"Jim Lesurf" wrote in message
...





Just to let people know I've now put up a page on a new cheap and simple
DIY headphone amp at

http://www.audiomisc.co.uk/HFN/HeadDAC2/HeadDAC2.html


There are purpose-designed chips for low voltage single-ended supplies that
would seem to be a better choice for a headphone amp running off of just 5
volts.

I have some positive experiences with the Philips TDA7050 low voltage
mono/stereo power amplifier IC. Puts out about 3 times the 0.5 vrms
mentioned in the article. While Philips rates this chip @ 10% THD that
implies a ton of clipping. Back her out of clipping to the reasonable output
voltage I mentioned, and the spurious responses are all 100 dB or so down.

In article , Arny
Krueger
wrote:

"Jim Lesurf" wrote in message
...

Just to let people know I've now put up a page on a new cheap and
simple DIY headphone amp at

http://www.audiomisc.co.uk/HFN/HeadDAC2/HeadDAC2.html


There are purpose-designed chips for low voltage single-ended supplies
that would seem to be a better choice for a headphone amp running off
of just 5 volts.

Quite likely. I doubt I'd have done it this way for a from-scratch design
for myself. The main point here, though, (as explained on the webpage) was
something as 'un-intimidating' to newcomers to practical electronics as
possible. In effect I wanted to hijack an existing cheap (8 UKP) and easily
available (CPC) kit. To make something seem feasible to readers of a
magazine like HFN who've never before dared to try making something.

Once they start, I'm sure we could coax some of them into deeper waters...
8-]

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

On 31/10/2012 16:11, Jim Lesurf wrote:


Once they start, I'm sure we could coax some of them into deeper waters...

Like building a SET power amp?

--
Eiron.

In article , Eiron
wrote:
On 31/10/2012 16:11, Jim Lesurf wrote:


Once they start, I'm sure we could coax some of them into deeper
waters...

Like building a SET power amp?

That's up to them, but I doubt I'd suggest that as the next step. :-)

Ab inito, though, I'll stick with suggesting projects that only use a few
AA cells and keep the voltages and powers down.

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 , Eiron
wrote:
On 31/10/2012 16:11, Jim Lesurf wrote:


Once they start, I'm sure we could coax some of them into deeper
waters...

Like building a SET power amp?

That's up to them, but I doubt I'd suggest that as the next step. :-)

Ab inito, though, I'll stick with suggesting projects that only use a few
AA cells and keep the voltages and powers down.


Idea: Build an amp that runs off of AA cells but puts out more clean power
than your average megabuck SET.

In article , Arny
Krueger
wrote:

"Jim Lesurf" wrote in message
...
In article , Eiron
wrote:
On 31/10/2012 16:11, Jim Lesurf wrote:


Once they start, I'm sure we could coax some of them into deeper
waters...

Like building a SET power amp?

That's up to them, but I doubt I'd suggest that as the next step. :-)

Ab inito, though, I'll stick with suggesting projects that only use a
few AA cells and keep the voltages and powers down.


Idea: Build an amp that runs off of AA cells but puts out more clean
power than your average megabuck SET.

As a project it is an intriguing idea. However I'm not sure it would suit a
newcomer who'd only just managed to make a HeadDAC-2! It would probably
end up looking like a switch-mode convertor driving a 'digital' sic amp
module. [1] Possibly easy to assemble, but then end up wiping out radio and
TV reception for all the houses in the street! ;-

My thoughts would be more along the lines of an RIAA stage or a preamp with
genuine tone and balance controls. Easy to drive with batteries but allow
the more confident and capable to add a main psu. And of course, could have
its own headphone amp. :-)

TBH I can't say I personally have much interest in SET, and people still
can (I think) get the kits that first appeared in HFW if they are keen to
experience burns and high voltage shocks. ;-

What I have wondered about is a simpler and more conventional low-output
transistor 'Class A' circuit as again these are (in component terms) easy
to build. The snag is the need for decent heatsinking, so it puts the
burden on suitable metal-bashing. Alas, that's not my strong point as you
can tell from the, erm, 'inventive' use I made of a place-mat. 8-]

Slainte,

Jim

[1] I did wonder about a more extensive 'modification' of the design that
ended up being HeadDAC-2. To change the choice of op-amp and include a
small convertor (5V in to dual 12V out) so it would give more output.
However it would have ended up like a new design rather than a simple
're-paint' of the Velleman mini-kit. And might also have had 'rf' problems
due to the convertor. But I may have a play one day... Athough currently
most of my time is directed to looking into DTTV (and 4G) rather than
audio. Yesterday I borrowed an HP8591 analyser from my old group so I can
check the signals I get and calibrate some other kit I've bought.

--
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

On 01/11/2012 09:41, Jim Lesurf wrote:
In articlec7mdnS1LOMpxEAzNnZ2dnUVZ_sSdnZ2d@giganews. com, Arny
Krueger
wrote:

"Jim wrote in message
...
In , Eiron
wrote:
On 31/10/2012 16:11, Jim Lesurf wrote:


Once they start, I'm sure we could coax some of them into deeper
waters...

Like building a SET power amp?

That's up to them, but I doubt I'd suggest that as the next step. :-)

Ab inito, though, I'll stick with suggesting projects that only use a
few AA cells and keep the voltages and powers down.


Idea: Build an amp that runs off of AA cells but puts out more clean
power than your average megabuck SET.

As a project it is an intriguing idea. However I'm not sure it would suit a
newcomer who'd only just managed to make a HeadDAC-2! It would probably
end up looking like a switch-mode convertor driving a 'digital'sic amp
module. [1] Possibly easy to assemble, but then end up wiping out radio and
TV reception for all the houses in the street! ;-

My thoughts would be more along the lines of an RIAA stage or a preamp with
genuine tone and balance controls. Easy to drive with batteries but allow
the more confident and capable to add a main psu. And of course, could have
its own headphone amp. :-)

TBH I can't say I personally have much interest in SET, and people still
can (I think) get the kits that first appeared in HFW if they are keen to
experience burns and high voltage shocks. ;-

What I have wondered about is a simpler and more conventional low-output
transistor 'Class A' circuit as again these are (in component terms) easy
to build. The snag is the need for decent heatsinking, so it puts the
burden on suitable metal-bashing. Alas, that's not my strong point as you
can tell from the, erm, 'inventive' use I made of a place-mat. 8-]

Slainte,

Jim

[1] I did wonder about a more extensive 'modification' of the design that
ended up being HeadDAC-2. To change the choice of op-amp and include a
small convertor (5V in to dual 12V out) so it would give more output.
However it would have ended up like a new design rather than a simple
're-paint' of the Velleman mini-kit. And might also have had 'rf' problems
due to the convertor. But I may have a play one day... Athough currently
most of my time is directed to looking into DTTV (and 4G) rather than
audio. Yesterday I borrowed an HP8591 analyser from my old group so I can
check the signals I get and calibrate some other kit I've bought.



I must remember the smiley next time I make a joke here.
Doesn't anyone remember the real McCoy and his sockpuppets
trying to get beginners to build dreadful one-triode amplifiers?

--
Eiron.