[diablo9]

never mind

 

[diablo9]

never mind again

 

[Garbz]

hope you have more luck with your christmas project then I do with mine

 

[skyskraper]

Quote:

Originally Posted by diablo9 What do you think?

i think blue pcb's look nice.

low voltage tube, check.
op amp/s (im assuming thats what the dip sockets are for), check.
nice case, check.
nice transformer, check.

i can't really decipher anything else, that forum link timed out as it was loading the external shots. do you have a schematic for it?

 

[palchiu]

SXT-1se is one of good headamp in China 2 years ago, fun with op, tubes and coupling caps rolling!!!

This amp can make your own sounding without professional skills.

Adjustable gain with dip switch.

To diable9,

Please check the "ALPS look" VR, and please replacing the headphone jack to Neutrik one.

Becareful the voltage with op rolling, check the datasheet first!!!

Will you try some silver foil PIO caps?

Happy X'mas to all~

Pal

 

[dsavitsk]

I don't get it. What's the tube doing?

 

[Jazper]

Quote:

Originally Posted by dsavitsk I don't get it. What's the tube doing?

It looks a bit like the tube is the first gain stage(single ended), followed by the opamp, then the mosfet single ended current buffer which is trimmed by the opamp in the feedback loop.

It's a very interesting design, but I think you could pull the tube out and wire across it, doing so would probably make it sound better
.

 

[dsavitsk]

Quote:

Originally Posted by Jazper It looks a bit like the tube is the first gain stage

The tube is a cathode follower which is a buffer with less than unity gain. While it will likely add some "tube" characteristics to the sound, it does seem like it will do more harm than good. Odd.

 

[Jazper]

Quote:

Originally Posted by dsavitsk The tube is a cathode follower which is a buffer with less than unity gain. While it will likely add some "tube" characteristics to the sound, it does seem like it will do more harm than good. Odd.

well I figured something like that..

 

[DaKi][er]

That has got to be one of the worst headphone amp designs i ever seen

Where to start....
I don’t know hat the designer was trying to achieve here, whack in all the basic topologies of what is flavor of the month and throw it at a wall and see what sticks

Let’s add in a tube, it doesn’t do anything useful but tubes are good right? Make it add some DC so we then add in a cap

Whack in some strange opamp topology that has some gain for it but add a bunch of DC offset to add in another cap to the output

Mosfets are meant to be good, add a basic singe ended one in there, more dc so big output caps again

Every stage needs a different voltage, so that is 6 rails to add to it

A fancy blue board with gold plating, no one will question us if we use that

I don’t know what the guy who designed it was thinking; I would really like to know.....

I don't know what it would sound like, but technically it sucks

 

[rickcr42]

The output section is a Szekeres Amp straight from the Headwize Project library with my long and often recommended power supply voltage increase.Does the site give credit to the designer or Headwize as the origin of the follower section ? A simple "based on" ?

There are also several things I personally do not like about the amp overall topology before the final stage but not my amp so not for me to say why.

 

[PinkFloyd]

Well worth $120 though! *** an enclosure alone would cost that in the UK!

 

[Porksoda]

And the board gives you a free frizbee to boot!

At least the parts look like they're good quality

 

[rickcr42]

Quote:

Well worth $120 though! *** an enclosure alone would cost that in the UK

one thing the Chinese hobbyists seem to have an abundance of access to is a wide variety of project cases that put anything we have easily available to shame and they must be cheap or the amps/kits would have to cost a lot more.Yes I am jealous because that is the worst part of a project : casing the thing and have it look good without spending a small fortune.

Having said that the circuits themselves from the orient are very suspect.
Designs ripped-off from all over the internet including some "known" commercial designs then sold as either kits or finished products without ever mentioning where the design originated.
Where they really screw up is they copy but not design.They take ciruit "parts" that are known to work in stand alone circuits then cob them together with apparently no actual reason as to why or what they are trying to accomplish since they really do not understand the circuit anyway but have in fact just copied it.The above is a prime example of one stage too many when two stages would do the same thing so why the "bloated" design ?

A vacuum tube AND an Op-amp AND and discrete stage in series for a headphone amp ? Surely it is not for gain so to what end ?
The "end" is knowing what folks want to see.they like the idea of a mosfet output.they like the idea of a tube stage and they like the idea of an opamp being conditioned to think this device is the be all/end all of audio design so why not shoot for the whole ball of wax in one amp ?Talk about an identity crisis !
I personally would lose everything before the output buffer or if i needed gain lose the opamp stage and work on getting the tube front end optimal for more of a "classic" hybrid amp type but that is just me

Quote:

At least the parts look like they're good quality

But are they ? Are they the actual parts they seem to be or cheap knockoffs with pretty sleeving and the correct label printing ? The Chinese are notorious counterfeiters and there is an huge amount of information out there on how many ebay purchases get ripped off buying parts that turned out to be something other than as labellled and especially so "designer" parts such as BG caps.As in most things it is "buyer beware" though I come from the "if it seems to good to be true it probably is" camp.I consider something that appears to be a serious bargain with suspician so when I add up what parts would cost even if purchased at a "quantity" price then add in all the extras and it comes out more than the final cost wonder what the actual deal is.

The amp may sound fine and is well constructed.I just don't care for the topology on a personal level and feel the guy tried to please too many camps while muddying the signal waters.

Just an opinion man.enjoy the amp build

 

[diablo9]

all right guy, I give up. when I PMed him over there on that Chinese forum, the guy doesn't even know English well and you call it plagiarism? a couple of similarity and you call it infringement of IP? say what ever you want to. all I want to do is to have some fun in Xmas, I'll surely assemble it and if I have any chance, I'll have some reputable guy do some test for me. but whatever, I'll shut up.