Πέμπτη 25 Ιανουαρίου 2024

Testing two Inkax models: EP33 (aka HiFI) vsR9


This is a text piece about my interest in audio engineering and my passion for testing audio equipment. I own a large collection of headphones and earphones including many from the Inkax series. I often purchase these from the local distributor, which offers a wide variety of smartphone products at very affordable prices.

The first I found / bought were so trebly which irritated my ears putting the 5+ kHz range with more than 20 db comparing to the remain audio spectrum. This was a reason I stopped for long time spending in earbuds and finding from competitors. 3 years ago their HIFI model was quite better in it response curve with trebly sound but not so high as their predecessors. A newer addition was replacing their sponge buds with comply type which added more bass than the relatively dull sound of the silicon. That translates into a model with near to real HiFi performance as for example the JBL T500 cabled model , one model I use for about 3 years.

The packing of

The latest model I found is the R9. I bet that it is a very recent fron its series of products with a new slimmer design . Marked as stales steel as the color used for the design of this plastic model separates well from is predecessor HiFi with the half on the rear part with the audio transformer and using a quite good insulated cable that seems to be closer to a higher level to the HIFi or even the Muse (design similar to the R9)

As with most of the Inkax models this includes also a microphone and a splitter/switch which can stop /play the music from the smartphone and still be cheaper than its predecessor

Operation and impressions.

I tested for a very short time with its own buds and immediately replaced them with Comply compatible buds. These buds can offer much better isolation then the typical bud and can keep the earphones better and stiffer inside the ear canal .

The first step was to listen to both using some Malaysian music of the 90s with a middle class DAP called Amoi C10 a brick like mp3 player . Malay recordings are usually more bright than the western counterparts with treble curve shaped as in Dolby cassette recording ,while Dolby is not used while tape is playing . An audio splitter is connected between the DAP and the two earphone sets. At first the R9 was not pushed enough into the air canal making the sound rather poor with low bass. A further press and keeping the tips , finger pressed added much of bass and closer to the HiFI model with identical sound response. Note that the HIfi model uses the 400 model tat is a bit wider than the T300 used on R9

Tested them in parallel and seen that the sound level is the same in both stakes: R/R and R/L modes There was no difference in sound level that can shift the audio point towards the left or right ear(eg R)

All together to listen to the music

Next step is testing their frequency rage. The set is very simple: A audio file is previously prepared with test tones , evenly spaced across the audio band with more emphasis on the higher spectrum total 25 tones WAV format! A lavalier microphone is touched in earbuds foam tip ad the sound is finally driven to the smartphone where a program records and saves the audio. The final stage is made in the computer with audio software for making he spectrogram.

The picture is quite clear. This picture joints with two spectrans showing the resulted curves form the above process for HIFi (2014) and R9 (2017)

HiFi shows a linear response on the voice part while the R9 has a steep response. The remain part is nearly similar to both. All recording settings are the sane for both As it clear e R9 is has a lower audio level than HiFi

The final part of the test : Checking microphones

Putting the microphones in front of the DAPs’s speaker and isolating them from outside noises with a ….dry sponge. I adjusted once the audio level because otherwise the result will be garbled. The two files were scanned with the software for spectrum analysis and grouped into one image.

My reflections : There is a hum of 55 Hz from R9 (at right) . R9 produces 12 db lower audio (or 4 times lower volume) than the HiFI with a peak on the upper level of voice and losing some lower notes . I have not tested in practice to the moment

Nothing more to notice .Both earphones have a good and reliable sound. The primary issue with HiFi is its splitter design, which causes the cable to tear after only 8 months and heavy use , rendering it unusable. The connections are lost in the one bud’s cable , in the splitter part , Will the R9, with a similar splitter design, be able to resist this problem? Only time will tell!

Πέμπτη 28 Δεκεμβρίου 2023

Testing two Neotec headphone Amplifiers

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 Neoteck 059 vs 106 Blueooth 



It has been over four years since I purchased the NTK 059 from Amazon. I bought it with the intention of enhancing my experience while watching TV shows and movies, as well as listening to music.

However, I have only used it less than ten times, totaling less than 20 hours. The reason for discontinuing use of the product was due to changes in my daily schedule, which involved frequent travel between my own home and my parents' home to care for them.

Despite this, I was pleased with the product's excellent sound quality, even when used in conjunction with a somewhat unconventional setup, which included an RF bypass for TV via

-RF bypass for TV via a Digital decoder
-TV connecting with a DVD recorder jus tin case..
-DVD recorder connects to a HiFi [lol] system
-The spare RCA outputs from the DTV were used to connect to the headphone amplifier via a provided cable. The output of the amplifier was then connected to a 5m 3.9mm cable extension to reach the AKG77 headphones on the other side of the salon (5.5+m).

Why do I refer to the Hifi? This is a pre-2000 all-in-one model with 3 CD, 2 cassette, and radio player, plus two mid-level speakers offered with the model, with sound quality inferior to these headphones. There are a few DSP modes for equalization that enhance the sound quality, but they still do not offer the good audio that these headphones offer!

Most times, I used it to watch musical programs from 3 TV stations on the weekends.  The best sound among them was on ERT, the Greek national TV network. The second station produced a sharper and more sibilant sound compared to the third station, which was considered to have lower quality sound.  The text is free from filler words and employs a formal register with precise word choice. Listening to ERT provided the best experience, with all instruments being heard clearly, although the drums had a slightly sharp sound.

The cable was consistently connected to the DTV receiver, while the amplifier was only used when necessary.

pack 106 

Looking here the bigger model HD106 Each model  has the same packing with these accessories included :   

- A 3,9 mm jumper  with one end 90d angled
-mini USB cable. Mini D  plug is used.
-Mini guide All these are put in the same part of the box. Rather not to be used as the  amp is very simple to be used. I have seen a video in the Ali page on how the BT can communicate
-the amplifier in the other part of the pack 

Both amplifiers have a similar design and controls, with slight differences in operation. The volume knob in the BT model controls the volume and acts as a switch, while in the non-BT model (NTK059), the middle switch functions as the power on/off button. In the NTK160 model, the middle switch acts as the volume gain control.

To activate the Bluetooth mode, simply turn on the NTK160 without plugging any cables into the input socket and activate the BT mode on your device. Both the computer and smartphone paired with the amplifier immediately.

Upon checking the fidelity, I noticed that the Digital TV decoder had a higher treble than expected. Once I plugged the amp with the SCART, I noticed a different audio signature with lower highs. I also tested the NTK 059 with a smartphone and found that the audio quality was poor and similar to the direct audio. Therefore, the NTK 059 appears to be transparent to my ears.

I chose to use a new Nintaus model. The Amoi model has a sibilant sound with less bass and slightly higher trebles in the 1.5-5 KHz range, making it uncomfortable for extended use to my ears .

After experimenting with the same song, which has both treble and bass, I found that the Nintaus model produced slightly more bass at the 1.5-2 db level while maintaining
the same overall sound quality. I also observed that the plug on the 160 cable was slightly larger, requiring more pressure to fit securely.


I opted for the utilization of a novel Nintaus model. The Amoi model exhibits a pronounced sibilant sound characterized by reduced bass and slightly elevated trebles within the frequency range of 1.5-5 KHz, causing discomfort during prolonged usage as perceived by my ears.

The aforementioned illustrates the disparities between employing a direct connection and utilizing the 106 as an amplifier. Extremely low frequencies are effectively amplified.

Contrary to my previous experience, I noticed that the 106 shows a more pronounced bass sound, as indicated by the left portion of each spectrum analysis, with some increased presence in the middle and higher frequencies.

JBL T501 BT and comapring with the T500 model

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The model was purchased with the aim of using a BT model in the city shack where I conduct most of my audio work, including Dxing, cross-testing audio equipment, and experimenting with antennas and wires to achieve the clearest possible radio reception in town, particularly for shortwaves and LMF. Additionally, it involves printing Dx and other related internet material at the lowest possible cost compared to the roughly double cost in the village.

This Bluetooth model is used mostly to remotely adjust the loop antennas for the lowest noise. The author mentions using it to remotely listen into shortwaves etc while assisting his elderly mother. Additionally, this Bluetooth model is used in part to remotely adjust the loop antennas for the lowest noise.


The BT500 and T501 have an identical design, with the only difference that the T500 is cabled while the other model includes a USB C socket for charging and a control panel . Unlike the other tested models, this model utilizes a separate button to initiate or terminate Bluetooth connectivity. When connected to either a PC or smartphone, it is identified as 'JBL Tune 510 BT'.



After conducting a sound comparison between the T500 and the newer 501BT, it was found that the sound level of the T500 is 14 steps higher when set to level 50. This equates to roughly a 10db difference. However, the T500 has higher bass while the 501BT has lower bass and slightly higher treble, resulting in a more 'linear' sound.  

When testing the audio quality between a smartphone and a laptop on the same channel, the sound is nearly identical.

Hope later to conduct the final test by using a tone generator file fo better crosstesting between both models


Τετάρτη 27 Δεκεμβρίου 2023

HOco E73 Pro min BT trasnmistter

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This transmitter receiver is one of the most affordable options in the local market, priced at only 13 Euros. I ordered two pieces over a month ago. Other models are available in the market starting from 20 Euros, but I was pleased to find the lowest price in Southern Greece. Payment was made in cash upon delivery,

and the model was received within two days. The first one was checked and found to be working well, except for some blinking during operation, which is normal. The problem was identified clearly.

The second model worked without any issues and was promptly returned. The staff were helpful in checking and sending the remaining model back home in less than a week, despite the fact that I received it two weeks later.

This type of transmitter is ideal for use with gear that does not include Bluetooth. I own several mini gear items, including shortwave radios and MP3 players.

The operation of this item is simple: press the TX RX switch to enter transmit mode and connect the AUX plug using the provided double nipple plug or the cable jumper included in the box. It may be challenging to find a nipple of this quality on eBay, except for some in black rubber at half the price.

To connect to a mini amplifier or headphones without Bluetooth, switch to RX mode and use the provided cable.

Please refer to the photo below for an example of how to connect the transmitter to a shortwave radio using the same 3.5mm jack as shown above.


I have several shortwave receivers and a few non-Bluetooth MP3 players that need attention. Specifically, I have a Tecsun shortwave and FM radio. I have used Bluetooth with a 3.5mm jack, which works well with wired headphones such as the JBL T500. I also tried the JBL 510, which is the Bluetooth equivalent of the T500, and found that the sound quality was even better.


Here is the second example. I used an older 3.9mm stock jumper cable to connect both the Nintaus MP3 player and the transmitter. The sound is good and slightly flatter than when using the T500.

In terms of distance, I tested the radio indoors while listening with the BT510 headphones  the VT counterpart of the T500 headphones . The reception is clear and uninterrupted in most rooms, except for those separated by three thin walls. The coverage distance is approximately 11 meters.

Κυριακή 6 Αυγούστου 2023

Checking a cheap inkax model

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The Inkax series model mentioned above is one of the most affordable options available in Salonica, priced at just 3-4 Euros for a small box containing around 10 pieces or more.  These pens are available in three colours. I purchased one to experiment with.


The small box contains only what is shown above: a mini plastic bag with earphones and a set of silicone buds. The packaging is simple and straightforward. The small box contains only what is shown above: a mini plastic bag with earphones and a set of silicone buds. There are no additional items included.


Here is the set with the cable detached.   The earphones have a nice design with thinner ends and a typical plug with reverse polarity for audio.


This may be the best angle to capture the back end of the earphone, which can be pushed comfortably into your ear.

Here is a good shot to show the button for stepping or releasing the playback.

The earphone design is quite good. Regarding the hearing results, I have a few comments and positive aspects to highlight.

The earphones have a good frequency response for both bass and treble, providing a full audio range.

In contrast, the audio provides a strong middle range at 400-700 Hz, which enhances speech clarity but reduces music listening quality by more than 6 dB compared to a 'linear' HiFi model (this is for comparison purposes only).

On the other hand, the microphone performs the opposite as tested with the now-extinct Inax HiFi model: it has relatively poor

bass with no increase in the middle range (which is

good) and higher treble than the other model. Listen to these files to better understand:

https://app.box.com/s/79ohgiunv1wo63us682pjqokvem6zl0l (for the HiFi model) and https://app.box.com/s/kp8mbq7w9yijt170vv7wgke3b7ai05dv

(for the other model).

Τρίτη 21 Φεβρουαρίου 2023

Crazy : SD memory ater 4 yers dead! and the smart's freezings ...

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This is more than  5 yes after buying my second smartphone. this is a 小米 Xiaomi Redmi  5A  NOte Model that was used quite heavy all that time< its features were very good for me with 13 + 5 MB camera  a i5 model plus 1280 x 720 and dual Simm  even that i used only the one.  16 GB internal memory , 2 RAM plus added  external SD memory 32GB

It was used  not only as mobile telephone but much more. My standard programs were Gmail that i  later stopped as i preferred to use the web version in google   due to low internal memory (just 16 GB ). MY fav programs of the start time were also Xiia  free edition that later was replaced with the pro version  and which later was removed due to ver low memory again. In the list thre were also a PDF reader and pdf manager - Foxit - and many more that i think are not reason to write them  here .

As always was fan of photographing and  with this smartphone I uploaded more thjan 4500  photos in Instagram  and deleted more than 5000 photos so far . 

last year - after Sept 22  Instagram app  made a twin cases of complete freezing the smartphone  that is i cold not do anything with it , neither even being abe to reset it. I can assume the problem lied mostly in the less than free 600 MB in the main RAM (not the SD)

The nly i could do was to wait until the battery goes zero and completely stop operating > And really this idea worked in full. Instagram application then was reset losing my personal data  . I then preferred  to use the web version only and lower the postings 

On Jan 23 we  did a trip to a nearby mountain and liked to walk along a small village nearby ours. Driving there was rather difficult into a meander of a thin road and finally ending after 25 minutes into a place of temperature 5 degrees lower than Litohoron !  It's name i Old Panteleimon

the place was really something really impressive and extraordinary with its very beautiful houses of the older style . this made me to immediately take a few pictures but without checking then after shot. Because we were a bit in a hurry 

After ending our adventure there ad returning back home i understood that no photos were saved except something black and only for the 2 out of the 5 shot. I tried unsuccessfully to find a better solution by checking via the menu. Neither the technicians on the smartphone office   found any solution except of backing up part of the  phones inner memory into another SD card

Finally the problem solved when  I returned back to the city – Thessaloniki- and given to a new PC technician. He spent around 2 days to analyze the memory problems , add a new memory and backup al the data . The reason was simple :

The SD CARD is  dead!

Backup was too slow that he inner data of 18-20  GB required around 15 hour to be transferred

The total cost was 25 EU  for service and 10 EU for the memory

After that I have seen some mysterious behaviours:

One of the dictionaries used by the Gtranslate cannot be downloaded. I use 4 languages  for offline translating together with Greek  and English Any who knows  me well already knows which are!

A voice recording program I use for writing my ideas does not identify well the save path I had to make a new path or directory to save the  new recordings

Any other  savings are OK and the camera still works OK after so long time of esp heavy use after 4 + years