About this page
The Don Classics is a UK name in build-it-yourself studio gear. Archived copies show it selling kits from this web address from late 2010 until late 2024, describing itself as the home of 500 series DIY kits of classic equipment. The kits were sold raw, for the buyer to solder at home.
TunedRoom now owns the thedonclassics.com address, which is why older links to the maker arrive on this page. We are an independent audio publication with no connection to the maker. We did not make these kits, we do not sell them, and we cannot provide parts, manuals, build support or warranty help.
Where the kits are sold now
During 2025 this address forwarded to Quantum J Audio (opens in a new tab), a UK shop that now sells an NV73, an NV73EQ and a 250 EQ. Its NV73 is offered as a full kit or a built unit, and the page credits the design to Don Classics and has its own documents tab. The shop also lists two FET compressors that had no price and could not be ordered when we checked in October 2026.
That shop is the place to ask about buying, documents and support. TunedRoom has no connection with it and cannot answer for what it supports. The old email addresses on thedonclassics.com no longer reach anyone, so please do not send orders, payments or warranty requests to them.
The rest of this page records what the maker published here, with the year of the archived copy each fact comes from.
Where The Don Classics came from
By the site's own account, the business was started by a freelance recording engineer working around London studios. They wanted gear they could carry from studio to studio and settled on the 500 series format. Their first target was a faithful copy of the 1970s Neve 1073 microphone preamp, built with three full gain stages and the same capacitor types as the original. They could not find one for sale, so they built it. Other engineers asked for copies, and the business followed.
The earliest archived copies of the site date from late 2010. The shop was still listing kits at the same prices in November 2024. In December 2024 the prices were replaced with TBC, and during 2025 the address forwarded to Quantum J Audio.
The kit range and the listed prices
These are the prices shown on the maker's site in archived copies from 2023 to November 2024. They were in pounds sterling and included worldwide shipping.
| Kit | What it was | Format | Listed price |
|---|---|---|---|
| NV73 | Class A microphone preamp with three gain stages, after the Neve 1073 | 500 series | £149 |
| NV73EQ add-on | Equalizer stage that turned the NV73 into a full preamp and EQ | 500 series, listed as dual slot | £129, or £248 with the preamp |
| U76a | FET compressor after the early 1176, revision A | 500 series | £149 |
| 250EQ | Five band fully parametric equalizer after the MEP-250A | 500 series, two slots, mono | £165, or £235 with concentric pots |
| 2NV-Rack | 1U rack with its own power supply, holding two 2NV modules | 19 inch rack | £169 |
| 2NV73 | Microphone preamp and EQ with line input and guitar input | 2NV rack | £225 |
| 2NV73+ | As the 2NV73, with a switchable high shelf frequency | 2NV rack | £259 |
| 2NV66+ | Preamp and EQ with frequency points chosen to sit alongside the 73 | 2NV rack | £259 |
Fully built modules were offered too, by email order. A 2016 copy of the site lists an assembled NV73 at £550.
Three of the kits have their own pages here: the NV73 preamp kit, the 250EQ kit and the U76a compressor kit.
What the kits were modeled on
Every module kit in the range was based on a circuit with a long studio history. The NV73 and the 2NV modules follow Neve console modules from the 1970s, chiefly the 1073. The U76a follows the first revision of the 1176 compressor, which went on sale in 1967. The 250EQ follows the Sontec MEP-250A parametric equalizer.
Original units of all three are expensive, and the vintage ones are decades old. A kit offered a version of the circuit to anyone willing to solder it. The 500 series format helped too, because several modules can share one small powered rack and travel in a bag.
The maker's pitch was accuracy, not novelty. The pages stressed original schematics and original part types, and each module's kit page pointed builders to the vintage schematic as a second reference alongside the maker's own drawing.
What came in a kit, and what did not
The Don Classics sold what it called raw kits. Each one held the circuit boards, the metalwork, the mounting hardware and any parts that were hard to find elsewhere. The rest of the parts were left to the builder, who ordered them through carts the maker had prepared in advance at parts suppliers.
Every kit page carried a build manual, a parts list, a schematic and a short list of common questions. The advice for a build that did not work first time was plain: look over your work again, read the manual again, and ask other builders.
What 500 series means
500 series is a modular format for studio hardware. Each module is a narrow card with a front panel, 1.5 inches wide and 5.25 inches tall, and it slides into a powered rack that supplies its electricity and its audio connections. One rack can hold a preamp, a compressor and an equalizer from three different makers side by side.
The rack supplies plus and minus 16 volts. Two of the kits list their own converter boards, one raising that to 24 volts for the NV73 and one to 30 volts for the U76a. The maker's figures put the NV73's draw at 125 milliamps at most.
If your interest is home listening rather than recording, the closest everyday relative of a studio preamp is the phono stage that lifts a turntable's signal to a level an amplifier can use. Our guide to connecting a turntable to speakers covers that, and we keep a list of turntables with a built-in phono preamp.
The rest of TunedRoom covers the listening end of the chain, from speakers and turntables to home theater, with tools such as our speaker wiring calculator.
Common questions
Is this The Don Classics website?
No. TunedRoom is an independent audio publication that now owns this address. This page explains what the maker sold here and where those kits are sold now.
Can I still buy a kit or a built module?
Not from us. Quantum J Audio, a separate UK shop, now sells an NV73, an NV73EQ and a 250 EQ.
Where can I find the build manual for my kit?
We do not host the manuals. Quantum J Audio has a documents tab on its NV73 page, and copies of the original pages are held by the Internet Archive's Wayback Machine.
Who do I contact about a faulty build or a warranty?
Not TunedRoom, and not the old email addresses, which no longer reach anyone. Quantum J Audio is the shop that now sells kits under these model names. We cannot say what it supports from the earlier kits.
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