Musical Fidelity A1 integrated amplifier

In 1989 I bought my second pair of Rogers LS3/5a’s from a guy on Staten Island who had them hooked up to a Musical Fidelity A1 integrated amplifier. After playing the speakers for me, he began removing the zip-tied speaker cables and paused to show me how on the amplifier side his red plastic Pomona Electronics banana plugs had been partially melted by the A1’s heat. We both laughed.

After first appearing in 1985, the A1 quickly became famous for its hob. The top plate got so hot because it was used as a heat sink for the output transistors, which were highly biased to class A. The A1’s hot top made headlines, but for me it was its bold, sinewy, non-transistoric sound and timeless sound. , sharply drawn styling that set it apart from cooler-running Brit-Fi competitors like Audiolab’s 8000A, Creek’s 4040, A&R Cambridge’s A60, and NAD’s 3020.

Despite the Daily mirror
According to the headlines, it was the A1’s completely natural sound and not the top plate temperature that made it an instant classic.

Now it’s back, priced at $1779, and it looks and feels cooler than before.

As I type this, it’s 35°C in my room, and I held my palm just an inch from the heatsink at the top of the A1’s chassis and felt barely any heat rising, maybe none at all. Using a digital oven thermometer, I measured the chassis. -top temperature at 60°C (140.1°F): too warm for toddler fingers, but 5° cooler than the original design-specified heat sink temperature of 65°Celsius.

History
My introduction to the melodic aesthetic of Musical Fidelity began in the late 1970s, when Anthony Michaelson ran a company called Michaelson & Austin, which sold EL34 tube amplifiers designed by the first audio designer I called a “Tall Wizard,” my soon-to-be boyfriend and Triode Mafia brother Tim de Paravicini. Tim’s design for the TVA-10 was a testament to our shared belief that in every well-designed audio amplifier, tubes and transistors sound the same. I believe Tim’s design for Musical Fidelity’s A1 proved that point.

When Musical Fidelity founder Anthony Michaelson retired in 2018, he sold the brand and its intellectual property to Austria-based Heinz Lichtenegger of Pro-Ject and its parent company, Audio Tuning. The relationship between Musical Fidelity and Audio Turning goes back decades.

Description
I asked PR whiz Wendy Knowles (who arranged this review) if anyone could verify that the A1 I’m reviewing bears more than just a cosmetic resemblance to the Tim de Paravicini-designed original. She asked Heinz, who replied: “Simon Quarry, our designer, respected Tim’s design 100% and only changed components to increase reliability.”

To that end, Musical Fidelity’s new A1 puts Tim’s original circuitry in a wider, thicker chassis, with more heat sink surface area, a larger transformer and power supply, better circuit boards, more capacity, tighter tolerances, higher temperature components and sturdier terminals. , more ventilation holes on the sides and more line level inputs (5). Plus Tape Out (fixed) and Pre Out (variable). All RCA. No balanced inputs or outputs. The chassis is 17.3 inches wide, 6.5 inches high and 38.5 inches deep. The A1’s output stage is class AB and delivers 25 pure class A watts at 8 ohms. The maximum voltage is specified as 42.5 V peak peak. factor is specified as 150, which suggests an output impedance of approximately 0.05 ohms. The specified RIAA response accuracy is specified as ±1dB.

The A1’s timelessly designed, touchscreen-free, blue-lettered front panel pleased me more every time I looked at it. The volume control felt firmly anchored and durable when turning the shaft of an ALPS RK series remote volume control. Speaking of remote control, the remote control that didn’t come with the original A1 is a 4-inch-long, solid aluminum contraption with three rectangular, rubber-covered buttons: Vol+, Vol, and Mute. Just like the A1 itself, it looks timeless.

Between the volume knob and the selection dial “Phono”, “CD”, “Tuner”, “Tape”, “Aux 1”, “Aux 2″ is an unlit Normal/Direct button that was also not on the original. “This switch allows you to completely bypass the gain block before the volume control,” says Musical Fidelity, “resulting in approximately 10 dB less gain. This feature proves particularly beneficial when working with modern or powerful digital sources, allowing fine tuning of the range of your volume potentiometer and accommodating sensitive speakers.”

According to the Musical Fidelity website, the new A1 has received an updated transformer from a split (1985 original) to a more efficient dual-mono (transformer) with split rail windings, resulting in amplifier stages powered by completely independent left and right speakers. Each amplifier now has double the original power supply capacity, resulting in less ripple and noise.” Elsewhere it says: “The A1 uses a discrete current mode input stage for the lowest noise with MC and MM cartridges. A low-noise current-to-voltage conversion stage is used for further amplification and RIAA equalization. Automatic input impedance matching for the selected MC input, along with increased gain, increases the versatility of the A1’s phono stage.” According to the owner’s manual, the moving coil phono input is best suited for cartridges not less than 100 µV and do not supply more than 800 µV.

I asked Heinz what that current-to-voltage stuff means. “The first stage that MM and MC cartridges see is a voltage-to-current converter, which also acts as an amplifier,” he replied. “Then, as described on our website, a low-noise current-to-voltage conversion stage is used for further amplification and RIAA equalization.

“In total, a significant amount of amplification is done” in the current mode. That means less noise than if pure voltage amplification were used throughout. “This is our very unique design that brings many sonic benefits.” One result of this approach is to effectively load the MM circuit with a resistance of about 50k ohms, Heinz said.

“Next, for the MC stage, we switch the emitter resistance of the transistor to a lower one! It is important to know that the gain factor on the discrete input stage depends on the emitter resistance of a transistor! So by switching that resistance, we increase the gain in MC mode (up to 60dB), while also automatically lowering the input resistance to match MC cartridges. This is a very different approach compared to typical MC stages. It amounts to approximately 1k ohms of input resistance of a very clean and tidy MC Phono Stage design, plus all the benefits of the current mode.

Play records
I could have written this review after playing just one record:
Festivals of the Himalayas (Nonesuch Explorer Series LP H-72065), recorded locally by David Lewiston, produced by Teresa Sterne and mastered by Robert Ludwig at Sterling Sound. I dropped the needle and my speakers lit up like a movie screen. The room came alive with sound.

As I listened as Nagaoka’s MP-200 moved the Permalloy cartridge into the MF A1’s MM phono input, I found myself grinning at the volume and extensive detail of the projected sound space. It was like looking at a real place through a wide angle lens.

In single-mic field recordings made by professionals, where the performance is unedited and the tape is unedited, the sheer dimensionality of the reproduction can be transporting. Through the A1’s MM phono stage, the three-dimensional space of the Himalayan festival appeared as an infinitely large dome, with drums and noisemakers, singing and diverse humanity entering from all sides. I could hear from the ground to the sky and felt something like a horizon or an outline where the microphones had lost sensitivity. The tone and texture were super vibrant and supported the illusion of being in the middle of a crowd, in an Indian village.

I’ve owned, repaired or reviewed legions of integrated amplifiers, including some very expensive ones, but none with a moving magnet phono stage impressed me more than the A1’s as it amplified the output of the Nagaoka MP-200 .

I tested the A1’s MC input with Dynavector’s XX2 moving coil cartridge. The 0.28 mV (280 µV) output and 6 ohm internal impedance seemed to be a good match for the A1’s “self-tuning” MC input. I know and love this cartridge; I’ve used it with every kind of SUT (including Dynavector’s own SUP-200), with JFET head amps, and with a range of transimpedance step-ups, including Sutherland Engineering’s SUTZ and Little Loco and Hagerman Audio Labs’ Piccolo Zero. Through the A1’s MC input, the XX2 sounded as fast as ever when it’s happy with the charge it sees. Transparency was reduced compared to Sutherland’s SUTZ transimpedance head amplifier, but through the A1 the XX2 sounded more powerful and bass-heavy than with SUTZ.

I tested how Tim’s unusual MC input would handle the 40 ohm Denon DL-103 MC cartridge. I found it played church-like, but not hallelujah level. Voices and instruments were not nearly as clear and confident as with my current favorite Hana MC, the Umami Blue. So I tried the Umami Blue.

On the A1, the Umami Blue’s 0.4 mV output and 8 ohm internal impedance provided a crisp, gain-is-just-right ambiance on every drive I tried. The A1’s MC input really lit up and clicked with the Umami Blue.

Musical Fidelity’s A1 has never sounded as exquisitely detailed or transparent as playing “Moonchild” from King Crimson’s In the court of the Crimson King (Atlantic LP SD 19155). I’m sure most of you know this record; I wish you could have heard how perfect and Windex clear this song sounded from my Falcon speakers. Once again the sound space was enormous, the presentation bold and very visual. I started to notice a pattern.