January 12, 2026

We currently have a lot of studio and production gear to sell at the moment! We need to make space for new projects, get a bigger R&D budget for upcoming projects on the side and thought about selling most of these units for a while now (if they weren’t already up on local platforms for some time like the 500 chassis), and now put everything we want to part ways with at the moment - even if it hurts a bit - on the relevant platforms.

For sale:

• ASM Hydrasynth Desktop in almost new condition
• Studer 963 2x Mono Mic/Line Preamp & EQ as racked channel-strips in custom wood case (cleaned, refurbed, overhauled and circuit checked with Osci and MM)
• Eylsia Karacter 500 Series Stereo Saturator with original packaging, used only twice in a rack, like new.
• 2x Fredenstein Bento 10S Chassis for 500 Series: 10-Slot Chassis with internal PSU. One with studio labeling stickers on it (easily removed), one with some rack burn from a touring case on the front panel (which made some of the LED writing less intelligable but works fine) - both cleaned, tested. One used to be rented out, the other one used to be one of our personal testing units and is in very good condition.

Previous storage and gear state/maintainance:

All hardware had been previously stored in a temperature and humidity controlled high-security storage unit with constant online climate monitoring, fire alarm etc. in rugged, shock-absorbant flight cases or in small non-smoking home to mid-sized studios or recording sessions of friends (where rental gear is concerned) as well as our R&D workplace at times depending on the unit in question: please just ask us directly if you have any questions or want to inquire about details about a certain device via [email protected]

Buying directly from us (B2B possible):

10% price reduction if you buy directly from us to save on reverb/ebay costs and up to 25% off if you take more than half of the stock!

Buying on Reverb and Ebay:

They’re also up on reverb and ebay as mentioned earlier:

1. Reverb.com
2. eBay

May 06, 2025

Formerly known as the “Don Classics Sontec MEP250” is now available again under new ownership by Quantum J Audio. As such we’re adding it on request to our catalouge of available hardware - built & customized to order.

Many more details and mods/customization options are discussed on our product website, see: 250EQ

— AZ, et. al.

March 31, 2025

It’s 2025 already! And we’re back!

Due to other work we had very little time to sell customized gear, and got less inquiries than expected, some potential customers went on for hours about potential needed features, but rarely this had the outcome of an actual order. We’re building high quality kits from link audio, JLM, CAPI and AML again. Modding / extending them as requested. As always: [email protected] is the primary contact point (now also routes correctly to our small team - you should get regular updates and fast replies - if you’re unsure, just drop us another line via mail!).

To keep long conversations that do not end in any actual orders shorter and to give more time to real customers, we will from now on happily discuss new ideas of e.g. custom summing mixers with different input options, specific OpAmps, transformers etc. - but can’t have e-mail threads that go on for weeks without an actual order. As such: from now on we’re going to charge for desgin and implementation work as soon as we see that more than a regular amount of email correspondence went into a discussion with a potential customer. We’ll of course let all potential customers know up front in time, and give you the option if you want us to work on your product, just chosse something off-the-line or we’d happily refer to other excellent audio and DIY shops that may even have the perfect product you’re looking for (as we always have!) instead. We hope you understand and are as happy as we are for cool upcoming additions!

We want to thank in particular: JLM and Link Audio as well as DIYRE for support and being there for our questions in the past on our way. As well as personal friends specializing in EE and audio PCB design - you know who you are :)

— AZ, et. al.

April 14, 2023

Ever wondered how diodes can be used to compress audio signals like in the famous old studio consoles by Neve or outboard units old and new? Unfortunately good articles on the topic are few and far around. One that’s worth reading concerning compressors using diode bridge rectifiers can be found here (it’s full of Ads unfortunately): https://www.whippedcreamsounds.com/diode-bridge-compressor/

A much better article on VCAs in general also describes the use of diodes and vari-mu tubes among all other common designs using components from LDRs (opto) to ICs (what most people in the professional audio and studio world call “VCA” compressors collectively) and describes why and how other compressors use these components to achieve compression and limiting, design drawbacks and common distortion reasons as well as the necessary technical background and examples: https://sound-au.com/articles/vca-techniques.html (website highly recommended for audio enthusiasts)

April 09, 2023

In 1966, Neumann GmbH presented a new type of transistorized microphone to the Norwegian 
Broadcasting Corporation, NRK. Norwegian Radio had requested phantom-powered operation.
Since NRK already had 48-volt power available in their studios for their emergency lighting
systems, this voltage was used for powering the new microphones (model KM 84), and is the 
origin of 48-volt phantom power. This arrangement was later standardized in DIN 45596.

— source: https://en.wikipedia.org/wiki/Phantom_power#History

It’s also advised to read the Technical Information and especially Caveats section on the Wikipedia page on Phantom power.

March 18, 2023

We’ve added a new section on the products we work on, currently offer and are available for pre-order or as customized made-to-order. So what’s new?

New Products:

1. CAPI VP312DI-Litz: CAPI VP312 pre-amp with DI/HiZ (passive or active) using high-grade custom Litz-wire Transformers
2. Link Audio 312 clones modded with parallel compression, saturation, tape sim and/or custom opamps

New Prototypes:

• We’ve received the first batch of five active summing units for Tascam/DSUB25 to XLR/TRS Combo Jack using a TI NE5332ADR opamp to test. Waiting on PC-ABS 3D printed cases for the active and passive summing prototypes

You can find the new sub-page and all info regarding the new items we have to offer over here.

March 13, 2023

At the moment some pictures and sites don’t render optimally on mobile platforms like smartphone browsers. We’re working on fixing this. We thought we should finally get the website online instead of moving the release date further back, so we have some info online right away. Most of the important information and contact details, shop etc. is already on the site.

Whats to come

We’ll add more content on analog audio gear, recording, tracking, mixing and mastering techniques in the analog domain as well as with hybrid set-ups. Extend the About Us section regarding the background of our namesake. We’ll also add a rental list and agreement and more information on custom pieces we’ve designed from the ground up or modified for customers.

Hope to see you back here soon!

— AZ

March 12, 2023

Welcome to our new website. Take a look at the content: you can hire us for custom work on analog gear, technical support during recording session, modifications and much more.

Shop

Don’t miss out and check out our Reverb Store. You just might find a piece of equipment you like. In the menu in the right corner you can find your way to our store or to rent equipment and hire audio engineering professionals.