March Audio HPA1

[Dialectic]

I've had in my possession for a few days the March Audio HPA1 headphone amplifier, designed by our own @BE718. It's a simple device, powered by a wall wart, with two balanced TRS inputs and a headphone jack. There is, by design, no volume control. To minimize distortion, the user is to control the volume digitally, with a DAC or in software.

Since Amir's measurements demonstrated the inadequacy of my Mytek 192 DSD's headphone amplifier for driving difficult loads like the HifiMan HE560, I've been on the lookout for a headphone amplifier that is simple and powerful. I also do not want a cheap potentiometer in the signal path.

I did some listening tests, using the Mytek as a DAC with its internal digital volume control. Paired with my HE560s, the HPA1 sounds significantly better than the Mytek's internal headphone amplifier, with which I did a number of A/B comparisons. The HPA1 was clearly more detailed, especially in the low end. Low frequencies also seemed more powerful through the HPA1 than through the Mytek's headphone amp. It clearly has enough grunt to control the HE560s.

Thus, my impression is that the HPA1 is a very well-engineered device. I hope that Amir's measurements confirm my impression.

Is it as good as the THX 789 headphone amplifier on Massdrop? I don't know, as I've never seen or heard the THX amp, and I haven't seen complete measurements of it or the March HPA1.

But the THX amp has a potentiometer, which is a point for the March.

The March HPA1 is an impressive device, and I'll probably buy one when March Audio puts it on the market. I'm now sending it on to Amir for some proper tests.

Many thanks to @BE718 for giving me an opportunity to use the prototype and for bringing to market a product that fulfills my precise need!

 

[March Audio]

Many thanks to Soundargument for testing out the prototype HPA1. As mentioned its off to Amir for some serious abuse testing.

Just one thing to mention, not being entirely satisfied with the enclosure, I am getting a solid milled and anodized unit manufactured.

Some pics of the DAC enclosure, the HPA will be very similar.

 

[derp1n]

Can you tell us a bit about the amp circuit?

 

[March Audio]

HPA1

 

[bakker_be]

Too bad it's Australian, will cost an arm and a leg just to get it to Europe

 

[March Audio]

Well, pretty soon Oz will have an open trade tariff free agreement with the UK and leave Europe behind

 

[March Audio]

Can you tell us a bit about the amp circuit?

Not quite yet. Let's see if Amir's measurements live up to the projected spec. Looking towards a best case scenerio of 118dB THD + N, however I doubt/not expecting the prototype will acheive that. Up to 5 v rms output and say 150 mW into a 32 Ohm load.

It's performance is beyond that of my measurement gear. I measure a THD + N at 107dB

 

[derp1n]

Not quite yet. Let's see if Amir's measurements live up to the projected spec. Looking towards 119dB THD + N, up to 5 v rms output and say 150 mW into a 32 Ohm load.

It's performance is beyond that of my measurement gear.

What about 300 Ohm?

 

[March Audio]

A quick bit of maths........you are obviously limited by output voltage with higher impedance cans. I make that 1. 5 mW. The classic hd650 is 300 Ohm and sensitivity of 102dB / volt. So they should get to 110dB without any significant distortion from the amp.

I believe Amir has HD650s amongst others, so his findings will be interesting. So far testing has only been with low impedance cans.

 

[Wombat]

Well, pretty soon Oz will have an open trade tariff free agreement with the UK and leave Europe behind

Big deal. Doesn't work for the rest of the big world market.

 

[March Audio]

Big deal. Doesn't work for the rest of the big world market.

I was just poking a bit of fun at Bakker (from Belgium)

 

[Wombat]

I was just poking a bit of fun at Bakker (from Belgium)

Note the face-palm.

 

[Veri]

Interesting design.

 

[bakker_be]

Since both this and the accompanying DAC seem to be nearing production, how about some info on pricing

 

[Blumlein 88]

I received these two items from Amir a few days ago. I can attest both the DAC and headphone amp are really good. For those wondering about high impedance phones I have some of the old DT880 Pro phones which are 250 ohm. These aren't the hardest to drive phones, but usually don't sound good without an amp. The March headphone amp does a excellent job of powering these.

Pricing info would be nice, but I'm not sure how far along things are yet.

 

[March Audio]

Since both this and the accompanying DAC seem to be nearing production, how about some info on pricing

I need to check out the quality of the enclosures first before I can make an announcement. Assuming they are OK I can be confident about the BOM cost. So soon

What I will say is I won't be trying to compete with the cheap end Chinese, but it will be competitive for the level of performance.

 

[bakker_be]

Since the review for the THX-amp is out and your comment on being competitive with it, power rating excepted, how about some pricing indication? Given that both devices would need to be imported into Belgium tax tariffs would be equal and I'd rather support a "small business" even though it's on the other side of the globe

 

[March Audio]

What's the price of the THX?

 

[bakker_be]

What's the price of the THX?

349.99$ US on Massdrop.

 

[bakker_be]

349.99$ US on Massdrop.

But the drop isn't open at this moment ...