FT5 vs JT1: which needs more amplifier?

The FiiO FT5 is 36Ω at 96.0 dB/mW; the FiiO JT1 is 32Ω at 88.1 dB/mW. This page covers what they ask of an amplifier, not how they sound.

The JT1 needs 7.9 dB more than the FT5 to reach the same loudness — 15 mW against 2.5 mW.

Side by side

The numbers that decide it

Specification	FT5	JT1
Impedance	36 Ω	32 Ω
Sensitivity	96.0 dB/mW	88.1 dB/mW
Sensitivity (voltage)	110.4 dB/V	103.0 dB/V
Power for 100 dB	2.5 mW	15 mW
Voltage for 100 dB	0.30 V	0.70 V
Current for 100 dB	8.4 mA	22.0 mA
Highest source impedance that leaves them alone (one-eighth rule)	4.50 Ω	4.00 Ω
Sources that reach 100 dB out of 280	280	278

What separates them

Where the two part company

2 of the 280 sources have the power for the FT5 but not for the JT1 — Apple USB-C dongle (EU), Steinberg UR22C.

278 of the 280 sources here reach 100 dB on both.

At the level you actually listen at

What each one needs from 80 to 105 dB

The JT1 is more demanding than 93% of the 567 non-electrostatic models in this database; the FT5 than 75%.

dB SPL	FT5 power	FT5 voltage	JT1 power	JT1 voltage
80	0.03 mW	30 mV	0.15 mW	70 mV
85	0.08 mW	53 mV	0.49 mW	0.13 V
90	0.25 mW	95 mV	1.5 mW	0.22 V
95	0.79 mW	0.17 V	4.9 mW	0.40 V
100	2.5 mW	0.30 V	15 mW	0.70 V
105	7.9 mW	0.53 V	49 mW	1.25 V

What drives both

The cheapest source that satisfies both

Source	Price	Headroom, FT5	Headroom, JT1	Output impedance	Noise
JadeAudio JA11	$20	10.3 dB	2.9 dB	0.5 Ω	1.7 µV
FiiO KA11	$29	18.5 dB	11.1 dB	0.7 Ω	1.7 µV
FiiO BTR11	$36	10.3 dB	2.9 dB	0.5 Ω	8.0 µV

Of the 280 sources here, 278 reach 100 dB on both. 70 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.

The cheapest of the 70 is the JadeAudio JA11, at $20. It leaves 10.3 dB of headroom on the FT5 and 2.9 dB on the JT1, its output impedance is 0.5 Ω against a one-eighth limit of 4.50 Ω and 4.00 Ω, and its noise figure puts the hiss floor 25 dB and 32 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.

Try any other source.

Frequency response

What each sheet prints, and what it is worth

Model	As printed	Tolerance	Standard
FT5	7Hz-40kHz	not printed	not printed
JT1	15Hz-30KHz	not printed	not printed

FiiO prints 7Hz-40kHz for the FT5. FiiO's German distributor shop lists 15Hz-30KHz for the JT1. That figure stands on FiiO's German distributor shop, not on a document published by the maker.

Neither range has a tolerance printed beside it, so a wider range on one sheet is not deeper bass or more treble.

Not a measurement; maker by maker.

Both pages in full

Both have a page of their own. In full: FiiO FT5 and FiiO JT1. Each figure on this page is labelled on those pages with where it came from, including the ones FiiO never published — what that maker publishes, counted.