Aiwa 8700+Pioneer SA 708+A.R.E.S. L10 Tech

To begin with, I should mention that everything arrived completely non-functional—both the amplifiers and the speaker systems.
This was followed by the repair and complete refurbishment of both units,
with a focus on maximizing the impact on sound quality.
I replaced almost everything: from faulty output transistors and capacitors to the input transistors in the Pioneer unit—a challenging task, given that the specific dual differential pair used there has been unavailable for years.
I had to source components from multiple units and match them manually.
For the speakers, I retained only the woofers and tweeters (incorporating my own modifications),
as their frequency characteristics were suitable for a three-way design.
The original mid-range drivers could not be used due to their limited frequency response and sensitivity.
I opted for the excellent FaitalPRO 4FE35-4F, which was a perfect fit in terms of both dimensions and design.
The internal volume allocated for this driver was increased.
Next came electro-acoustic measurements, simulation, crossover construction, and listening tests.
During final tuning, the internal damping was adjusted—strategically applied exactly where needed.

The frequency response was measured on-axis with the tweeter at a distance of 1 meter in a standard room. The impedance does not drop below 3.5 ohms; these are 4-ohm systems.

My goal was to create a cohesive system delivering a sound that is effortless, composed, and well-defined, yet punchy when required.
It offers a fatigue-free listening experience—avoiding “pseudo-detail” or booming bass. …along with a balanced frequency response.

Here is a customer comment:

I had almost given up hope of ever hearing my system play again.
I discovered Mr. Janečka online; he did a fantastic job modifying the setup—tuning, damping, and installing new speaker crossovers, as well as modifying two vintage amplifiers—with excellent results.
The sound is dynamic, balanced across all frequency ranges, and non-fatiguing.
It was a major undertaking, but Mr. Janečka tackled it successfully, breathing new life and soul into the system.
He is the right man for the job—someone who works with heart and soul—and I am grateful for the experience and his assistance.
I highly recommend Mr. Janečka; he is a true expert.