Hi there,
I have started to build a box that I want to use on stage so I can run my own effects. Vocal pedals are too limiting imho. Something like the eventide mixing link or the radial vocoloco, but more simple and not $350+
So mic in > transformer > fx loop > transformer > mic out
I’m wondering: do I need a preamp and not just a transformer? If so, is there a simple/small diy xlr preamp kit that could fit into a small enclosure? I keep wondering what is in an audio interface because it probably costs next to nothing.
Also, is there a specific set of transformers someone could recommend? I took one out of DI box and another one out of an in-line low-high z plug. But after the first run prototype I want to make a better one with any revisions that come to mind. I hope to keep the cost as low as I can but still sounding good.
I’ve seen some very small preamp pcbs on Ali express but not sure if I should but the bullet or if I will run into issues with PSU requirements/complexity.
If you were going to build such a device and wanted to keep it simple, how would you go about it?
I have started to build a box that I want to use on stage so I can run my own effects. Vocal pedals are too limiting imho. Something like the eventide mixing link or the radial vocoloco, but more simple and not $350+
So mic in > transformer > fx loop > transformer > mic out
I’m wondering: do I need a preamp and not just a transformer? If so, is there a simple/small diy xlr preamp kit that could fit into a small enclosure? I keep wondering what is in an audio interface because it probably costs next to nothing.
Also, is there a specific set of transformers someone could recommend? I took one out of DI box and another one out of an in-line low-high z plug. But after the first run prototype I want to make a better one with any revisions that come to mind. I hope to keep the cost as low as I can but still sounding good.
I’ve seen some very small preamp pcbs on Ali express but not sure if I should but the bullet or if I will run into issues with PSU requirements/complexity.
If you were going to build such a device and wanted to keep it simple, how would you go about it?
You can't make an entirely passive and galvanically isolated device because you need to provide phantom power for the mic.
If I were going to make one it would look like mic > mic chip > fx loop > opamp buffer > out. You could probably use 2 Aliexpress boards like an INA217 board and an NE5532 board, and either build phantom power using discrete or even more premade boards. You would need a small number of discrete components to make it all work together.
If I were going to make one it would look like mic > mic chip > fx loop > opamp buffer > out. You could probably use 2 Aliexpress boards like an INA217 board and an NE5532 board, and either build phantom power using discrete or even more premade boards. You would need a small number of discrete components to make it all work together.
Guitar pedals have very little overhead on 9 volts.
So you dont need massive signal gain going in.
Most the gain is still at the mixer.
Most vocal mics are passive so no phantom power.
Other wise for active mics you use a direct box
with phantom power, and then use 1/4" out on
the direct box to the pedals.
Basically what you need if you wanna complicate things
a direct box with balanced or unbalanced out
AKA xlr or 1/4"
otherwise with a normal xlr to 1/4 mic cable
you just go into the effects and done.
been done many times when singers use
guitar pedals and need to turn them on off
on stage and have the effects go to main.
Also a simple mixer with effect send works.
run the pedal chain in the send.
Another way also to include phantom power
is using basic mixer with 1 send to the pedal
chain
So you dont need massive signal gain going in.
Most the gain is still at the mixer.
Most vocal mics are passive so no phantom power.
Other wise for active mics you use a direct box
with phantom power, and then use 1/4" out on
the direct box to the pedals.
Basically what you need if you wanna complicate things
a direct box with balanced or unbalanced out
AKA xlr or 1/4"
otherwise with a normal xlr to 1/4 mic cable
you just go into the effects and done.
been done many times when singers use
guitar pedals and need to turn them on off
on stage and have the effects go to main.
Also a simple mixer with effect send works.
run the pedal chain in the send.
Another way also to include phantom power
is using basic mixer with 1 send to the pedal
chain
isn’t the impedance difference is like 1900 ohms? I don’t think I need phantom power, if I’m using a dynamic mic though, correct? I just want to do it in a way that doesn’t cause any gain staging issues. Even an xlr to TS cable should have a resistor to properly convert. This is what I was taught in audio school anyway. I thought you can’t just go from a balanced dynamic to unbalanced instrument level or give versa, otherwise why would DI boxes be a thing? I know it’s the other way Orin’s but the need should be the same in both directions, no?
I basically want a 2 channel direct box but one of the channels going from low to high. A normal di used in reverse doesn’t attenuate the signal properly. If I just go straight in, the gain needed for a usable signal will introduce a lot of noise.
For posterity and some clarity/background, here’s a list of devices on the market that do low to high z with an fx loop. Most of them are active though and I don’t think that’s necessary. I don’t want to power it unless I need to to keep the signal clean and noise free. I also think there must be a way to throw 2 transformers in a box for a lot less money than even the cheapest $150 options:
$300 Eventide mixing link
$150 Banjolit mic match
$160 Hotone A station
$170 audio technica sick fly vp-01
$230 pigtronix keymaster
$250 Revival Electric Synapse Vocal Effects Integrator V2
$300 Death by audio echo master
$260 Cusack music Petal cracker
$300 Old Blood Noise Endeavors MAW
$300 EAS gigmix 4 (mixer loop trick)
$350 analog alien EPi
$360 Radial vocoloco
$375 HornFX Blow! By Zorg
$390 Colortone Preacher 58
$400+ Meris 440
$500 EBS Stanley Clarke Signature
$585 grace Design Rex
$900 grace design Roxi
For posterity and some clarity/background, here’s a list of devices on the market that do low to high z with an fx loop. Most of them are active though and I don’t think that’s necessary. I don’t want to power it unless I need to to keep the signal clean and noise free. I also think there must be a way to throw 2 transformers in a box for a lot less money than even the cheapest $150 options:
$300 Eventide mixing link
$150 Banjolit mic match
$160 Hotone A station
$170 audio technica sick fly vp-01
$230 pigtronix keymaster
$250 Revival Electric Synapse Vocal Effects Integrator V2
$300 Death by audio echo master
$260 Cusack music Petal cracker
$300 Old Blood Noise Endeavors MAW
$300 EAS gigmix 4 (mixer loop trick)
$350 analog alien EPi
$360 Radial vocoloco
$375 HornFX Blow! By Zorg
$390 Colortone Preacher 58
$400+ Meris 440
$500 EBS Stanley Clarke Signature
$585 grace Design Rex
$900 grace design Roxi
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Electric guitars have a rather high impedance, especially at high audio frequencies, so a guitar effect pedal should be noise-optimized for a high source impedance. Its equivalent input noise voltage is then probably far above the 2 nV/√Hz or so thermal noise of a dynamic microphone.
I have no idea if it is bad enough to be a problem, but technically you need either a step-up transformer or a microphone preamplifier to get a good noise match. In either case, that will reduce headroom.
According to https://www.diyaudio.com/community/...pping-in-solid-state-e-guitar-preamps.391513/ electric guitars can easily produce levels of 500 mV peak-peak. You need about 133 dB SPL to get that out of a typical 2 mV/Pa dynamic microphone, so I guess you can live with some headroom reduction.
I have no idea if it is bad enough to be a problem, but technically you need either a step-up transformer or a microphone preamplifier to get a good noise match. In either case, that will reduce headroom.
According to https://www.diyaudio.com/community/...pping-in-solid-state-e-guitar-preamps.391513/ electric guitars can easily produce levels of 500 mV peak-peak. You need about 133 dB SPL to get that out of a typical 2 mV/Pa dynamic microphone, so I guess you can live with some headroom reduction.
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All in all it works out well because yes the impedance for guitar pedals is more than suitable
for dynamic microphone.
And the pedals have realistically less than 9 volts overhead.
So most gain is applied after the pedals.
Mic, pedals, pre
You could use a small mixer with effect send.
Having done many times, you quickly learn
that pedals wont take to much gain
and would have to be careful with send levels.
all in all way easier to go xlr to 1/4 then straight
to the pedals and never worry about gain.
You just set levels with the mixer like you normally
do with straight microphone.
for dynamic microphone.
And the pedals have realistically less than 9 volts overhead.
So most gain is applied after the pedals.
Mic, pedals, pre
You could use a small mixer with effect send.
Having done many times, you quickly learn
that pedals wont take to much gain
and would have to be careful with send levels.
all in all way easier to go xlr to 1/4 then straight
to the pedals and never worry about gain.
You just set levels with the mixer like you normally
do with straight microphone.
A dynamic microphone behaves as a floating source between XLR pins 2 and 3, so you can simply convert a dynamic microphone's signal to unbalanced form by connecting both the shield (XLR pin 1) and the negative side (XLR pin 3) to ground, preferably at the receiving side, so in the TS connector. We did that all the time at the local radio station here, when connecting MD-21 microphones to reporting equipment with unbalanced microphone inputs. Putting a resistor in the cable will only increase noise.
The more complicated options with transformers, microphone preamplifiers or mixers used as microphone preamplifiers have the advantage of a lower noise floor and the disadvantage of less headroom.
Yeah, XLR to 1/4
Just that easy.
Did same thing back in the day
Needed different effects.
Used pitch Shifter , Flanger and Delay
Digitech shifter, Boss for the Delay Effects.
Used EV microphones.
Way more clarity, dont feedback
much stronger signal than typical garbage 58's
As mentioned if you apply gain as usual with a
mixer then use effect sends. Guitar pedals
especially delays distort.
With the mic straight into the pedals no problem.
The effects out to mixer channel and apply gain as usual.
XLR to 1/4 cable = all done
Just that easy.
Did same thing back in the day
Needed different effects.
Used pitch Shifter , Flanger and Delay
Digitech shifter, Boss for the Delay Effects.
Used EV microphones.
Way more clarity, dont feedback
much stronger signal than typical garbage 58's
As mentioned if you apply gain as usual with a
mixer then use effect sends. Guitar pedals
especially delays distort.
With the mic straight into the pedals no problem.
The effects out to mixer channel and apply gain as usual.
XLR to 1/4 cable = all done
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