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Jez1983
29-01-2011, 15:14
Hi all
Been looking for an upgradeded power supply for my 7520 DAC. Came across these guys

http://www.fidelityaudio.co.uk/beresford_psu.shtml

Has anyone had any experience using this website or tried one of these power supplies. They cost more than the actual DAC! :lol: Would they be worth it, will there be an increase in sound quality or is this company just trying to make silly amounts of money?

Reid Malenfant
29-01-2011, 15:25
Yes it is a lot of money in reality, i'm not sure if anyone on here has tried one either..

If you wanted to try out a linear PSU you could buy a PSU for a CB radio (http://cgi.ebay.co.uk/13-8V-DC-Regulated-Mains-Power-Supply-Unit-XM20W-3A-/320631012898?pt=UK_ConsumerElectronics_SpecialistR adioEquipment_SM&hash=item4aa718fe22) as these are regulated & adjust the voltage to 15V ;) Or you could buy a perfectly good laboratory PSU (http://cgi.ebay.co.uk/NEW-CALTEK-60w-Bench-Top-Laboratory-Power-Supply-30V-2A-/200393835011?pt=UK_BOI_Electrical_Test_Measurement _Equipment_ET&hash=item2ea8674203) & again set it to 15V :eyebrows:

Now it's starting to look expensive :eek:

Ali Tait
29-01-2011, 15:42
I'd go for Mark's suggestion of the CB supply. No need to shell out silly money.

Techno Commander
29-01-2011, 16:07
This would seem to be something that many people ask for. I am surprised that Stanley hasnt come up with something yet. Many of the aftermarket PSUs seem to be going for silly money and I am sure that a very well designed, specced and manufactured PSU could be quite easily retailed for substantially less than £100.

What do you reckon Stan? :)

chapter three
29-01-2011, 16:11
I bought the Maplin CB supply on Stan's recommendation. It made a significant improvement to my Caiman compared to the 15v Maplin's switcher I was using before. Took about 2 minutes to open up and adjust the voltage.

For less than £30 it's a no brainer.

Techno Commander
29-01-2011, 16:15
This would seem to be something that many people ask for. I am surprised that Stanley hasnt come up with something yet. Many of the aftermarket PSUs seem to be going for silly money and I am sure that a very well designed, specced and manufactured PSU could be quite easily retailed for substantially less than £100.

What do you reckon Stan? :)

If it had a second output for powering a squeezebox, you could corner another market as well.

Techno Commander
29-01-2011, 16:16
Bu@@er.

I appear to have quoted instead of editing. :doh:

keiths
29-01-2011, 17:44
I bought the Maplin CB supply on Stan's recommendation. It made a significant improvement to my Caiman compared to the 15v Maplin's switcher I was using before. Took about 2 minutes to open up and adjust the voltage.

For less than £30 it's a no brainer.

Stan has said that the Maplin CB supply is only an improvement over the supplied switch-mode PSU if you have done he Murata regulator mod on your Caiman.

http://theartofsound.net/forum/showthread.php?t=5893

chapter three
29-01-2011, 18:45
I had one of the first Caimans that came with a 7520 supply. I bought the Maplin switcher and set it to 15v. The linear sounds better to my ears by quite a bit. I've since got a Gator but the rest of the Caiman is unmodified. I've never heard the caiman supply that Stan now ships so it may be different for others.

Reid Malenfant
29-01-2011, 19:23
I'd have thought that a linear supply feeding the Caiman whether the Caiman was modified or not should improve the performance ;) All SMPS will have some kind of switching spikes superimposed on the output as well as some 100Hz ripple & the standard regulators inside the Caiman will in no way be "fast" enough to get rid of these. They'll probably deal with the ripple voltage, where as one of the upgraded regulators stands more of a chance dealing with the spikes due to the higher performance.

A small amount of ripple at 100Hz from that CB PSU is nothing to fuss over, the internal 10,000uf capacitor will just about kill that off. The standard internal regulators should reduce that further, i'd expect the upgraded regulators to just about eliminate it entirely :)

The internal cap probably has more capacitance that the CB PSU :lol:

Puffin
29-01-2011, 19:41
Wasn't it suggested that if you are using a linear PS it is worthwhile removing the 10,000uf cap?

Reid Malenfant
29-01-2011, 19:46
I haven't clue Rob ;) However with a fairly substantial cable run between the external PSU & the PCB of the Caiman i'd have thought it made sense to have some low impedance source internally :)

Jez1983
29-01-2011, 19:49
Could someone point me in the right direction of what power supply to buy for under a 100 quid?

Reid Malenfant
29-01-2011, 19:56
Could someone point me in the right direction of what power supply to buy for under a 100 quid?
Well it depends on how much you want to spend :eyebrows:

The Maplin supply should be a reasonable choice, though it does have about 10mV of ripple on the output. That lab supply i linked to manages 0.3mV which is a lot less & better than the internal regulators can manage :lol:

Just type "laboratory power supply" into ebay search & see what you can find. Make sure it can do a minimum of 2Amps output & you can adjust it to 15V DC & you are probably laughing..

chrism
29-01-2011, 21:14
Well it depends on how much you want to spend :eyebrows:

The Maplin supply should be a reasonable choice, though it does have about 10mV of ripple on the output. That lab supply i linked to manages 0.3mV which is a lot less & better than the internal regulators can manage :lol:

Just type "laboratory power supply" into ebay search & see what you can find. Make sure it can do a minimum of 2Amps output & you can adjust it to 15V DC & you are probably laughing..

In reality the 2A supply is way overkill. Good quality regulators supplying 600-800ma are fine as the Caiman draws much less anyway - not many regs seam to do much more (Avondale, Teddy etc).

I have tried the Maplins bench and Muratas and have now gone for low cost self built linear PSU's. One for the analogue (12v) and one for digital (5v). Well worth the effort and costs came in at around £80.00 or so each.

Regards

Reid Malenfant
29-01-2011, 21:21
In reality the 2A supply is way overkill.
Agreed, if the Caiman was using 30W (15V @ 2A) it'd nearly fry an egg :eyebrows:

You try finding a smaller CB power supply though ;) 2Amps is about as low as you'll get, 3 or 5Amp is more common (continuous rating).

Still there is something to be said for going overkill on any PSU :cool:

The Grand Wazoo
29-01-2011, 23:23
Could someone point me in the right direction of what power supply to buy for under a 100 quid?

Oooooooooh Jez!
You've got to Post Number 5 and you still haven't introduced yourself to the fold! Would you mind nipping over to the Welcome section & telling us all about yourself, your hifi & your music.
That'd be great, cheers

Alp
19-02-2011, 13:08
Following good advice on this thread I have purchased the Maplin XM20W Linear Power Supply. Before adjusting the voltage to 15V, I thought I'd check the output voltage with my multimeter. To my surprise it showed 16.25V vs. 13.8V. I have several questions:

i) Will it harm the Caiman at 16.25V?

ii) I have recently converted to use the excellent passive mod (again thanks to AOS) but have read somewhere on AOS that only the op-amps need 15V, so with the passive mod, 13.8V is OK for the Caiman. Is this correct or will the caps benefit from the higher voltage, as Stan B. used to say for the 7510 with the Maplin switcher supply?

iii) Would I see a significant improvement in addition to the linear supply and passive mods if I shell-out £96 on the Murata Regs modification from Tirna?

Puffin
19-02-2011, 14:02
If you can solder you can make some of these. About a £fiver each.

http://i73.photobucket.com/albums/i239/saxonsex/regboosterlabeled-1.jpg

Clive
19-02-2011, 15:34
What does it do vs a std reg? Reduced noise?

ps, better remind folks to get the tant polarity right too.

Reid Malenfant
19-02-2011, 15:58
It looks like a ripple eater to me :scratch: I don't give that transistor a very long life though as it's only rated to 100mA maximum collector current. Also it'd be better off on the output (well with a transistor with enough current capacity) & a diode on the ground connection of the regulator to offset the voltage drop of the transistor :)

Puffin
19-02-2011, 18:23
Have you tried it?

Reid Malenfant
19-02-2011, 18:32
Have you tried it?
No, i don't think i'd like to :eyebrows: If you have the collector connected to the input of the regulator as stated in your post & it looks like the base is connected to the resistor & capacitor, i figure that the emitter is now the input? :scratch:

Why are you using an NPN transistor? Surely a PNP would be better like a BC557C, it might actually do something. Taking the emitter higher than the base on an NPN will cut off the transistor, sorry, i just can't see how the hell it works or what it's mean't to do :scratch:

Puffin
19-02-2011, 18:44
Just occurred to me that what I said earlier was incorrect:doh:
The Collector is attached to the IN pin and the Emitter is connected to the IN leg of the 7805. It may not change your mind that it is rubbish, but I thought I had better correct my muppetry:lol:

(the transistor shown in the pic posted earlier is the wrong way round. NB I did not draw the pic and I believe it was corrected by OP on PFM)

http://i73.photobucket.com/albums/i239/saxonsex/bc547_large.jpg

leo
19-02-2011, 23:16
I presume its a simple cap multiplier ? can be used on input or output of the reg, I'd personally go with the input so keeping regs lower output impedance. Anyway these things are cheap, they help filter out crud which goes through most basic regulators.
For lower voltage a BC184C is ok.

Edit
Make sure the transistor pin outs are correct