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Geshelli Archel2 Headphone AMP Review: another champ?

Jimbob54

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Ah, I'm running a splitter out of the phone into both of my amps for AB comparison, and the cable hooked up to the Archel is flat and grey and blends with my bedsheets :) you can see it under the headphone cable.
I see it now!
 

Human Bass

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!!!!! International buyers be aware!!!!!
I ordered archel 2 pro and declaration for customs was quoted value 179 I steed 139. The custom duties was unnecessary high which made me angry and is unforgiving human mistake. So buyers be aware.
Puny and naive person. Dealing with customs is an art I mastered as brazilian who can be taxed 100% of the price.

I can teach you the dark arts of deceiving and manipulation to avoid the opression of those who dont believe in free markets.
 
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This is a review and detailed measurements of the Geshelli Labs Archel2 headphone amplifier. It was kindly sent to me by the company. I am told the Archel2 will sell for US $149.99 but there is an early order discount down to $119.99.

The industrial design with metal box and clear/smoked Plexiglas is similar to other Geshelli products:


Hitting the power button once turns on the unit. Hitting it again lights up little LEDs inside.

Next is an input switch which works overtime as a gain switch as well. Hold it down 3 seconds and it will toggle the gain with a corresponding red LED lighting up on the right.

The volume control is on the smaller side but feels solid and good.

As you see, you have just one output in the form of 1/4 inch headphone jack.

I am told the Archel2 will come in multiple stock colors (red, white and purple) and others on request.

The back panel shows two inputs which you can independently select:

I have included the power supply so you can see how small it is. It outputs 12 volt at half an amp. The small size is very much welcome although I suspect it may limit the amount of current available to the unit for low impedance headphones.

In corresponding with Sherri and Geno at Geshelli, I am impressed with their operation. They took excellence in performance to heart, and purchased an Audio Precision APx555 analyzer. In addition, the company is vertically integrated with their own pick-and-place unit (PC board automated assembly). Most importantly, they put the product fully through FCC and regulatory certification. For such a small operation, this approach is surprising and certainly appreciated on my part.

Headphone Amplifier Measurements
As usual, we run our dashboard in unity gain with 2 volt in, 2 volt out for unbalanced devices:

View attachment 36217

You are seeing what I am seeing? There are essentially no distortion products down to whopping -150 dB. That small tick may actually be in my analyzer. This is just stunning performance with no help from THX feed-forward technology as some of our other headphone amplifier champs use. Naturally, the Archel2 takes the crown for the lowest distortion amplifier and possibly audio device I have tested so far:

View attachment 36218

The good story continues to noise performance:
View attachment 36219

Wow, 125 dB full power signal to noise ratio:

View attachment 36220

It should also be quite noise-free with sensitive IEMs:
View attachment 36221

Intermodulation+noise performance in low gain is exceptional as well:
View attachment 36222

High gain raises that some but still in very good territory with distortion levels that beat even our champion Drop THX AAA 789 in high gain by a bit.

Same is reflected in THD+N versus power level into 300 ohm load:
View attachment 36223

Note that as I have mentioned before, this measurement is not with highest performance mode of my analyzer. Turning that on (not shown) resulted in even lower distortion in low-gain mode!

We have plenty of power here, easily breaking past my requirement of 100 milliwatts of power in high gain mode.

Switching to 33 ohm maintains the excellent performance but power is not as high as I like to see:
View attachment 36224

The JDS Labs Atom in contrast produced 1 watt of power.

Given use of analog volume control, we have the usual channel imbalance:
View attachment 36225

The low gain mode is unity-gain (what goes in, is what comes out) so maybe you don't need as much attenuation. High gain is 4X by the way.

Output impedance is very low seeing how my fixture itself is about 0.9 ohm:
View attachment 36226

EDIT: forgot to include this.
Frequency response is dead flat as it should be:
View attachment 36236

Headphone Listening Tests
I started with my very low impedance (25 ohm) closed back Drop Mrspeakers Ether CX. In high gain there was plenty of volume to get loud. I was however able to push the Archel2 into distortion and cutting out. Mind you, I would not be listening at this level but this is a test that other high performance amplifiers pass.

The situation turned around completely with Sennheiser HD-650 headphones. There was incredible amount of power, detail, authority and fidelity to die for. It is as if this amp and the headphone are made for each other.

Conclusions
Yes, we have another state-of-the-art audio product. Not just headphone amplifier but audio product. And from a company with a one-person designer. Yet we have much larger companies making excuses for the performance of their unit.

You now have no less than 5 choices in high-performance headphone amplifiers that are provably transparent in sound reproduction. They respect the content you play by not polluting it with noise and distortion, letting its fidelity to shine through.

Headphone users are living the golden age of amplification. It is so gratifying to see companies like Geshelli putting performance first rather than some mythical story as to why their device sounds better.

The only weakness here is that you can't drive low impedance headphones to deafening levels.

It is my pleasure to strongly recommend the Geshelli Labs Archel2 headphone amplifier.

------------
As always, questions, comments, recommendations, etc. are welcome.

A local university researcher specializing in glues of all things has approached me to glue the head to the beheaded pink panther. He says with some grant money, he can do that without a trace that the head had even blown off! So, please help me help him by donate using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
What is the difference in their first model, and this one? It seems the specs are impressive. I am considering buying this. I have a desktop ASUS computer and a Lenovo laptop --- just bought a pair of 16 ohm Sony 1AM2 headphones, they are rated 3 Hz - 100 Khz. Mostly sound great, just wish certain music passages were a little louder. Your review shot down the $499.00 Neve amplifier, but praised this one. Do you think it will meet my simple needs? Just want a simple unit that has a 3.5 mm input. I can buy a simple adapter to plug my 3.5 mm headphones into the 1/4" jack. Thanks again, for your informative review! Most thorough review of any website I have found, yet!
 

Veri

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What is the difference in their first model, and this one? It seems the specs are impressive. I am considering buying this. I have a desktop ASUS computer and a Lenovo laptop --- just bought a pair of 16 ohm Sony 1AM2 headphones, they are rated 3 Hz - 100 Khz. Mostly sound great, just wish certain music passages were a little louder. Your review shot down the $499.00 Neve amplifier, but praised this one. Do you think it will meet my simple needs? Just want a simple unit that has a 3.5 mm input. I can buy a simple adapter to plug my 3.5 mm headphones into the 1/4" jack. Thanks again, for your informative review! Most thorough review of any website I have found, yet!
Should easily meet your simple needs :)
 

Jimbob54

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What is the difference in their first model, and this one? It seems the specs are impressive. I am considering buying this. I have a desktop ASUS computer and a Lenovo laptop --- just bought a pair of 16 ohm Sony 1AM2 headphones, they are rated 3 Hz - 100 Khz. Mostly sound great, just wish certain music passages were a little louder. Your review shot down the $499.00 Neve amplifier, but praised this one. Do you think it will meet my simple needs? Just want a simple unit that has a 3.5 mm input. I can buy a simple adapter to plug my 3.5 mm headphones into the 1/4" jack. Thanks again, for your informative review! Most thorough review of any website I have found, yet!
Between the Archel 1 and 2, more cleaner power and a few $. The Archel 2.5 adds balanced xlr inputs but only the same standard single ended 6.35mm at the front.

Simple needs, Archel 2. 0!


Edit! You already got! Glad you're happy
 
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Between the Archel 1 and 2, more cleaner power and a few $. The Archel 2.5 adds balanced xlr inputs but only the same standard single ended 6.35mm at the front.

Simple needs, Archel 2. 0!


Edit! You already got! Glad you're happy
Their customer service is fantastic. I called them to thank them. Gino and his wife, Sherri are super cool. Family owned and operated business, I like that. Made in U.S.A.
 

Degru

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Has anyone tried using a higher amperage power brick with the Archel2 Pro? Does it improve its performance for headphones that push it to its limits? For example, the iFi iPower 12v adapter that can put out 1.8A instead of the stock brick's 0.5A.
 

JohnYang1997

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Has anyone tried using a higher amperage power brick with the Archel2 Pro? Does it improve its performance for headphones that push it to its limits? For example, the iFi iPower 12v adapter that can put out 1.8A instead of the stock brick's 0.5A.
no and it's worse in current leakage
 

solderdude

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Has anyone tried using a higher amperage power brick with the Archel2 Pro? Does it improve its performance for headphones that push it to its limits? For example, the iFi iPower 12v adapter that can put out 1.8A instead of the stock brick's 0.5A.
It is pointless to do so because output power is limited internally by the used DCDC converters, not by the connected power supply.
Even if you connect a 12V 20A power supply nothing will change.
12V/0.5A = 6W and is already more than the DCDC converter's maximum rating.
 
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Degru

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It is pointless to do so because output power is limited internally by the used DCDC converters, not by the connected power supply.
Even if you connect a 12V 20A power supply nothing will change.
12V/0.5A = 6W and is already more than the DCDC converter's maximum rating.
What is the internal converter's rating? I'm asking because I have a Stax SRM-252 which says it uses 4W and the stock brick is 400mA, however when I attach a 3A power supply it sounds noticeably better in bass and dynamics. I don't currently have extremely hard to drive headphones to test the Archel2 with tho.
 

solderdude

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The internal converter is rated at 2W. This feeds both channels so about 1W is available per channel.
This jives with the specs and Amirs measurements.

So you can connect a 12V 100A power supply all day long and believe it will help but the output power is limited to 1W/channel.
It's the DCDC converter's properties and used secondary reservoir caps that determine output power. Not the power supply feeding the DCDC converters.
 
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Degru

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The internal converter is rated at 2W. This feeds both channels so about 1W is available per channel.
This jives with the specs and Amirs measurements.

So you can connect a 12V 100A power supply all day long and believe it will help but the output power is limited to 1W/channel.
It's the DCDC converter's properties and used secondary reservoir caps that determine output power. Not the power supply feeding the DCDC converters.
Ah, good to know. I figured that was probably the case but my experience with the 252 made me question it. Tho Stax are pretty different, and most lower-tier energizers are generally underpowered.
 

JohnYang1997

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Just had a question. And it seems to be the elephant in the room. Didn't see any results by searching.
Was the 33ohm load measurement tested single channel driven.
 

Jimbob54

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Just had a question. And it seems to be the elephant in the room. Didn't see any results by searching.
Was the 33ohm load measurement tested single channel driven.
For the laymen and generally ignorant (me) , could you elaborate on what the implications are if it is (or isnt) ?
 

JohnYang1997

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For the laymen and generally ignorant (me) , could you elaborate on what the implications are if it is (or isnt) ?
The power of 33ohm here is 612mW which looks not as good but comparable to single ended output of 789. If this is single channel driven, then it should be much less when both channel driven. As it's current limited by the power supply, the power will drop to 153mW per channel. For the longest time I had a feeling of this set of measurements being weird that something was wrong. Recently I'm looking at designing portable amplifier. And today I was just so happen looking at this thread and saw the issue.
Now this part makes sense:
"
Headphone Listening Tests
I started with my very low impedance (25 ohm) closed back Drop Mrspeakers Ether CX. In high gain there was plenty of volume to get loud. I was however able to push the Archel2 into distortion and cutting out.
"
 

Jimbob54

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The power of 33ohm here is 612mW which looks not as good but comparable to single ended output of 789. If this is single channel driven, then it should be much less when both channel driven. As it's current limited by the power supply, the power will drop to 153mW per channel. For the longest time I had a feeling of this set of measurements being weird that something was wrong. Recently I'm looking at designing portable amplifier. And today I was just so happen looking at this thread and saw the issue.
Now this part makes sense:
"
Headphone Listening Tests
I started with my very low impedance (25 ohm) closed back Drop Mrspeakers Ether CX. In high gain there was plenty of volume to get loud. I was however able to push the Archel2 into distortion and cutting out.
"
Only one man can answer that one. Mr @amirm kindly lay some truth on us please.
 
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