This is just to let people know that I've now put up a webpage describing
the design of the simple headphone DAC I've been experimenting with during
the last few weeks. The page is at

http://www.audiomisc.co.uk/HFN/Headp...C/HeadDAC.html

The aim was to produce something inexpensive and easy to build so that
anyone willing to use a soldering iron and drill some holes in a metal box
could make one if they wished. :-)

It doesn't use any fancy items made of unobtainium, etc. I deliberately
bought all the bits from CPC so they'd be easy to source. But if anyone
wanted, it might make a nice basis for experiments and no doubt could be
'improved' or tweaked in all kinds of ways. That said, the unit described
works nicely here and I'm enjoying listening using it.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Good post, and good linked content. It's nice to see some "proper" hi-fi audio content
posted here.


Martin

"Jim Lesurf" wrote in message

This is just to let people know that I've now put up a
webpage describing the design of the simple headphone DAC
I've been experimenting with during the last few weeks.
The page is at

http://www.audiomisc.co.uk/HFN/Headp...C/HeadDAC.html

The aim was to produce something inexpensive and easy to
build so that anyone willing to use a soldering iron and
drill some holes in a metal box could make one if they
wished. :-)

It doesn't use any fancy items made of unobtainium, etc.
I deliberately bought all the bits from CPC so they'd be
easy to source. But if anyone wanted, it might make a
nice basis for experiments and no doubt could be
'improved' or tweaked in all kinds of ways. That said,
the unit described works nicely here and I'm enjoying
listening using it.

The big missing piece in this project is the measured performance. There's
some reason to believe that the transformer, which is rated at -7 dBU @ 50
might be pushed to over load in some applications.

"Arny Krueger" Jumped in head first and wrote in message
...
"Jim Lesurf" wrote in message

This is just to let people know that I've now put up a
webpage describing the design of the simple headphone DAC
I've been experimenting with during the last few weeks.
The page is at

http://www.audiomisc.co.uk/HFN/Headp...C/HeadDAC.html

The aim was to produce something inexpensive and easy to
build so that anyone willing to use a soldering iron and
drill some holes in a metal box could make one if they
wished. :-)

It doesn't use any fancy items made of unobtainium, etc.
I deliberately bought all the bits from CPC so they'd be
easy to source. But if anyone wanted, it might make a
nice basis for experiments and no doubt could be
'improved' or tweaked in all kinds of ways. That said,
the unit described works nicely here and I'm enjoying
listening using it.

The big missing piece in this project is the measured performance. There's
some reason to believe that the transformer, which is rated at -7 dBU @
50 might be pushed to over load in some applications.

And Jim covered that in his online article.

"Jim Lesurf" wrote in message
...
This is just to let people know that I've now put up a webpage describing
the design of the simple headphone DAC I've been experimenting with during
the last few weeks. The page is at

http://www.audiomisc.co.uk/HFN/Headp...C/HeadDAC.html

The aim was to produce something inexpensive and easy to build so that
anyone willing to use a soldering iron and drill some holes in a metal box
could make one if they wished. :-)

It doesn't use any fancy items made of unobtainium, etc. I deliberately
bought all the bits from CPC so they'd be easy to source. But if anyone
wanted, it might make a nice basis for experiments and no doubt could be
'improved' or tweaked in all kinds of ways. That said, the unit described
works nicely here and I'm enjoying listening using it.

Slainte,

Jim


Hi Jim
It's looking good.
That DAC has been around for a while, Richer sounds were selling it
so one particular mag gave rave reviews so as to perk up Julian.
It is also badged up under other brands (in the old days that was
known as faceplating):
http://ukhdmi.com/digital-to-analogu...erter_QQ101638
http://www.lindy.co.uk/spdif-digital...ter/70408.html

Anyone reading who wants to give Jims excellent project a go,
the DAC can be found in an online search under the term "au-d3",
Can be got from ebay for about a tenner.

Previously when I checked it out it was impossible to locate a spec
sheet for it or anyone who had actually opened one? But will have
another look later today. A guess is it is the same intergrated chip-
Filter/2xO/S, into conversion found on intergrated MoBo chipsets
or soundcards etc.

--
Please use the address on the audiomisc page if you wish to email me.
Electronics
http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Arny
Krueger
wrote:


The big missing piece in this project is the measured performance.
There's some reason to believe that the transformer, which is rated at
-7 dBU @ 50 might be pushed to over load in some applications.

I think I said in the report that the response was flat with -1dB points at
about 20Hz, 20kHz, and that the distortion level was below 0.01 percent for
0dBFS. Also pointed out that the transformers will distort the signal if
you use too high a load (i.e. above a few hundred Ohms), but no problem
with typical headphones. Is there something else you'd be interested in
seeing added? It is just for headphone use, of course.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Fed Up Lurker
wrote:

"Jim Lesurf" wrote in message
...
This is just to let people know that I've now put up a webpage
describing the design of the simple headphone DAC I've been
experimenting with during the last few weeks. The page is at

http://www.audiomisc.co.uk/HFN/Headp...C/HeadDAC.html

Hi Jim It's looking good. That DAC has been around for a while, Richer
sounds were selling it so one particular mag gave rave reviews so as to
perk up Julian. It is also badged up under other brands (in the old days
that was known as faceplating):
http://ukhdmi.com/digital-to-analogu...erter_QQ101638
http://www.lindy.co.uk/spdif-digital...ter/70408.html

Thanks. Useful to know that.

Anyone reading who wants to give Jims excellent project a go, the DAC
can be found in an online search under the term "au-d3", Can be got from
ebay for about a tenner.

Previously when I checked it out it was impossible to locate a spec
sheet for it or anyone who had actually opened one?

FWIW I've been in contact with CYP and am hoping for more info on the DAC
(and on some other items that may 'surface' in projects later).

I may also add a little more about the battery PSU side later. At present I
haven't even determined the size of the power connector! :-) It isn't the
usual 2-and-a-bit-mm i/d. But I found another connecter that fitted that I
had in a component tray without knowing the size! When I make sure of the
size I'll add it (and a part number) to the webpage.

However it may well be that people can find other DACs and transformers
that they prefer. As Arny pointed out, these small 'NTE4' ones do saturate
easily at LF. They seem fine for 20Hz up in this case since the AU-D3 only
gives about 1Vrms out for 0dBFS - not the 2Vrms common for CD players. That
said, my interest was in it being a 'cheap and easy-to-make' project that
someone could duplicate if they can solder and drill a few holes.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

"Jim Lesurf" wrote in message
...
In article , Arny
Krueger
wrote:


The big missing piece in this project is the measured performance.
There's some reason to believe that the transformer, which is rated at
-7 dBU @ 50 might be pushed to over load in some applications.

I think I said in the report that the response was flat with -1dB points
at
about 20Hz, 20kHz, and that the distortion level was below 0.01 percent
for
0dBFS. Also pointed out that the transformers will distort the signal if
you use too high a load (i.e. above a few hundred Ohms), but no problem
with typical headphones. Is there something else you'd be interested in
seeing added? It is just for headphone use, of course.

Slainte,

Jim


Take it easy Jim, It's what Arny does.
Under my various guises over the years (that will bait Keef)
I would occasionally lob in a "I was just about to say that".
Just to gee up old Arny as thats what he does.
You know his style, " I assumed you knew I meant that without
me having to say it" sort of thing Arny does when pulled up.
He does it all the time, as a thread evolves and the details unfold
he will pick out the relevent points and envelope them back into
the melee to give the impression he can keep up with the neighbours.
Your project and article are just fine Jim, and evolving nicely.

This TDA1541 machine that is itching for you to NONOS it and
write a groundbreaking report, I've been thinking of strapping
it to the back of PMi's motorcycle and get him to run it up and
across the border to you?

On 27/07/2010 10:36, Fed Up Lurker wrote:

This TDA1541 machine that is itching for you to NONOS it and

Maybe you could explain what you mean by NONOS for those of us
who haven't kept up with these things.

--
Eiron.

"Fed Up Lurker" wrote in
message
"Arny Krueger" Jumped in head first
and wrote in message
...
"Jim Lesurf" wrote in message

This is just to let people know that I've now put up a
webpage describing the design of the simple headphone
DAC I've been experimenting with during the last few
weeks. The page is at

http://www.audiomisc.co.uk/HFN/Headp...C/HeadDAC.html

The aim was to produce something inexpensive and easy to
build so that anyone willing to use a soldering iron and
drill some holes in a metal box could make one if they
wished. :-)

It doesn't use any fancy items made of unobtainium, etc.
I deliberately bought all the bits from CPC so they'd be
easy to source. But if anyone wanted, it might make a
nice basis for experiments and no doubt could be
'improved' or tweaked in all kinds of ways. That said,
the unit described works nicely here and I'm enjoying
listening using it.

The big missing piece in this project is the measured
performance. There's some reason to believe that the
transformer, which is rated at -7 dBU @ 50 might be
pushed to over load in some applications.

And Jim covered that in his online article.

Experienced workers know that just saying something is so doesn't make it
so.