Hey Head-Fi community!
I recently revisited the Fostex HP-P1, a classic portable DAC/amp combo from 2011, and decided to test it across several iPod models to document how it handles DAC and amp bypass depending on firmware and cable types.
This test is especially helpful for anyone still using iPods as part of their portable chain or modding setups with line-out docks and external amps.
iPod Models:
Using Sennheiser HD600 and Sony MDR-1AM2 for comparison, the Fostex DAC offered clearer imaging, more defined bass, and wider soundstage compared to the iPod’s internal DAC. The filter switch (Position 1 vs. Position 2) also made a tangible difference—one is tighter and clinical, the other is smoother and more musical.
Full video demo & cable behavior breakdown here:
YouTube Link to the video
Feel free to ask me anything about cable setups, gear pairing, or sound differences. Happy to contribute more data if others are running similar setups!
I recently revisited the Fostex HP-P1, a classic portable DAC/amp combo from 2011, and decided to test it across several iPod models to document how it handles DAC and amp bypass depending on firmware and cable types.
This test is especially helpful for anyone still using iPods as part of their portable chain or modding setups with line-out docks and external amps.
What I Tested:
iPod Models:
- iPod Classic Gen 5 (Video 5.5)
- iPod Classic Gen 6 & Gen 7 (stock and Rockbox)
- iPod Nano Gen 6 & Gen 7
- iPod Touch 1st Gen
- 30-pin to USB (for digital out)
- 30-pin to 3.5mm Line Out Dock (FiiO L9)
- OEM BMW iPod cable (iDrive model)
Key Results:
- iPod Classic Gen 6 & 7 (stock): Full DAC and amp bypass via USB confirmed. Clean signal, noticeable clarity improvement using the Fostex DAC.
- iPod Classic Gen 5: Partial functionality. Audio plays via USB if music is already playing before connection—but no UI control. Likely a form of car-mode behavior.
- iPod Classic Rockbox builds: DAC bypass via USB does not work (expected), but amp bypass using line-out jack works.
- iPod Nano Gen 6 & 7: Surprisingly, DAC bypass via USB works! Not just amp-level output. Much cleaner than expected.
- iPod Touch 1st Gen: Works via USB with full DAC+amp bypass. Improvement over internal sound stage and bass control.
- BMW iPod Cable: Bypasses amp and charges, but DAC stays internal. Still a unique dual-function option for car or stationary use.
Listening Impressions:
Using Sennheiser HD600 and Sony MDR-1AM2 for comparison, the Fostex DAC offered clearer imaging, more defined bass, and wider soundstage compared to the iPod’s internal DAC. The filter switch (Position 1 vs. Position 2) also made a tangible difference—one is tighter and clinical, the other is smoother and more musical. Full video demo & cable behavior breakdown here: YouTube Link to the videoFeel free to ask me anything about cable setups, gear pairing, or sound differences. Happy to contribute more data if others are running similar setups!
