u/Primary-Feedback2296

Today the EUIU EI-01 arrived, a cheap iem that surprised me a little.

First, the packaging is very good, thats standard these days.

First surprise, it comes with a little leatherbag that have two metal bands to open it, press it and it opens. Maybe some of you know it from 50 years ago, cars came with these bags for the keys.

Second surprise was the fit. First i feel that the iem could be a little bit fat (they are). I installed the grey M-Size eartips and wow... they fit in my ears like with a sslurrrp and its in. Like they only were made for it. They feels big, but they fit so easy and light and feels very lightweight. I only know this before at the Kefine Klean SV.

Ok the sound. The bass is okay, nothing missed, but its a very little bit fat, not too much, but a little bit.

The mids and treble are present but not loud, clarity is missed a little bit. But im old, so its a personal note, not a real judgement.

Isolation is good too.

A bro is a very sensitive to treble and this iem could be a match for him. I read that some others here are sensitive too and feels treble very harsh sometimes. With IE-01 it should be better.

If i compare it with my Waner SG II i can state that the EI-01 is clearly better. While Waner SG II mixes all to a juice a little bit and loose control, the EI-01 dont do that. Control is good and louder listening is not a problem. It doesnt sound 'cheap' like the Waner.

So for the price of only 30 bucks it is a good iem as allround outside and on the way.

Had a very scratchy and etched dustcover. Some weird etched spots, like there was a cyanocrylate glue on fingers, looks very weird.

So i used wet sandingpaper grit 1500 and sanded wet by hand in small circulating moves. Like on carpainting to remove orangepeel or some defects.

I used two strips of ducttape to fixate the cover on the table. Otherwise the polisher will give it a free flight.

Then used a rotatingpolisher and a middlehard foampad 165mm diameter.

The polishing compound is the Sonax Ultimate Cut, Menzerna SHCC will do it too. They are polishingcompounds for carpainting to polish sanded surface from grit 400-800up.

At lowest speed (600rpm) i polished the cover in one direction, then 90 degrees across, it needs two rounds.

Comes out phantastic. Its crystalclear and even.

At last step i used a headlight restorer for cars, thats avaiable in every car-care shop for cheap. Thats mostly a light polishingcompound with a bit of sealant.

That removes every dust and covers every possible hologram from polishing and seals the surface a little.

It looks incedible new.

Had an idea to test my EF95 5654 6AK5 6Zh1P tubes with a small tester at 24 volts, instead of 120 (my lab psu can only up to 30v). And its safer.

The readed values will be converted based on the factory-values. And i have some already multiple tested 'bad' and 'very good' tubes as reference.

This would be the circuit. But im unsure, my last build with tubes was nearly 25 years ago.

Please take a look, are there errors? Better ideas?

Any help is welcome.

Okay, at r/budgetaudiophile they say its a headphone.

So i proudly post it here

I was happy to receive an xDuuo TA-10R.

It works not only as a headphone amplifier, but also as a nice little preamp.

It has an optical and a coaxial digital input, as well as a USB input that can be used with drivers for Windows, Mac, and Android. But I suspect it will also work as a USB audio device without drivers. I assume it will work the same way with Ubuntu.

A analog line inomput is avaiable too.

And theres a line output to connect to any amplifier. So its a preamplifier and easy to use with old amps wich only have one Aux-input.

The display is a 0.96" yellow-blue type, similar to those found on the ESP8266 MCU or standalone. It shows the selected input, the volume, and for digital inputs, the format and sampling rate.

Pressing the volume control selects the various inputs; turning it adjusts the volume in several clicks, and there’s a noticeable click stop on the control.

The included tube is a 12AU7 stamped with the “X” for xDuuo, maybe a standard chinese tube, maybe they differ depending on imventory at manufacturing, who knows. More on that later.

So plugged in the old Tinhifi T2 and connect a HK DVD25 via coax digital to run CDs.

One negative point now. You cant 'shut down' the amp or set it to stand-by. You have to switch off at the back. It results in a loud 'pop' in headphone, even at 0 volume. So plug off the headphone first. Luckily at line out theres no pop.

The initial listening test was somewhat disappointing, the sound was muddy and muffled.

So I inserted a Telefunken ECC82 (manufactured in Ulm, Germany, Diamondbottom). Immediately, the sound took on a whole new dimensio, wide open, with clear, strong highs and mids. The bass was precise and powerful. It rocks. But I still felt there was a slight veil over the sound; it was as if the handbrake were still partially engaged, somewhat muted. Not full attack.

Then I tried an S&H Siemens ECC82. It was truly mind-blowing. The haze was gone instantly, and it really rocked very hard. Everything was clear and light. The bass was even more precise, the electric guitar really cut through, and the bass guitar was significantly more precise. The drums had real punch, and the cymbals were delicate and clear. The vocals stood out cleanly among the instruments.

It sounded as if a thin silk curtain had vanished.

That really rocks hard, anyone who’s into metal will love this.

But I still had the original 12AU7 from xDuuo. I let it break in for 10 hours. Lo and behold, it’s not nearly as bad as it was at the start. It sounds clear and well-defined; the soundstage is open, and the bass is round. But it doesn’t quite match the incredible attack and clarity of the Siemens or the Telefunken. Still, I’m giving it another 50 hours.

There's still the Shuguang 12AU7-T to try, a very good, completely new design featuring triple mica and a few remarkable details, such as the metal surface enlarged by many small, fine ripples, a shield between the two sections, very fine and close windings (slightly visible thru the holes), and a monocrystalline glass coating. I love everything about it. I like it when a new design manages to improve on this old technology, even just a little.

Even the very first listen when it was brand-new was already impressive. It renders details with incredible precision.

The other headphones are the K702 and the Deva pro and the Wa'ner SG. Same results. Even the Deva pro was not lame like on other amps (he cant rock hard, but nice).

That's enough for now. Once the original tube and the 12AU7-T have burn in, there will be more.

I was happy to receive an xDuuo TA-10R.

It works not only as a headphone amplifier, but also as a nice little preamp.

It has an optical and a coaxial digital input, as well as a USB input that can be used with drivers for Windows, Mac, and Android. But I suspect it will also work as a USB audio device without drivers. I assume it will work the same way with Ubuntu.

A analog line inomput is avaiable too.

And theres a line output to connect to any amplifier. So its a preamplifier and easy to use with old amps wich only have one Aux-input.

The display is a 0.96" yellow-blue type, similar to those found on the ESP8266 MCU or standalone. It shows the selected input, the volume, and for digital inputs, the format and sampling rate.

Pressing the volume control selects the various inputs; turning it adjusts the volume in several clicks, and there’s a noticeable click stop on the control.

The included tube is a 12AU7 stamped with the “X” for xDuuo, maybe a standard chinese tube, maybe they differ depending on imventory at manufacturing, who knows. More on that later.

So plugged in the old Tinhifi T2 and connect a HK DVD25 via coax digital to run CDs.

One negative point now. You cant 'shut down' the amp or set it to stand-by. You have to switch off at the back. It results in a loud 'pop' in headphone, even at 0 volume. So plug off the headphone first. Luckily at line out theres no pop.

The initial listening test was somewhat disappointing, the sound was muddy and muffled.

So I inserted a Telefunken ECC82 (manufactured in Ulm, Germany, Diamondbottom). Immediately, the sound took on a whole new dimensio, wide open, with clear, strong highs and mids. The bass was precise and powerful. It rocks. But I still felt there was a slight veil over the sound; it was as if the handbrake were still partially engaged, somewhat muted. Not full attack.

Then I tried an S&H Siemens ECC82. It was truly mind-blowing. The haze was gone instantly, and it really rocked very hard. Everything was clear and light. The bass was even more precise, the electric guitar really cut through, and the bass guitar was significantly more precise. The drums had real punch, and the cymbals were delicate and clear. The vocals stood out cleanly among the instruments.

It sounded as if a thin silk curtain had vanished.

That really rocks hard, anyone who’s into metal will love this.

But I still had the original 12AU7 from xDuuo. I let it break in for 10 hours. Lo and behold, it’s not nearly as bad as it was at the start. It sounds clear and well-defined; the soundstage is open, and the bass is round. But it doesn’t quite match the incredible attack and clarity of the Siemens or the Telefunken. Still, I’m giving it another 50 hours.

There's still the Shuguang 12AU7-T to try, a very good, completely new design featuring triple mica and a few remarkable details, such as the metal surface enlarged by many small, fine ripples, a shield between the two sections, very fine and close windings (slightly visible thru the holes), and a monocrystalline glass coating. I love everything about it. I like it when a new design manages to improve on this old technology, even just a little.

Even the very first listen when it was brand-new was already impressive. It renders details with incredible precision.

The other headphones are the K702 and the Deva pro and the Wa'ner SG. Same results. Even the Deva pro was not lame like on other amps (he cant rock hard, but nice).

That's enough for now. Once the original tube and the 12AU7-T have burn in, there will be more.

I have bought a little 5V 15VA psu for a little headphone amp that need 5V 2A. Sadly i can hear a high frequency buzzing and sometimes a whining and queeking. And it runs very warm even if the amp delivers nearly lowest power.

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Tried different cable for dc, a standard, a twisted pair and i fletched a cable out of three twisted pairs to rise the inductivity in hope it can supress the noise a bit.

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The transformer have two windings, 2x 9V / 7.5A. I measured 13.5 volts after rectifier. So i think the 9V windings are in parallel to reach the 15VA.

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The LDO is a LT1085 and the circuit is the standard referencelayout by LT.

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But i think its not a legit Linear Technology, the printing is very bad and the "LINEAR" is wrong.

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So could it be that 13.5 volts are too much in general for a LDO that is adjusted to 5V? And its noisy because its a bad LDO?

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Would a genuine LT or Analog Devices better in handling the 13.5 volts?

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Or is the standard reference layout not enough (not clean enough) for use with a amp?