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Latest BS Amplifier from Fosi - T3 with 2 preamp tubes, no output tubes or transformers - 50wpc???

Xulonn

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Meaning of travesty in English: Something that fails to represent the values and qualities that it is intended to represent, in a way that is shocking or offensive:

Photo from Audiophonics, who sells it for 139€
Fosi T3 Amplifier.jpg

Fosi T3 Amplifier Specs.jpg
 
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Xulonn

Xulonn

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This is what a "proper" 6F2+6P1 $160 vcuum tube amplifier looks like - and it is rated at 12wpc.

Nobsound 6F2 Amplifier.jpg
 

fpitas

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ROOSKIE

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This is what a "proper" 6F2+6P1 $160 vcuum tube amplifier looks like - and it is rated at 12wpc.

View attachment 244060
I am seeing $300ish usd shipping from the USA for the DIY kit or $265 shipped completed from China.

Maybe there are little switch-mode power amp modules inside.
The USA Amazon listing has this Fossi T3 as class AB with tubes for the headphone section only.

Ebay's listing however states a chip amp TPA3221
 
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fpitas

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There's a huge market selling tube kits to unsuspecting noobs. If they're lucky, the unit is more or less safe. But some are quite dangerous, as well as being trash sonically. Caveat emptor...
 

sarumbear

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From their Amazon entry.

  • Real audiophile sound. T3 is equipped with 6F2 tubes to get warmth sound and with class D efficiency.RMS 50Wx2 power,providing enough power to drive the speakers with a strong dynamic response for more sonic detail.
 

fpitas

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KSTR

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I wonder if the tubes are even hooked up, other than the heaters.
My guess would be the tube is used in the input/gain/tone-control section and the actual power amp is some (chip amp) class-D as that's what their description is hinting to.
 
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Xulonn

Xulonn

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It is very likely a class-D amp with a "tube preamp" section, but the ad copy is extremely misleading by listing "Amplification type" as "tubes".

It would be interesting if an ASR regular bought one to see what class-D chip/board is in it and sent it to Amir for testing. I would guess that the tubes actually degrade the class-D amp performance.

Even so, it might still be a decent and cool desktop amplifier!
 
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Xulonn

Xulonn

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It looks like there are some variants of this hybrid tube/Class-D amplifier out there - likely manufactured by the same Chinese company. Here's the $150 Dayton version which has a top-front USB input, but no bass & treble controls. With USB in, and subwoofer and headphone out, I would really like to see Amir test this version. Most tablet and phone music player apps have bass + treble or multi-band EQ built in, so in the applications for which amps like this are usually purchased, the bass & treble knobs found on the Fosi version would probably not be missed. And the USB input would be useful (although a $9 Apple USB dongle would probably have better fidelity).

Dayton Hybrid Amp.jpg

The Dayton Audio HTA20BT combines the efficiency and power of solid state class D amplifier topology with the warmth and character of a vacuum tube preamp section. The results are a delightfully articulate and natural sound that is sure to please even the most refined ears.
 
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fpitas

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It looks like there are some variants of this hybrid tube/Class-D amplifier out there - likely manufactured by the same Chinese company. Here's the $150 Dayton version which has a top-front USB input, but no bass & treble controls. With USB in, and subwoofer and headphone out, I would really like to see Amir test this version. Most tablet and phone music player apps have bass + treble or multi-band EQ built in, so in the applications for which amps like this are usually purchased, the bass & treble knobs found on the Fosi version would probably not be missed. And the USB input would be useful (although a $9 Apple USB dongle would probably have better fidelity).

If I just had to get one of these bizarre contraptions, Dayton Audio is most likely wired safely on the AC line input. The same can't be said for a lot of the cheapy stuff.
 

DanielT

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But a pre amp with tubes and power amp part consisting of class D or transistor class AB does not have to be bad in itself. It depends on the construction.:)

Here a construction of a tube pre amp with good performance. A DIY designed by skilled engineer. I am attaching some data, measurements and some different pictures of some who built it. So a pre amp with tubes can really have excellent performance.:)



Edit:
On the other hand. Designing a well-performing power tube amp is, ...well, let's say...more expensive anyway. You need good output transformers and those are (as you who write in the thread are well aware of) expensive stuff.;)
€139, 50W all through tube amplification (even the power part) with good performance, it doesn't exist.
 

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SoNic

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Truthfully, if one is looking for "tube sound", it matters less if is in the preamp section or in the final amp section - as long as the power amp it is transparent and doesn't add coloration.
Tube THD+N performance is below modern solid-state amps, even in class D, so there is a chance that this will sound legit.

Now, of course the purists want what they want, and this will not satisfy them. That's OK.
 

DanielT

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Truthfully, if one is looking for "tube sound", it matters less if is in the preamp section or in the final amp section - as long as the power amp it is transparent and doesn't add coloration.
Tube THD+N performance is below modern solid-state amps, even in class D, so there is a chance that this will sound legit.

Now, of course the purists want what they want, and this will not satisfy them. That's OK.
It seems contradictory. If any tube "sound" is heard it is accomplished by adding audible distortion. That distortion is coloring. Maybe also tube "sound" is deviations in FR. Elevated midrange perhaps gives a tube "sound".

The worse the construction, the more adding coloring, the more tube "sound". Or in some backwards way, the worse the construction is the "better" tube "sound" it will be.:) If you like it, that is.;)

"Tube THD+N performance is below modern solid-state amps, even in class D"..Are you serious?
 
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