MvX upgrade?

[zettelsm]

Pardon me if this was already discussed -- has anyone had a chance to hear the latest Momentum amps with the MvX upgrades and compare them to the previous versions?

https://dandagostino.com/products/mo...lock-amplifier

From the website:

Advancements in Every Area

Every major section of the amplifier - power supply, input, driver, and output stages - have all been enhanced in this advancement. A new transformer winding pattern provides over 50% more current output from the same transformer footprint. This additional current offers greater headroom during dynamic passages.

A reinvisioned input stage combines a brand new circuit topology with advanced components feeding the driver and output stages. Crucial to the new circuit are the bipolar transistors powering the front end of the amplifier. In the Momentum M400 MxV amplifiers, new devices deliver ten times the current and power of the original devices. These wider bandwidth, higher power components extend low and high frequency performance with reduced distortion in both frequency extremes.

Energizing the driver stage is a new bias stability circuit providing a nearly 50% increase in operating bias. Increasing Class A operation directly correlates to better sound quality. However, there is a limit to bias level in any amplifier. With this new circuit topology and our unique Copper heatsinks, thermal issues are not a practical concern in the Momentum M400 MxV amplifiers.

The new bias scheme ensures bias consistency, preventing excessive temperatures even under the greatest demand. Additional power transistors in the output stage reduce workload for each device. By minimizing stress on each individual device, the entire output section works more efficiently. The result is a richer, more dynamic, intimate presentation regardless of musical genre.

The final output stage features new output transistors that were originally sourced for the flagship Relentless Monoblock Amplifier. The high-output transistors used on the Momentum M400 MxV are among the fastest available. Using 26 on the Momentum M400 MxV amplifiers they run at a blistering 69 MHz, permitting the Momentum M400 MxV to achieve incredible bandwidth. Each transistor mounts with two stainless steel fasteners—a rarity among flat-package transistors—for maximum thermal transfer to the copper heat sinks.

A capacitor/resistor network connected to the base of each transistor ensures stability even at high frequencies and with low-impedance speakers. Additionally, every output transistor is measured and only devices that match the required performance specifications are included in the production of Momentum M400 MxV amplifiers. As with all D'Agostino models, the Momentum M400 MxV amplifiers feature discrete, direct-coupled balanced circuitry, the most accurate circuit platform possible.

I spoke with Alex at the D'Agostino factory and the upgrade sounds like they jack up the case and drive a completely new amplifier underneath. $10K for the S250 stereo amp. I didn't ask about the M400 monos, but I'd guess it would come in at $10K per.

Steve Z