xDuoo TA-20 Tube Balanced Headphone Amplifier Review

[muslhead]

As long as you run that shiit ballanced, it's a fine amp.

i duoo

 

[muslhead]

The Modius is a DAC, did you mean the Magnius?

https://www.schiit.com/products/magnius

Easy to mix up those names

What the heck is a Magnius? That doesn’t sound Norse.
It’s like Modius. When we were developing a bigger, better, balanced Modi, we started jokingly calling it “Modius Maximus.” The name stuck. So when we also started working on a bigger, better, balanced Magni Heresy, we started calling it “Magnius.” That name stuck too. So now you’re stuck with Modius and Magnius.

But you’re conflating Norse mythology with Roman terminology!
Right.

But that doesn’t make sense!
Dude, you used the word “conflating.”

Sigh. Okay. Fine. I guess that’s all we should expect from a company that gets all its Norse mythological information from comic books.
And Wikipedia. Don’t forget Wikipedia!

The Magnius measurements and spec's look good, how does the audio drive compare to the TA-20? What is the impedance for your
headphones? And, which DAC do you use?

Spoiler: Magnius power / specs

Balanced Headphone Output:
Maximum Power, 16 ohms: 6.0W RMS per channel
Maximum Power, 32 ohms: 5.0W RMS per channel
Maximum Power, 50 ohms: 3.2W RMS per channel
Maximum Power, 300 ohms: 1000mW RMS per channel
Maximum Power, 600 ohms: 500mW RMS per channel

Single-Ended Headphone Output:
Maximum Power, 16 ohms: 2.2W RMS per channel
Maximum Power, 32 ohms: 2.0W RMS per channel
Maximum Power, 50 ohms: 1.3W RMS per channel
Maximum Power, 300 ohms: 300mW RMS per channel
Maximum Power, 600 ohms: 150mW RMS per channel

Note: Maximum power rated at 1% THD, high gain

THD+N:
Low Gain, Balanced Output: Less than 0.0001% (-119dB) at 4V RMS into 32 ohms
High Gain, Balanced Output: Less than 0.0003% (-110dB) at 4V RMS into 32 ohms
Low Gain, SE Output: Less than 0.003% (-90dB) at 1V RMS into 32 ohms
High Gain, SE Output: Less than 0.004% (-87db) at 2V RMS into 32 ohms

IMD:
Low Gain, Balanced Output: Less than -112dB at 4V RMS into 32 ohms, CCIF
High Gain, Balanced Output: Less than -110dB at 4V RMS into 32 ohms, CCIF
Low Gain, SE Output: Less than -73dB at 1V RMS into 32 ohms, CCIF
High Gain, SE Output: Less than -72dB at 2V RMS into 32 ohms, CCIF

SNR:
Low Gain, Balanced Output: Greater than 125dB, unweighted, referenced to 4V RMS
High Gain, Balanced Output: Greater than 115dB, unweighted, referenced to 4V RMS
Low Gain, SE Output: Greater than 105dB, unweighted, referenced to 1V RMS
High Gain, SE Output: Greater than 110dB, unweighted, referenced to 2V RMS

Crosstalk:
Less than -90dB, 20 Hz-20 kHz, either gain, 300 ohm load
Less than -70dB, 20 Hz-20 kHz, either gain, 32 ohm load

Output Impedance: Less than 0.1 ohms at either gain
Input Impedance: 50k ohms

Gain:
Balanced Output: 1 (0db) or 5 (14db)
Single-ended Output: 0.5 (-6dB) or 2.5 (8db)

Topology: Composite amplifier with OPA1688 input buffers, LME49724 differential amplifier, TPA6120A2 current feedback output stage, DC coupled.

Protection: Standard failsafe DC power input and muting relay

Power Supply: “Wall wart” style 24VA 15VAC transformer, linear regulated +/- 13.5V rails with over 6,000uF filter capacitance

Power Consumption: 6W idle, 21W max

Size: 9 x 6 x 1.5”

Weight: 2 lb

APx555 Report for Magnius

yes i meant the Magnius. Thanks for catching the error.
I use the matrix audio element as my dac
The hifiman he1000v2 impedance is 35 ohms

 

[hmscott]

Going back to the PSVANE to see if i get some hours on them the microphonics will disappear.

So far the PSVANE 12AU7-T MKII sound best for vocals - I really enjoyed listening to spoken content on them.

I'm sticking to the RCA Clear Tops for now. The Left tube that ping'd is much less pronounced in the sound back from tapping it, the Right tube is silent.

Hopefully, your PSVANE microphonics will reduce with usage too.

Jazz Trumpet Essentials

Spoiler: Details...

The very first jazz icon, New Orleans’ Buddy Bolden, played the trumpet’s cousin, the cornet. He never released a recording, but fortunately, the generations of great trumpeters to emerge over the past century did. This playlist surveys jazz’s oldest soloist tradition, from Louis Armstrong to Dizzy Gillespie, Miles Davis, Freddie Hubbard and present-day standouts like Christian Scott aTunde Adjuah. (Photo: Unsplash)

https://tidal.com/browse/playlist/829456c2-acfc-44b4-81bf-37c356f1c471

Trumpet Concertos by Tine Thing Helseth
Amazon Music: https://music.amazon.com/albums/B001AM28SO?ref=dm_sh_c104-bce8-97a3-e159-da855
Tidal: https://tidal.com/browse/album/2394754
Youtube

Tidal Video Mix
https://tidal.com/browse/mix/004997f458a688cc66f865b77b5b12

@Noodles: None of the tubes had apparent hiss with the Beyerdynamic 600 ohm / 16 ohm or Sendyaudio AIva headphones, but when I plugged in the KZ ZAX's on a 4n Pure Silver balanced 4.4mm cable, the RCA Clear Top Baldwin NOS Tubes lit up with a wall of hiss - stronger in the left channel. I've got the 12AU7-T MKII's in right now and they have no hiss from 0-95 on the TA-20 volume. The listening level on the KZ ZAX is 45. I'll test the stock tubes later.

 

[hmscott]

@Noodles: None of the tubes had apparent hiss with the Beyerdynamic 600 ohm / 16 ohm or Sendyaudio AIva headphones, but when I plugged in the KZ ZAX's on a 4n Pure Silver balanced 4.4mm cable, the RCA Clear Top Baldwin NOS Tubes lit up with a wall of hiss - stronger in the left channel. I've got the 12AU7-T MKII's in right now and they have no hiss from 0-95 on the TA-20 volume. The listening level on the KZ ZAX is 45. I'll test the stock tubes later.

I've since tried a few other IEM's and all were noiseless, no HISS, but then I plugged in the newish KZ ASX and - no HISS, not hiss but a haze that goes away when there is content playing. It is only there when nothing else is playing. It is very low, but it is there.

The KZ ASX's have the largest range of drivers in KZ's history, there must be a BA in there that is sensitive to these tubes. The ASX has 10 BAs on each side, 20 total - the "haze" is equal in both earpieces. I also tried the last highest BA count IEM's that KZ put out, the AS16's and there isn't a hint of haze with those. The KZ ASX added 2 more BA's per earpiece and at least one pair of those is sensitive enough to show the haze.

The KZ ZAX, KZ AS16, KZ ZSX, BQEYZ Spring 2, and all of my headphones sound quiet as can be on the PSVANE 12AU7-T MKII's, but it seems there is a sensitivity for some IEM's on Tube's not shared across all IEM's on all Tubes, so I'm going to keep testing IEM's.

Also, some more feedback from Xduo:
"Xduoo reply below 8V is all no problem. if it is above 8v, it will cause distortion." - [email protected]

The D90 MQA XLR at most outputs 4Vrms @ 0dBFS, so it won't overdrive the TA-20.

How goes your testing? How is the 12AT7 performing?

 

[Noodles]

Well i've finished tube swapping and checking and doing shit... JJ tubes, best tubes
Stock tubes have very good sound for free tubes (and 8 bucks a pop aftermarket) - but there is a lot of variance.
12AT7 from JJ are a ton less noisier and have better gain than 99% of 12AU7 tubes out there.
Overall the JJ tubes i got better bass, more resonance for certain instruments and accurate highs. I have not heard anything going on in the mids with them.
The PSVANE's i got are all microphonic... other than that they are alright. They seem to suck out all the bass enjoyment out of the music though (makes bass more accurate and fast but less punchy) ... especially with the HD800.
Mullards i got have ~bass, bit bloaty honestly. They mostly cater to mids lovers - vocal stuff is a tad better, but the difference from them on the TA20 and my A90 is quite minimal.
In my opinion - to get better tubes you need to spend a ton more money, so you know ... don't.
In my limited experience tubes have so much variance that it is just not worth experimenting that much because all you do is throwing money away. I got 6 JJ tubes and only have 1 dud with the 12AU7's having no noise whatsoever and only the 12AT7 having an audible noise floor.
This has been an interesting experiment ... a fairly costly one - but informative. If i did not have the HD800/DT880 i would not buy a tube amp again.
I'm sticking with JJ tubes.
Just my 2 cents, you do your math.


@hmscott i used to test with KZ ASX, but gave them to a friend. I'm now testing with my IKKO OH10 as it appears to have the same sensitivity as the KZ.

Edit: on a side note - the tube sockets on the TA-20 are starting to show wear and the amp is giving me protection errors when seating tubes from time to time... and it's not been more than 50 swaps yet. Take that as you will.

 

[hmscott]

Well i've finished tube swapping and checking and doing shit... JJ tubes, best tubes
Stock tubes have very good sound for free tubes (and 8 bucks a pop aftermarket) - but there is a lot of variance.
12AT7 from JJ are a ton less noisier and have better gain than 99% of 12AU7 tubes out there.
Overall the JJ tubes i got better bass, more resonance for certain instruments and accurate highs. I have not heard anything going on in the mids with them.
The PSVANE's i got are all microphonic... other than that they are alright. They seem to suck out all the bass enjoyment out of the music though (makes bass more accurate and fast but less punchy) ... especially with the HD800.
Mullards i got have ~bass, bit bloaty honestly. They mostly cater to mids lovers - vocal stuff is a tad better, but the difference from them on the TA20 and my A90 is quite minimal.
In my opinion - to get better tubes you need to spend a ton more money, so you know ... don't.
In my limited experience tubes have so much variance that it is just not worth experimenting that much because all you do is throwing money away. I got 6 JJ tubes and only have 1 dud with the 12AU7's having no noise whatsoever and only the 12AT7 having an audible noise floor.
This has been an interesting experiment ... a fairly costly one - but informative. If i did not have the HD800/DT880 i would not buy a tube amp again.
I'm sticking with JJ tubes.
Just my 2 cents, you do your math.
@hmscott i used to test with KZ ASX, but gave them to a friend. I'm now testing with my IKKO OH10 as it appears to have the same sensitivity as the KZ.

Edit: on a side note - the tube sockets on the TA-20 are starting to show wear and the amp is giving me protection errors when seating tubes from time to time... and it's not been more than 50 swaps yet. Take that as you will.

Well, so far the cost of the tubes isn't as much as it could be, as there are NOS tubes out there for $hundreds$ more for one pair, IDK if that will help audibly, perhaps it's more of a "tube collectors" hobby than audiophile related.

There are several you and I haven't mentioned still that I would like to try, and over time I will get around to it for now I'm happy with the PSVANE tubes, and you are happy with the JJ tubes.

I'll probably order some of these JJ tubes next:

JJ ECC802 / 12AU7 Long Plate Gold Pin Vacuum Tube - $29
https://www.amazon.com/JJ-ECC802-12AU7-Plate-Vacuum/dp/B003H7KPFS/

Pair of JJ ECC802s/Hi-Performance 12AU7 Gold Pin Preamp Vacuum Tube - $50
https://www.amazon.com/ECC802s-Hi-Performance-12AU7-Preamp-Vacuum/dp/B07BHTJ59K

Which JJ model is your recommendation? Do you think the extra gain of the 12AT7 JJ tube is worth the higher noise floor?

It turns out the TA-20 stock tubes aren't what I thought, here is the feedback from Xduuo:

https://www.aliexpress.com/item/1005001745244020.html
"This one xduoo replied it is not the original one with the TA20, but the original tube is not available now because the former factory is moving to new place, and they stopped production for two years already."

I did a little research, found this at PSVANE's site, and I've asked Hifigo/Xduoo if the stock tubes are "Shuguang" tubes:

"... Shuguang tube factory’s shutdown in 2019 due to sale of land and relocation..."

More detail from this site:

"2. Laser beam focus:
When business grows, they do tend to increase their offering to cover more market segments to increase revenue. Psvane indeed have taken the golden opportunity to expand and fill in the void left by Shuguang tube factory’s shutdown in 2019 due to sale of land and relocation, and Psvane has set the stage for expanding into the mass production guitar amp market, which mostly use small signal tubes and EL34/KT88/KT66 etc. Large triode tubes such as 300B/845 tubes are mostly used by HiFi market and are not the focus of the guitar amp musician market."
https://premiumvacuumtubes.com/

I'll post when I hear back from Hifigo/Xduoo.

Since my last post I've been listening to TinHifi P1's on the PSVANE 12AU7-T MKII's and I was surprised at how different they sound since the last time I listened to them. The P1's sound much more mellow on the TA-20 than when I last listened on the A90. I'm now running the D90 MQA at 00.0dB - full output via XLR to the TA-20, btw. I'm really enjoying the P1's now, they do take more power than the other IEM's, listening around 60 vs 45-50. Of all the IEM's I've tried so far the P1's really show the benefit of the tubes.

For me the TinHifi P1's started out as immediate rejects - they were offensively bright and painful to listen to. I had to burn them in for weeks offline before I could stand to listen to them, but then their benefits were apparent - very large sound stage and detailed presentation - which shines through even more clearly on the TA-20. Opera on them is outstanding. I'm really enjoying them TA-20!

Too bad about the tube sockets on the TA-20. If they do wear out I can replace them, I've seen ceramic sockets and they are inexpensive. I tried to use the socket savers, but the recessed sockets on the TA-20 make them difficult to use. The socket saver pulls out of the TA-20 before the tube pulls out of the socket saver.

Here are some other tubes I'd like to try, I've got them saved on AliExpress, have you tried any of these?:

1Pair Shuguang New 12AU7-TG
https://www.aliexpress.com/item/1005001346481544.html

PSVANE COSSOR 12AX7 12AU7 12AT7 ECC83 ECC82 Vacuum Tube
https://www.aliexpress.com/item/4000307706036.html

Shuguang Natural Sound 12AT7-T/12AU7-T/12AX7-T
https://www.aliexpress.com/item/32957081117.html

New Matched Pair TJ Fullmusic 12AU7 ECC82
https://www.aliexpress.com/item/32812198503.html

And, I discovered these, they look like the TA-20 stock tubes

Tube bile 12AU7 12AX7 12AT7 made in China / Shuguang
https://www.aliexpress.com/item/1005001585590528.html

Spoiler: Details

Tube bile 12AU7 12AX7 12AT7 made in China

Shuguang Electron Tube Factory was founded in 1958 and mainly produces electric vacuum devices and electric vacuum materials. It is a professional factory producing various electronic tubes, and passed the ISO9000 quality system certification in 2000. Strong technical force, rich management experience, complete testing methods, product quality as the life of the enterprise, and has an advanced quality assurance system. The Shuguang electronic tube produced by the factory has won the National Quality Silver Award, the Ministry of Excellent Product Award, the Provincial Excellent Product Award and so on. The products are not only sold throughout the country, but also exported to more than 60 countries and regions in North and South America, Europe, Australia, Japan and Southeast Asia.

As the world's largest and strong tube manufacturer, Shuguang's treasure series of tubes have been widely praised worldwide.

Changsha new Shuguang tube 12AU7 ECC82 original pairing free pairing.

 

[Noodles]

Which JJ model is your recommendation? Do you think the extra gain of the 12AT7 JJ tube is worth the higher noise floor?

I am content with either one of these:
https://www.tonefactory.nl/jj-12au7-ecc802s-e82cc-balanced
https://www.tonefactory.nl/jj-12au7-ecc802s-gold-pin-balanced

They are essentially the same tubes but the gold pins are allegedly lower noise and tighter tolerances.

With the intended use (high impedance headphones) the slightly higher noise from the 12AT7 is not going to be audible. If it's worth it - depends on how hard the headphones you use are to drive.
Say if you are trying to drive an HE6, maybe worth it (for the gain).
For HD800/DT880 - they are not needed.

Regarding the cost - i personally have now spent about 50% more than the price of the amplifier on tubes, so i will definitely not continue with more experimenting. There is way too much variance in tubes and i will just not throw money in the wind to see if i can get a good pair ...
I will get myself a second pair of JJ's and that will be that.

 

[hmscott]

I am content with either one of these:
https://www.tonefactory.nl/jj-12au7-ecc802s-e82cc-balanced
https://www.tonefactory.nl/jj-12au7-ecc802s-gold-pin-balanced

They are essentially the same tubes but the gold pins are allegedly lower noise and tighter tolerances.

It looks like you bought 2 kinds of the same tube, the ECC802s, the Long Plate - those are supposed to have lower noise than the EC802, but different sound.

You have convinced me to try the JJ tubes next, and I've bought the two different pair: the ECC82 Short Plate Gold Pins, and the ECC802s - Long Plate Gold Pins.

JJ Electronic - ECC82 / 12AU7 - GOLD
JJ ECC82 / 12AU7 Gold Pin Preamp Vacuum Tube
JJ 12AU7 / ECC82 Gold Pin Vacuum Tube (10 reviews)

JJ Electronic - ECC802S - GOLD
JJ ECC802s / Hi-Performance 12AU7 Gold Pin Preamp Vacuum Tube
JJ ECC802(s) / 12AU7 Long Plate Gold Pin Vacuum Tube (5 reviews)

Spoiler: JJ ECC82 / ECC802s tubes closeup side-by-side photo

As far as stopping the tube hunt, I understand, you are way ahead of me in tube rolling. I'll try to cover other tubes than you've done too to add to the info should anyone come across this thread with tube choice questions.

 

[Noodles]

To whomever finds these ramblings upon further swapping the JJ's to Mullard/Tungsol/Sylvania/EH/PSVANE:
There appear to be a-lot more energy somewhere in the 6k-10k register with the JJ's - In most cases that is not an issue, but you will come across songs where if you are using them with an HD800(S), there will be pain.

 

[hmscott]

To whomever finds these ramblings upon further swapping the JJ's to Mullard/Tungsol/Sylvania/EH/PSVANE:
There appear to be a-lot more energy somewhere in the 6k-10k register with the JJ's - In most cases that is not an issue, but you will come across songs where if you are using them with an HD800(S), there will be pain.

I've noticed that same phenomenon with my fast tube swapping too. I find the sound mellows after a few hours of running, gradually getting better sound the longer they run. I hear the same in the comments about the JJ tubes, from multiple sources. "I gave it a few minutes to warm up and the sound wasn't good", others say "after a few hours of warming up it sounded better and kept sounding better the longer it ran"

So, "fast tube rolling" a bunch of tubes probably isn't really a thing we can do with much success unless there is a way to keep the tubes hot while waiting their turn. To set up a half dozen amps each with different pre-amp tubes all warmed up to compare would be ideal.

From all of the positive comments about the JJ tubes, including your comments from long term use, I will probably enjoy the JJ tubes. If not then tubedepot.com has a 14 days cash return policy and 90 days warranty. I'll try to not use the return path and simply enjoy the unique attributes of the JJ tubes.

The HD800s can be sensitive to bright source material, so I'll watch for that in my listening too.

Thanks for the heads up, and please keep the listening comments coming, it does help.

 

[BubbaJay]

I've had the TA-20 for over a month now and I really enjoy it a lot. I bought a few tubes to see what kind of changes I could get and both sets sound a little different which is what I wanted and they both sound really nice. When it's the right kind of distortion it can really make your headphones sound very good. The TA-20 is quite clean sounding with a touch of warmth that you can bring out even more with the right tubes.

 

[hmscott]

I received an Apos notice email, Xduoo has released 2 more affordable SS/Tube Hybrid headphone amps:

xDuoo MT-601 Tube Class-A Headphone Amplifier – Apos Audio - Single Tube $89

xDuoo MT-602 Tube Class-A Headphone Amplifier – Apos Audio - Two Tube $99

Xduoo also recently released the upgraded TA-10R, which includes a DAC too.

XDUOO TA-10R AK4493EQ XMOS Tube Headphone Amplifier — HiFiGo

 

[BubbaJay]

I got the same email but the TA-20 is their best hybrid amp as far as I know and I'm very happy with it, paired with my iFi Neo and using my Z1R, AP2000ti, and Arya all sound great. I've finally found my desktop setup, along with the A50s for the solid-state amp.

 

[hmscott]

@Noodles - The JJ Electronics Gold Pin ECC82 and ECC802S gain matched pairs arrived from tubedepot.com :

Spoiler: Image...

Out of the box the JJ ECC802S Matched Gain pair has a tight and narrow sound stage. It will take a few hours to open up, but it is already sounding detailed while not overly bright listening on a Beyerdynamic DT770 16 ohm.

Update: Well well, this is interesting. My Sennheiser HD598cs came alive with the JJ ECC802S's, it really blossomed like I haven't heard before. The HD598CS's are normally solid and a little boring, but not so on the JJ ECC802S tubes. Is this the "magic" I have heard about when driving Sennheiser headphones with tubes?

I've been on the fence for a while on which Sennheiser to get next, an HD58x or a HD6xx or a Sennheiser HD 650 original. After hearing the HD598cs (balanced 4.4mm) on the TA-20 with the JJ ECC802S tubes - and double-checking the tube sound effect across a number of media, I've ordered a Sennheiser HD650.

I'm excited to hear how the HD650 performs when driven with the TA-20 + JJ ECC802S's

 

[bgtip]

I learned the hard way that xDuoo TA-20 requires a very good source to sound it's best. I used to feed it from SMSL SU-8 and FiiO Q5s. Not bad, and I was audio happy. But then I bought SMSL SU-9. The new sound hit me as a ton of bricks. I was mesmerized. Finally I glimpsed into what 'audiophile' means. Basically it's a non-stop audiogasm. I am not being sarcastic and I am not kidding. That has been my experience. YMMV.
My rig:
SMSL SU-9 -> xDuoo TA-2 -> Monoprice M1060c Open Mod
Tubes: Philips 5814A Blue Label Matching 12au7a NOS USA Tv7 Tested

 

[hmscott]

I learned the hard way that xDuoo TA-20 requires a very good source to sound it's best. I used to feed it from SMSL SU-8 and FiiO Q5s. Not bad, and I was audio happy. But then I bought SMSL SU-9. The new sound hit me as a ton of bricks. I was mesmerized. Finally I glimpsed into what 'audiophile' means. Basically it's a non-stop audiogasm. I am not being sarcastic and I am not kidding. That has been my experience. YMMV.

Yes!!, that is exactly the synergy I heard when I put in the JJ ECC802S tubes and plugged in the Sennheiser 598cs, the change in the sound coming out of the 598cs is simply "magical". Thank you for sharing your moment of discovery.

It really is difficult to describe well enough for someone to understand that hasn't heard it themselves.

Even before that moment, all of the previous hours of listening on the TA-20 with other tubes, IEM's and headphones were a big step up from the SS-only sound. I'm still listening to the Sennheiser 598cs since swapping in the JJ ECC802s tubes! Maybe the other headphones and IEMs will also sound better too?

I've personally heard tube-only amp playback on headphones and speakers many years ago. That experience is why I started on this Tube amp re-discovery path now. I'm taking the slow route starting with a Tube / SS Hybrid, there is no need to rush through it all, it is a lot more fun to take the time to enjoy all the steps along the way.

BTW, I'm using a Topping D90 MQA => XLR => TA-20, and also have a Topping A90 Headphone Amp - currently sitting there cold and quiet.

My rig:View attachment 106509
SMSL SU-9 -> xDuoo TA-2 -> Monoprice M1060c Open Mod
Tubes: Philips 5814A Blue Label Matching 12au7a NOS USA Tv7 Tested

Where did you find the 5814A NOS tubes? Link? Thank you!

I'm a bit concerned that the NOS tubes may not be good for IEM's. The one NOS tube gain matched pair I've tried - the RCA Cleartop Baldwin NOS which was pre-screened for low noise puts up a "wall of HISS" when I listen with my IEMs. All of my headphones sounded great on that tube pair - no noise or HISS - but IEMs were useless under that level of HISS noise.

The PSVANE 12AU7-T MKII's (new production tubes) were great with IEM's - all except for the KZ ASX which has 10 BA's per earpiece and it had a "haze" of perceptible noise that went away during media playback but was just audible between tracks. The KZ AS16 with 8 BA's per earpiece didn't exhibit that sensitivity to noise on those tubes - it was silent between tracks. All of my headphones were also dead silent.

The JJ Electronic ECC802s tubes are also silent, and they are also new production tubes.

Do you have any IEMs that you could listen to on the TA-20 with 5814a tubes? It may be some IEMs are ok on NOS tubes, while others are sensitive enough to pick up the noise. And, some tubes might be noisy with many IEM's too.

I have discussed with a couple of NOS tube providers about adding a test with an IEM to the list of acceptance tests - at least for the tubes that I want to purchase. I might need to send them an IEM for the testing.

What other tubes have you tried?, and plan to try next?

 

[bgtip]

...

Where did you find the 5814A NOS tubes? Link? Thank you!

ebay

...

Do you have any IEMs that you could listen to on the TA-20 with 5814a tubes? It may be some IEMs are ok on NOS tubes, while others are sensitive enough to pick up the noise. And, some tubes might be noisy with many IEM's too.

I have Tin P1, T2 and blon 03, tried them with tubes, didn't like the sound. No noise though, at least with a 4.4 balanced cable, didn't try SE.

I have discussed with a couple of NOS tube providers about adding a test with an IEM to the list of acceptance tests - at least for the tubes that I want to purchase. I might need to send them an IEM for the testing.

Nothing better than a test.

What other tubes have you tried?, and plan to try next?

I have:
Matched Pair Amperex 12AU7/ECC82 Orange Globe Logo Heerlen Holland O-Getter 1967
Vintage Sylvania 12AU7A PLATINUM PLUS+ GRADE Tubes Matched Pair Test 100% NOS
Philips 5814A blue label factory matching 12AU7A NOS NIB USA
and the original.
They all sound different, and I change them according my mood, but the Philips 5814A make most difference. With them the soundstage is way out of my skull, imaging is pinpoint sharp and 3D holographic, and highs are presented in a strangely pleasing way. The whole picture is like if you watched a movie in standard definition, and suddenly you switched to 4k HDR.

 

[icsi85]

I can say now, that i am very happy with my choice. Really great amp to pair with something like a SMSL M500 (ESS)
Cant wait to get home, and play anything. ( i turned down a thx 789, it was not working in my setup)

I'm reading alot about tubes, i dont know wich to choose now. I search something like a spacious (3D), and a nice banging, like to get more, but tight bass with fast impact. ( I'm not a basshead, but i like it if its done right)

Thanks guys for sharing your experiences, it helps alot!
Great to see this topic go on...

 

[bgtip]

... I search something like a spacious (3D), and a nice banging, like to get more, but tight bass with fast impact. ( I'm not a basshead, but i like it if its done right)

Your description matches closely the Philips 5814A sound. I'm reluctant to recommend them at this price though ($49.19). I bought them in 2019 for $28.

 

[icsi85]

Your description matches closely the Philips 5814A sound. I'm reluctant to recommend them at this price though ($49.19). I bought them in 2019 for $28.

In Europe, on eBay, I could get a pair for $67-$98... . Anyway, I'm looking around. Thx!