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Talisman

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This is NOT a review, but an overview of the Aoshida A6 amplifier

DISCLAIMER

I know that many on ASR completely denigrate tube products, especially the very cheap ones with more aesthetic than functional purposes, as in this case, but considering the probable intended use of an amplifier in this price range and the other characteristics, I thought was an interesting product to try.
IMG_20230319_212401.jpg


I still don't quite understand what the relationship is between aoshida, douk audio, xduoo.... Many of these products seem to come from the same working group.
This amplifier is currently on sale on amazon italy for 99 euros. It seemed very interesting to me given some characteristics:

- Bluetooth LDAC
- MA12070 amplifier chip (single)
- Headphone output
- Dedicated RCA and Bluetooth input selector
- aux output usable to drive another amplifier or a sub
- Buy for a song
IMG_20230319_212331.jpg


It has just arrived and I can already make some considerations.
It is built very very well, solid, knobs of both volume and tone controls that go in steps and with good feedback, wider than the fosi audio tb10D that you can see next to it in a photo. The front thumbsticks feel solid. The backlighting of the tubes can be set to orange, green or off, I like orange light. Behind there are the outputs for the passive speakers, the RCA stereo input, the bluetooth antenna and the aux output with 3.5mm mini jack.
IMG_20230319_212428.jpg

I first tried bluetooth to see if it was indeed ldac as advertised, and indeed my huawei connected in ldac. This feature for me is already worth the 99 euros! Although the analog to digital conversion is done by the bluetooth chip, this will always be a much less problematic bottleneck than the difference between for example ldac and SBC or aptx. I have also tried the RCA input with my external DAC and it works as you would expect. Same thing for the aux output from which the full range signal comes out, so it will then be the task of a possible sub to carry out the lowpass cut.
IMG_20230319_221951.jpg

The supplied power supply is a 24V 4A (not 24V 2.5A as erroneously written on amazon), and I imagine that the power is about the one you get with smsl AO100 or sabaj A1 (new version), therefore not high, presumably around 20in clean watts into 8 ohms.

The tone controls seem to work well, they should attenuate or boost the relevant bands by +-6db, there is no louder signal or step to pinpoint the flat point, but by ear it seems to be right in the middle or very close .
IMG_20230319_212459.jpg


I noticed that using bluetooth, when I stop playback from my phone, after about 3/4 seconds I hear a "clack" as if a relay was interrupting the circuit, the same noise is heard immediately when playback resumes. From the little I've heard so far it seems to play normally, with nothing broken, by ear I don't think I would be able to distinguish it from the fosi audio bt10D.
IMG_20230319_210616.jpg

At the moment I have nothing more to say, listening tests will follow in the next few days and I will update the post if there are other interesting things to say.
IMG_20230319_212346.jpg

For the moment, the feeling is that with a good amplification chip, a good Bluetooth, finally ldac in a product under 100 euros, a good construction and a flashy but nice aesthetic, and its aux output, it is a product that is fully worth the little money required
 

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Blumlein 88

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Did it come with the J.A.N. tubes or did you substitute those?
 
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Talisman

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Sure sounds like a review to me.

Jim
I don't have the ear, the expertise, or the tools to write a review.
I can give my very own listening impressions, but by no means should this be considered a review.
Just my thoughts on a product that seemed interesting to me.
 
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Talisman

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Forgive me, I'm not a native English speaker, and maybe something got lost in the translation.
The concept I wanted to express is exactly what you said.
I am not a reviewer, my personal listening opinions apply only to me and for this reason I do not consider this a "review" at all.
I focused on the device functions, aesthetics, functionality, but I have no objective element to evaluate the audio quality, and my subjective comment is no more or less than any subjective comment of an untrained listener.
Really, I don't understand what bothered you, I'm saying exactly the same things as you are saying.
 

mhardy6647

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Sure sounds like a review to me.

Jim

The Treachery of Reviews.
the-treachery-of-images.jpg

:cool:
It's not an objective review, but it's the preamble to a review in terms of use and listening impressions, which is fine! Some of us are interested in vacuum tubes for audio reproduction -- although, for some of these mysterious and inexpensive little boxes, it's more morbid curiosity than interest (at least for me!).

OK, on topic. So, what tubes does it use? Some sort of little pentodes, like the little FX-Audio boxes?

Do we know what they're used for?

Do we know what sort of power amplifier/chip it uses? Operating topology (class)?
I guess I shall google...
EDIT: Google I have. See below.
 
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TonyJZX

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tubed staged infineon w/ that garish 'tube shield' w/ neon sign?

if i was standing up I'd say I'd have to sit down for this
 

mhardy6647

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tubed staged infineon w/ that garish 'tube shield' w/ neon sign?

if i was standing up I'd say I'd have to sit down for this

It looks like the little acrylic billboard could be removed (i.e., not installed) if the end-user so desired(?).



1679318566482.png


So - if the top image is accurate, the tubes appear to be 5725 pentodes:

The tubes shown in the bottom image are obviously some sort of larger power tube, though. I realize it's just a stock image, but I still just thought I'd mention that.
 
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Talisman

Talisman

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The Treachery of Reviews.
the-treachery-of-images.jpg

:cool:
It's not an objective review, but it's the preamble to a review in terms of use and listening impressions, which is fine! Some of us are interested in vacuum tubes for audio reproduction -- although, for some of these mysterious and inexpensive little boxes, it's more morbid curiosity than interest (at least for me!).

OK, on topic. So, what tubes does it use? Some sort of little pentodes, like the little FX-Audio boxes?

Do we know what they're used for?

Do we know what sort of power amplifier/chip it uses? Operating topology (class)?
I guess I shall google...
EDIT: Google I have. See below.
The tubes are these in the photo, I don't know if they are authentic or not. I assume they are used in the preamp circuit.
The amplifier chip is, as I wrote above, the Infineon MA12070.
I confirm that the bright neon sign can actually be removed (you can also see it in the photos of the first post)
IMG_20230320_143331.jpg


IMG_20230320_143345.jpg
IMG_20230320_143530.jpg
IMG_20230320_143535.jpg
 

tomtoo

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Nice show amp. If the tubes dont destroy to much great price.
 

fpitas

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I'll admit I don't get it, but for $119 or so it's not an expensive toy.
 
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Talisman

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I'll admit I don't get it, but for $119 or so it's not an expensive toy.
That's right, the right word is "toy", I paid it only 99 euros, and it has a preamplified output, a bluetooth chip that supports ldac, a decent amplifier chip and a slightly over the top look, which some might Sounds tacky, but I like it, plus I like the input selectors, I hate it when bluetooth is always on.
I don't expect anything remotely close to SOTA, it's just a cheap box, with many interesting functions, to be used in the office, or in the bedroom, or on the PC.
 

fpitas

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Be a little careful about AC safety. Some of the Chinese stuff gets rather creative about safety grounding.
 

mhardy6647

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Well, at least they do look like actual US made tubes (on the basis, mostly, of the exhaust tip morphology) -- to my semi-practiced eye.
EDIT:That said, the workmanship (for lack of a better word) on the pins doesn't look like anything I've ever seen on a US-made tube.
index.php

index.php



No idea about the "German" chip.

My default assumption with little boxes like this one is that any recognizable component (brand name) is counterfeit until and unless demonstrated to be otherwise. :(
 

Blumlein 88

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I wonder about those tubes. I don't think any have been made like that since the 1970's or maybe late 1960's. J.A.N. is joint army navy. Tubes made for USA military. That tube appears to be something for high frequencies, usually high frequency switching. Are they using it for switching of the class D amp I wonder? Or is it just a decoration that actually does not do anything?

I saw a post on another forum for a similar unit that had those tubes, and someone confirmed it has voltage to the tubes. There are a few others very similar on Amazon all for about the same price. All use JAN made in the USA tubes. Maybe someone found a huge stockpile of them.
 
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fpitas

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mhardy6647

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There are, or at least were in the relatively recent past, immense stockpiles of surplus JAN tubes. I.e., they could well be legit. The label looks a little messier than I'd expect on a legitimate JAN tube, too -- but there were tubes being made - somewhere - for US military purposes (?!) into the '80s, at least, and I really don't know what the quality of the last of them might've been like.

I reckon they're running in a plate-starved "space charge" configuration -- but, who knows?! They're probably doing something, but not necessarily anything good with respect to the input signal(s).
EDIT: PS, persuant to @fpitas's post, they could be connected as triodes. :rolleyes: I don't intend this as a value judg(e)ment, just a statement. ;)
 

fpitas

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There are, or at least were in the relatively recent past, immense stockpiles of surplus JAN tubes. I.e., they could well be legit. The label looks a little messier than I'd expect on a legitimate JAN tube, too -- but there were tubes being made - somewhere - for US military purposes (?!) into the '80s, at least, and I really don't know what the quality of the last of them might've been like.

I reckon they're running in a plate-starved "space charge" configuration -- but, who knows?! They're probably doing something, but not necessarily anything good with respect to the input signal(s).
EDIT: PS, persuant to @fpitas's post, they could be connected as triodes. :rolleyes: I don't intend this as a value judg(e)ment, just a statement. ;)
A single-ended pentode with any amount of signal will certainly give a tube sound. Triode connection will make that a lot better, I suppose.
 
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