For the longest time the headphone outs on most interfaces were weak and would usually distort as you got close the volume level that you needed. Most manufacturers are hip to this these days so you’ll generally find enough level if you need it, but that doesn’t mean they sound good. This is super important to today’s home studio owner, especially with so much mixing now done on headphones. That’s the best reason to upgrade to a dedicated outboard headphone amplifier, and a good one to check out is Heritage Audio’s new O.H.M. Headphone Matching Amplifier.
Headphone Matching
First of all, it’s called a “Headphone Matching Amplifier” because it matches the output impedance of the amplifier to your headphones. When this is properly matched, not only will you get the most level but the smoothest frequency response as well.
This is accomplished through the Impedance switch on the front which allows you to select before Low (for earbuds), 32, 50, 80, 250 and 600 ohms. While most popular headphones are in the 80 ohm range, some of the higher end phones like Beyers and Sennheisers are usually closer to 600 ohms. This means that the level drops way down when connected to the normal built-in headphone output of an interface because it’s looking for a lower impedance, but you’ll get all the level you need when it’s matched on O.H.M.
Ins And Outs
There are three types of inputs on the unit that are selectable from switches in the middle of the front panel: a Bluetooth input for playback from a phone or tablet (complete with high-end Burr Brown convertors), balanced, and unbalanced. These are fed from the combo XLR/phone inputs, or RCA inputs on the rear of the unit. Each channel also has a Through jack for passing the signal through to another device.
The headphone output jacks on the front panel are either standard ¼ inch or mini-jacks, so you no longer have to worry about finding the right adapter. The level control to the right of the unit uses the high quality Alps “Blue Velvet” potentiometer to eliminate crackling or jumps in the audio level like you get on cheap pots.
All in all, O.H.M is a serious box built to the highest standards for audiophile performance. Like I said at the beginning, if you’re mixing on headphones, then you owe it to your mixes to be able to hear the smallest details, and a super-high-quality headphone amplifier is something worth considering.
Heritage Audio O.H.M. Headphone Matching Amplifier retails for $499 and is available from most pro audio dealers.
You can find out more here, or watch the video below.
