Siemens AUSO ELA 75-85 Dual Line Preamp

Siemens AUSO ELA 75-85 – Dual Line Amplifier

Offered for sale is a rare Dual Line Amplifier module from Siemens AUSO – an obscure yet highly sophisticated branch of Siemens audio technology, developed in Italy and Switzerland.

While Siemens Germany is widely known for legendary analog designs like the V72 tube amplifier, and later the transistor-based SITRAL series with classics like the V276 mic preamp, W295b EQ, and U273 compressor (aka Neve 2254), the Austrian WSW (Wiener Schwachstromwerke) division also contributed a range of excellent professional audio modules.

Siemens AUSO, however, remains largely undocumented. Little is known, and most available references relate to telecom equipment. But one glance at this module makes it clear: the construction quality and components match the best of its German and Austrian siblings. The gold-plated PCB traces and four high-grade audio transformers speak for themselves — likely custom-made equivalents to the famous Haufe designs used in German broadcast gear.

As no official schematics could be found, we’ve reverse-engineered the module and provide full pinout documentation. The connector type is still commonly available through standard electronics suppliers. All modules offered have been tested and confirmed working.

The default gain is approx. 34 dB, but we carefully increased it to around 44 dB without noticeably increasing the noise floor. Higher gain is possible but should be evaluated per application.

Important: The module is sold as shown, unmodified and without cables. We include a pinout guide for DIY integration.

We also stock a number of other rare and valuable modules from the same broadcast console series, including:

• ELA 75-75 Dynamic Compressor
• ELA 75-85 Dual Line Amplifier
• ELA 75-86 Microphone Amplifier
• ELA 75-87S Stereo Mic Amplifier
• ELA 75-91 MS-XY Matrix
• ELA 75-84 Output Amplifier
• ELA 75-79 Effect Filter
• ELA 75-83 Echo Send
• ELA 75-80 From Echo Amplifier
• ELA 75-81 H.L. Amplifier
• ELA 65-07 Intercom
• ELA 06-08 Fader
• ELA 06-09 Fader
• ELA 23-16 Power Supply

We are currently working on documentation and testing procedures for these modules. If you happen to own schematics or manuals for any of them, we’d be grateful to exchange them — we maintain an extensive archive and are happy to share in return.