DI & Reamp Guide

Recording a DI'd signal and reamping it later are two ends of the same chain. Tap what you've got.

⚡ What are you plugging in?

Passive guitar

single-coil / humbucker

Active guitar

EMG / onboard preamp

Passive bass

Active bass

EMG / onboard preamp

Pedalboard, buffered

has an active/buffer pedal

Pedalboard, true-bypass

everything true-bypass

Keyboard / synth

line out

Acoustic w/ piezo

Amp speaker out

re-amp send

Passive vs active - which type?

Passive DI - use when:

Source is already strong and low-impedance (active pickups, line-level gear). Need transformer isolation for ground loops. No phantom power around - passive needs none.

Best for: active basses, keyboards, live splitting. Jensen-transformer passives (Radial J48 passive, Whirlwind IMP-2) are the gold standard.

Active DI - use when:

Source is high-impedance and low-output (passive guitar/bass, piezo). Long cable runs need buffering. A passive DI is loading the source and dulling the tone.

Best for: passive guitar/bass, piezo acoustic, long stage runs. Radial J48 (active), Rupert Neve RNDI.

Impedance reference

Source	Output impedance	DI input needs
Passive guitar pickup (humbucker)	~7-15 kΩ	≥1 MΩ input (active DI recommended)
Passive bass pickup	~5-20 kΩ	≥500 kΩ input (active DI)
Active bass / EMG pickup	~100-1000 Ω	10-50 kΩ is fine (passive DI works)
Keyboard / synth line out	~100-600 Ω	10-50 kΩ (passive DI works well)
Amp speaker out (re-amp send)	~4-16 Ω (speaker)	Use a load box - don't DI a speaker output directly
Piezo pickup (acoustic guitar)	1-10 MΩ	10 MΩ+ input needed - specialized piezo preamp or Fishman-style buffer

Ground loop fix

Ground loops cause 60 Hz (US) or 50 Hz (EU) hum - the same signal traveling through two ground paths at slightly different potentials.
The transformer in a passive DI breaks the loop by coupling the signal magnetically instead of connecting the grounds electrically.
Still humming after the DI? Check the ground lift switch (lifts pin 1 of the XLR). Try both ways - one will hum, one won't.
Don't use ground lifts as a default. A lift in the wrong place floats the chassis ground and creates a shock hazard.

Common use cases

Passive guitar → recording interface

Use the interface's Hi-Z input directly, or an active DI. Skip a passive DI here - it loads the pickups and kills the top end.

Bass → FOH + monitor split

Passive DI with a Jensen transformer. XLR to FOH, thru to amp, second XLR to monitor world. Handles the split without level loss or ground issues.

Keyboard → two console inputs

Passive DI or Y-cable. The DI adds isolation and prevents a ground loop if keys are on a different power circuit from the console.

Amp speaker out → interface

Never connect a speaker output to an interface input. Use a proper load box (Two Notes Torpedo, Rivera RockCrusher) with a DI out, or mic the cab instead.

⚡ What will you send the signal back through?

Dedicated reamp box

Radial ProRMP, X-Amp, Lehle…

Passive hum box / isolator

Pyle PHE400, ART DTI…

Passive DI box

run it in reverse

Active DI box

e.g. Behringer DI800

Interface reamp output

Apollo, SSL 2+…

Spare line output

no dedicated gear

Why a plain interface output sounds wrong

Interface line out is ~24 dB too loud and the wrong impedance - tone goes dull, compressed, no attack.

Guitar pickup~-20 dBu · high-Z

Interface line out+4 dBu · low-Z (~100 Ω)

Reamp box output~-20 dBu · ~10-50 kΩ

How a reamp box fixes it

A reamp box (or a passive DI in reverse) uses a Jensen-style transformer to:
• Step impedance up from ~100 Ω to ~200 kΩ, closer to what pickups expect
• Attenuate line level (~+4 dBu) down to instrument level (~-20 dBu)
• Provide electrical isolation to break ground loops

Signal levels reference

Guitar pickup output (passive humbucker)~-30 to -20 dBu

Guitar pickup output (active EMG)~-10 to -5 dBu

Interface line output (balanced)+4 dBu

Interface line output (unbalanced consumer)-10 dBV (~-7.8 dBu)

Reamp box output (line in → instrument out)~-20 to -15 dBu

Amp instrument input impedance~500 kΩ - 1 MΩ

Interface output impedance~50 - 200 Ω

Reamp box output impedance~10 - 50 kΩ

Recording the DI for reamping

Raw signal, dry, peaking at -12 dBFS. Everything else causes problems when you reamp.

Pre-FX only

Instrument input on the interface, before pedals. Raw pickup signal, nothing printed on it.

Level

Peak ~-12 dBFS Too hot clips. Too quiet hits the noise floor when you crank the reamp send.

No time FX

Delay/reverb on the DI gets reamped and doubled. Record dry, add FX in the mix.

Phase

Tracked DI + mic together? Align phase before the reamp session. Saves headaches.

Complete signal chain diagrams

Instrument → DI Box → Interface (XLR) → DAW track (dry)

reamp later

DAW track → Interface line out → Reamp Box → Amp input → Mic → Interface

The DI track is your safety net. Record it clean, reamp when the song is done.