High cable capacitance forms a low-pass filter against your cartridge or preamp output impedance. Find the -3 dB corner, plot the full curve, and check whether your setup loses treble inside the audible band.
My setups
Save cable + cartridge + phono-stage combinations. Useful when you're picking between cable choices or auditioning phono stages.
-3 dB corner-Where treble loses half its power.
Total loading-Cable + phono-stage input capacitance.
Audibility-
-5 tiers from "Serious loss" to "Inaudible".
Side-by-side
CurrentCurrent
vs
Saved-
Source
cartridge / line
Pick a cartridge to set its recommended load. Line-level sources (DAC, preamp): leave Custom and set source impedance below.
Typical interconnect: 0.5-3 m. Long studio run: up to 30 m / 100 ft.
Phono stage
load
pF
From your phono preamp manual. Typical: 100-300 pF.
High-frequency response
live
Log axis 1 kHz - 100 kHz. The -3 dB point is where treble is half-power; below it the response is flat, above it rolls off at 6 dB/octave. The audio band (≤ 20 kHz) is lightly shaded. Aim to keep the corner above 17 kHz for inaudible response.
Show the math
How cable capacitance steals treble
The RC low-pass filter
Any capacitor in parallel with a load and source resistance forms a low-pass filter with corner frequency f = 1 ÷ (2π x R x C). For an MM cartridge at 47 kΩ with 300 pF total loading, the -3 dB lands at roughly 11.3 kHz - audibly inside the music band.
Total capacitance = cable pF/m x length + phono-stage input pF. Shorter, lower-cap cables move the corner up; so does a phono stage with lower input loading.
Practical loading targets
MM cartridges are optimised for 150-300 pF total loading. Keep total cable + input capacitance under 250 pF to put the -3 dB above 17 kHz. Some cartridges (Shure, Audio-Technica) publish ideal loading; honour those numbers.
MC cartridges sit at 10-100 Ω output impedance, so cable capacitance barely registers - the corner stays north of 100 kHz on long runs. The cable-cap problem is mostly an MM problem.
Typical capacitance, by cable type
pF/m is the spec to chase if you have a phono front-end. Multiply by length, add the phono stage's input pF, and you have the cartridge's load.
Cable type
Capacitance
Where it shows up
Generic shielded RCA (PVC dielectric)
120-250 pF/m
Bargain-bin AV cable. Worst on long runs with MM.
Standard hi-fi interconnect
80-130 pF/m
Mid-tier RCA. Fine for line-level, marginal for MM.
Quality interconnect (PE / PTFE)
50-90 pF/m
Reference audio cable. Headroom on phono.
Tonearm cable (specialist phono)
20-60 pF/m
Designed for cartridge loading.
Studio mic cable (Star-Quad XLR)
35-60 pF/m
Pro audio long runs. Low pF/m is part of the spec.
Coaxial digital (75 Ω S/PDIF)
~67 pF/m
Fixed by the 75 Ω geometry. Not relevant here.
USB cable
N/A (digital)
Irrelevant - bit-stream regenerated by receiver.
FAQ
Cable capacitance and treble roll-off FAQ.
Why phono cable capacitance kills high frequencies, what specifications to look for, and when it stops mattering.
Why does cable capacitance matter for phono cartridges?
Moving-magnet (MM) phono cartridges are spec'd for a specific load capacitance (typically 100-300 pF including the phono cable). High-capacitance RCA runs push the resonant peak below the audible band, killing treble. The calculator finds where the -3 dB roll-off lands for your cable length and source impedance.
What is a safe cable capacitance for line-level RCA runs?
Below ~150 pF total for short (<1 m) runs is fine for any modern source. Long runs (3-5 m) start to need lower-capacitance cable: aim for under 30 pF/foot to keep the -3 dB point above 30 kHz. The calculator shows the actual roll-off curve based on your numbers.
How do I find my cable capacitance specification?
It is usually printed on the cable jacket or in the manufacturer datasheet, listed as picofarads per foot or per meter. Generic RCA cables are 30-50 pF/ft; high-capacitance cables can be 80+ pF/ft; specialty low-capacitance cables for phono use are 15-25 pF/ft.
Can cable capacitance affect digital signals like USB or HDMI?
Practically no for properly impedance-matched digital interfaces. The issue is reflection and ringing, not roll-off, and modern receivers re-clock the bitstream. The calculator targets analog applications where capacitance combines with source impedance to form a low-pass filter in the audio band.
What is the right cable capacitance for an Ortofon 2M Blue?
Ortofon recommends 150-300 pF total loading for the 2M series. Subtract your phono stage's input capacitance (often 100-220 pF) and the remaining 50-200 pF is your cable budget. A 1 m run at 50 pF/m is comfortable; a 1.5 m run at 100 pF/m gets close to the upper limit. The calculator shows total loading and where the -3 dB falls.
My phono stage hums and the treble is rolled off, is it the cable?
Hum is grounding, not capacitance. Check the ground wire to the phono stage chassis and the tonearm grounding scheme. A rolled-off treble that the calculator predicts (below 12 kHz -3 dB) is a capacitance issue; swap to a lower-pF/m cable or use a phono stage with selectable input capacitance (Pro-Ject Phono Box S2 and similar). Both fixes are usually free or under $200.
