Frequently Asked Questions



Q1. Why does a simple circuit give the best tone?

A. Every time an analogue audio signal passes through a component or stage there is some loss of fidelity of the signal (e.g. the noise level may increase, the signal may be distorted, the equalisation or frequency response may be disturbed, or the dynamic range of the signal may be changed). Many guitarists may have tried passing a signal through a chain of effects pedals and will have noticed that the end result can be a severe loss of tone quality in the guitar signal (sometimes even when the pedals are switched out and even with 'true bypass'). This is one reason why many guitarists keep coming back to the sound produced by 'guitar + high quality cable + amp'.

The same phenomena can easily occur inside an amplifier, especially where channel switching and solid-state effects loop drivers, etc. are involved. Even in an all-valve amplifier, too many valve stages, extra 'tweak' switches and tone modifying circuits can compromise the overall tone.

IRVING amplification in common with other 'boutique amplifier' designs, keeps the circuit as simple and uncompromising as possible. With use of high quality components and meticulous hand-wiring and with simple controls, we hope you will find the tone you are looking for.

Nevertheless, our amplifiers will benefit from the subtle use of studio effects, such as digital reverb, and are also very 'pedal-friendly' for live performance.



Q2. What does 'pedal-friendly' actually mean?

An amplifier which sounds good, and does not misbehave, when various pedals are used at the input. Technically this implies: a sufficiently high input impedance (even when the pedal produces enough voltage boost to drive V1 into grid conduction), not too much gain in the pre-amp (otherwise things can start to sound like two distortion pedals in series which can rapidly get out of control), a not too 'peaky' frequency response curve (so that subtle tones introduced by the pedal are not swamped).



Q3. Can 'hand-wired' give a better tone?

A. In any electronic circuit the spacing and orientation of components and connections causes additional capacitance and mutual inductance among the elements of the circuit. These effects are called 'parasitic' or 'stray' because they are generally not beneficial to the performance of the circuit. In valve circuits, stray capacitance can be particularly problematic it can even cause an amplifier to oscillate. In a printed-circuit design, with components machine loaded, the designer has to be careful to avoid problems, but is limited in the spacing of the components and connections by the two-dimensional nature of the PC-board. In a hand-wired amplifier, the components and wiring are generally more widely spaced (reducing stray capacitance) and a skilled designed/builder can adjust the orientation and spacing to good effect.

The beneficial effect of hand-wiring on sound quality is often noticeable at the higher and middle harmonic frequencies of the guitar tone, and is perceived as an 'authenticity' of tone it sounds like you are hearing the guitar transparently through the amp. In other words you are hearing what your guitar actually sounds like. If you have spent a lot of money on a hand-made guitar, built using the highest quality wood and other components, does it make any sense to run it through a cheap mass-produced amplifier where the components, design and build may have been compromised to minimise cost?



Q4. Are IRVING amps clones?

A. No, we design the circuits and component layouts ourselves. Many classic circuit configurations are used of course but we also introduce some unique elements and adopt some modern improvements where appropriate.



Q5. Will I be able to change the valves myself and would I need to re-bias.

A. Yes you can, and no bias adjustment is required. (See 'Valve Replacement' section in the User Manual for further details.)



Q6. How long will an amplifier last and how often should it be serviced?

A. Our amplifiers are designed and built to give good service for many years. Valves do 'age' and will need to be replaced periodically (further guidance in the User Manual). Other components should give good service for many years, even decades. All parts and labour are covered by the first year warranty. After the first year we would recommend that you should have the amplifier checked periodically by a qualified technician.