Rupert Neve Designs 5045 Primary Source Enhancer
Two channels of transformer-coupled feedback suppression that a live engineer can set and forget - and that will happily chop a quiet word in half if you ask it to.
Pro-Sound (December 2019, p.40) documented live engineers favoring microphone selection by subtle frequency-response differences, noting that swapping capsules can force changes to gain structure and EQ.
Overview
The 5045 Primary Source Enhancer is a two-channel, line-level device built for one job: getting more gain before feedback out of a live microphone without gutting the sound. The operating principle is simple. The unit senses when someone is singing or speaking into a mic, passes the signal, and then reduces gain once they stop. That is the same basic behavior as a conventional noise gate, but it gets there by a different route. The manual is explicit that the 5045 does not use filtering or digital processing to get its results. It's an analog box and it behaves like one.
When it's working correctly, it sounds like nothing at all. The noise floor at the main output, measured unweighted across 22 Hz to 22 kHz into a 50-ohm terminated input, is better than -100 dBu with the feedback suppressor bypassed and better than -95 dBu with it engaged. Total harmonic distortion and noise at 1 kHz and +20 dBu output into no load is better than 0.002% whether the suppressor is in or out of circuit. Channel-to-channel crosstalk is better than -80 dB at 16 kHz. Those numbers say the 5045 is not the weak link in a signal chain. You patch it in and stop thinking about it, which is what a live engineer wants from a utility processor.
The frequency response runs from 20 Hz down 3 dB to 150 kHz down 3 dB. That bandwidth is deliberate, and the manual spends real space explaining why. The argument, drawn from work by Oohashi and Kunchur, is that human hearing resolves timing far better than a 20 kHz ceiling would imply. Kunchur's peer-reviewed demonstrations put temporal resolution at roughly 5 microseconds, where 20 kHz implies 9 microseconds and a 44.1 kHz CD sample rate bottoms out at 23 microseconds. The manual also notes that most gain stages show rising distortion at higher frequencies, including more intermodulation distortion. A common IM test mixing 19 kHz and 20 kHz sine waves will reveal a 1 kHz product if the device generates one. The designers conclude that keeping sufficient bandwidth with minimal phase shift, while minimizing high-frequency artifacts, is not academic.
The controls are few and the manual is honest about the tradeoffs. THRESHOLD sets the level at which the processor activates. Louder voices or hotter signal levels generally want higher, more clockwise settings. The key indicator is the green PROCESS ACTIVE LED, which should glow solidly while the performer is vocalizing and dim when they stop. DEPTH sets how much attenuation is applied once the signal falls below threshold. At 0 there is no attenuation and the 5045 does not affect gain. Around -10 dB is described as moderate and reasonably safe from accidentally chopping off a word. At -20 dB the attenuation is deeper, and the manual warns plainly that it can audibly cut off words with certain sources. Setting up the 5045 so it does not clip the quiet bits while still fighting a difficult feedback problem is described as a challenge sometimes, particularly with singers who alternate between whisper and full voice while demanding loud monitors.
TIME CONSTANT selects the attack and release behavior. In peak mode the attack is fixed at 20 ms, and release is selectable across six positions: 20 ms, 200 ms, 1 second, 2 seconds, 5 seconds, and 30 seconds. A separate RMS/PEAK button chooses the detection mode. The manual's recommended starting point is PROCESS ENGAGE off, TIME CONSTANT at C or D, RMS mode selected, THRESHOLD all the way down at -18, and DEPTH at 0. Then engage the process while someone is singing. There should be no change in level if everything is connected properly.
Connectivity is transformer-coupled on both ends. The line inputs are transformer balanced at 10K ohms, wired pin 1 ground, pin 2 hot, pin 3 cold. The main output comes off the output transformer secondary, balanced and ground-free. The manual notes this guarantees freedom from hum and RF interference when feeding a balanced destination such as a mixer input. The transformer can also be used with one leg grounded without any change in performance, so unbalanced destinations are fine with appropriate adapters. Maximum output level is +25 dBu, which gives substantial margin over what any downstream equipment is likely to require. Because the 5045 accepts and outputs line level, it sits naturally on the insert send and return of a console, or between a microphone preamplifier and a line input.
Power comes from an external supply, and the 5045 dissipates about 15 watts, so it gets warm in use. Each module contains an internal high-quality DC-to-DC converter that provides stabilized and filtered +/- 17.5 VDC to the amplifiers, so audio quality does not depend primarily on the external mains supply. The input is protected against reverse polarity, and the connector center pin must be positive. The external supply works from a wide range of mains voltages and frequencies found worldwide. Units leave the factory with standard US power cords, and any suitable cord may be substituted as long as it does not defeat the third-pin grounding. The manual advises against sharing a mains outlet with air conditioning or other equipment that switches on and off regularly.
Warranty service runs through Yamaha Commercial Audio Systems, which distributes the Portico line in the United States, with claims processed through local Yamaha service facilities. Coverage is one year from date of purchase against defects in materials and workmanship, with repair or replacement at the manufacturer's option.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.