Perhaps one preamp didn’t amplify your signal enough to be audible. Or maybe you want to blend the tone of multiple preamps to have a unique. Whatever your reason, can you use two preamps?
You can use two preamps as long as you balance the gain on the preamps to have enough headroom, so the audio signal doesn’t clip or distort. You can either connect the preamps in series or parallel and mix the two tones together. However, keep in mind not to feed phantom power into from the second preamp into the first to avoid damage.
Using multiple preamps is something talked about frequently. There are quite a lot of misconceptions about the idea of combining two or more preamps in a single chain. However, there is totally nothing wrong with using two preamps — if you do it right.
In this article, we’ll learn about the problems associated with using two preamps and how to solve them. And then, we will look at some creative ways to combine the preamps to make the most out of the setup. Now let’s take a look at the reasons to consider using two preamps.
Reasons to Use Two Preamps
Here are some reasons why musicians choose to use two or more preamps
1. To boost the audio signal’s gain
The primary purpose of a preamp is to boost an audio signal from a mic level or instrument level to a line-level signal. Mic and instrument are very low audio signals; you can barely hear them without any form of amplification. This is where the preamp comes in.
But sometimes the signal is too weak; one preamp is not enough to boost the signal’s gain. For this reason, adding another preamp in the signal chain is an excellent way to boost the gain of the signal before it gets to the power amp or audio interface.
This is not too common, but it happens once in a while when you are recording an instrument such as an acoustic guitar with a microphone. However, caution must be taken when using two preamps to boost microphone signals, and I’m going to talk about the possible problems later in the article.
2. To have a unique tone
Although the main function of a preamp is to boost a low-level audio signal to a high-level signal, it’s no news that preamps add a certain color to the audio signal after processing.
Some preamps give a cleaner tone to the audio signal processed through it. Others give it some dirt and grittiness.
Electric guitarists, especially, love the color some preamps give to their guitar tone. Combining two or more preamps gives a much unique tone because you are combining multiple “colors” to your sound.
Problems with Using 2 Preamps
Here are some issues you may encounter with using two preamps.
1. Increased noise floor
Noise floor is essentially the level of background noise in a recording. The noise in a recording may be due to your home or studio’s HVAC system, refrigerator, noise from outdoors, faulty audio cable, or even the microphone or the preamp itself. Noise is undesirable in any recording, and we want to keep it as low as possible.
However, by using two preamps, you amplify the noise as much as the actual signal, and this increases the noise floor. This can be very problematic in situations where you need the lowest possible noise in your recording.
This is a problem that can be fixed with the right gear and recording technique. If there is no noise going through the preamp in the first place, there wouldn’t be any noise to amplify.
To reduce the noise floor in your recording, it is advisable to record in a soundproof space. Also, I recommend using a balanced cable that is in good condition. Balanced cables prevent radio interference and send a cleaner signal to the preamps.
I wouldn’t worry too much about noise from the preamp unless you are using an old preamp made in the r early 2000’s or older. That’s because even budget preamps made recently are relatively quiet and have a very low level of noise.
2. Signal Distortion
Another issue you can encounter with using two preamps is your audio signal can distort.
If the gain is set high on both preamps, the first preamp will send a “hot” line-level signal into the second preamp, and the second preamp will boost the signal even more. The signal will surpass the maximum allowable limit of amplification, and your signal will begin to distort or clip. This will drastically reduce the quality of your audio.
You certainly don’t want this to happen, unless you are doing it on purpose to have an overdrive effect on your signal.
Distortion can be easily prevented when using two preamps by turning down the gain on both preamps. Reduce the gain on preamps simultaneously till there is enough headroom for your signal.
The Different Ways to Connect Two Preamps
This is, by far, the most common way to connect two preamps.
Connecting your preamps in series means the first preamp’s output will be connected to the second preamp’s input.
In essence, you will plug your microphone, guitar, or any instrument into the first preamp. The first preamp will amplify the audio signal from the mic or instrument. After the preamplification, the signal will be sent out from the first preamp through the Line-Out into the input of your second preamp. The second preamp will also process the signal, and then you will get the final output signal out of the second preamp’s Line-Out. I think this is a very simple concept to understand.
As I mentioned earlier, you want to keep the gain on the two preamps at low levels to prevent signal clipping and distortion.
However, you can get creative with the gain. What do I mean by this?
You can create a unique tone for the signal by experimenting with the two preamps’ gain levels.
For instance, let’s say the first preamp boosts the mid-range frequencies a little, and the second preamp adds a little bit of distortion to the audio signal. So, if you want more boost in the mid-range frequencies over the distortion, then turn up the gain of the first preamp, and reduce the gain on the second preamp. If you prefer more distortion over the mid-range frequency boost, then turn down the gain on the first preamp and turn up the second preamp.
At this point, it’s all about experimenting with different gain levels to get a color that sounds good to you. Just keep in mind not to over-amplify the signal.
You can really get unique results by connecting your preamps in parallel. You will need a bit more gear and cables to do this, but it gives you more flexibility. Also, there is a slim chance of increasing the noise floor or distorting the signal. Here is a summary of how to do it.
First, connect your mic or instrument to an audio splitter device. The splitter will duplicate the signal from the mic or instrument and transmit it through two output jacks.
Now connect one output to each preamp. This means the same signal will be processed separately by the preamps.
And then, connect the Line-Outs of both preamps in a multiple channel mixer. You can now mix both signals in the mixer however you want to get that unique color you need. Once that’s done, send the mixer outs to your power amp or audio interface.
Alternatively, you can connect the two preamps directly to your audio interface or power amp if it has multiple inputs, without the need for a mixer.
For guitar and bass players, I recommend Lehle P-Split III Splitter (on Amazon). This is an excellent high impedance splitter, meaning you can connect a passive guitar or bass directly, and they will work just fine. It has a phase switch to help prevent phasing issues with the doubled signal. This splitter is also made to work with both balanced and unbalanced signals.
If you are recording a microphone and want to use two preamps, the Whirlwind Splitter 1×2 (Amazon) is a good microphone signal splitter for a couple of reasons.
First, you can feed phantom power through the splitter into your condenser microphone from one of the preamps. It also sends a clear signal to your preamps with virtually no hum or hisses in your signal.
Can you run phantom power into preamp?
If you connect two preamps in series, never run phantom power from the second preamp into the first preamp. This will damage the first preamp in no time.
Turn on the phantom power on the first mic preamp to power the microphone and then turn off the second preamp’s phantom power.
You can use two preamps to give your audio signal a different character or boost the audio signal. However, you have to make sure the gain on the preamps is at the right level to prevent the signal from clipping or distorting.
You can also connect the preamps in series or parallel to have total control on the overall sound.