Ultra high performance headphone amplifier QRV09

[peranders]

63 mAT is a good value and the cover is ordered separately. I should have added this mechanical part.

 

[UrSv]

I remembered the cover but forgot the fuse 🙂 It worked just fine with 5 A but will be replaces ASAP...

Not sure if mAT is good in the US. Perhaps more common to call them 63 mA slow blow?

 

[peranders]

Possibly, but the fuse is marked with a "T".

 

[dfidler]

Okay, that's retarded; 18p for a little piece of plastic? 😛

 

[dfidler]

Can't say I really like Hammond. They haven't really got anything that looks OK.

I'll probably go for the cheaper and time saving option of this:

UrSv, which case is that? Any other recommendations for a chassis for this thing?

 

[UrSv]

In Sweden I would be happy if it was only 18p 🙁

You have at least two shops that sell the chassis I bought and deliver from the UK. I paid GBP 42.80 including shipping which is more than fair considering I don't have to operate any heavy machinery and may assemble under the influence. And it includes the knob, switch and some other bits and pieces. This is the one I bought:

DIY Audio Aluminium Chassis Headphone amp Metal case S | eBay UK

DIY Audio Aluminium Chassis Headphone amp Metal case S | eBay UK

Plenty of people sell it from China/HK, search eBay for "DIY chassis"...

 

[dfidler]

Wow, they're 20 mins drive from me and no machining required; sold! Thanks!

[Edit]Oh wait, "no local pickup"; bastards[/Edit]

 

[PedroDaGr8]

Wow, what a coincidence I just stumbled upon this as I have some TPA6120A samples from TI and last night was trying to decide on if I know enough to try and come up with something using this chip. Your design looks awesome!

 

[UrSv]

Wow, they're 20 mins drive from me and no machining required; sold! Thanks!

[Edit]Oh wait, "no local pickup"; bastards[/Edit]

Actually, looking at the pics and the whereabouts it seems more than likely that the two shops are actually the same guys. So, if you decide to get one then take the cheapest 🙂

 

[dfidler]

Actually, looking at the pics and the whereabouts it seems more than likely that the two shops are actually the same guys. So, if you decide to get one then take the cheapest 🙂

I noticed that too; the layout of the descriptions are exactly the same which makes me wonder if it comes from the UK at all.

 

[maravedis]

A bit off topic..

Did anyone try this chip to drive a compression driver / horn?
I'm intrigued....

 

[MrSlim]

Well, its maximum power output is 1.5 W into 32 ohms(minimum), so not sure it would be capable..

 

[UrSv]

I noticed that too; the layout of the descriptions are exactly the same which makes me wonder if it comes from the UK at all.

That remains to be seen. They shipped mine the 26th so if it gets here next seek I now it was from the UK. They wouldn't get it to Sweden from HK in less than two weeks..

 

[maravedis]

but..

"ABSOLUTE MAXIMUM RATINGS
minimum Load impedance 8 ohms"


for a 16 ohm driver 118db/1m/1w.... could be sweet. Or perhaps with a nice 2:1 nickel OPT?

 

[MrSlim]

hmm.. didn't notice the absolute minimum..
I didn't know compression drivers sensitivity could be that high..
The LME49600 might be another choice..

 

[UrSv]

A quick and dirty installation is done. Listening over the weekend begins in a few hours.

 

[MrSlim]

Nicely done UrSv. I hadn't thought about mounting it sideways. It certainly keeps the power and signal lines nicely separated

 

[UrSv]

Thanks. I was thinking it through for a while and decided that straight and separated cables would look fairly nice and would most likely work quite well.

 

[MrSlim]

So, how does it sound?

 

[UrSv]

As far as I can tell it sounds excellent. I run it on the outputs of my Muse USB DAC (PCM2702 as USB receiver to PCM1793 DAC) which uses something they call "reference Solo headphone amplifier" which essentially is a standard output transistor assisted OP-amp headphone stage. The QRV09 sounds, at least in an open placebo susceptible listening test, very open and calm. The top seems less harsh and the bottom end somewhat extended compared to the Muse.

I'd say, as before, that for my first SMT project the outcome is a success and the sonic qualities will probably match anything ready made at the same totalt cost which was about SEK 1300/GBP 130/USD 200.

Thanks again P-A!