In article 8L_6o.74338$2%2.70629@hurricane, Ian Iveson
wrote:

[snip interesting comments]

Once you realise you need MORE POWER, and therefore a power supply,
there are umpteen simple designs available.

Well, I found that I *didn't* need 'more power' - even in lower case! :-)
The result sounds loud enough for me, Indeed, I'm using it with the volume
wound down by about 6dB most of the time. So in my case, experiment
disagreed with your theory. :-)

However I appreciate that *others* might like 'more power'. FWIW I am
looking at alternatives, and others can do so if they wish. I'm not trying
to sell the design or tell anyone that the circuit I made is perfect and
would suit everyone. Just that it is an example that is *very easy to make
for people new to electronics* and can give useful results.

A dual opamp, a couple of caps, and a few resistors isn't hard to do.

Yes, I could easily have done that. Although of course your list isn't
complete. e.g. need for a board/support and psu. And the maker being
confident they could put that together without problems - particularly if
they have no scope, test kit, experience, etc, etc.

But the design idea was to make the circuit easy for *others* to build who
*haven't* already built many bits of electronics and are deterred by what
they usually see. Something they could assemble easily with no real
support, kit, or experience. I also liked the idea of seeing how 'minimal'
I could get in that respect.

A problem here is that those of us who have over many years become familiar
with practical electronics building can easily forget how confusing or
daunting it can be to someone with no experience starting with no equipment
or components. Particularly if they have no local friend or relative who
can show them how it is done.

I know you just wanted to check out the transformer idea, but you could
have done that in your head,

But then I would not have known the actual performance or been able since
to enjoy using it. I find I enjoy actually listening to music more than
just reading a score. ;- Nor would I have established that I didn't
personally need 'more power'. Indeed, so far the rise in LF distortion
isn't a problem in my case, either. Music isn't usual a 20Hz 0dBFS tone or
similar - at least the type I listen to. Although when I tried the HeadDAC
with a test recording of a synth rock concert on TV with a fair bit of LF
it sounded OK to me... at least to the extent that "The Pet Shop Boys at
Glastonbury" would sound OK to me, anyway! 8-]

I would have thought, and then done something more sensible instead.

I'm not stopping you (or anyone else) from doing a 'better' design and
posting it on the web. if you do and it looks good to me, Indeed, I'd
welcome/encourage you doing so. I'd also consider telling people about it
as an alternative if you put up the results. So do what you think is
'sensible' and let us know!

That said, you might find it worth building the HeadDAC design and trying
it yourself in practice with some phones like the EH350s. Then say if -
with phones of that kind of sensitivity and impedance - it seems
unacceptably quiet to you.

BTW I am also myself thinking of simple active designs. As a possible
alternative for more confident/experienced people. *And* of perhaps getting
more capable and appropriate transformers. Alas, CPC and the other 'usual
suspects' for home construction electronics didn't seem to have these. At
least I couldn't find any to fit my 'minimal fuss' brief for the design
aimed at drawing newcomers into DIY/modding. But I'd like to have
'improved' versions to point people to if they wanted something 'better'
(for them) and were willing to go for something more complex or expensive.
That said, I'd imagine that many such are already available. Indeed, I did
buy a small 'kit' of one as part of my experiments but haven't reported on
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