HPA-9 (Reference class headphone amp)

steve in jersey · « **Reply #20 on:** 10 Nov 2015, 07:00 pm »

This headphone amp looks pretty interesting . I do have a question about the "L --- H" slider on the front panel . Is this meant to be used for "gain" or "Impedance" ?

rustydoglim · « **Reply #21 on:** 11 Nov 2015, 01:43 pm »

Gain.

Oh, I should mention that the impedance handling of HPA-9 is astounding.

steve in jersey · « **Reply #22 on:** 11 Nov 2015, 02:23 pm »

He,he,he.... After thinking about my question yesterday, I really couldn't think of any Headphone amp that
I've used that this "wasn't" for gain .

(thanks for answering my "half awake, should have had some coffee" question)

Armaegis · « **Reply #23 on:** 11 Nov 2015, 06:32 pm »

I've actually seen a few headamps with switchable output impedances... Centrance Hifi-M8 and Teac HA-501 come to mind.

Armaegis · « **Reply #24 on:** 12 Nov 2015, 04:14 am »

I'm surprised the HPA-9 does not have a balanced headphone output. Even if not truly balanced, many high end headphones and cables are coming balanced now, so having an XLR-4 port up front is highly convenient.

rustydoglim · « **Reply #25 on:** 13 Nov 2015, 07:39 pm »

he he he, you have to buy DAC-10H.
May be in the future, but today's cost doesn't allow us to offer true balance out at this price.

steve in jersey · « **Reply #26 on:** 13 Nov 2015, 11:43 pm »

For some reason,I've never felt any of my headphones (including my HE6) displayed any weaknesses running
them single-ended.

Now that I think of it ,though, more than likely having an Equitech 1.5 Q line conditioner in front of everything
may be responsible for this. In the long run running the headphones balanced may be the less expensive proposition, so as they say "You picks your Poison" I guess !

Armaegis · « **Reply #27 on:** 16 Nov 2015, 04:23 am »

Quote from: rustydoglim on 13 Nov 2015, 07:39 pm

he he he, you have to buy DAC-10H.
May be in the future, but today's cost doesn't allow us to offer true balance out at this price.

The HPA-9 has dual headphone outputs correct? Are they individual outputs or are they simply paralleled?

Silly bootstrap idea is for one of the outputs to be phase inverted from the other, which allows us crazy headphone enthusiasts to build an adapter that provides bridged balanced outputs. It's not an altogether new idea; I've seen similar things done in the past.

Any plans to release a fully balanced headphone amp? (perhaps the HPA-9.5 haha!)

dB Cooper · « **Reply #28 on:** 16 Nov 2015, 12:29 pm »

Quote from: rustydoglim on 11 Nov 2015, 01:43 pm

Gain.

Oh, I should mention that the impedance handling of HPA-9 is astounding.

Not sure what "impedance handling" is unless it is a sideways reference to output impedance, which is a spec I would like to know.

rustydoglim · « **Reply #29 on:** 18 Nov 2015, 06:38 pm »

Normally headphone amp is designed to work well for a limited range of headphones impedance but HPA-9 supports 16 to 1000 ohms.

mfwalker1 · « **Reply #30 on:** 27 Nov 2015, 02:45 am »

Hi. HPA-9 looking very tasty...

Q: Are the two RCA outputs fixed volume, or after the vol control?
REgards,
Matt Walker

rustydoglim · « **Reply #31 on:** 27 Nov 2015, 06:33 am »

I think one RCA output is fixed volume.

quint · « **Reply #32 on:** 8 Dec 2015, 02:50 pm »

Looks like a fabulous product. Sorry if this has been answered and I missed it, but does it have remote volume control?

rustydoglim · « **Reply #33 on:** 14 Dec 2015, 02:40 pm »

Quote from: rustydoglim on 27 Nov 2015, 06:33 am

I think one RCA output is fixed volume.

I am wrong about this, both RCA outputs are controlled by volume.
There is no remote control.

rustydoglim · « **Reply #34 on:** 14 Dec 2015, 02:44 pm »

Today I had the chance to discuss with the engineer about HPA-9 and what he has told me made me believe that HPA-9 is the best headphone amp on the market, at any price. He said that he can show plots of HPA-9 against a $30,000 single ended pure class A headphone amp.
We have been too busy getting these new products out the door, now we have time to provide more technical info.

mfwalker1 · « **Reply #35 on:** 14 Dec 2015, 10:39 pm »

Hmmm.
I can't see the purpose of two RCA outputs both after the volume control?
What's the thinking here?
If one of fixed, then the HPA-9 could be used as a phono pre for the DAC-9 (which has no phono input)...
But this is compromised, somewhat by the HPA-9 output being after the Vol control.
All food for thought...
Regards,
Matt

Quote from: rustydoglim on 14 Dec 2015, 02:40 pm

I am wrong about this, both RCA outputs are controlled by volume.
There is no remote control.

kevb · « **Reply #36 on:** 14 Dec 2015, 10:59 pm »

I was thinking the same thing. I am trying to figure out the logistics of running a TT with the DAC-9/HPA-9 combo. If you want to hear the TT through speakers, you have to either unhook the DAC-9 from the power amp and hook up the HPA-9 to the power amp, or run the HPA-9 through the DAC-9 if you want remote control. However, if you want to listen to the DAC-9 through headphones, you then have to disconnect the outputs of the DAC-9 and run them to the HPA-9 instead of to the power amp.

Seems like a bit of a cluster.....

rustydoglim · « **Reply #37 on:** 17 Dec 2015, 06:05 am »

HPA-9 can be used with STA-9 (besides having THREE simultaneous headphone amp outputs):

Stereo to STA-9 (stereo)
Stereo to 2 x STA-9 (mono mode)
Bi-amp 2 X Stereo to 2 X STA-9 (stereo)
Bi-amp 4 X STA-9 (mono mode) Wow 4 X 290W

rustydoglim · « **Reply #38 on:** 17 Dec 2015, 06:12 am »

HPA-9 is the best headphone amp in the world, feel free to compare it against anything at any price.

But it can also be used as a class A preamp. If you have very good analog source, and want to bypass the A2D of DAC-9, then follow this setup where the HPA-9 RCA outputs go to STA-9 RCA inputs.
And the DAC-9 balanced outputs go to STA-9 balanced inputs.
It is a little inconvenient to use the balance/unbal switch of the STA-9 but if you want the ultimate purest phono to amp solution and still combine your best digital source, this is the only way, and may be only one in the world that can do it.

mfwalker1 · « **Reply #39 on:** 17 Dec 2015, 10:10 pm »

I don't want to sound negative on what looks to be a great product, but that arrangement doesn't work for me.
Having to reach around to the back of the STA-9 to flick the Bal/Unbal switch.
IMHO it would have been nice to have included a headphone amp in the DAC-9.
I'm assuming the DAC-9 is a IMA-8 with the amplifier section removed. So there should be space in there?