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What does it do?

The V-Stack is designed to simulate the tones of vintage era guitar amplification gear, as if set up in an anechoic chamber and sampled through a microphone and microphone preamp. The specific tone it is based on is that of a germanium treble booster feeding into a classic all-valve amplifier stack; arguably one of the most representative blues/rock tone setups to emerge from that era. The V-Stack can transform just about any audio amplifier into a screaming lead stack!

Where/How can it be used?

The V-Stack is designed for home, studio, or stage use. If you don't have a valve amp, or can't take your rig with you, or need to practice quietly and don't have a "power brake", or even want to ease-off on the volume to extend the life of the valves in your amp, the V-Stack is an ideal solution. If you need to record your guitar, the D/I recording capability of the V-Stack provides a very convenient and cost-effective alternative to miking a full rig. With the DRIVE control set between 0 and 2 (typically), it can also function as a transparent treble-boost/clean-boost unit.

Who should use it?

The V-Stack is intended to be used by professional musicians and recreational players alike.

Is it basically a treble booster combined with a distortion pedal?

No. The V-Stack architecture combines a treble booster with a valve stack simulator, which is very different animal. Distortion pedals tend to be one-dimensional effects with limited tonal range. The valve stack simulator portion of the V-Stack has a much greater tonal range. Also, distortion pedals in general are not suitable for use with full-range amplifiers, or for D/I work, whereas the V-Stack is designed with these applications in mind.

Please note that the V-Stack is designed primarily for the recording/practice environment. It can also function as a versatile pedal, but it behaves unlike most other pedals in this role. On this point, it should be noted that guitar amps in general do not produce a flat response with their tone controls set in a neutral position, whereas the "true" sound of the V-Stack (as demonstrated by the D/I recorded sound samples on this site) requires a moderately flat amplifier channel to be reproduced faithfully. With some guitar amps, this can make the process of finding appropriate EQ settings between the amp and the V-Stack more involved. If you are thinking about using a V-Stack primarily as a pedal for stage work, you are strongly encouraged to try it first with your particular guitar and amplification equipment.

How much does it cost?

For current pricing and special offers, please refer to the Orders page

Does it have a warranty?

Yes. The pedal is warranted against defects in materials or workmanship for one year.

Does it use an external power adapter?

No. The V-Stack was designed with portability in mind. The low battery drain and resulting long battery life means that a power adapter is really not necessary.

How long will the battery last?

Typical battery life is 500 hours for an alkaline battery, and 300 hours for a standard zinc-carbon battery. However, the unit will continue to operate for some time (i.e. beyond these guidelines) with a weak battery. A deterioration in the tonal quality of the pedal is an indication that the battery needs replacement.

How do I connect it to a stereo/home theatre audio system?

The most common standard for home audio is the phono/RCA connector, so in this case an adapter which converts from the 1/4" mono phone plug standard to stereo phono/RCA plugs is required. The home audio/multimedia hookup kit, offered for sale on this website, is suitable for this purpose. Any spare audio input should be suitable. Start with both the amplifier volume and the V-Stack master level at minimum when setting up and testing for the first time. Some home audio system components already have standard 1/4" microphone inputs, so this is another possibility, but care must be taken with the V-Stack master level control to avoid overloading the microphone channel in this case.

How do I connect it to a multimedia computer?

The best connection to make to a computer is usually through the line input on the soundcard. Most soundcards use the 3.5mm stereo jack socket standard for audio input and output. Some external audio/multimedia ports may also use phono/RCA connectors for compatibility with home audio equipment. The home audio/multimedia hookup kit, offered for sale on this website, provides the correct adapters and patch cable to address either case.

Does it use DSP?

No. Like the early vintage equipment it is designed to simulate, the V-Stack is 100% analog. No DSP means no sampling artifacts and no quantization noise. Additionally, the absence of latency through the simulator means that it can produce very natural and musical types of feedback.

Can the treble booster be turned off?

There is no switch to turn off the treble booster as such, but the relative amount of treble boost is controllable using the V-Stack bass control.

What amps can the amp simulator section simulate?

While there are no presets for specific amplifiers, the "harmonic signature" amp modeling approach used by the V-Stack is quite general, and can approximate the harmonic signatures of many examples of vintage all-valve amplifiers which use push-pull output stages. The V-Stack overdrive range is adjustable from "clean" to "crunch" to "metal", and since many popular amplifiers tend to be placed in one of these categories, this is usually a good stating point when adjusting the V-Stack to achieve a particular amplifier tone.

How does the "harmonic signature" amp modeling approach work?

The harmonically rich tones produced when an all-valve amplifier is overdriven consist of both odd and even order harmonics. Due to electrical symmetry considerations, the even order harmonics are produced in the preamp stages, while the output stages add typically only odd order harmonics. The balance of these two types of harmonics define a "harmonic signature" for a particular amplifier. The "harmonic signature" amp modeling approach used by the V-Stack works on the principle that variable amounts of preamp and output type distortion can be blended together over a continuous range from "clean" to "infinite sustain" by varying the guitar volume control and the V-Stack DRIVE control respectively. This approach is put into effect by the provision of both a preamp triode simulator and a symmetrical push-pull output simulator in the amp simulator section of the V-Stack. In general, a wide range of tones can be achieved using the guitar controls alone. Note that for cleaner tones, it will typically be necessary to reduce the guitar volume to clear the headroom through the preamp triode simulator stage.

What sort of pickups work best?

The bass control range of the V-Stack is designed to accommodate humbucker and single coil pickups equally well.

What amps can it work with?

The V-Stack is designed to be usable with both full-range audio amplification equipment and guitar amplifiers. Note that for maximum flexibility of tone setup in a real-time situation, it is recommended to use delay and equalization pedals as downstream companion effects. Please see also the comments under "Is it basically a treble booster combined with a distortion pedal?", above.

What are the rules for chaining it with other effects?

The universal output of the V-Stack means that it is signal level compatible with most if not all types of guitar/audio effects on its output side. Effects that are connected to the V-Stack input should deliver (or be adjusted to deliver where necessary) signal levels that are within the normal range of a typical guitar signal. Most analog wah pedals, for example, will be suitable for use on the input side. However, only high quality effects should be used on the V-Stack input side to avoid degrading noise performance.

What is the return policy?

The product may be returned for a full refund of the purchase price, less a $20 processing and re-stocking fee, provided a return request is received within 1 week of the date of receipt, and that the product is returned in mint condition. ATD reserves the right to refuse to accept a returned product if it shows any signs of wear and tear. We suggest you listen to the D/I recorded sound samples and review carefully the information presented both in this FAQ and elsewhere on the website, so that you may make an informed purchasing decision. Requests to return a product should be addressed to:


Last updated 06.30.03