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First (Incomplete) Impressions: Audiophonics HPA-T400ET 3 Way Purifi

gsalakirov

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#1
Folks, this is my first post on the forum - I've been lurking for awhile and I'm really grateful for everything I learned here over the last couple of months.

I'm sharing first impressions from the Audiophonics HPA-T400ET 3 Way Purifi amplifier.

Unfortunately, the unit I received was defective (faulty power relay), which prompted me to return it.
I took the opportunity to return it as I incidentally found that Apollon Audio is releasing a new 3 channel Purifi amp with adjustable gain that goes to 29dB that's a much better match to my Denon x3600.

I also found Apollon's support more personal and engaged, and along with the perceived higher quality custom build helped justify the higher price.

All things considered, I'm reasonably content with my Audiophonics experience, and I will consider their products in the future. Being in Europe I find that they offer the best prices for Class D builds on the market.

I'm leaving my original post and impressions for posterity:

I got this amplifier to power my L/R Kef R5s and center L2C speakers. It's paired to a Denon X3600H receiver. Depending on how things go, I might trade my current receiver with one that supports disabling the internal amps (e.g. 3700, 4700 or this year's models) for a clean 2V output on all channels.

Order experience:
  • Ordering was a breeze, the Audiophonics support was responsive and answered all of my questions in a timely manner.
  • The amplifier arrived within a few days from France. I'm based in the Netherlands.
  • Packaging was good, with a generous amount of padding and protection.
First impressions:
  • The industrial design is okay, it has a clean, if generic look. No massive stickers/logos which I appreciate. The fins on the chassis are quite sharp and uncomfortable to hold. It's not a deal breaker, but makes handling it unpleasant. (photos below)
  • The finish is matte black and doesn't attract fingerprints.
466A2DF6-4C1A-4859-8473-33C3E896C6B5_1_105_c.jpeg 6A19B936-2542-42D2-A0B4-467722DAE65C_1_105_c.jpeg

  • There's no manual in the box or online, which I didn't expect and I find as an oversight. The only feature that strictly requires a manual is the gain adjustment, which is documented in a blog post.
  • Initial installation was simple, as expected. Nothing of note or concern. The trigger works.
  • The power button and trigger are all connected to the same controller. As others have observed with other Audiophonics models the trigger overrides the power switch.
IMG_2106.jpeg


Issues, Troubleshooting & Return:

  • Unfortunately, and unsurprisingly there is a hum when the RCA->XLR cable is connected to the amplifier. I was already prepared for this risk, the main suspect being the XLR->RCA cable.

  • [Audiophonics support confirmed that's not expected behavior] There's no hard power switch / way to turn off the amplifier without unplugging. My unit draws 33 watts when it's plugged in. There's no tangible difference in the power draw in stand by (LED off) and ON (LED on). Given the high power consumption and 0 difference between on/off, I'm uncertain of what the stand by state actually does.
IMG_2109.jpeg IMG_2110.jpeg

[Update 4/21/21]: The Audiophonics support confirmed that the behavior described below is not normal.
  • This is where it gets fun. A full day into owning the amp, I've still yet to get it to work. I've contacted support a few hours ago, and I'm waiting for a response. Communication is only through email/website service form, so some latency is expected.
  • After connecting the amplifier to the receiver, I discovered the gain/output was incredibly low. The speakers barely produced any sound (audible only if I put my ear to them).
  • Next step was checking the gain level adjustment of the amps. Happily, they were already configured to 25dB gain, as I requested with my order.
  • After playing around for an hour last night, I discovered that the speakers continue to produce (the barely audible) sound even when the amplifier is in standby. I find this strange and continue to wonder what the stand by mode actually does.

[Update 5/06/21]
  • Audiophonics confirmed that the power relay is faulty.
  • There was no resolution for the gain issue. General Audiophonics advise was to use 20dB/4v gain, despite the amp offering 25 dB gain.
    Given the positive feedback on using the 25dB gain option (see @TomekNet 's comment below), I'm still confused about this advice and assume it was a glitch in their otherwise good support.
  • Ultimately, I decided to return the unit, and go for an Apollon amp that has adjustable gain to 20/25/29 dB, matching well with the Denon pre-outs.

Layout photos:

I opened the amplifier to check the gain settings on the amps, and took the opportunity to make a few photos of the layout.

IMG_2092.jpeg IMG_2093.jpeg IMG_2094.jpeg IMG_2095.jpeg IMG_2096.jpeg IMG_2097.jpeg IMG_2099.jpeg IMG_2100.jpeg
 

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TimoJ

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#2
Looks like there is a AC disconnect relay on that trigger board and the front panel switch also controls that. So there should be very low standby current draw, only used by that extra power supply on the trigger board. Maybe they wired it incorrectly?

The AC socket is not properly insulated, there is live part exposed. Not that it matters in normal usage:

iec0.jpg
 

DerRoland

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#3
Check your RCA->XLR cable, should be always wired like this (adapter cables are often sometimes false connected):


Taken from this thread.

The standby story is strange. Wait for the audiophonics answer.
 
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digitalfrost

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#4
My unit draws 33 watts when it's plugged in. There's no tangible difference in the power draw in stand by (LED off) and ON (LED on). Given the high power consumption and 0 difference between on/off, I'm uncertain of what the stand by state actually does.
This seems really high to me, especially given it's a Class D design. The AHB2 needs 12 W idle, and I've seem Class D amps with as little as 7W (B&O IcePower, or Crown Audio).
 
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gsalakirov

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I just got a confirmation from the Audiophonics support that the stand by power consumption is not normal, so it's probably a defective unit, which is a bit of a bummer.

I'll post more updates once it's working.
 

JimB

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#6
I just got a confirmation from the Audiophonics support that the stand by power consumption is not normal, so it's probably a defective unit, which is a bit of a bummer.

I'll post more updates once it's working.
You've got three SMPS600s in there, each of which idles at ~8W, so there's 24W of your 33W idle, leaving ~3W each for the input and amp module of each channel. Standby is another matter...
 

MakeMineVinyl

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#7
J3-32 on the NC500 module is the nAMPON pin. This pin controls whether the module is in a low-power 'standby' state or not. When this pin is LOW, the amplifier module is enabled - when HIGH, the module is in standby.
 
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gsalakirov

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I'm closing the thread, since I returned the unit.

The standby issue was caused by a faulty power relay, which would have been resolved under warranty.

After discussing the gain issue with the Audiophonics support we didn't get to a conclusion beyond that it's best to pair the unit to a 4v (20 dB gain) source which prompted my decision to return it.

Incidentally I found that Apollon have a new 3 channel Purifi amp that offers gain adjustment to 29dB which makes it a great match for my Denon x3600 AVR.

I'll make a new post once I receive my Apollon amp.
 
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#9
That's strange. I have MPA-M400ET (Purifi mono) connected to Denon x3700 center pre-out. It is set to 25.3dB gain and I find no problems driving KEF R2c speaker. For L&R channels I use NAD c298 (Purifi stereo, 28.6dB gain) and Audyssey easily handles the differences within -2dB +2dB levels
 
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gsalakirov

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I was similarly surprised from the Audiophonics support advice to only 4v/20 dB is advised to feed the amps, but decided not to pursue further given the better options.

I was pretty confident that the setup would work since I saw your posts in other threads.

Although I was itching to spend more time on the unit and get to the bottom of this, ultimately I opted for the easy solution and spend more time listening to music (and learning more about REW/EQ :) ).
 
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gsalakirov

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Dont they test the AMP before sending them to customers?
I believe they do, given the many happy customers on the forum.

My assumption is this unit fell through the cracks, and given it's a brand new model there might have been quirks that need to be ironed out.
 

AdamG247

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#13
I believe they do, given the many happy customers on the forum.

My assumption is this unit fell through the cracks, and given it's a brand new model there might have been quirks that need to be ironed out.
Welcome Aboard @gsalakirov. Did you say you want this thread closed?
 
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gsalakirov

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Thank you @AdamG247!

I think it might be a good idea, while there's still value in the context and layout photos.

I'm weary of this being perceived as a bash on what it looks like good product, that just ended up being defective and not an ideal fit.

What do you think?
 
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