Arcam Alpha 5 [Archive] - The Art of Sound Forum

aquapiranha

01-12-2008, 21:26

Hi guys. I have been very lucky and was given an Alpha 5 CD player. I would like to do a couple of mods on it and compare the original and after modification. However, I am no expert and would like to do simple, inexpensive mods if this is possible.

I will be greatful for any suggestions!

Many thanks!

Filterlab

01-12-2008, 22:03

I'm no DIY expert, but if I was modding an Arcam Alpha 5 (great machine btw) I'd go straight to Trichord's site and get a new clock and psu for it. You could try a separate offboard DAC as well, or try to find a Black Box - immediate improvement.

Ahhhh the Alpha 5, my first proper CD player. :)

aquapiranha

01-12-2008, 22:06

Thanks Rob. I will take a look. I already have a nice Meridian, I just wanted this as a spare and also to get busy with the soldering iron! I just hope I don't end up upsetting the meridian with a new improved Alpha 5 !

alb

01-12-2008, 22:20

There should be plenty of threads and articles about the Alpha 5.

Here's one.
The non-oversampling mod must be one of the most worthwhile.
http://www.diyaudio.com/forums/showthread/t-54617.html

Here's another. More of an alternative output stage than a tweak.

http://www.lampizator.eu/index.html

Marco

01-12-2008, 23:59

Hi Steve,

Les W from Avondale Audio (he's a member here but more active over on pfm) should be your first port of call for advice. The Alpha 5 is (and has been been for years) a prime candidate for his modifications. I should imagine that what he doesn't know about modifying the AA5 isn't worth knowing. He's also a very nice and helpful chap :)

Marco.

leo

02-12-2008, 00:57

NOS mod
recap it, PSU's and regulation lines
Change output filter op-amps (NE5534 ) to same as the I/V op-amps (op27)
Remove muting transistors
Change Bi-polar output coupling caps to 1-10uf films
Change standard diodes to something like schottky 11DQ10

Theres a lot of things I can suggest but some things are not recommended for beginners.
Having somebody like Les to mod it would be the best bet IMO if your not sure

aquapiranha

02-12-2008, 08:21

I will look into all of the suggestions, there seems to be a lot of things that can be done. It will give me something to think about prior to xmas stress-fest.

:)

Yomanze

10-12-2008, 12:23

It's worth thinking about larger value replacements for those 14x decoupling caps around the TDA1541A. Arcam were onto this already, hence the 4x 0.47uf orange tantalum caps for the MSB and, err, next MSB decoupling caps... it would be worth considering increasing the first pair or two to 1uf and the rest to 0.47uf.

DSJR

10-12-2008, 13:08

Les W is well worth getting to know, whatever you do with an A5, as he keeps mechs for them, either new or fully refurbished with warranty......... bearing in mind the short production life of these consumables, it's worth knowing IMO...

aquapiranha

12-12-2008, 23:23

Thanks again chaps. I have been away and so have not had a cjance yet to check out all the options. Hopefully I will have a good look over the next week or so.

aquapiranha

19-07-2009, 19:13

Well I finally dusted off the soldering iron and had a go... I replaced a total of 10 diodes in the PSU section with lovely Schottky's and also ripped out a couple of opamps and replaced them with new Burr Brown OPA134's on sockets so I can replace and roll them easily. Plus I had to replace the broken RCA connectors.

And yes, it does sound better, the transients are unbelievable and the sound now has more of a 'live' quality to it. I will be ordering some more opamps to replace a couple of OPA27's I have not yet changed, plus perhaps some boutique caps also. anyone considering doing these mods should definitely give it a go!

DSJR

19-07-2009, 21:39

Try to get a spare loading gear for the drawer as these fail and originals are no longer stocked.

The CDM-9 tracked too well and Arcam's implementation of it was one of the best of all for clean tracking of badly scratched discs I found. After this era, Philips mechs were almost intentionally downgraded to the 1200 series which will play a disc within spec but not ones that aren't.......

aquapiranha

19-07-2009, 21:53

leo

19-07-2009, 23:24

Don't be quick to judge OP27 on its lowish spec
This op-amp doesn't sound half bad if used with care and makes a not too bad I/V stage, it don't like DC on its inputs, Arcam implemented a nice nulling circuit on the output of the dac chip which takes care of the DC (a lot of places don't bother with nulling ), could be one of the reasons why these chips work well in this cdp

BTW, this unit is dead flimsy in build, its picky what its sat on;) get it wrong and it'l sound flat as pancake

aquapiranha

20-07-2009, 05:26

Hi Leo, and thanks for the advice. I will be using sockets on the board so will be able to swap opamps at will, as I have with the 134's. Also, I will be trying different materials underneath.

NRG

20-07-2009, 08:23

I was going to add Leo's yer man for tweeks on the Arcamn he helped me greatly with my DIY dac based on an Arcam DAC board which is the same cct as in the 5.

The supply decoupling to the 1541 makes a big difference as does making the voltage difference between the -5v and -15v as close to 10v as possible. IE 0.1 to 0.3 volt.........0.5v is audible.

aquapiranha

20-07-2009, 11:05

thanks Neal. I am afraid my knowledge extends no further than following instructions on a sheet, however my soldering is prett good! So if anyone can point me to some step by step instructions I would be grateful!

Thanks :)

leo

27-07-2009, 18:56

If theres a good clear pic of the audioboard and mainboard I could edit it and add a few easy things to try

Obviously will keep things really simple :)

aquapiranha

27-07-2009, 21:15

Hi Leo, that is very good of you! is this any good?

http://i205.photobucket.com/albums/bb256/aquapiranha/Various%20HIFI/CIMG3155.jpg

A bit bright due to the flash. And this one of the business end...

http://i205.photobucket.com/albums/bb256/aquapiranha/Various%20HIFI/CIMG3109.jpg

Let me know if they are no good. I have already changed two of the opamps as you can see, and I have two more, I just need to order the push fits.

Thanks!

leo

27-07-2009, 21:18

Looks good, if changing caps on the main big board would not be a pain take a pic of that too, apart from improvements in sound you get better reliability;)

aquapiranha

27-07-2009, 21:35

Will do Leo. I have already changed 10 PSU diodes on the main board to Schottky's so no problem wielding a soldering iron!...

http://i205.photobucket.com/albums/bb256/aquapiranha/Various%20HIFI/CIMG3157.jpg

http://i205.photobucket.com/albums/bb256/aquapiranha/Various%20HIFI/CIMG3158.jpg

sorry, I am no David Bailey!

leo

27-07-2009, 21:46

Ok, first audioboard, its pretty simple tbh but worth a try, parts won't leave you poor:lol:

Where do you order your bits from, Farnell? The film caps I used to like are no longer available so will need to try a few alternatives to compare

Of course we can go further, much further with the audioboard but isn't easy, some things need to be built on veroboard like a new output stage

Things like the clock and voltage regulation does benefit from upgrading but will add much more to the cost

http://i273.photobucket.com/albums/jj220/kingbusoms/a5mods.jpg

aquapiranha

27-07-2009, 21:53

Great thanks Leo! I do have an account with Farnell, who I find to be very well priced. The two opams you have arrowed, I have already changed the NE's to OPA134's. (if you look closely you can see the sockets I added) I was thinking of trying a couple of others, but I will leave that until I have done some more of the mods you suggest. (have you seen the bloody price of OPA627's???)

Thanks again, I will get ordering tomorrow...

Oh, what does NHG mean?

leo

27-07-2009, 22:14

main board

and Farnell parts, obviously some come in packs of 5

http://i273.photobucket.com/albums/jj220/kingbusoms/a5mods2.jpg

1000uf 50v NHG (9 needed) http://uk.farnell.com/panasonic/eca1hhg102/capacitor-1000uf-50v/dp/9693009

100uf 25v NHG (2 needed) http://uk.farnell.com/panasonic/eca1ehg101/capacitor-100uf-25v/dp/9692827

10uf 25v oscon (4 needed) http://uk.farnell.com/sanyo/25sc10m/capacitor-10uf-25v/dp/9188690

Can't find 3300uf, I think its 25v? been a while since I been inside this cdp
You can use what you like, worth changing mainly for reliability

I personally liked OP27 best in both I/V position and the output but use what you like best
I wouldn't waste money on OPA627, its not that great IMHO, vastly overpriced

leo

27-07-2009, 22:19

You want to try NOS??? you loose the digital output but some swear by NOS in these players

aquapiranha

27-07-2009, 22:19

cheers Leo, I will have a look at Farnell tomorrow. And thanks very much for taking the time and effort, even to the point of getting me the part numbers!great!

Steve

leo

27-07-2009, 22:20

NOS mod can be done so its reversable but it requires care ;)

aquapiranha

27-07-2009, 22:23

I have seen one or two NOS option by the likes of netaudio, I do not need the digital out so was considering it!

leo

27-07-2009, 22:27

I have seen one or two NOS option by the likes of netaudio, I do not need the digital out so was considering it!

all it costs you to try is a soldering iron, solder, desolder wick or pump ,steady hand, a few bits of wire:eyebrows:

aquapiranha

27-07-2009, 22:31

all it costs you to try is a soldering iron, solder, desolder wick or pump ,steady hand, a few bits of wire:eyebrows:

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

leo

27-07-2009, 22:56

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

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:

aquapiranha

27-07-2009, 22:59

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:

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!

:)

leo

27-07-2009, 23:28

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/jj220/kingbusoms/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

aquapiranha

28-07-2009, 09:02

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.

acccruz

04-08-2010, 13:15

leo

04-08-2010, 16:06

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

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

DSJR

04-08-2010, 18:54

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

leo

04-08-2010, 19:08

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

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

Paul

12-12-2010, 21:35

Hi guys

Can these mods be done on an Alpha 5+ ?

Cheers
Paul.

andreime

17-12-2010, 23:18

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... :)

Paul

19-12-2010, 15:30

Thanks
I'm currently using it as a transport into my DAC . If I undertook these mods would it sound superior on it's own and do any of these mods improve the digital output ? not that it sounds crap thru the DAC .

I love it as it is but wanted to make it even better, I have a couple of upgrades on the cards for the DAC ( gator board and opamp plus psu ) so wanted to improve the input into it , to get the best out , if you know what I mean?

I also wanted a decent stereo amp as I only have my surround amp atm, so looking at getting the best out of what I have before buying a new amp.

Thanks
Paul

andreime

24-12-2010, 00:01

these mods don't improve much on the transport side - most of them are for the DAC--BUT if you change they cannot hurt it. It's a good thing to mod the digital supply on the main board as suggested in one of the pictures. You could also change the recovery diodes for low noise ones and that's about it.
For a better transport you need to check the laser circuits but that's not so easy and can ruin the diode if mistakes are made. There's also a good chance it's running fine - not perfect but fine.
Hope this helps.

Paul

24-12-2010, 20:59

Thanks again,

I'll have to get my soldering iron out and start tweaking . :eyebrows:

I read somewhere that you can add a seperate power supply to these ( as I know Avondale do) and also saw pictures but now can't find them anywhere on the net , and I have tried lookig quite a bit.

Have a good Christmas
Paul