s most outstanding musical talents including The Stones, The Beatles and The Shadows and countless others.
The AC30 is one of the most recorded guitar amplifiers in rock history, not surprising given its universally acclaimed warmth and three-dimensional tonal character. What is slightly surprising is that it seems to have lost none of popularity over the years, quite the reverse in fact.
AC30’s can be seen on stages and in recording studios the world over and are being used to make great, modern rock music.
The demand for these classic valve sounds is bigger than ever before, and we keep on building them to the same high standard and specifications as the ones that were responsible for some of history’s best known and loved music.
Plug a guitar into the new AC30 Custom Classic, and you’ll understand exactly why the music fraternity has taken these amplifiers to their hearts.
The new AC30 Custom Classic is the culmination of over 45 years of high quality, guitar amplifier design and fabrication. VOX has taken the best AC30 designs and added a number of useful, very cool features to create the most tonally flexible and affordable AC30 to date!
History in the making
Why has the AC30 been an icon for decades? It's the amplifier's unique, warm tone, its player friendly "feel" and its primeval circuit design. With its straightforward "what you see is what you get" control format, the AC30 was a hit with artists from the very beginning. Back then, VOX owned the '60s "British invasion" and to this day the AC30 is widely used by all kinds of guitarists performing in a huge range of musical styles.
With a number of modern enhancements including blendable channels, a true bypass FX loop, spring reverb and master volume, to name just a few, the new AC30 Custom Classic is an evolution of the original that is sure to become a classic in its own right.
Attaining the highest standards
In order to achieve tonal nirvana, this AC30 is manufactured in our vertically integrated manufacturing facility. What this means for you is that we have total control of the design, the quality and the sound of your amplifier. Our factory is capable of many processes not found in most guitar amplifier factories. We design and manufacture our own transformers, speakers (except for the venerable VOX "Blue" & "Neodog" which are manufactured by Celestion), cabinets and we build our own electronics. All components have been designed, manufactured or selected so that the performance and sound of your AC30 Custom Classic is second to none.
An evolution in tone
When we set out to create the AC30 Custom Classic, we started from our most highly acclaimed model to date, the AC30 Hand Wired. With twin inputs (high and Low) and a Master Volume circuit, these amps offer highly interactive Bass and Treble tone controls, as well as the VOX Tone Cut control (which varies the presence in the power amp section) for even greater tonal variety. We also included Classic Tremolo with variable Depth control and a spring reverb with Level and Tone controls as well as a Dwell switch.
Two blendable channels, a first
Not only does the AC30 Custom Classic include two channels, it also offers the ability to blend those channels together (a first for the AC30!). The Top Boost Channel serves up that classic AC30 tone, while our new expanded Normal Channel now offers two modes, Normal and Bright, which allow you to achieve the sounds of an assortment of vintage AC30s. Use the channels individually or blend them together for increased tonal flexibility to create a unique sound and feel that's all your own.
Control freaks rejoice!
The AC30 Custom Classic is fully equipped with well thought out and easy to use controls. With a Custom/Normal EQ switch, Tone control and Dwell switch for the spring reverb, Master Volume, fully variable Tremolo on all channels and a true bypass Effects Loop, we've thought of everything! We've even included a switchable cathode resistor that lowers power output and increases tube life. Of course, the AC30 Custom Classic comes with our standard controls like Treble, Bass, Tone, Volume, Standby and more.
Multiple configurations
Not only is the AC30 Custom Classic the most flexible AC30 to date, it comes in our most expansive array of models ever to cover a variety of needs and player preferences.
Technical Discussion of Old and New Features
Tone Cut control
As used in AC30s since 1959 and AC15s before that, this control cuts high frequencies. It is placed in the power amp section after the phase inverter and before the output tubes. It works like this: The preamp signal goes into the phase inverter. The output of the phase inverter has two signals one of which is 180 degrees out of phase with the other. When signals that are out of phase are combined equally, they cancel each other out. The Tone Cut control works by combining only high frequency signals from one side of the phase inverter with the other. The components included to achieve this are a potentiometer (pot) and a capacitor. The pot controls the amount of signal while the capacitor value sets the cutoff frequency as capacitors allow high frequencies through and block low frequencies. The larger the cap, the lower the frequency. The value of 0.0047 has been used in most AC30 guitar amps (as opposed to AC30 bass amps – yes they did exist!) since 1959 and is most appropriate. You can think of the Tone Cut control as a high-pass filter or low-cut filter.
Master Volume control
There are many different Master Volume circuits. The one used in the AC30CC is the same as used in the modern AC15 and the AC30HW. It is post phase inverter. The advantage of a post phase inverter MV is that it is part of the power amp. A pre phase inverter MV is after the preamp but not the power amp.
MVs are usually used to get distortion at low volumes. Distortion in traditional tube amps (non MV) is created in all sections of the amp including the preamp, power amp (phase inverter and power tubes), transformer and speaker. Using a post phase inverter MV which is after the phase inverter tube, but before the power amp tubes, give you more authentic traditional tube amp distortion as compared to pre phase inverter MVs.
It works by combining the signal from one side of the phase inverter with the out-of-phase other side of the phase inverter.
Channel linking
Guess what? Not only can you combine the AC30CCs two channels, it can be turned into a channel switching amp! How do you achieve this? All you need is an external A/B box. The benefit is that the user can switch between two different AC30 tonalities. The Link switch has to be set to the up (non linked) position. An A/B/Y box will allow you to select and combine channels.
Reverb
Steve G. designed a completely new circuit which, as you have heard, sounds amazing. Here is a short version of an explanation from a web article written by our own Nick B.
In the analog domain there are basically two types of spring reverb drive and recovery circuitry used in guitar amps – valve and solid-state. Both have their pros and cons. A valve circuit has an inherent soft-clipping characteristic that's rich in even-order harmonics and is pleasing in terms of both sound and feel. As valve circuits involve a transformer it is relatively expensive. Other drawbacks of a valve driven circuit are that the valve creates heat and eventually wears out with use. Also, particularly with high-gain circuits, there's a lot of radiation from the wiring and transformer which can cause instability and noise. The solid-state option is cheaper but has usually less headroom and a harsh clipping characteristic in the drive circuit. Because of these reasons, solid-state reverb drive and recovery circuits were chosen and Steve decided to develop a brand-new circuit to get over the drawbacks normally associated with solid state designs.
“Although some of the solid state reverb circuits already out there are pretty good, it has always been my impression that no-one, and I include myself here, has taken them far enough in getting a really good sound or maximum benefit out of the reverb. I've managed to find a special M OSFET that works in the same mode that a valve does and, even though its gain characteristics are slightly different, you could unplug a valve from an amp's preamp circuit, solder this M OSFET in its place and the amp would work without you having to change or add any other components. And, being a M OSFET, it has the even order harmonics similar to those you get from a valve. The MOSFET is being used in both the drive and recovery stages of the Custom Classic 's reverb to emulate the soft clipping that naturally occurs in a valve circuit.
In addition, I've used five special op-amps in parallel and as they are 60 volt devices as opposed to the regular 30 volt ones they give a lot of headroom and also provide a great deal of current/drive capability without saturation. They are wired in a circuit configuration that emulates the behavior and characteristics of a transformer.”
Dwell switch
The dwell switch allows you to select Low or High reverb drive settings. In effect, it is a “post fader effects send level switch” (in this case the effect is reverb). When using spring reverb you need to be driving the input as hard as possible in order to maximize the signal-to-noise ratio while getting good reverb depth. If the circuit is not driving the springs hard enough then you've got to add more gain to the recovery stage which will add noise and possibly cause instability and feedback.
Most guitar amp reverb units (especially those guitar amps capable of high gain settings) have drawbacks because you have to compromise how much drive you put it in verses how clean or overdriven the amp has to perform. Obviously, if the preamp's running clean it is not going to be driving a lot of signal into the reverb. Conversely, if the preamp is turned up then there's going to be a much higher signal which then starts saturating the reverb and you get an undesirable ‘crashiness'.
If the AC30CC is set to a clean sound and you want a lot of reverb, you can increase the level of drive into the reverb by selecting High. If you want to run the preamp hotter, lower the reverb drive level by selecting Low.
Normal channel Brilliance switch
The Normal channel gives you two distinct, classic AC30 sounds. With the brilliance switch “off” this channel is the classic Normal AC30 sound. This is the channel that Brian May uses along with his booster pedal. With the Brilliance switch engaged, this channel becomes almost identical to a vintage “Treble” AC30's Normal channel. This is the sound of the early Beatles. Both channels are eminently usable signature AC30 sounds.
Custom/Standard Tone switch
This mini-toggle switch offers you two passive EQ options on the Top Boost channel. Standard gives you the classic, highly interactive Vox AC30TB tone stack while Custom reconfigures the components into something closer to the more common guitar amp tone stack as used by most designers. FYI, the Custom tone stack option is what is used on the Top Boost channels of both the AC30HW and the modern AC15. When both tone controls are set at 12 o'clock the difference between the two EQ settings are minimal. Once either or both controls are turned up the difference becomes more obvious. As the Bass control is turned clockwise , there is a mid scoop (cut) in the Standard EQ setting that is far more pronounced than in the Custom setting. In Custom, adjusting either control has less affect on the other. This difference is achieved simply by switching the bottom leg of the bass to ground. The Custom setting is recommended for higher gain sounds because of the consistent mid response.
Cathode bias resistor value switch (Output Bias)
The cathode resistor value sets the bias of the EL84 power tubes. The lower the resistor value, the lower the bias voltage and the higher the current draw. Conversely, the higher the resistor value, the higher the bias voltage and the lower the current draw. The Warm setting is the 82 ohms, the same setting as the original 4 input AC30s from 1959-1960. The Hot setting is 50 ohms, a similar value to AC30s from 1960-2004. At 50 ohms, the amp will produce about 33 watts clean and at 82 ohms the amp will produce about 22 watts clean and the tubes will last longer.
Smoothing capacitor value switch
The power supply works by converting the 120 volt AC wall supply into various the AC and DC voltages that make the amp operate. The power transformer converts the 120 volts AC to various AC voltages some of which are then converted to DC which is need to make the pre and power amp tubes operate properly. Rectification is needed to convert AC to DC. Vintage and modern AC30s use a high quality full-wave tube rectifier with an input choke pi-filter and 16uf smoothing capacitors both before and after the choke. This low value of 16uf was enough to get rid of most of the hum and keep ghost notes to an acceptable level while keeping the feel nice and loose (sag). Because of the nature of tube amp manufacturing, in some AC30s hum and ghosting was higher than others and a somewhat objectionable. In the AC30HW we used 50uf capacitors before and after the choke. The potential hum and ghosting problems were eliminated but the feel became a little tighter (less sag). Not bad, but not the same as a vintage AC30.
In the AC30CC we give the user both options. The low value (Vintage) is 22uf which is slightly higher but operationally virtually identical to a vintage AC30 or AC30TB. The high value (Modern) is 44uf.
The 22uf capacitors are always in the circuit. To achieve 44uf, additional 22uf capacitors are switched in both before and after the choke through 10k resistors which eliminate any potential popping when switched.
Vox AC30CC2X 30 Watt 2x12 Combo
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WHIRLWIND LINE/INST LE18 ELITE 
Fender Tuner PT100 Pedal 
