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Got Fleas?

Wires in, Arcam very nicely provided a wire link right into the flipflop for my 0V

The red wire inputs are very close to the targets too, one was a link and one a resistor. Getting nervous now!

clockwires.jpg
 
Nice one Trancera:cool:
Let us know how it sounds

I have not got the A5+ circuit infront of me yet, so you have the flea XO feeding the 74HC175 and the SAA7220?
It may be worth feeding the SAA7310 direct instead of having that 7220 digital filter pollute that nice clock if your using nos.
I think its pin9 of the 7220 which sends the clock signal to the SAA7310, to make it easier you should be able remove that 120R (R224)and fit the Fleas XO out there.
Wait for somebody else to comment first but If your using NOS it makes sense to get rid of the SAA7220 altogether if theres already a divider for the TDA1541A
 
How important is the length of the feed wire connecting the flea to the motherboard? I have seen some professionally upgraded CDPs where the clock upgrade is a considerable distance from the original clock.

Also, once the flea is installed will it still be possible to use an external DAC?

Regards,

Mus
 
trancera said:
Yes, the intention is that 7220 and all associated will come out.

In your picture is the red wire on the right going to pin 11 of the SAA7220?
If it is try removing that wire and R224, fit the wire inplace of R224 (hole nearest the edge of the pcb) if it works ok theres also a filter on the motherboard in this circuit which may be best to remove.
If you don't fancy trying it I'll try it with mine as soon as it arrives and let you know if it works ok;) I'll compare it both ways too see which sounds best
 
Mus said:
How important is the length of the feed wire connecting the flea to the motherboard? I have seen some professionally upgraded CDPs where the clock upgrade is a considerable distance from the original clock.

Also, once the flea is installed will it still be possible to use an external DAC?

Regards,

Mus

Hi Mus,

It would be best to keep the wiring as short as you can especially if its unshielded, maybe they fitted the clocks like that due to space:confused:

If your cdp uses oversampling (depending what model it is ) using a separate dac would be fine
 
Mus - Guido Tent reckons using twisted-pair up to 100-150mm *maximum* is OK with teh Tent XO. That said, shorter is better from an EMI and signal-integrity point of view. The longer the connection the clock drives, the more lumped capcitance there is to degrade the nice steep rise-and-fall.

If your CD player has SPDIF output this will work just fine after fitting another clock.
 
Ron : Yes it is going to Pin11 but for now Im going to leave it like that, im a bit of a novice bodger and would like to wait until you have done yours if thats ok, but yes I guess the best way to use the flea is straight into the flip flop (as it is) and straight to the decoder with shoprtest/best cable possible.

Also at the moment my PSU isn't Ideal - its running off an external computer psu with rather a long cable to power the flea. I have had this psu apart before and its just a lil transformer, rect and cap so in a couple of days im going to see if i can squeeze into the left of the Arcam, just want to make sure my flea is reliable first.
 
Thanks Martin/Ron

Guido Tent reckons using twisted-pair up to 100-150mm *maximum* is OK

I guessed this was the case from Andy's earlier comments, however, several clock upgrade vendors have whopping great leads in their photos.

If your CD player has SPDIF output this will work just fine after fitting another clock.

Is this true for both the TOSLINK and COAX outputs? Will the benefits of the flea still be noticeable when using an external DAC?

It was reasonably easy to work out where to point the first output of the flea i.e. where the old clock used to live. How do you decide where, if at all, to use the second output?

Regards,

Mus
 
The second output is ... kind of an optional convenience that got assumed into the Flea; you don't have to use it.

Naim CD players from CDS2/ CDX/CD3.5 on (and many other makes) use a little inverter to generate the clock, and to buffer it separately to the decoder and DAC. Most aftermarket clocks would simply replace the reference oscillator, and leave the inverter doing the distribution. Having two clock outputs means you can bypass the whole inverter - and any jitter/ PSU sensitivity it may add - and put your clean signal where you want it directly. Example: item 3.

As to whether the benefit would be noticed with an external DAC - that rather depends on everything that follows, since SPDIF/toslink is far from ideal (the mancester coding of the output can give rise to all sorts of problems in recovering the clcok cleanly in the real world), but in principle it should help.
 
trancera said:
Ron : Yes it is going to Pin11 but for now Im going to leave it like that, im a bit of a novice bodger and would like to wait until you have done yours if thats ok, but yes I guess the best way to use the flea is straight into the flip flop (as it is) and straight to the decoder with shoprtest/best cable possible.

Also at the moment my PSU isn't Ideal - its running off an external computer psu with rather a long cable to power the flea. I have had this psu apart before and its just a lil transformer, rect and cap so in a couple of days im going to see if i can squeeze into the left of the Arcam, just want to make sure my flea is reliable first.

No problem, I'll try it first and let you know:) I just hope it comes on Monday.
I've got a little 6VA transformer with 2 x 0-9v secondarys which I'll wire up as a centre tapped so it gives me 18-0-18v which should be enough, I'll hopefully be able to squeeze it in;)
 
I have a Flea on the way and a CDX / XPS waiting here for the Flea - anyone else looking to fit into the CDX?

A couple of options I see here -
a) Look for a suitable unused XPS output (if there by off chance is one)
b) Use the old unused power supply section of the CDX after seperating the 0v line

If anyone else is Fleaing the CDX I would like to share the stress in getting the setup perfected as although a consumate bodger, have not ventured into the digital domain before!

Regards

Martin
 
Yes, I'm planning to fit a Flea in my CDX.

As for the PSU, I have a DIY one which is an XPS clone using super-regs. The way NAIM are using the XPS is that the +/-22V is used for the analogue amp/filter, the +/-10 for the A/D, and the 2x15 for the digital circuits and control/motor. Each of these supplies if further regulated internally using 317/337. The +/-22 is reduced to +/-18, the +/-10 to +/-5 and the +15 to +5. Since the Flea has a capacitor multiplier at it's input I would assume that you it would be OK to use one of the +15V (maybe increase the Flea's capacitor, just to be on the safe side).

I'm not sure that using the internal supply is a good idea. One of the benefits of using external PSU is not to have a transformer working in the CD case (See Mr Tibbs thread about disconnecting the transformer even when it is not powered...)

Cheers, Teddy
 
Martin - option b looks a good one to me. I beleive, but haven't verified, that the clock layout is very close to the arrangement described here under items 2&3.

I'm not sure that using the internal supply is a good idea. One of the benefits of using external PSU is not to have a transformer working in the CD case
Maybe, but I reckon using the 'unused' internal supply to power the flea independantly will dwarf any benefit from not using said supply.

It's easily reversible that way, too - no new holes to make in the case.
 
I just noticed that the Flea requires 18V, so using the +15V is probably not an option.

I tend to agree than with Martin Clark and would use the internal PSU. Using the XPS +/-22V doesn't seem good because it's used to power the analogue which is the most sensitive (I think so), and is not happy to share, so if you don't want to drill holes use the internal. I think that in this case (of using the internal PSU) you need to be careful regarding the power-on order.

In my case I will probably add another supply to my DIY XPS and add more pins to the Burndys.

Teddy
 
using the +15V is probably not an option
That will work if you swap the 7812 out for a 7809.

Start-up time is no problem with the filters at 10K/3u3uF on the cap multiplier and LED reference - you only run the risk of problems if these resistors' values are substantially increased. The clock supply needs to start up 'first' ie at the same time the players other digital supplies come on - or before you turn the player on, if you use a diy offboard supply for the flea. Otherwise the decoder will lose control of the servos (symptom is the CD disc motor spinning up like a turbine!)
 
"symptom is the CD disc motor spinning up like a turbine!" aha thats what happens when you turn them on in the wrong order! :D

Martin, I changed he 10uf Tant for a 22uf Electrolytic (Panasonic NHG) I hope thats ok. (My PSU might get to about 33V when I install an internal one I have).

I still dont know how to describe what im hearing, made myself late for work having a quick listen this morning. Seperation of instruments :confused:
 
trancera said:
I still dont know how to describe what im hearing, made myself late for work having a quick listen this morning. Seperation of instruments :confused:

Is that good or bad?
BTW I've heard from various people the Tent XO's need a couple of hours run in before they sound their best

Mine arrived this morning, I also have a rest day from work too:D

Just a couple of questions guys if you don't mind
I ordered just the XO and PCBS seeing as though I already had most of the bits
Will a BC547B and any 5mm green Led be suitable? if so I can get it up and running today, I also found a 50pf polystyrene cap in my scrap box I could probably use for the AD797
 
I can't answer your questions (although I suspect the green LED will be fine), but if you do need any of the other parts, there's still a couple of BC547Cs and 47pf C0Gs left over... I got a few extra just in case people needed some after the group buy had finished.
 


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