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Best CD clock upgrade?

Having just returned from an extended holiday, it's great to catch up on this thread and I haven't missed out with the components lying on the door mat waiting for me to come home. Am I glad that I ordered the second Flea board without a clock! Nice bonus.

Thanks once again Carl and all other contributors.

Martin, I guess that you would try to include in the build manual all the little tips and tricks summarised from here?
 
I don't envy Martin. Quite a job!
Thanks very much Martin in advance!
Will you place it onto a web site?

Oz
 
I've posted a few parcels today and emailed the lucky recipients. The rest will go off tomorrow lunchtime.

With regard to using a flea reg (sans XO module) to power a DAC, Martin is quite right that the reg is stable without any series resistance... I tried it last night on my cd3.5 and the device is drawing a constant 15mA and sounds great.

Obligatory p0rn:

The wires are from the flea (out of shot) that is powering the DAC and go into the holes that used to belong to a 10uf tant that used to decouple the DAC's +vin supply. The decouping is now provided by 2x 3.3u film caps in parallel (see the acoustica website for more details), leaving the two holes free to add external power:

w_DSC00498.jpg



The flea powering the DAC. The two 1Rs in parallel are no longer there as I've replaced them with a wire link:

w_DSC00497.jpg



The clock output/ground wires are now about an inch long and neatly tucked under the flea:

w_DSC00499.jpg



The whole lot from a bird's eye view:

w_DSC00495.jpg



Cheers,
Carl
 
hacker said:
With regard to using a flea reg (sans XO module) to power a DAC, Martin is quite right that the reg is stable without any series resistance...
Click to expand...

What's the benefit of using the flea for this application, as opposed to a super-reg?

Regards,

Mus
 
I wanted to ask that !

Simpler to build but performance comparable with such lower power requirements? Just a guess?

If Martin says it aint as good, how long before Carl swaps it out ;) an hour?! Hehe
 
What's the benefit of using the flea for this application, as opposed to a super-reg?
Click to expand...
None, just that it's compact and easy to implement. Don't forget that with something like an NE5534 used instead of the AD797 it's dirty-cheap too, but will still far outperform a regular 317 or other 3-pin reg. The other thing is, this is a low power regulator (say 30-40mA max) - an ideal match to something like the TDA1305 dac analogue stage which only draws 6-9mA.

Basically, there's a little room* for bodging the flea into other applications. Try it at low cost/risk and if you like what you hear - go for a 'proper' superreg.

* limited by power handling in the opamp
 
Good news one and all: the fleas are all packed (with more than a little help from Mrs Hacker) and ready to roll...

...expect postage tomorrow and, all being well, UK-based fleas to arrive on Saturday :D

Anyway, my ears don't lie (too often) and these fleas are the bees knees, sure to please so don't tease! Hmm, one too many beers I fear...

Carl
 
Well done Carl, that's no mean task and we all appreciate it. A beer (or three) well earned!

The manual will be posted here on or before Saturday morning...
 
Thanks to Carl and Mrs. Hack-a-flea for service beyond the call of duty.
Does anyone care to specify what type of sonic improvements are being gained with the pink-flea/tent combo? What does our cute little fella sound like? :p
 
All posted (the lady behind the counter at the post office was less than impressed when I turned up with a box stuffed with dozens of padded envelopes at lunchtime!)... you UK bodgers should have them tomorrow.

For people in the US/Canada and other exotic places, I had to fill out a customs declaration for each package with a value attached to each one. I put down £30 for each one, as I didn't know off the top of my head what was in each package (there were a lot). I trust this won't cause any problems.

Slawney, I'll try and answer this one, but I'm a bit crap at describing subjective things like sound improvements... it all really boils down to a refinement of detail. Tiny levels of distortion are stripped away, leaving just the music without the garbage. I especially like the way cymbals sound with the flea. Then there's the sheer openness of the music (sorry, don't know the correct terminology) which gives the impression of the performance being bigger, yet more intimate as you can really get to grips with what each performer is doing (of course, it will depend on the music, artists, production etc). All very fluffy-bunny stuff ;)

For me, I know it's working wonders because I still get a big grin every time I turn it up - and that's a sure-fire way of knowing that it's a great upgrade. I really hope you all like it :D

There shouldn't be any problems with the kits, but if you have any parts missing etc, just let me know and I'll sort it out straight away. One thing you will notice is that there are two extra resistors in each kit: a 33R and a 100R. I couldn't be bothered with the hassle of identifying each one and replacing them with the correct SMD parts, so I just added the SMDs to the kits... the resistors are only a couple of pence each when bought in this kind of quantity, and it saved me loads of hassle to just leave 'em in.

Anyway, I should go do some work...

Cheers,
Carl
 
Hi Carl,

Just received my parcel this morning, many thanks for all the effort in putting all the packages together for everyone.

I'll hopefully get on to putting it togther later this weekend.

However I've just realised an issue when using it in my application. My present clock (superclock 2) is powered from a dedicated netaudio PSU (trafo and full wave rectifier etc.) Problem is this only outputs 12V and I've just realised that the PFM uses a 7812 on it's input so needs more than 12V to run it! (why didn't I spot this before?!!).

So, question to everyone really, what is the easiest way to get it to run off 12V input?

Presumably I could use a LM317 (instead of 7812) to reg down to say 10V - would the flea work OK like this? OR will I have to change the trafo in my PSU to give more than 12V output?

Suggestions please...

Thanks,
Stu.
 
Cant you just leave the 7812 out, put the net audio 12v to where the 7812 would be and actually have a slight better power supply than we all will!

That is of course unless you want to sell the superclock and psu together which will give you a nice profit!
 
Stu - swap the 7812 for a 7808. This works fine, since the opamp 'sees' that plus 2v from the LED, plus the 78-- needs maybe 1.8v dropout at the low operating current. Any lower output voltage is getting very marginal for full benefit from the AD797 (not specified for rails under +/-5v ie 10v single rail). I have run one down to 6.9v(!), using a 7805, in anticipation of such questions but it definitely works better as designed!

The capacitance multiplier only drops 1.2-1.6v, but feed your power in after that (to the +ve of C1) if need be. That should allow a 7808 to be used. Since the NetAudio supply should be regulated I doubt it will make matters worse. Is there any scope for increasing the output of the netaudio supply at all...? A higher raw supply *is* the better answer.

(I'm just finishing the build guide now, but I'll tack this info in there somewhere)

Trance - not quite. The 3-pin reg is also the constant-current source for the LED, so STu would need to hack in a JFET or similar to run the voltage reference. Anyway, the cap multiplier/ 78xx is a super-quiet combo on its own ;)
 
Its been a while since I've posted on PF:)

My Flea has not arrived yet but hopefully it will be here monday, I'm already itching to get this thing fitted:D
After the great results with my first modified Arcam Alpha5+ I recently brought a standard A5 to play about with.
I'm planning to fit something like a 74HC163N to be used as a divider to feed the BCK pin of TDA1541A dac directly (similar to whats used in the A5+) and also feed the SAA7310 directly. I already have converted this unit to NOS so theres no need for the SAA7220 at all.

Thanks again to ALW,Martin,Carl etc
 
Andrew L Weekes said:
Hi all,

The PCB's arrived today, I'll be shipping these to hacker tomorrow, so that should keep him out of mischief for a bit ;)

Now all we need is some to be built and debugg... oops I mean tested ;)

:)

Andy.
Click to expand...

The PCBs were very good quality, who did you get to make them in the end?

Regards,

Mus
 
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