Neve Additional Inputs

Another commission from our friends at Coral Sound, this PCB is used in adding up to 8 additional inputs (per layer) to a vintage Neve 80xx series console. It accepts three kinds of input transformer which then feeds an external fader loop and returns to a BA440 (or BA640) buffer amplifier which can drive an external mute/solo/assign and then drop onto the mix buss. It is just the right shape to mount on the bulkheads or sit in the belly of a 8-channel bucket such as the righthand end of an 8058 frame.

In keeping with the application RC decoupling, coupling, and termination was done in Neve style, along with a serpentine ground. Metalwork in the example pictured by Coral Sound.

Neve BA618 Replacement PCB

Some Neve channel amplifiers contained a daughterboard which switched between MIC and LINE inputs using optoisolators. Decades later, these photoreceptors are starting to wear out and replacement can be problematic. Granted, Coral Sound asked us to draw a PCB which would replace the optos with a brand new relay instead. This is not only more reliable but also lowers noise, distortion, and crosstalk.

H-Pad Relay PCB

Coral Sound hired us to draw this handy relay bypassable H-Pad PCB called "Padwich".

1272 Sensitivity Switch

Converting a Neve 1272 Buss Amp for use as a mic preamp has been a controversial issue at times, but it need not be, because there is a right way to do it: following the exact Neve spec as spelled out in a 1063 schematic, except omitting the high-gain positions where the missing amplifier stage would be switched in (1063 has three, but 1272 has only two stages). Glide On Fade recognized this and hired Eisen Audio to help design a sensitivity switch kit for implementing this electronically authentic upgrade.

Details and sales:


Vintage Trident consoles often featured integral patchbays built from PCB-mounted ADC jacks. 30-40 years later, said jacks are often in awful shape and causing intermittent connections, which makes the console impractical to use. Since cleaning or trying to replace said ADC jacks can be futile, Eisen Audio is sometimes hired to create entirely new jackbay cards as shown below. We use the highest quality nickel plated jacks which should last virtually forever. These retrofit cards can be user-installed as a direct replacement for the vintage cards, however a new top panel must be machined to hold the cards in place, accounting for the difference in the physical footprint of new jacks versus old jacks. This is not an inexpensive process, but it typically costs less and requires significantly less work (and down time) than the alternative approach of removing the Trident patchbay altogether and rewiring/reterminating the multipin connectors for an external wired patchbay. Contact us for an estimate if you’d like to purchase a similar retrofit for your console.

Power Supply Replacement PCB

Often times in recording studios you can find vintage equipment which is still very valuable and in demand, but has long since been discontinued (and unsupported) by its manufacturer, or whose manufacturer is long since out of business. Sometimes when replacement parts are unavailable, we have to build our own.

This example shows (below) an original PCB which was irreparably damaged by contaminated flood water, and (above) a copy that Eisen Audio was hired to draw.


A colleague was rebuilding some very rare vintage Neve modules (1058 Germanium transistor, powered by negative 24V, with black panels and black knobs), and they were missing their B100 preamp PCBs, so he hired Eisen Audio to layout a replacement. Note that we didn’t just scan and trace the original card, but rather completely re-drew it, resizing and repositioning the component footprints as we saw fit. This was done to keep all holes on a 0.1″ grid for modern fabrication techniques and automated assembly.


Uptown moving fader automation systems did not include a mute circuit, and so it was up to the techs installing said systems to supply their own.

When Echo Mountain Recording Studio hired Tech Mecca, Inc. to install Uptown Automation in their Neve 8068 console, John Klett designed a compatible silent opto mute circuit, and hired Eisen Audio to draw the PCBs. We added an optional discrete transistor buffer circuit which would’ve blended in nicely with the Neve amps.

8-Channel Balanced Output Driver

Coral Sound, Inc. hired Eisen Audio to draw this line-driver PCB, which is used in several applications, such as adding eight direct outputs to a mixer, or balancing insert sends.

TO-99 to DIP8 Adaptor

Eisen Audio drew this tiny PCB and hired one of our fabrication partners to build/assemble several hundred of them. It is used to replace obsolete TO-99 octal format IC op amps with DIP8 format parts.

Eisen Audio and its associates (Coral Sound, Inc. Tech Mecca, Inc.) are often involved in the rebuilding of vintage analog mixing consoles for use in contemporary recording studios. And when we run out of vintage components, or when the client requests an upgrade, creative solutions are required.

Replacement Relay Card Neve B316

A vintage Neve mixing console contained B316 relay switching cards with obsolete reed relays which were failing and could not be reliably repaired, so Tech Mecca and Eisen Audio built drop-in replacement cards using modern equivalent components. The console owner was able to swap in these cards himself, avoiding an expensive tech visit.

Neve 6×1 submixer conversion to 6-channel mic preamp

1RU Neve 6×1 Audience Reaction Mixer contained six mic input stages, which summed to one line output stage.

Eisen Audio added a PCB containing six BA440 output amplifiers, modifying the wiring and metal work. Power supplies and output transformers shall be located externally.

Neve Kelso Direct Outputs

Neve Kelso is a coveted compact mixing console from the 70s, which has great-sounding mic preamps, but lacks direct outputs for multi-track recording.

Tech Mecca, Inc. tasked Eisen Audio with building a space-saving, yet authentic-sounding, output stage called LULO9000. We drew a PCB which solders atop the wire terminals of a Neve/Mainair LO2567 output transformer, providing the sockets and support circuitry for a Neve BA440 output amplifier.

The end result is electronically equivalent to the output stage of a 1081 channel amplifier, and Coral Sound, Inc. was able to fit ten of them into the back the console pictured below. Another photo shows a pair of Neve 3116 channel amplifiers that Eisen Audio racked using a pair of LULO9000 for proper output stages.