Arcam Alpha 5

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Originally Posted by aquapiranha

Really? I was under the impression it meant the addition of components, not the bypassing of them!

:)

Oh, I prefer a pump, though a freind likes the wick

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NOS = zero oversampling, you basically bypass the digital filter on the i2S lines feeding the dac;)

I'll try and think of the easiest way to try it, normally you take out the SAA7220, cut off 6 of its pins and fit wire links bypassing where those pins went (you end up with 3 x links bypassing 6 holes)

There is another way you can try making it reversable incase you don't like the results
The hardest bit is me trying to explain it or trying to draw a pic:scratch:

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Originally Posted by leo

NOS = zero oversampling, you basically bypass the digital filter on the i2S lines feeding the dac;)

I'll try and think of the easiest way to try it, normally you take out the SAA7220, cut off 6 of its pins and fit wire links bypassing where those pins went (you end up with 3 x links bypassing 6 holes)

There is another way you can try making it reversable incase you don't like the results
The hardest bit is me trying to explain it or trying to draw a pic:scratch:

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I ma sure I could get hold of another SAA7220 should I wish to reverse the changes. I can see a few nights slaving over a hot soldering iron in the near future!

:)

You shouldn't even have to remove the chip to try it, no legs need to be cut:eyebrows:

See if this makes any sense

http://i273.photobucket.com/albums/j...oms/nosmod.jpg

Those three resistors are on the output of the SAA7220 i2S going to the dac chip.
if you remove those resistors from the pcb, solder wire onto the resistors ends so to extend the legs and wire on the bottom of the board like in the pic

If unsure just let me know

TBH I would try the new caps first, give em chance to burn in before trying the NOS mod, too many mods at once can cause confusion if theres something you don't like sound wise

Thanks Leo. I have ordered the majority of caps this morning from Farnell. As you say it would be best to do incremental upgrades so I can see the difference.

Hi Mr. Leo:

Please let me know what do you think about this way to implement the Non Over Sampling mod:

1-Lift or cut pins 1,2,3,15,16,18 of SAA7220 from the board.
2-Join the vacated holes with wire thus: 1 to 18 2 to 16 3 to 15.
3-Cut the track between Pins 2 and 4 of the TDA1541a chip.
4-Connect pin 4 to the adjacent ground pad ground (pin 5).

I want to put my beloved Arcam Alpa 5 running in NOS, but I´m not how to do it without serious demages!

Many thanks in advance for helping,
acruz

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Originally Posted by acccruz

Hi Mr. Leo:

Please let me know what do you think about this way to implement the Non Over Sampling mod:

1-Lift or cut pins 1,2,3,15,16,18 of SAA7220 from the board.
2-Join the vacated holes with wire thus: 1 to 18 2 to 16 3 to 15.
3-Cut the track between Pins 2 and 4 of the TDA1541a chip.
4-Connect pin 4 to the adjacent ground pad ground (pin 5).

I want to put my beloved Arcam Alpa 5 running in NOS, but I´m not how to do it without serious demages!

Many thanks in advance for helping,
acruz

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Hi acruz,

Please could you just nip into the welcome section of the forum and introduce yourself before the site owners get you :)

The wiring for the zero oversampling mod seems to be correct.
For those wanting a pic I found this http://nacl.de/philips/nos.jpg

Cheers,
Leo

So that £99 Net-Audio board isn't necessary then, or does it do summat else?

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Originally Posted by DSJR

So that £99 Net-Audio board isn't necessary then, or does it do summat else?

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I think it does the NOS and adds simple reclocking on the I2S lines similar to whats found in the Arcam Alpha5+

Hi guys

Can these mods be done on an Alpha 5+ ?

Cheers
Paul.

yes and they give even better results. partly due to the superior clock in the 5+ and also there are some other differences.
These CD-players can be taken to a very high-end level with a few pounds invested in them... :)