Discover the ideal solution for your Audio Innovations 700 or 800. The 23S72 power transformer is a 100% compatible replacement, precisely engineered to ensure optimal performance and reliability.

Why Choose Our Transformer

• Certified Quality: Built with premium materials to ensure durability and long-term reliability.
• Full Compatibility: Specifically designed for Audio Innovations 700 and 800, guaranteeing a perfect drop-in replacement.
• Zero Risk: Unlike used or salvaged transformers, our product is brand new, eliminating any risk of degraded insulation.

For more information about the complete restoration of Audio Innovations 700 and 800 amplifiers, visit this page.

Trust Us for a Safe Replacement

Avoid scams and endless searches. Buy your transformer from a trusted source. Contact us now to ensure uncompromised sound and an amplifier built to last.

Related Articles:

• Graaf GM20 Repair and Overhaul

• 6C33 Tube Tester and Analyzer

TE Audio 4071 – Replacement Part Compatible with Graaf GM20

I’m proud to present the perfect clone of the TE Audio model 4071 choke, an essential component for the Graaf GM20 amplifier. This replica is the result of a detailed reverse-engineering process carried out to solve a common issue faced by GM20 owners: the difficulty of finding a proper replacement for the TE Audio 4071 choke. In this article, I describe the component’s characteristics, the reverse-engineering process, and how this clone effectively eliminates the annoying hum produced by the Graaf GM20 when the original choke fails.

Pair price: €350, shipping within Italy included
Price updated May 2023
If interested in purchasing, please contact me via this form.

The TE Audio 4071 choke plays a crucial role in the proper operation of the Graaf GM20 amplifier. It regulates current flow within the circuit and suppresses power supply ripple. This is not a simple single-winding choke, but a complex component with multiple windings whose behavior within the GM20 circuit is quite sophisticated. In fact, it could be more accurately described as part of a filtering and noise-neutralization network rather than a conventional choke.

Eliminating the Graaf GM20 Hum

The hum produced by the Graaf GM20 can completely ruin the listening experience. With our TE Audio 4071 choke clone, this issue can finally be solved. Replacing the original choke with a high-quality replica is essential to restoring the amplifier’s silent and clean operation.

The creation of the TE Audio 4071 choke clone was made possible through meticulous reverse engineering. The original component was disassembled and analyzed in detail—materials, internal structure, and design specifications were all examined. This effort ensured that the replica perfectly matches the original in both characteristics and performance.

The Result

After an extensive reverse-engineering and testing process, I am pleased to present the perfected clone of the TE Audio 4071 choke. Crafted with the utmost precision and high-grade materials, it ensures outstanding performance and perfect compatibility with the Graaf GM20 amplifier. The result is a clear, noise-free sound and the complete restoration of the GM20’s original sonic purity.

TU Marshall 9200 – Price € 157.00
	Type: Push-Pull Designed for tubes: 4x EL34 or 4x 6L6GC Rated power: 100 W RMS Clone/replacement of the output transformer for the Marshall 9200 and Marshall EL34 100/100 amplifiers, for guitar and bass use. Not suitable for Hi-Fi applications. Available either with flying leads or solder lugs.

TU AC30 Clone – Price € 133.00
	Type: Push-Pull Designed for tubes: 4x EL84 Rated power: 30 W RMS 1:1 clone of a vintage Etherphon output transformer, fully compatible with the VOX AC30 push-pull parallel configuration using 4×EL84. Replacement unit. Not suitable for Hi-Fi use. Primary impedance 3350 ohm, secondary taps 4/8/16 ohm. The photo is indicative: the supplied transformer has black covers.

Below is a list of transformers I have already reverse-wound and for which I have complete winding data. They can be replicated without repeating the analysis process, but I still need the damaged original to recover laminations, bobbins, and hardware, since many parts are non-standard and hard to source.

Esoteric Audio Research “E.A.R. 509” Output Transformer
Faithful replica of the original transformer used in the legendary E.A.R. 509 monoblocks. Designed for KT88 tubes in ultralinear push-pull configuration, it delivers outstanding transparency and dynamics, perfect for restoring this prestigious amplifier.

Luxman MQ70 Output Transformer
Reproduction of the output transformer used in the classic Luxman MQ70 amplifier. Optimized for 6CA7/EL34 tubes, it restores the warm, refined tone typical of top Japanese amplifiers of the 1970s.

Rowe Ami R4359A Output Transformer
Replacement for Rowe Ami jukebox amplifiers. Restores the original vintage sound while fully preserving the electrical and tonal characteristics of the original unit.

Harman Kardon A300 Output Transformer
Clone of the transformer used in the famous Harman Kardon A300 integrated amplifier, with a 6V6 push-pull circuit. Ideal for faithful restorations and for preserving the authentic American tone of the 1950s.

Milbert BAM 230 Output Transformer
Replica of the transformer used in the rare Milbert BAM 230 car tube amplifier. Designed for maximum efficiency and isolation while maintaining the original mobile topology.

Radio Elettra Modulated Oscillator Power Transformer
Can be built entirely from scratch based on the original Radio Elettra oscillator circuit. Perfect for restorers and collectors of vintage educational equipment, with windings calibrated to the original design.

Cirse Sound Projector Power Transformer
Made for Cirse Sound audio projectors, this power transformer is essential for bringing classic Italian cinema equipment back to full functionality.

Audio Innovation Reference 210 Power Transformer
Clone of the original transformer used in the prestigious British Audio Innovation Reference 210 amplifier. Built to high-quality specifications, ideal for restorations or custom projects requiring robust, low-noise power supplies.

If you are interested, you can contact me here. I can also clone other output or power transformers if you provide the damaged unit. Click here for more information.