The new version of the Merope amplifier introduces significant upgrades that expand the versatility and sonic potential of the original design. While preserving the core philosophy, version 1.1 integrates a new power transformer that allows the use, in addition to 6L6GC and 5881, also of EL34 / 6CA7 and KT66 tubes connected in triode mode, simply by adjusting the cathode bias network through resistor replacement. This upgrade opens new tonal possibilities without compromising the circuit philosophy.
Who is Merope?
Merope is one of the seven Pleiades in Greek mythology, daughters of Atlas and Pleione. Unlike her sisters, she is often portrayed as the most shy and reserved, sometimes barely visible in the night sky because, according to the myth, she felt shame for having married a mortal. This delicate and mysterious figure has become a symbol of hidden elegance and silent refinement, qualities that well represent the sonic philosophy of the amplifier that bears her name.
Circuit Architecture
The output stage operates in push-pull triode class A configuration, with self-bias and self-balancing according to the Blumlein principle, which ensures dynamic balance between the output tubes without the need for manual adjustments.
The input stage is based on an ECF80/6BL8, where the pentode works as a current generator cascoded with a long tail formed by an ECC82, while the triode section of the ECF80 acts as the input stage. This architecture provides excellent drive symmetry and precise control of the entire output stage.
Signal path capacitors are kept to a minimum, only two capacitors separate the phase splitter from the output stage, benefiting transparency and signal integrity.
Power Supply and Rectification
Rectification is handled by diodes with filtering in a dual CLC configuration, with one independent cell for each channel, ensuring stable voltage and low ripple. This solution improves channel separation and preserves microdynamics even at low listening levels.
Merope is more than an amplifier, it is a journey into the world of high fidelity audio. Discover sound like never before with this symphony of tubes and advanced technology. Enter the future of audio, where the beauty of tradition merges with modern innovation.
This is a premium project commissioned by “E.S.”. It is a 10 watt RMS integrated amplifier using a push-pull configuration of 6L6GC and 5881 tubes connected in triode mode as the output stage.
Let us see the build made by E.S.
The Premium Project Kit
In the premium version of the Merope project, the heart of the power supply section is based on components manufactured to SB-LAB specifications.
The photo above shows exactly the set that will be supplied to the buyer of the premium project. In addition to the components, the kit includes the complete electrical schematic updated to version 1.1, with precise indications for installing 6L6GC, 5881, EL34, 6CA7 and KT66 in triode configuration, depending on the user’s choice. A solid starting point to build a state of the art hi-fi amplifier.
A Passionate Return After Two Years:
Sometimes passions intertwine over time, and the stories behind projects come to life in unexpected ways. Two years after completing the “Merope” project for our valued customer “E.S.”, it was an exciting moment when he decided to travel to us to share his enthusiasm and experiences related to this unique creation.
A Dialogue in Tubes and Notes:
In an atmosphere filled with passion for audio and tube technology, we sat down to discuss the journey that “Merope” has taken over these two years. The client, animated by his own creation, expressed his satisfaction and his lasting affection for the amplifier he commissioned. A dialogue that went beyond simple technical conversation, revealing the deep bond between the artist and his work.
Detailed Measurements for Complete Transparency:
During the visit, we took the opportunity to carefully measure the performance of “Merope”. This measurement session was intended to provide precise and detailed information, to be shared on our website for a deeper insight into the extraordinary capabilities of this amplifier. We are proud to announce that “Merope” exceeded expectations in all measurements, confirming its status as a true work of audio art.
The Merope amplifier reveals its power and versatility through flawless performance. With an RMS power of 9.7 watts measured before clipping and capable of reaching 11 watts at clipping, Merope stands as an exciting audio experience. Its damping factor, measured at an impressive value of 10, helps maintain stable control of the output. The bandwidth at 1 watt is exceptional, reaching from 5Hz to 100kHz (-1dB) with minimal phase rotation. This result is due both to the outstanding performance of the transformers and to triode connection, highlighting the care and attention in the design.
Total harmonic distortion at 1 watt is 0.74 percent, indicating a very high level of sonic purity. The graphs also include square waves, further highlighting the extraordinary quality of the output transformers. In every aspect, Merope proves to be not only a powerful amplifier but also an example of excellence in audio design.
100Hz
1khz
10khz
A Continuing Journey:
This meeting was more than a simple technical check, it was a moment of shared passion and a renewal of the bond between the creator and the creation. The journey of “Merope” continues, fueled by the affection and dedication of those who believed in this project from the beginning. Its story is now enriched by new chapters, written through conversations, measurements, and the continuous evolution of a work of sonic art. But now let us hear from the owner of Merope:
Listening impressions: I have listened to only a couple of tracks, which I know very well, and I can already say with confidence that I am fully satisfied with the sound, which is very natural and extended in frequency. Compared to the tube amplifier I own, I immediately noticed a substantial increase in bandwidth, especially in the high end, and in clarity. Instruments sound more real. I would like to point out that I did not do any A vs B test by connecting and disconnecting the two units and making comparative tests. It was not necessary because the improvement in sound quality is substantial and immediately noticeable.Overall experience: I decided to start the adventure of building a DIY amplifier because I was not fully satisfied with my old tube amp and I believe that the cost of hi-fi electronics is in most cases unreasonable and unjustified. After about six months since I first contacted Stefano Bianchini, I am now listening to a 10 watt class A amplifier designed by SB-LAB and entirely built by myself, which sounds better than any device I have ever owned. The experience, however, goes beyond a well sounding device. During these six months I had to study electronics, components, tubes, measuring instruments, and more. This allowed me to learn more in this short period of time than in the previous 20 years of passion for audio reproduction. Today when I read an industry article or a hi-fi review, I do it with different eyes. This experience made me aware that audio reproduction quality is based on good design, correct construction, quality components, mathematics, more than on NOS tubes and 1000 euro cables. Thank you Stefano!