APS audio transformers

This is now included on all our Limited Edition MK2 DAC upgrades

Click here for our new Vocm buffers for the MK1

Priced per pair (2) installed.

These are installed here in-house. We may consider selling just the circuit boards to qualified technicians. The transformers need to be removed in order to install these also it takes a lot of heat and knowhow to remove the stock caps where these get installed.

$278 / pair. Send us a message.

In Stock

Introducing Our Enhanced Vocm Modification:

Superior Performance with Lower Noise and Power Consumption

In the pursuit of audio fidelity and efficiency, we've developed a new Vocm (common-mode voltage) modification that represents a significant leap beyond the traditional resistor divider found in the stock MK2. This upgrade ensures much lower impedance across the entire frequency spectrum, delivering a cleaner, more dynamic and accurate sound.

Unlike the stock design, which relied on a pair of 1k resistor divider, our new circuit eliminates both these resistors entirely creating a much better and more stable Virtual ground. This streamlined design results from meticulous measurements revealing that the existing thin film resistors contribute around 2 dB of additional noise. By removing these components, we tighten the control over lower frequencies.

Practically, this modification behaves almost like having a genuine bipolar power supply, which naturally avoids the noisy resistors and and creates a near perfect V Ground. Additionally, the new Vocm buffer draws only 4 mA per channel.

Ultimately, this thoughtful and efficient redesign offers audiophiles the best of both worlds: enhanced sonic purity. Percussive instruments have never sounded better. It stands as a sophisticated solution that refines the tonal balance and dynamic response of audio equipment without the practical complexities of a bipolar supply. As audio technology continues to evolve, such targeted improvements hint at the future of clearer, more natural sound reproduction.

We totaly redesigned the whole Vocm process with this newly designed and built Vocm buffer circuit. 

This new Vocm modification approach supersedes the previous stock Vocm, allowing one to hear Ted Smith original design as this is one area that was downgraded to save money. The innovation in this approach has led to a breakthrough in audio performance for this DAC. Users have reported astonishing improvements, with the audio quality reaching levels that surpass previous benchmarks.

This continual research and development by APS demonstrate their commitment to refining and enhancing the DAC experience. While some may feel disappointed at not receiving this new upgrade earlier, the ongoing advancements highlight the brand's dedication to excellence and innovation in digital audio technology.

Our new Vocm buffer:
Impedance Across the Frequency Spectrum:
Low Frequencies (DC up to ~100 Hz) Where we need this low impedance stabilization.
Input Impedance (\(Z_{IN}\)): 
Extremely high (typically 10⁶ Ω for bipolars, 10¹² Ω to 10¹³ Ω for JFET/CMOS). It appears as near-infinite to the source.
Output Impedance (\(Z_{OUT}\)): Excellent 
Very low (fractions of an ohm to <10 Ω) because of maximum negative feedback.

Upon conducting our A/B comparison between the old stock Vocm and the new buffer mod, we immediately noticed the incredibly tight bass and dynamics. The soundstage projected by the new buffer Vocm mod is undeniably superior. The speakers disappear even more than before, and the sound is significantly more realistic. In comparison, switching back to the old method is simply disappointing. The old stock Vocm sounds dull and lacks dynamics. 

In conclusion, for audiophiles and enthusiasts, it offers an opportunity to experience unparalleled sound quality that redefines expectations. This DAC continues to be one of the finest sounding devices available, proving that even established standards can be elevated through thoughtful engineering and passionate research.