Tom Christiansen Audio HPA-1 Update

JLM · « **Reply #20 on:** 10 Feb 2020, 04:51 pm »

Understood, but why not offer a balanced output too? Maybe the inside/front panel is too small?

adydula · « **Reply #21 on:** 10 Feb 2020, 07:33 pm »

JLM thats a good question, I dont have an answer but I did send Tom a PM.

mresseguie · « **Reply #22 on:** 11 Feb 2020, 01:00 am »

So I'm gonna 'spill my own beans' so to speak.

A few months ago when I decided I just had to try Tom's new HPA-1, I knew that it would ship while I was over-wintering in Taiwan. Well, rather than asking Tom to hold it for a couple months, I came up with a wild scheme to host a small tour with my new, never heard HPA-1 as the star attraction. I contacted 8 or 9 AC or AN members to see who was interested in taking part in a mini-tour. Once I had succeeded in ~~conning~~...er...persuading 5 or 6 to take part, I informed Tom of my plan. He was delighted to help out.

In the next few weeks, you can expect to read a number of fellow audiophools' impressions of this headphone amp in their respective systems. My HPA-1 is currently burning in at mcgsxr's home. Perhaps, he'll post his impressions soon?

Michael

mcgsxr · « **Reply #23 on:** 11 Feb 2020, 01:05 pm »

I received the unit late last week and let Tom and mresseguie know it had arrived safely.

My first mistake! Now I’ll never be able to steal this lovely unit and disappear into the Net.

I felt really special getting to participate in this tour and receive the unit first.

Pics below don’t do the packaging and presentation justice. This feels really well cared for in terms of how it was packed (great styrofoam cut outs, double boxed etc) with care. The volume pot alone makes me want to steal this. It’s so smooth in operation and a cinch to nail the right volume.

I plugged it into a Bolder power cable and into my modified Grant Fidelity TubeDAC-11 via Bolder Nitro IC’s. then a 1/4 adapter and my Noble iems. The Nobles are likely not the ideal match but don’t tell the TPA amp that.

Right out of the box it sounds really nice. Richness and PRAT to spare. The soundstage surprised me. My exposure to phones and amps in the past had not delivered much of that. Makes me wish I still had my Senn’s or Grado full size cans to see how it drives them, but at the moment I’m down to just iems for phones.

I’ll pass it along next week (please remind me who is next) and look forward to what others think. I threw in a set of isolation feet for mresseguie to thank him for the generous offer to play around with his new toy!

Pics of the unboxing below.

adydula · « **Reply #24 on:** 11 Feb 2020, 03:32 pm »

Awesome!

Please let us know what you think!

Freo-1 · « **Reply #25 on:** 11 Feb 2020, 04:52 pm »

Looks like a quality product. Should be an enjoyable experience to review.

adydula · « **Reply #26 on:** 11 Feb 2020, 06:56 pm »

I think we all know measurements arent everything in this "hobby" but the design specs for Tom's amp are nothing short of spectacular.

That said the THX AAA amps are spectacular in measurements as well...

That said Schiit's new Magni 3 Heresey has spectacular measurments as well....

Having so many amps here, there are differences, but realistically the diffrenences are subtle at best when you get down these very
low diminishing tolerances...

Its a really great time in headphone and audio in general for many stellar choices, that are affordable as well!

Alex

tomchr · « **Reply #27 on:** 11 Feb 2020, 10:47 pm »

The HPA-1 is now in stock and shipping. The first batch of orders shipped about 10 days ago and the amps have started to arrive in the various destinations. One of these days I should send out a newsletter saying, "hey... buy my stuff..." I've been busy with the Florida Audio Expo and with assembling and shipping the amps.

Quote from: JLM on 10 Feb 2020, 03:47 pm

Another product that has balanced on one side (input/output) and single ended on the other. What's up with that?

The reason is pretty straight-forward, actually: There is no real meaningful technical advantage of the balanced or 4-pin output. Yes, you do get rid of the few mΩ of shared ground impedance in the 1/4" plug, and, yes, that does improve the channel separation slightly. But that's it. The channel separation in the HPA-1 with the 1/4" output is about 100 dB. With a 4-pin output (balanced or not), you could possibly improve that to 110-115 dB. That sounds dramatic, but both are way below audible, so the difference is honestly only of academic interest.

The other reason is that I cannot fit another connector on the front panel of the HPA-1. So I would have to bring to market an amp that had only the 4-pin output. That's a non-starter. The 1/4" output is a must have whereas the 4-pin output is a nice to have.

Some may argue that a balanced output could provide better performance (lower distortion). That may be true in some high-distortion designs, such as many tube amps. However, in low-distortion designs, such as mine, I generally find that trying to cancel out distortion by going with a balanced circuit actually results in worse performance (higher THD and 6 dB higher noise).
One area where the balanced output does shine is the output power. Assuming the output stage is not current limited, a balanced output stage could deliver four times the output power of a single-ended stage from the same power supply rails. However, this higher output power would only be available on the 4-pin connector and not on the 1/4" connector. I don't think the customer should just have to accept lower performance on the 1/4" connector. Many don't have headphones with 4-pin connectors.

That said, the 4-pin output certain has some marketing advantages. Many will perceive an amp with a large-and-in-charge 4-pin output on the front panel as a more serious amp. And certainly, a 4-pin output would be a must have on a more expensive (say $1500-2000) amp; even if only for marketing reasons.

Tom

mcgsxr · « **Reply #28 on:** 14 Feb 2020, 06:40 pm »

I’ve had my fun, and the unit has shipped off to the next lucky participant.

Really enjoyed my brief time with the amp and look forward to what others find and think with their own gear combinations.

adydula · « **Reply #29 on:** 14 Feb 2020, 10:04 pm »

Great!

Who is next on the list?

Alex

timind · « **Reply #30 on:** 15 Feb 2020, 03:03 am »

The amp is on its way to my house. Looking forward to spending some time with it. I may take some time out from speaker listening to listen through the little amp. Might even use the balanced inputs.

Freo-1 · « **Reply #31 on:** 15 Feb 2020, 03:08 am »

Looking forward to your observations.

Jon L · « **Reply #32 on:** 15 Feb 2020, 06:05 pm »

Quote from: adydula on 11 Feb 2020, 03:32 pm

Awesome!

I am on the list!

Looking forward to comparisons with the amps I have in house and a variety of headphones!

Alex

Didn't know about this. How do you get on the list? Would love to try HPA-1 on my Abyss 1266 Phi TC!

adydula · « **Reply #33 on:** 15 Feb 2020, 10:14 pm »

This amp belngs to : mresseguie and its a list that he compiled for specific reasons.

Alex

mresseguie · « **Reply #34 on:** 18 Feb 2020, 09:31 pm »

I asked Tom whether removing the cover would void the warranty. Sure enough. Removing the cover or damaging/defacing the serial number will void my warranty.

Please be nice to my HPA-1. Leave the cover on.

Freo-1 · « **Reply #35 on:** 19 Feb 2020, 12:39 am »

Quote from: mresseguie on 18 Feb 2020, 09:31 pm

I asked Tom whether removing the cover would void the warranty. Sure enough. Removing the cover or damaging/defacing the serial number will void my warranty.

Please be nice to my HPA-1. Leave the cover on.

Absolutely. There's a nice picture of the inside on the website.

adydula · « **Reply #36 on:** 19 Feb 2020, 01:07 am »

Roger on the case cover!!

mresseguie · « **Reply #37 on:** 19 Feb 2020, 06:11 am »

Actually, Alex, I'm pretty certain you're next after Timind has his turn at it. Keith's turn is after yours, no?

poseidonsvoice · « **Reply #38 on:** 19 Feb 2020, 11:31 am »

Quote

This was the only room I went back to for a second time to ensure my ears weren’t deceiving me, it was just that insanely good.

Scroll down:

https://hometheaterhifi.com/features/show-reports-film-festivals-concerts/florida-audio-expo-2020-coverage/

Best,
Anand.

adydula · « **Reply #39 on:** 19 Feb 2020, 02:32 pm »

mresseguie! Yes your correct!!!

poseidonsvoice, thanks for sharing!

Cant wait to test!

Wonder how the audio quality would compare to the DIY only HP2?

Alex