Waves EQP-1A About the Modeling, Total Harmonic Distortion, Hum, Transformers, Upon Instantiation

1.3 About the Modeling

Many different elements contribute to the unique sonic characteristics of analog gear such as the Pultec EQP-1A. Waves painstakingly modeled and incorporated these elements into the PuigTec EQP-1A in order to fully capture and replicate the sound and performance of the original equipment.

These are some of the most important elements of analog behavior:

•Total Harmonic Distortion

Perhaps the most important analog behavior is Total Harmonic Distortion or THD, which is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. THD is usually caused by amplification, and changes signal shape and content by adding odd and even harmonics of the fundamental frequencies, which can change the overall tonal balance. THD can also change peak output gain, usually by no more than +/- 0.2-0.3 dB.

•Transformers

Some hardware uses transformers to stabilize or change Input/Output loads and signal levels. In earlier days, transformers did not have a flat frequency response, and often introduced low and super-high frequency roll offs. The original Pultec EQP-1A has transformers which cause high frequency roll off, so if you encounter loss above 10kHz, this is due to the modeled transformers.

•Hum

Waves modeled both 50Hz power current and 60Hz power current. If you listen closely, you will hear that there is a difference in hum level between 50Hz and 60Hz. Since hum is unique to each region and dependent upon the local electrical conditions, you may find that the modeled hum is different than the hum already present in your studio, and may not be suitable for your particular use.

•Upon Instantiation

Upon instantiation of the PuigTec EQP-1A, you may hear a small change in frequency balance, which sounds like top end boost, introducing about 1dB of gain. This replicates the actual behavior of the modeled hardware, and will vary as you change the low cutoff frequency. This is also an attribute of the original hardware, caused by the interaction of its filters.

Waves PuigTec EQP-1A User Manual

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