Integrated amplifiers conveniently include audio preamps and power amps in one combination unit. They simplify the process of audio playback and remove the need for separate preamps and power amps.
Can I use an integrated amp as a power amp?
In the vast majority of cases, the HT bypass input can be used to skip the preamp section. The integrated amp then acts exclusively as a power amplifier and can be used with an external preamp. This does however depend on the specifics of the integrated amp.
Due to the variety of integrated amplifiers available, you may need to use alternative methods to use the device solely as a power amp.
If you’ve acquired, or are considering getting a standalone preamp to use with your audio system, then using the integrated amp as a power amp will do the trick. However, there are some potential drawbacks.
In this guide, I’ll cover the pros and cons of doing this, and the methods you can use.
How To Use an Integrated Amp as a Power Amp
Although integrated amplifiers contain everything you’ll need to prepare an audio signal for playback, sometimes they have certain limitations.
Preamps are used to prepare the audio for amplification, and they have a large impact on the tonal aspects. That’s why specific preamps exist for vocal mics, electric guitars, and bass guitars. Each preamp colors the signal in its unique way.
This explains why someone may feel the need to bypass the preamp section of their integrated amplifier and use it exclusively as a power amp.
To successfully use an integrated amp as a power amp, it must have specific inputs which facilitate this, These inputs allow you to bypass the integrated preamp and only use the power section of the device.
If your integrated amp has this particular type of input, it is likely to be labeled as ‘HT Bypass Input’, or something along those lines. Without this, you are likely to run into problems when trying to bypass the preamp section of the integrated amp. I’ll discuss these issues in detail in a later section.
If your integrated amp does indeed have an HT bypass input, all you’ll need to do is connect your standalone preamp to it, and then send the output to your monitors or speakers.
This will bypass the integrated preamp and allow the unit to be used solely as a power amplifier.
I have written an article that explains the differences between a headphone amp and a pre amp. You can read it here.
Integrated Amps & Line Inputs
Most integrated amps have line inputs, but not all of them include the specific bypass input I described in the previous paragraphs. The line input can also be used to make the integrated amp function as a power amp, but some additional considerations need to be made.
Line level inputs are designed to receive signals which have a considerably strong output.
They vary from microphone-level signals in terms of voltage, Line level signals are generally in the region of 1.000 volts, or 0dBV, while microphone level signals are around -60dBV (0.001 volts) to -40dBV (0.010 volts).
If your integrated amp doesn’t provide a bypass input which would allow you to use only the power amp section of the device, your other option would be to use the line input in the same way.
The risk when using this type of input is that it is prone to producing a lesser sound quality than a bypass input. This is because the line input is designed to receive a signal with a strong output.
As a result, the volume control on your preamp would need to be set to a very low level when you are using the integrated amp to compensate for the high power of the input.
This is quite inconvenient, as it reduces the headroom you have available to adjust the level of the audio using the preamp.
Impedance mismatches are also likely to occur when using the line-level input to make this connection. This occurs when the input impedance of the input doesn’t match up with the output impedance coming from the preamp.
Despite the aforementioned drawbacks of using the line input to use your integrated amp as a power amp, this method will allow you to use an external preamp. You may experience issues with sound quality and volume, but it will still allow you to successfully achieve your aim.
Separate Preamps & Power Amps
Using an integrated amp provides undeniable convenience and is a cost-effective way to playback audio. Since audio equipment has shifted from being predominantly analog to modern, digital devices, having a separate preamp isn’t as important as it once was.
This video illustrates the benefits and explains how to use an external preamp with your integrated amp.
Despite this, there are still some key benefits that using separate preamps and power amps offers.
Rather than having an all-in-one device, you gain more control by having two individual boxes. The settings and parameters on each device can then be tailored to have a greater impact on the sound of the audio.
- Using the integrated amp as a power amp and combining it with a standalone preamp will afford you more control over the various tonal and dynamic aspects of the audio when it is played back through the monitors.
In addition to improving the audio quality, using a separate preamp and power amp combination is also likely to lessen the amount of internal interference which could mar the audio signal.
This is because the two devices will use their power supplies, rather than both drawing power from the same source, which is the case when using an integrated amp unit that contains both the preamp and power amps within it.
It’s therefore a good idea to use a preamp/power amp separately if you want to maximize the quality of your audio.
If achieving the best listening experience is important to you, relying on an integrated amp to perform both roles may not suffice, unless it is a particularly high-quality device.
Active vs. Passive Preamps
As we’ve established, using your integrated amp as a power amp will allow you to use a standalone preamp of your choice. With so many types of preamps on the market, it can be difficult to know which would get you the results you desire.
Preamps can be narrowed down into two categories – active and passive.
Both are designed to perform the same function, preparing the audio signal for the boost provided by the power amplifier. However, the way they achieve this and their effectiveness at doing so varies considerably.
Using an active preamp with your integrated amp acting as the power amp is perhaps the more reliable choice. These devices are defined by their inner circuitry, which is capable of amplifying line-level voltages over a measure known as ‘unity gain’.
If you’ve never come across the term unity gain before, it simply means the level that the signal is at when it first enters the preamp’s input. It’s common for active preamps to include tone-enhancing mechanisms such as transistors, tubes, or op-amps to increase gain.
Each of these mechanisms causes the sound of the audio to be colored and tonally affected in its way. A tube-based active preamp will add warmth and potentially a little saturation to the signal when it is transmitted to the integrated amp acting solely as the power amp.
To summarize, active preamps offer the following:
- Amplification of line-level signals
- Inclusion of transistors, op-amps, or tubes for gain
- Coloration of tone
Alternatively, you could choose to use a passive preamp with your integrated amp device. The simple difference between these preamps and the active variety I just described, is that they do not contain gain-producing devices such as tubes, transistors, or op-amps.
Consequently, passive preamps have less of an impact on the coloration and tonal characteristics of the audio signal before it is sent to the input of the power amp.
Commonly, passive preamps contain impedance matching devices that ensure that they run smoothly, such as specially designed transformers. One of the downsides of these devices is that they are incapable of amplifying a line-level signal. Here’s a summary of passive preamps:
- No gain-producing devices
- Often include transformers for impedance matching
- Less impact on tone & coloration
- Cannot amplify line-level signals
Can a preamp be used as a power amp?
Although preamps and power amps perform very similar roles, there is one key difference that prevents them from being interchangeable. Preamps give the weak signal a boost to reach line level, which power amps provide further amplification for playback.
Do receivers have built in amplifiers?
Stereo receivers commonly include a pair of built-in amplifiers. These devices facilitate dual-channel speaker configuration, which allows different audio to be played back through the left and right speakers.
Do I need a standalone DAC to use with my integrated amp?
Using a standalone DAC can sometimes be beneficial, but all integrated amps already have one built-in. If this device isn’t up to standard, it may affect the performance of the unit, but most DACs perform the same function.