Some situations may require connecting your microphone(s) to a guitar or bass amplifier. you could be in a makeshift space without a PA system or looking to add crunchy distortion (and other effects) to your voice.
how do we connect a microphone to a guitar or bass amplifier? To connect a mic to a guitar/bass amp, we need to fit the mic cable to a ts (tip-sleeve) connector and insert the ts into the amp input. note that trs would also work but it’s not the ideal connection. if you use an active microphone, make sure there is an in-line power supply between the microphone and the amplifier.
In this article, we’ll go over the cable adapters or wiring needed to connect a microphone to a guitar or bass amp. we’ll also discuss the issues once a microphone is connected to a guitar or bass amp.
adapt xlr mic cable to 1/4″ ts
Microphones typically have balanced xlr outputs, while guitar amps almost always have unbalanced 1/4″ tip-sleeve inputs.
so, to connect a microphone to a guitar amp, we must have an adapter cable to connect the microphone to the guitar amp.
This adapter requires a female xlr on one end and a 1/4″ ts (or alternatively a trs) on the other end. there are two main adapter styles for this:
- xlrf to ts cable: this is any length cable that has an xlrf on one end and a 1/4″ ts connector on the other.
example: tisino xlrf to 1/4″ ts adapter (link to check price on amazon).
- xlrf to ts adapter: this is a simple adapter that can be attached to the end of a regular xlr cable (at the xlrm end) and adapts the xlr connector to a 1/4 ″ ts socket.
example: tisino xlrf cable to 1/4″ ts 25′ (link to check price on amazon).
With any of these adapters, we can easily connect a microphone to a guitar or bass amp.
for more information on the xlr connector, check out my article why do microphones use xlr cables?
It’s important to note here that an xlrf – 1/4″ tip-ring-sleeve would probably also work, even though the amp’s connector is designed for tip-sleeve.
This is because the microphones send balanced mono audio. As long as the tips and sleeves of the connections connect, there should be no problem. the ring of the trs connector would be canceled in the ts connector of the amplifier.
providing power for active microphones
connecting a microphone to a guitar amp is one thing. having a signal transfer from the microphone to the amplifier is another.
with passive microphones (moving coil dynamics and most ribbon dynamics), the signal is transferred without the need for external power.
Active microphones (all condensers and some ribbon microphones), on the other hand, require external power. this power is usually provided by a dc bias voltage, phantom power, or an external power supply, neither of which is provided by a guitar amplifier.
so how do we power active microphones that are connected to a guitar amp? we must provide the necessary energy by other means.
Note that tube mics often have external power supplies and can easily be plugged into and output to guitar amps as long as they are powered.
For phantom powered or DC biased microphones, we need to find alternative ways to supply the necessary power. external power supplies are easy ways to apply the necessary voltage to these microphones.
for phantom powered mics, check out the new 1 channel phantom power supply (link to check price on amazon).
As for DC bias microphones, most of them are lavalier microphones that plug into and are powered by wireless transmitters.
To connect a wireless microphone to a guitar amp, set up the wireless system, and then match the output of the wireless receiver to connect to the guitar amp.
for more information on wireless microphones, check out my article how do wireless microphones work?
For more information on proper microphone power, see the following articles on new microphones:• Do microphones need power to work properly?• Do microphones need phantom power? to work properly?
mic signals in guitar and bass amplifiers
Guitar and bass amplifiers typically receive electric guitar or bass audio signals. microphones also output audio signals, although there are some notable differences, including:
- frequency response
- balanced/unbalanced levels
frequency response is limited in an amplifier
guitar and bass amps/cabines do not produce sound across the entire audible sound spectrum from 20hz to 20,000hz.
generally they only produce up to about 6khz. bass cabinets are capable of producing lower sounds (below 40hz), while guitar amps typically have a higher low cut.
A typical microphone will have a much wider frequency response than that. therefore, a guitar/bass amp will not reproduce a microphone signal as accurately as possible.
For more information on frequency response, see my article complete guide to frequency response of microphones (with microphone examples).
balanced microphone output – unbalanced amplifier input
xlr mics output balanced audio while guitar/bass amps have unbalanced (ts) inputs. the adapters mentioned above will take care of changing the audio from balanced to unbalanced.
As discussed above, it’s generally fine to connect a balanced trs plug to an unbalanced ts plug, so it’s no big deal if the adapter is an xlrf to 1/4″ trs.
That said, I wouldn’t recommend fitting the mic signal into an unbalanced cable connecting it to the amp. long unbalanced cables are susceptible to electromagnetic interference and can cause unnecessary signal degradation.
For more information on balanced and unbalanced signals, see my article Do microphones output balanced or unbalanced audio?
additional gain (amp expects instrument level, not mic level)
Another distinction to make between the typical microphone output and the expected amplifier input is the signal level.
Microphone signals are generally weaker than instrument level signals (guitar and bass pickups, etc.). therefore, more amplifier gain would be required to drive the signal at the same volume.
for more information on microphone gain, see my article what is microphone gain and how does it affect microphone signals?
For more information on mic and instrument levels, see my article Do microphones output mic, line, or instrument level signals?
connect a microphone to pedalboards and guitar effects pedals
Guitars and basses often go through effects pedals before being connected to their respective amplifiers. microphones can also be connected to pedals and pedal boards before connecting to an amplifier.
Guitar and bass pedals typically have 1/4″ tip and sleeve connectors, as do guitar/bass amps.
To connect a regular xlr microphone to a guitar pedal, follow the instructions above for connecting a microphone to an amplifier. all you need is an xlrf – 1/4″ ts adapter!
a note about comments
Like any speaker, a guitar/bass amp/cabinet will be prone to microphone feedback (when a microphone is plugged in).
To avoid feedback, keep the amplifier gain below the gain-before-feedback threshold while trying to distance the microphone from the cabinet, and point the microphone away from the cabinet.
For a more in-depth reading of microphone feedback, check out my article 12 Methods to Prevent & eliminates microphone/audio feedback.
why put a microphone in front of an amplifier? In recording situations, placing a microphone in front of a guitar or bass amp will record a strong, isolated audio signal from the amp. In live situations, placing a microphone in front of an amplifier will help reinforce the amplifier’s sound by allowing its sound to be projected by the public address system and not just the amplifier’s speaker.
To read about my recommended microphones for miking amplifiers, click on the links below.• best bass cabinet microphones• best cabinet microphones electric guitar (live)• best microphones for electric guitar cabinets (studio)
what do you connect a microphone to? Although microphones can be connected to any type of audio input (with the appropriate adapter cables), they are usually connected to microphone inputs with microphone preamps. These inputs/preamplifiers provide the necessary gain to bring the mic level signal down to line level for use with other audio equipment.
For a detailed description of the microphone jacks and connections, see my article what do microphones plug into? (complete list of microphone connections).