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Review and Measurements of Benchmark HPA4 Headphone Amp/Pre

RichB

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My LA4 is connected to a pair of Benchmark AHB2s with a trigger out for each.
The LA4 balanced inputs are connected the Emotiva RMC-1 (HT) and the Benchmark DAC3B (music).
For music, I use only the Benchmark stack, sounds wonderful driving the Salon2s full range.

I use a Pronto Remote activities to turn on the RMC-1 or just the LA4/DAC3B.
The LA4 is configured to turn off the display since it is below my screen and find it distracting for music as well.

My only complaint is that Benchmark does not provide discrete code to select the input so sometimes they misfire input selection.
I can only assume that that the device is difficult to update, otherwise, it seems to be a no brainer to provide an update to select all inputs discretely.

Personally, I would not leave the HPA4/LA4 on 24/7. There is a bright display that can wear.
I suspect that a power surge is worse if the unit is powered on, and they do happen.

- Rich
 

laidick

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My LA4 is connected to a pair of Benchmark AHB2s with a trigger out for each.
The LA4 balanced inputs are connected the Emotiva RMC-1 (HT) and the Benchmark DAC3B (music).
For music, I use only the Benchmark stack, sounds wonderful driving the Salon2s full range.

I use a Pronto Remote activities to turn on the RMC-1 or just the LA4/DAC3B.
The LA4 is configured to turn off the display since it is below my screen and find it distracting for music as well.

My only complaint is that Benchmark does not provide discrete code to select the input so sometimes they misfire input selection.
I can only assume that that the device is difficult to update, otherwise, it seems to be a no brainer to provide an update to select all inputs discretely.

Personally, I would not leave the HPA4/LA4 on 24/7. There is a bright display that can wear.
I suspect that a power surge is worse if the unit is powered on, and they do happen.

- Rich
I have very similar setup and exact comments.

luckily my AVR has digital output to my topping DAC
so basically I use AVR as player (roon player), output to Topping, then to LA4 then to AHB2.

I don't really need to switch the input of LA4 as it only has 1 input source now.
 

enricoclaudio

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Thanks for your inputs, guys. Yes, the HPA4 is working just fine with AUTO-ON enabled. It stays ON during the day, from like 8 am to 9 pm, then it turns OFF when I turn OFF the lights in my office. Display dims after 30 secs and goes to sleep (off) after 30 mins of inactivity. This way works perfectly for me.
 

richsto

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Thanks for your inputs, guys. Yes, the HPA4 is working just fine with AUTO-ON enabled. It stays ON during the day, from like 8 am to 9 pm, then it turns OFF when I turn OFF the lights in my office. Display dims after 30 secs and goes to sleep (off) after 30 mins of inactivity. This way works perfectly for me.
Glad you are enjoying the HPA4, looks spectacular in your setup.

I decided not to send my HPA4 back - couldn’t part with it even though I fully intended to do so. Benchmark is smart to offer a 30 day trial. :)

I have the HPA4 triggered by a Parasound Halo A21+ which is controlled/triggered by a Phillips Hue Smart-plug (trigger only). The Smart-plug is controlled by a Harmony Elite Remote enabling seamless control for various activities. Works great.

I would not leave it on 24/7 either, even though you can configure the display to auto dim. I have the display turn off after a few seconds, no distractions that way especially during movie viewing.

And, yes unfortunately they cannot seem to easily update with discrete input codes (my biggest and only real gripe).

Enjoy and keep us posted on your impressions.

Rich S.
 
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enricoclaudio

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I'm pretty sure this is me been paranoid but I have a question:

I noticed that when turning the HPA4 ON, I see a vertical white strip on the right side of the screen like about ¼ of the display size that last no more than a few milliseconds. Then I can see the Benchmark / THX logo. I'm guessing this is caused by the firmware/software booting up and sending video signal to the touchscreen so wanted to know if this is normal?

I put a video in my YouTube account so you can see this:

 

RichB

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I'm pretty sure this is me been paranoid but I have a question:

I noticed that when turning the HPA4 ON, I see a vertical white strip on the right side of the screen like about ¼ of the display size that last no more than a few milliseconds. Then I can see the Benchmark / THX logo. I'm guessing this is caused by the firmware/software booting up and sending video signal to the touchscreen so wanted to know if this is normal?

I put a video in my YouTube account so you can see this:

My LA4 flashes white on power on. It is not an issue, for me.

- Rich
 

enricoclaudio

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My LA4 flashes white on power on. It is not an issue, for me.

- Rich
Thanks for confirming it and calm down my OCD
 

richsto

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Thanks for confirming it and calm down my OCD
Mine does the same….thanks for helping my OCD as well.

Another curiosity: after power off, my HPA4 makes some higher pitched warbling like noises. Very low in level but audible if you are quite close to the unit.

Odd but probably some processor inside doing it’s thing to prepare me for some more jaw dropping audio the next time I use it. :)

Rich S.
 

enricoclaudio

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Mine does the same….thanks for helping my OCD as well.

Another curiosity: after power off, my HPA4 makes some higher pitched warbling like noises. Very low in level but audible if you are quite close to the unit.

Odd but probably some processor inside doing it’s thing to prepare me for some more jaw dropping audio the next time I use it. :)

Rich S.
Yep, mine does the same. There are lot of relays inside that thing, enough to make lot of noise when shutting down Which is a good thing, though :)
 

enricoclaudio

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Also got confirmation from Rory from Benchmark that the white flash on power ON is normal ;)
 

RichB

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Also got confirmation from Rory from Benchmark that the white flash on power ON is normal ;)
Ping him about discrete input code for the analog inputs.
I plan to keep bugging them until they tell me there is a technical reason that it cannot be done.

- Rich
 
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enricoclaudio

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Ping him about discrete input code for the analog inputs.
I plan to keep bugging them, until they tell me there is a technical reason that it cannot be done.

- Rich

I see no technical reason why they can't do discrete input codes. While there is no firmware update port outside, there is a micro USB port that you clearly see when you take the top cover which I'm guessing it's for firmware updates and initial firmware flashing. Taking the top cover shouldn't void the warranty because they even sell the top cover for the LA4 and HPA4, meaning it's user replaceable.

Benchmark-HPA4-Headphone-Amp-Pre-inside-rotated.jpg
 

ObjectiveSubjectivist

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I see no technical reason why they can't do discrete input codes. While there is no firmware update port outside, there is a micro USB port that you clearly see when you take the top cover which I'm guessing it's for firmware updates and initial firmware flashing. Taking the top cover shouldn't void the warranty because they even sell the top cover for the LA4 and HPA4, meaning it's user replaceable.

View attachment 261098
Yes it's for firmware update. Actually there was firmware update for HPA4, it enabled 'big screen mode'.
Which basically displayed large 'volume' number while changing.
More info:
 

enricoclaudio

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Mine is even running a newer software version, 2.2.1 and firmware 1.0.2:

IMG_7395.jpeg



IMG_7396.jpeg


Mine was manufactured the same day I placed my order, Jan 17th, 2023. They shipped it the same day as well.
 

enricoclaudio

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I got confirmation from Rory over email that there is no technical limitation to implement discrete input codes. So at this point I'm not sure why they haven't after so many customers asking for it.
 

richsto

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I got confirmation from Rory over email that there is no technical limitation to implement discrete input codes. So at this point I'm not sure why they haven't after so many customers asking for it
Interesting. Before purchasing I asked about discrete input codes and received a response that it was not possible…..seems they should be able to do it. Such a fundamental and basic need and something that is offered on most any remote controlled preamp I can think of.

Rich S.
 

enricoclaudio

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Schiit Freya S and S+ also have no discrete input codes/selection. You have to scroll between inputs too. I'm guessing good measuring pre amps have this limitation. This is not a deal breaker for me because mi HPA4 is on my desk at fingers distance but I know for some of you guys is a must have. In my main system I have a Parasound Halo P6 which has direct input selection, though.
 

DJBonoBobo

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HPA4 in the house :)

View attachment 259392


View attachment 259394


View attachment 259395

First impressions:

As a pre amp, which is the main reason I got it, all I can say is that I have depth regrets for not purchasing it long time ago. Compared to my Drawmer CMC3 monitor controller, the CMC3 sounds like a toy. As a pre amp, the HPA4 is TRANSPARENT, period. Do I hear differences between the HPA4 and the CMC3, of course I do. As a headphone amp, compared to my Topping A90D, honestly, I can't hear any difference. Both sound exactly the same to me. Both drive my H660s and Sundaras effortless. The HPA4 is going to stay for sure. 2 hours only since started playing with it and I love it.

Pink Panther is happy too ;)

View attachment 259401
Just out of curiosity, why don´t you use the UCX II as a monitor controller?
 

enricoclaudio

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Much better volume control (analog) and to avoid an extra ADC - DAC conversion from my X-SABRE 3 if it pass through the UCX II which also add extra latency . Also, I bring my UCX II to my work office sometimes and leave it there for a couple of days. The HPA4 stays on my desk always.
 

enricoclaudio

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Also have an Apogee Duet 3 but it's too noisy and the Apogee Control 2 software makes my Mac Studio running macOS Ventura go crazy. RME TotalMix is a much better software than Apogee Control 2 my miles. I use the Duet 3 only when traveling.

IMG_7398.jpeg
 
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