The importance of electricity might not be always at forte, but how important is it to some music lovers shows the example below. It's one of the examples of how far audiophiles are willing to go to pursue the perfect power delivery. 

Some people went to crazy extends to achieve the best possible result. For illustration, Taiko Morita, an ardent audiophile from Japan installed a 40-foot-tall concrete utility pole along with a private transformer. For him: “Electricity is like blood. If it is tainted, the whole body will get sick.” 

As a fact, were are dealing throughout the high-end audio with multiple applications to ensure the cleanest power handling possible. But, before the electricity enters into any of the high-end audio components it all starts with the source of pure power.

While I didn’t go to such extreme measures as some Japanese audiophiles I feel thankful for having the chance to have a separate electric line from the transformer substation. This was sort of a lucky incident that coincided with the building of my new listening room/house and the nearby renovation of power rails.  Like many of you, I'm always interested in everything that can relate to pure power, albeit I'm reserved about most of the active power distributors for various reasons. This particular topic deserves a standalone article and I'll address it in some of the future articles. 

When I’ve learned about the release of the new Doepke residual current circuit breaker I was instantly interested. A few days after the arrival of Doepke DFS 4 063-4/0,03-F audio Grade Differential Switch also the Kemp Elektroniks Supreme³, single - gold Cylindric Fuse Cartridge and matching accessories arrived, as suggested by Ronald Kemp. He ensured me that these additions will push even further the overall system performance. As will be revealed later, I'm more than happy I've taken the time and install Kemp Electroniks Supreme³, single - gold Cylindric Fuse. The review package included HiFi-Tuning Supreme³ Copper Fuse 10x38 mm, WA-Quantum Power Chip and Gabriel-Tech Chips for mains power applications GDF55.

Doepke residual current type F circuit ensures a high system availability due to its resistance to transient surge currents as well as the reliable detection of AC and pulsating residual currents with a rated frequency (50 Hz), even if other frequency components are present in the residual current, as may occur in modern audio devices with transformer or network parts.

DFS 4 063-4/0,03-F Audio four pole circuit breaker is optimized for protecting electric circuits that are connected to high-quality audio systems/products that are highly sensitive to mixed frequencies from 10 Hz to 1 kHz. DFS 4 is mains-voltage-independent and designed from the ground up for audiophile applications. 

This particular "HD" design is resistant against corrosive gases and moisture operates with minimal power dissipation at each pole and offers higher system availability (short-time delayed, selective for the establishment of stacked applications). 

All connection terminals are silver-plated and DFS 4 is VDE certified. 


Ronald Kemp from Kemp Elektroniks has sold and installed many of the Doepke switches and its complete power-related products to many happy customers, including quite a few Mono and Stereo readers. With his years of practical experience and understanding, Kemp is the best choice and the perfect authority to provide further insights.

Your differential switch. You know it's somewhere in the meter cupboard, and you know it has something to do with electrical safety. Congratulations, you just realized you really want one, as, without it, your safety may be compromised. But there's more. We'll discuss what it is, what it does, and how it affects your audio/video experience.

Simply said, a differential switch compares the incoming and outgoing currents in the entire system it protects. In an ideal world, these currents should be equal. What comes in, goes out for the full 100%. If for any reason, this is no longer the case, the differential switch immediately acts by disconnecting the affected circuits from the mains, preventing any current from going through the body of a human being ... which is highly dangerous!

So, bottom line: you really want one. For safety's sake. It's a great invention that enhances safety while using electricity. There is, however, another side of the differential switch: it incorporates several parts that are not really encouraging sound and visual quality to say the least. For the system to work, inductors to sense and compare the incoming and outgoing currents are used. And of course, there have to be contacts in it - after all, it is in fact nothing more than a controlled switch! Both the neutral and the live have contact in series.

Regarding the inductors - these have a certain inductance that is highly unwanted, as they tend to counteract sudden rises in current consumption, thus reducing dynamics in your audio.

Regarding the contacts - these add resistance and thereby noise, as they were purpose-built to just survive the load, for the best (read: lowest) price possible ….

Some reckless audiophiles have been experimenting with bypassing their differential switch - which sounds better indeed! No wonder, you just cut corners, both in terms of unwanted components in your mains as in... SAFETY! Because of the latter, we strongly discourage doing so. It just takes ONE insulation fault in ONE of your components to receive a possibly deadly electrical shock... But now, in 2020, you don't have to bypass your differential switch anymore. Finally, there's a perfect alternative for it, both in terms of safety as in audio/video properties! 


Meet the Doepke DFS. From the outside, it may look the same as your current differential switch for 99% - but the internals are completely different wherever you may look.

The first, very important difference is the absence of these dreaded inductors, they have been replaced by a straight rod, which of course has negligible inductance, as it doesn't even have a single turn! Here, an important step has been made to ensure an unhindered flow of peak currents, strongly encouraging dynamics in your system.

Then; the contacts. No effort has been spared to ensure the lowest possible resistance and noise. The best materials and oversized contacts with unusual high contact pressure all contribute to the ultimate goal of negligible resistance and noise. 

Of course, your safety hasn't been forgotten, in fact, has been emphasized. The Doepke differential switch copes with non-sinusoidal waveforms admirably - waveforms like this nowadays do occur due to a large number of switch-mode power supplies (SMPS) everywhere around you, even non 50 Hz components of the current are no problem at all. Safety is assured under all circumstances. Now, and in the future.

The Doepke DFS is in fact the very best of both worlds - it protects you and your loved ones from electrical shocks under all circumstances while it greatly restores your audio/video experience to what it should have been right from the start - it doesn't add any artificial effects, it just makes sure your equipment gets the very best foundation to extract the ultimate audio and video quality by removing unwanted, restraining components from the mains.


Modern consumer units use automatic, resettable fuses. They measure the current flow on a magnetic basis to interrupt the current in case of overload or short circuit. This automatic fuse contains an inductor and several (small) contacts. An advantage of these fuses is the reset function, a big disadvantage is a negative influence on the sound quality.

Automatic fuses (as used in every modern house) react extremely quickly to overvoltages that exceed the rated current. Many amplifiers with large power supplies have no inrush current limiter and cause an automatic breaker to trip immediately. This is entirely due to the extremely fast response of these breakers. Fuses with a melting wire, as used in Kemp Electronic Cylindric Fuse Cartridges prevent these mishaps. In almost all applications a 16 amp fuse should be more than sufficient, even in combination with very powerful amplifiers.

Kemp Elektroniks Supreme³ circuit breaker is a Supreme version of the classic Cylindric Fuse Cartridge. It has cryogenically treated and silver/gold plated contacts. The Supreme³ fuse is supplied by HiFi-Tuning and WA - Quantum Power Chip has been applied to the module. Spare fuses are standard silver-plated fuses.

Kemp Elektronik's single - gold Cylindric Fuse Cartridge (CE, IEC, EN, DIN and VDE certified ) is a Supreme audio grade replacement for standard circuit breaker.

It is available in 16, 20, 25, and 32 A slow-blow (time delay, aM) and combines a single-pole switch in one housing  (DIN rail mount) and can accommodate cables up to 10 mm²/3 AWG. 

As with anything to do with electricity, it is recommended that the installation be done by a professional electrician. My installation was simple, straightforward and trouble-free.


I cannot say that before evaluating the products of Doepke and Kemp Elektroniks I was not satisfied with my power line and all the surrounding equipment, but my personal and professional curiosity keeps me constantly on the lookout for objective and possible upgrades. 

As with everything in high-end audio, skeptics might argue that the "power of imagination" is taking place. Both Doepke and Kemp Elektroniks had an influence on my reference system that went far beyond an emblematic depiction. For yours truly, their practical results set their stand-out value. 

The Doepke Differential Switch addressed the primaries and introduced a significant increase in performance with a considerable shift in the dynamic impact and balance of the overall system. 

In my particular listening configuration, the Doepke DFS 4 lets the music inhabit the sound. For everything that has to do with power-related products, the usual norm is the other way around. A fascinating, yet very lucid change in quality took place, that is not easy to forget or ignore. 

With Doepke, the general micro-macro-dynamics were more realistic and present with more captivating credibility. 

I liked and loved the new reality, which felt enriched with the spatial cues and much better density. 

Kemp Elektroniks Supreme³, single - gold Cylindric Fuse Cartridge has introduced some interesting further refinements in terms of microscopic insights and has glued everything together to an even better harmonic whole. 

My first reaction to the newly acquired quality was a thorough examination of whether it was not just an accumulation of perceived definitions and subjective mind pattern formation. And... It was not!

When perspective shifts occur, the objective consideration of facts should not be ignored. My experiences with Doepke and Kemp Elektroniks were not only positive but of profound difference. 

In the world of stratospheric pricing, both the Doepke DFS 4 063-4/0.03-F audio differential switch and Kemp Elektroniks Supreme³, single - gold Cylindric Fuse Cartridge feel like a real bargain compared to what (and how succinct sonic increase) you can get for their given price tags these days. 

It is not difficult to highly recommend both and award them with the 2020 Mono and Stereo Highly Recommended Products Award. 

Matej Isak


  • Price: DFS 4 063-4/0,03-F Audio four poll - €845.00
  • HiFi-Tuning Supreme³ Copper Fuse 10x38 mm - €79.00
  • WA-Quantum Power Chip € - 50.00
  • Kemp Elektroniks Supreme³, single - gold Cylindric Fuse Cartridge - €175.00
  • Gabriel-Tech Chip for mains power applications GDF55 - € 55.00


  • sensitive to mixed frequencies from 10 Hz to 1 kHz, mains-voltage-independent
  • for audiophile applications
  • higher system availability: short-time delayed, selective for the establishment of stacked applications
  • "HD" design: resistant against corrosive gases and moisture
  • minimal power dissipation at each pole
  • silver-plated connection terminals
  • VDE certified
  • Supreme audio grade replacement for standard circuit breaker
  • Durably silver/gold plated contacts for best conductivity
  • Cryogen treated and demagnetized
  • HiFi-Tuning Supreme³ Copper Fuse 10x38 mm supplied
  • Including silver plated spare fuse
  • Available in 16, 20, 25 and 32 A slow-blow (time lag, aM)
  • WA-Quantum Power Chip
  • Single pole switch and fuse combined in one package, DIN-rail mount
  • CE, IEC, EN, DIN and VDE certified
  • Capable of accommodating cables up to 10 mm²/3 AWG
  • Weight 62 gram / 2.2 ounce
  • Sizes 18x81 mm / 0.7x3.2 inch


Kemp Elektroniks
Quellijnstraat 9 - 15
1072 XM Amsterdam
The Netherlands

Tel: +31(0)20-7764464
Fax: +31(0)20-7775446
Mobile: +31(0)6-54691901