2. Poor Headroom in 8078 Console Monitor Paths

Although famous as Neve’s last 45 series music consoles, the 8078 has an "Achilles’ heel" in that the Monitor path headroom is only 20dB (ref. 0dBu) whilst the rest of the console is at least 26dB. The cause of this is the use of a "two gang" Front – Rear pan pot with around 7.5dB insertion loss rather than a "four gang" pot, as used on the Channel paths. This (less expensive) potentiometer means that the BA440 (or BA640) output amplifier has a normal operating level of –2dBu instead of the "Neve Standard" of –8dBu. The Neve standard is based on the amplifier clipping at +18dBu and this level being further raised by the output transformer’s 8dB gain to provide +26dB headroom above 0dBu.

The Front – Rear pan pot sends to the 4T bus bar at –10dBu (implying >+26dB headroom) but the poor little BA440/640 is croaking long before that, especially when operated at +4dBu = 0VU. This raises its normal level to +2dBu and clipping will occur 16dB above this. Not good!

The fix we have used to overcome this is to replace the pan pot with a four gang device and fit a buffer amplifier between the left – right pan pot and the front – rear pan pot (in the same manner as the EMI-Neve consoles that preceded the 8078). This arrangement eliminates the loading aspect of the cascaded pan pots in the 8078’s 32425 module, and permits the use of a more accurate pan law.

We can supply a kit of parts to perform this modification, call us for details!

BACK • NEXT