Does the Drop THX AAA 789 drive the Koss Porta Pro?
Computed from measured specifications · target SPL 110 dB · load 32 Ω
Verdict
AmpleThe Drop THX AAA 789 drives the Koss Porta Pro with ample headroom (~28.2 dB headroom at 32 ohms; needs ~2.8 mW, delivers 1800 mW).
Headroom
28.2 dB
28.2 dB
Required (110 dB SPL)
2.8 mW
2.8 mW
Delivered (@ 32 Ω)
1800 mW
1800 mW
Required voltage
0.45 Vrms
0.45 Vrms
Koss Porta Pro
Dynamic · on-ear
| Impedance (rated) | 60 Ω |
| Impedance (measured) Source: reference-audio-analyzer.pro/en/r… | 72.15 Ω measured |
| Sensitivity (rated) | 101.0 dB/mW |
| Sensitivity (measured) | 105.6 dB/mW measured |
| Driver | Dynamic |
| Spec basis | Measured |
Measured by Reference Audio Analyzer (https://reference-audio-analyzer.pro/en/report/hp/koss-porta-pro.php)
· Source ↗
Drop THX AAA 789
Desktop Ss · Single Ended
| Output impedance manufacturer | 0.1 Ω |
| Power @ 16 Ω | 3000 mW |
| Power @ 32 Ω | 1800 mW |
| Power @ 300 Ω | 200 mW |
| Power @ 600 Ω | 100 mW |
| Power source | Manufacturer |
Drop product page SE figures: 3000/1800/200/100 mW at 16/32/300/600 Ω. THX AAA topology, output impedance <0.1 Ω (class spec).
· Source ↗
Where to buy
Disclosure: links above are Amazon affiliate links. As an Amazon Associate this site earns from qualifying purchases — at no extra cost to you. Affiliate commissions do not influence verdicts; all analysis is computed independently from the data.
Other amplifiers for the Koss Porta Pro
| Amplifier | Headroom |
|---|---|
| Schiit Lyr 3 | Ample 33.4 dB |
| JDS Labs Atom Amp 2 | Ample 29.8 dB |
| Schiit Magni Heretic | Ample 27.6 dB |
| FiiO K7 | Ample 26.5 dB |
| Little Dot MkII | Ample 15.6 dB |
| Apple USB-C to 3.5mm | Ample 10.5 dB |
Other headphones the Drop THX AAA 789 can drive
| Headphone | Headroom |
|---|---|
| Grado SR80x | Ample 27.9 dB |
| AKG K371 | Ample 27.3 dB |
| AKG K702 | Ample 16.9 dB |
| HiFiMan Edition XS | Ample 16.6 dB |
| Beyerdynamic DT 770 Pro 250 | Adequate 7.5 dB |
| Beyerdynamic DT 990 Pro | Adequate 6.4 dB |