The I/70 is an integrated amplifier by Audio Research that delivers 70 watts x 2 channels continuous from 20 Hz to 20 kHz, typically 1% THD at 1 kHz and below 0.1% at 1 watt. It was released in 2021. It is a 2-channel design using a Class A/B output stage. The I/70 is an all-valve design, running 4x KT120 output, 3x 6922 (one input, two driver) input. Biasing is Auto-bias. Speakers connect via binding posts. Its output transformer offers 4 / 8 ohm taps, and matching the tap to your speaker's impedance matters more here than a minimum-load figure would on a solid-state amplifier. The Audio Research I/70 has an MSRP of $9,950.
Performance Specs
One of the most important factors when deciding on an integrated amplifier is its power ratings and compatibility with your speaker's impedance requirements. The Audio Research I/70 is rated at 70 watts RMS into 8-ohms.
Here are the main highlights of its performance specs:
- 70 watts into 8-ohms (7 Hz-30 kHz)
- 4 / 8 ohm output transformer taps - match the tap to your speaker's impedance
How loud will 70 watts actually play in your room? →
Which speakers suit the Audio Research I/70?
70 W into 8 ohms.
We rank every passive speaker we cover against it on power, impedance safety and current
delivery.
Need more power?
Audio Research I/70 is rated at 70 watts into 8 ohms, which puts it in our 61 to 90 watts band. The next band up is 91 to 120 watts, which is worth about 1.5dB more output. That is a real difference in headroom on peaks, and a modest one in how loud the system plays - power and loudness are not the same thing.
Before buying watts, check what your speakers actually need: the amp and speaker matcher works it out from their sensitivity, impedance and your room. Plenty of systems are better served by the Up to 60 watts band and better speakers.
When pairing the Audio Research I/70 with a passive Bookshelf (Stand mount) or Passive Floor Standing (Tower) speaker, you have to check if their Max Power Range is below the max wattage of the amp for the given impedance levels.
Operating your amp outside of this max range may damage the speakers.
What size of room is the Audio Research I/70 Amplifier good for?
An essential deciding factor is the size of the room in which you intend to employ the Audio Research I/70 amplifier. Here, taking into account its maximum power parameters, we analyzed its applicability to various size environments:
| Listening Environment |
Suitability |
| Near-field | Poor |
| Small Room | Average |
| Mid-size Room | Good |
| Large Room | Average |
| Very Large Room | Poor |
Inputs and Outputs
Besides the performance specs of the Audio Research I/70, the next important feature set that you have to evaluate is the input and output selections that it offers.
Audio Research I/70 has total of 4 Analog inputs .
Inputs
- Total Number of Analog Inputs: 4
Outputs
- Speaker Outputs
- Preamp Outputs
- Yes Headphone Output
Bluetooth Connectivity
Audio Research I/70 doesn't have bluetooth connectivity feature. In order to stream your music via bluetooth, the easiest way is to connect an external bluetooth receiver to your Audio Research I/70. Two bluetooth receivers that we recommend are the
iFi Zen Blue V2 and the
Audioengine B1.
Among the amps in the same price range, these are the 5 amps that have Bluetooth Connectivity:
Phono Input
Audio Research I/70 doesn't have a phono input so in order to play your vinyl albums, Audio Research I/70 has to be paired with a Phono Preamp that is MM (Moving Magnet) or/and MC (Moving COil) depending on your cartridge type.
Audio Research I/70 Pros and Cons
Drawn from the published figures on this page, not from listening.
- ✓70 watts per channel into 8 ohms.
- ✓A valve design running 4x KT120, which is the point of buying one.
- ✓4 analogue inputs, enough for a full rack of sources.
- ✓Pre-outs (Yes) leave room to add a power amplifier or an active subwoofer later.
- ✓Headphone output.
- ✓Made in USA.
- ✗Valves are consumables: they need replacing periodically, and often biasing, which a solid-state amplifier never asks of you.
- ✗Analogue inputs only - a TV, computer or CD transport needs an external DAC.
- ✗No Bluetooth and no network streaming - everything arrives over a cable.
Audio Research I/70 External Dimensions and Weight
Audio Research I/70 has external dimensions of (H x W x D) 8-1/4 x 16-9/16 x 13-3/8 inch (210 x 420 x 340 mm ). The unit weighs
24.95 kg (55 lbs).
Base Surface Area
Base surface area of an integrated amplifier may become an important decision factor when the space in your room or desk is limited.
The base area of the Audio Research I/70 is approximately 1428.0cm2 / 221.3inch2.
- Width: 420.0mm (16-9/16")
- Height: 210.0mm (8-1/4")
- Depth: 340.0mm (13-3/8")
- Weight: 24.95 kg (55 lbs)
- Base Surface Area: ~1428.0cm2 / 221.3inch2
- Volume: ~30.0 liter / 7.9 gallon
Available colors
Audio Research I/70 is available in Black and Silver color options.
| General |
| Brand |
Audio Research |
| Full Model Name |
Audio Research I/70 |
| Release Date |
2021 |
| Amplifier Type |
Integrated Amplifier |
| Number of Channels |
2 |
| Amp Class |
Class A/B |
| Amplifier Technology |
Tube |
| Tubes |
| Output Tubes | 4x KT120 |
| Input and Driver Tubes | 3x 6922 (one input, two driver) |
| Total Tube Count | 7 |
| Topology | Push-pull |
| Biasing | Auto-bias |
| Output Transformer Taps | 4 / 8 ohm |
| Performance |
| Watts RMS per Channel into 8-ohms |
70 watts |
| Watts RMS per Channel into 6-ohms |
N/A |
| Watts RMS per Channel into 4-ohms |
N/A |
| Frequency Bandwidth |
7 Hz-30 kHz |
| THD |
|
| Minimum Impedance |
|
| Signal to Noise Ratio |
N/A |
| Digital Music |
| Built-in DAC |
No |
| Bluetooth |
No |
| WiFi |
No |
| CONNECTIONS |
| Total Analog Inputs |
4 |
| Phono Input |
No |
| Preamp Outputs |
Yes |
| Headphone Output |
Yes |
| Removable Power Cord |
|
| Speaker Connectors |
Binding posts |
| PHYSICAL SPECS |
| Height |
210.0mm (8-1/4") |
| Width |
420.0mm (16-9/16") |
| Depth |
340.0mm (13-3/8") |
| Weight |
24.95 kg (55 lbs) |
| Available Colors |
Black,Silver |
| OTHER |
| Parts Warranty |
|
| Labor Warranty |
|
How much power does the Audio Research I/70 have?
The Audio Research I/70 delivers 70 watts x 2 channels continuous from 20 Hz to 20 kHz, typically 1% THD at 1 kHz and below 0.1% at 1 watt.
Does the Audio Research I/70 use vacuum tubes?
Yes. The Audio Research I/70 is an all-valve amplifier: vacuum tubes do the amplifying from input to output. It runs 4x KT120 output, 3x 6922 (one input, two driver) input.
Does the Audio Research I/70 need biasing?
Biasing is Auto-bias. That means the amplifier sets the operating point of each output valve itself, so there is nothing to adjust and nothing to measure - you can change tubes without a meter or a screwdriver.
How long do the tubes in the Audio Research I/70 last?
Output valves are a consumable. In normal domestic use a set lasts somewhere between about 2,000 and 5,000 hours - a few years for most people - and they degrade gradually rather than failing outright. Input and driver valves last far longer, often the life of the amplifier. Check the warranty card before you buy: valves are almost never covered by the amplifier's own parts warranty, and are usually warranted separately for 90 days to a year.
What speakers suit the Audio Research I/70?
A valve amplifier is judged on the speaker's sensitivity, not just on watts. At 70 watts, the safe rule of thumb is a speaker of about 88 dB or better - an insensitive speaker will run out of headroom long before the amplifier sounds bad. It also has 4 / 8 ohm output transformer taps. A valve amplifier has no minimum impedance the way a transistor amplifier does; you match the tap to the speaker, and a speaker whose impedance swings a long way will shift the tonal balance slightly because a valve amplifier follows that curve.
What amplifier class is the Audio Research I/70?
The Audio Research I/70 uses a Class A/B amplifier design. Class A/B is the traditional linear design: it runs warmer and is less efficient than Class D, but it is long valued for its natural, low-distortion sound.
Does the Audio Research I/70 have a built-in DAC?
No. The Audio Research I/70 has no built-in DAC, so a digital source such as a streamer or CD transport needs its own converter, or you connect it over analogue.
Can I connect a turntable to the Audio Research I/70?
No. The Audio Research I/70 has no phono input, so a turntable needs an external phono preamp (or a deck with one built in) before it can be connected.
Does the Audio Research I/70 have Bluetooth?
No. The Audio Research I/70 does not have Bluetooth built in; you would need an external Bluetooth receiver connected to one of its inputs.
Does the Audio Research I/70 have a headphone output?
Yes. The Audio Research I/70 has a Yes-inch headphone output on the front panel for private listening.
How much does the Audio Research I/70 cost?
The Audio Research I/70 has a manufacturer's list price (MSRP) of $9,950.
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