In the world of high-end stereo systems, every component plays a crucial role in ensuring excellent audio reproduction. Among these components, the power transformer is fundamental, as it converts the AC mains voltage into the appropriate DC voltages used by amplifier circuits. For tube (valve) amplifiers such as the Audio Innovations 700 and 800 series, the transformer is not only an essential component but also a critical element in achieving a clear and powerful sound.

The 23S72 Transformer Model: A Reliable Solution

The 23S72 power transformer is specifically designed as a replacement part for the Audio Innovations 700 and 800 tube Hi-Fi amplifiers. This component stands out for its reliable performance and full compatibility with the specified models, ensuring a perfect restoration of the original functionality.

Main Features:

• Output Voltages: The 23S72 is engineered to provide the voltages required by these Hi-Fi amplifiers, ensuring audio performance consistent with high-quality expectations.

• Dimensions and Physical Compatibility: The component is designed to guarantee a perfect fit inside the Audio Innovations 700 and 800 amplifiers, avoiding any spacing or connection issues.

The 23S72 power transformer is more than just a spare part; it is a solution to ensure your Audio Innovations tube Hi-Fi amplifier continues to deliver the audio performance it was originally capable of. Investing in a high-quality transformer like the 23S72 is a step toward a more exciting and satisfying listening experience. If you are interested in purchasing, contact me through the contact form.

If the transformer of your Fender Deluxe Reverb has stopped working, there is now a reliable and high-quality solution: the new SB-LAB 25S108 power transformer. This transformer is designed to be a direct replacement for the original Fender 125P33A model, maintaining the same secondary specifications to ensure identical operation to the original.

Main Features

• 230V primary – The standard model is designed to operate with the 230V European mains supply, but custom versions with different input voltages or even multi-voltage input are available upon request.
• Identical secondaries to the original – The transformer provides the same voltages and currents as the original, ensuring full compatibility with the Deluxe Reverb circuit.
• Custom construction – The transformer can be wound entirely from scratch or rebuilt using the end bells from the burnt original transformer, to maintain a vintage appearance and original mounting integrity.
• SB-LAB quality – Each transformer is carefully and precisely built to offer long-term reliability and high performance.

Need a replacement for your Fender Deluxe Reverb?

If your amplifier needs a new power transformer, look no further. Contact me using the contact form on my website for more details or to request a custom configuration. I will be happy to help you restore your Fender Deluxe Reverb to its original performance. Don’t let a faulty transformer ruin your sound: choose the SB-LAB 25S108 model for a professional-quality replacement!

Are you looking for the perfect transformer for your vintage Marshall amplifier? The SBLAB_Drake_784-139 model is exactly what you need. This output transformer is a faithful clone of the legendary Marshall Drake 784-139, used in the famous 50 Watt Marshall amplifiers produced between 1968 and 1973. Our reproduction is built with extreme precision to deliver the same tonal characteristics and performance as the original, preserving the authentic and powerful sound that defined an entire generation of rock music.

Main Features

• 1:1 replica of the original winding: Unlike cheaper solutions on the market, where only the impedance is considered, our transformer was carefully copied from an original Drake 784-139 disassembled specifically for this purpose, guaranteeing an authentic reproduction of the original specifications.
• Production options: We can build the transformer completely from scratch, or, upon request, reuse laminations and end bells recovered from damaged original transformers to ensure a sustainable approach without compromising quality.
• High-quality components: Every component used in the construction of the SBLAB Drake 784-139 is carefully selected to faithfully replicate the original design and performance, maintaining the same robustness and long-term durability.

I deliberately do not publish technical specifications such as frequency response, impedance or other transformer measurements, because they are simply identical to the original. The SBLAB_Drake_784-139 is a 1:1 replica of the Marshall Drake 784-139 transformer, so anyone who knows the original knows exactly what to expect: the same sound, the same performance, with no compromises. This is not an approximation or a transformer designed from scratch, but the faithful reproduction of the component that defined the sound of a generation.

In the photo below you can see the version built entirely from scratch, without using recovered end bells or laminations, yet preserving the same specifications and dimensions.

Beware of incorrect information!
How to avoid common mistakes when choosing a quality transformer

In the world of vintage amplifiers, it’s not uncommon to come across incorrect information circulating online, which can lead to poor choices, especially when it comes to crucial components such as transformers. Recently, I was contacted by a technician who, unfortunately, ignored the accurate information I provided and preferred to rely on online schematics and theories.

This technician, despite not having access to an original transformer and having the option to receive a faithful replica of the Marshall 784-139, kept asking whether my transformer was wound according to a schematic found online from an unknown source and whether it used GO laminations, which he mistakenly considered “superior.”

Winding diagram found online from unverified sources, which has nothing to do with the authentic Marshall Drake 784-139 transformer layout.

Despite the detailed and verified explanations I gave him, he decided not to purchase my transformer, convinced that GO laminations would improve the sound.

This belief is unfortunately far from reality. GO laminations, although useful in certain contexts, can alter the saturation point of the transformer, changing the original sound entirely. A transformer that aims to faithfully replicate the Marshall 784-139 must strictly follow the original specifications, without trying to “improve” it with theoretical solutions never used by the original designers. Every deviation can irreversibly change the final result, turning the amplifier into something completely different.

Detail of the laminations of an authentic Marshall Drake 784-139 transformer: thick silicon-iron laminations, just like the original. GO laminations, which are much thinner, would be about one-quarter the thickness of those in this image.

In the end, that technician chose not to purchase my transformer, and while we don’t know what he bought instead, I can say with certainty that his choice will never deliver the same authentic sound that only a faithful and correctly built replica can offer. Meanwhile, my clients who chose the true replica are already enjoying the sound they expect from a vintage Marshall.

This is the testimony of another customer who made the right choice and recognized the value of a transformer built faithfully to the original, unlike those who gave up based on incorrect theories about how it should be made:

Hello Mr. Stefano,
I’m sending you a couple of photos of the amplifier I built using your “Drake” output transformer.
Thank you very much! It sounds excellent! Thanks!
As soon as I finish the dual channel modification and the cabinet,
I will send photos of the finished amp.
If everything goes well, I will begin production.

In any case, I will soon order more transformers.
Thanks again!

The lesson here? Don’t be misled by inaccurate theories or advice from forum hobbyists. When it comes to components that define your tone, trust those who truly understand the product and follow the original specifications. There is no room for modifications that distort the sound: authenticity is essential, and the only way to achieve the right tone is to choose a replica that fully adheres to the original design.

Our goal is not only to provide you with a quality transformer, but to give you the confidence that your amplifier will have the authentic sound and reliability that Marshall is known for. Don’t settle for approximate reproductions: choose SBLAB Drake 784-139 for a sound experience that reflects the original in every detail.

Contact us today for more information or to customize your order!