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chebby
05-04-2009, 12:48
Hello Stanley.

On the Beresford.me website TC-7520 page I am seeing a new power supply (with "exclusive to beresford" printed on it).....

http://www.beresford.me/UK/images/PSU.jpg

http://www.beresford.me/UK/Stereo_Audio_Digital_to_Analogue_Converter_USB2FCO AX2FTOSLINK.html

My TC-7520 (purchased early Feb) has the older style plug-top PSU.

Is this new style PSU a 'repackage' of the same one I have or an upgraded version?

If it is an upgrade, is there any way I can purchase it please? (Your website does not list it as a seperate item.)

Thanks

ps what is the other - circular - object pictured on that page with the 'exclusive for beresford' label embossed on it?....


http://www.beresford.me/UK/images/PC2.jpg

Getgaff
05-04-2009, 16:33
I too would be interested to hear about the new PSU.

Dougr33
05-04-2009, 16:55
He mentioned previously that the circular cap is the custom made power cap inside the 7520. It took awhile to get the embossed top made, but all 7520's have that cap, even if not marked.

I'm pretty sure.

Radiotron
05-04-2009, 22:24
New PSU? Want to know more!

ReachtheSky
06-04-2009, 02:46
Stan has previously indicated that a new upgraded PSU was due out about end of March. Being a new product, it has apparently been subject to the relevant approval processing procedures. I suspect this action is taking longer than anticipated. I’m sure Stan will enlighten us all once it is available.
(The picture on the website might suggest that it is not that far off.)

chebby
07-04-2009, 10:19
Since my last update I have upgraded to the 'new' TC-7520 power supply. It arrived this morning.

I have connected it with a TM3 Connections shielded/braided figure-of-eight mains connector (with high quality MK Tough-Plug) that I had lying around....

http://i24.ebayimg.com/03/i/001/06/3c/85b0_1_sbl.JPG

Not quite sure if it has improved anything yet. Too early to say after an hour or two. But it certainly does not sound any worse and at least I have what is now the 'standard' TC-7520 PSU rather than one borrowed from the TC-7510.

Covenant
08-04-2009, 08:31
Chebby pease keep us posted about this. When Stan first talked about an upgraded supply he was trialing linear supplies then he changed to a switched mode ps. If the improvement is minimal I may look for a linear one.

StanleyB
08-04-2009, 09:46
When Stan first talked about an upgraded supply he was trialing linear supplies then he changed to a switched mode ps. If the improvement is minimal I may look for a linear one.
Why would a linear external PSU give a larger improvement compared to the TC-7520 external PSU:scratch:? The TC-7520 draws its supply from the internal PSU, not the external one. The external PSU is used to charge up the internal PSU and keep it topped up.

Covenant
08-04-2009, 10:57
Why would a linear external PSU give a larger improvement compared to the TC-7520 external PSU:scratch:? The TC-7520 draws its supply from the internal PSU, not the external one. The external PSU is used to charge up the internal PSU and keep it topped up.

'I'll have a new external power supply out by March. After wasting my time believing all the junk that various power supply designers from numerous factories have been telling me, I realized that these guys weren't even suitable to clean my shoes. So I have worked on a matching design whose sole purpose is to feed my DAC and a few other products I have in the design stage. The DAC doesn't need a lot of current. In fact it only draws 100mA on average. What it needs is a low ripple voltage and current. So far only off the shelf linear power supplies can produce those types of figures at a low price.

StanleyB
08-04-2009, 11:19
That doesn't answer my question I posed to you.

Covenant
08-04-2009, 11:57
Your last sentence implies that linear is better, obviously you have a different perspective on it. I guess because I noticed a considerable difference changing to a linear supply for my squeezebox I anticipated that a linear may be better for the 7520.
I wasnt having a go-just want to know which is best.

Peter Stockwell
08-04-2009, 12:40
I guess because I noticed a considerable difference changing to a linear supply for my squeezebox

What did you do for the Squeezebox psu ?

Covenant
08-04-2009, 13:11
Hi Peter,
I had it made for me. Basically its a wooden box about 150x150mmm with switch on the back and 64000 uf capacitors inside. Cost £100.
Very pleased as it seemed to open up the soundstage.

chebby
08-04-2009, 14:37
In order to drown out the sound of engineers - installing central heating - next door, I opened up the volume a lot more than usual this morning.

'Sinatra at the Sands' followed by some Eurythmics and some George Thoroughgood & the Destroyers and the Shamen and Blur.

A mixture of mostly lossless iTunes files and a couple of 256kbps AAC from the laptop (USB).

After that I slipped on Roy Orbison's Black & White Night DVD (DVD/HDD recorder is connected via digital optical audio output to the TC-7520) and gave that a blast.

The slightly higher volumes used today helped to confirm that this unit is performing extremely well!

Please bear in mind that I have only had the LM4562NA opamps upgraded for about a week, so some of this improvement is - no doubt - due to them as well. Also bear in mind the TM3 connections fig-8 shielded mains lead which is not standard with Stanley's new power supply.

Compared to before I first bought the TC-7520, it now sounds like someone has dropped a 50 watt Sugden pure class A amp into the system without my knowledge!

Krisbee
10-04-2009, 15:51
chebby,

Have you formed an opinion on the difference, if any, between the old style plug-top PSU and the newer PSU when used with the TC-7520?

As Mr.B has said "The TC-7520 draws its supply from the internal PSU, not the external one. The external PSU is used to charge up the internal PSU and keep it topped up." I wonder if there's much mileage to be gained from changing from the old style plug-top PSU.

trailer
20-04-2009, 12:46
Any update as to availability?

Covenant
26-04-2009, 20:21
Have a look at this:
http://www.powersuppliesonline.co.uk/product/18w-12v-1-5a-desktop-regulated-linear-psu/jc93/default.htm
A possible alternative?

Getgaff
27-04-2009, 15:21
^

I strongly advise people to avoid that POS power supply.

My first PSU failed 3 months after the warranty expired. The second PSU failed after just 3 months. My third PSU now sits in a drawer gathering dust.

If you want a second opinion read this,

http://forums.slimdevices.com/showthread.php?t=61090

Covenant
27-04-2009, 15:28
Thanks Getgaff,
Glad I asked on this forum before buying it. Craptastic is the word.
Stan has gone quiet about the new supply, any other suggestions?

Gazjam
27-04-2009, 19:33
I use the Maplin one long recommended for the 7510

http://www.maplin.co.uk/Module.aspx?ModuleNo=48517

I use it wilth an after market power lead ( as thick as yer wrist!) and I find it a good improvement over the standard.
The noise floor seems lower, less mush in the background.
Dynamics are better too.

It can be set to 12v or 13.5v, some recommend one setting, some the other.
Suck it n see.

I run it at 12V as 13.5v acts like a "loudness" button in my system, artificially boosting the dynamics and generally being a less subtle sound.

I'd go with this one if your looking for a PSU - it makes a good difference.

Cant comment on Stans new one - it could be better, who knows?

Gazjam
27-04-2009, 19:50
^

I strongly advise people to avoid that POS power supply.

My first PSU failed 3 months after the warranty expired. The second PSU failed after just 3 months. My third PSU now sits in a drawer gathering dust.

If you want a second opinion read this,

http://forums.slimdevices.com/showthread.php?t=61090


I had one of those PSUs and it was fine, was using for my Squeezebox and I found it improved the sound.
I only passed it on when sound improvements introduced by the 7520 negated the improvements the PSU made.
Swapped it for an NVA Digital coax and got even more improvement! :)
Opinions are varied on the use of a PSU for the Squeezebox, but there is no question about a better PSU for Stans Dac.

When I had this PSU it never failed, ran hot or any other problems.
Perhaps you had a bad 'un?

Covenant
27-04-2009, 20:13
[


Cant comment on Stans new one - it could be better, who knows?[/QUOTE]
....and we wont know unless we get some feedback.

Gazjam
27-04-2009, 20:16
Yup.

In the meantime though........

technobear
27-04-2009, 20:41
Have any of you guys tried running your StanDAC on a battery? :)

Covenant
27-04-2009, 20:53
Yes I did-wasnt impressed.

How about a PS kit? http://www.quasarelectronics.com/cfe004.htm

leo
27-04-2009, 22:51
I don't think a lot of regulated linears are going to be the best match for one of these dacs, you want something with a stiff output to keep thousands of uf's worth of input caps charged

Gazjam
27-04-2009, 22:59
Any recommendations Leo?

I'm happy with the Maplin + Krystal Power lead, but be good to get some potentials?

leo
28-04-2009, 00:15
If you have the Maplin SMPS one I don't think its worth upgrading tbh, you may only get small differences
I know lots of linear regulated psu's which have cleaner outputs than a SMPS but their not suited for the type of supply in this dac, they just don't go with high uf's on the output.

Gazjam
28-04-2009, 06:29
Thanks Leo

StanleyB
28-04-2009, 07:28
I shall add the new PSU as a separate item for purchase in May. The initial feedback from customers who have tried it with the TC-7510 is very positive, as is the feedback from those with a TC-7520 who upgraded from the TC-7510 psu to the TC-7520 psu. Upgrade price is £21 for UK and £23 for the rest of Europe. That includes P&P.

Stan

Covenant
28-04-2009, 10:45
Well that seems a very reasonable price.
Could you give a bit more detail about it Stan-its design in relation to the old one.
Would you like the old one back by the way (I hate waste)?

Covenant
04-05-2009, 13:22
Have a look at this alternative:
https://www.picstop.co.uk/Power-Supplies/Ansmann-APS-1012---Power-Supply
A cheap linear jobby-anyone used this or any other linear regulated supply?

freddiecas
04-05-2009, 17:11
is that model a linear supply? presumably then they get the output voltage range by switching the transformer secondary, otherwise there would be a lot of dissipation across the regulator at low output?

I have the 1612 model and that one is a switching.

Covenant
04-05-2009, 17:59
Here is another supplier who describes it as a linear supply:
http://www.batterytastic.co.uk/Search_Data_Sheet.asp?ID=APS1012

sr1329
05-05-2009, 06:52
What is wrong with you guys? You were just told that a regulated linear is not ideal for this DAC and the rest of the thread is speculation about some PS being Linear.

Anyway, I think I'm going to go with the PS from the guy who made the DAC. I mean it's 23 Euro. You can't do any better than that.

StanleyB
05-05-2009, 07:11
What is wrong with you guys? You were just told that a regulated linear is not ideal for this DAC and the rest of the thread is speculation about some PS being Linear.

Anyway, I think I'm going to go with the PS from the guy who made the DAC. I mean it's 23 Euro. You can't do any better than that.
Finally someone who is on the ball and paying attention.

Stan

Covenant
05-05-2009, 07:57
In the words of Stan himself:
'What it needs is a low ripple voltage and current. So far only off the shelf linear power supplies can produce those types of figures at a low price'.
No disrespect to Leo but when the designer makes a comment like that it seems reasonable to be to look at alternatives.

leo
05-05-2009, 08:36
In the words of Stan himself:
'What it needs is a low ripple voltage and current. So far only off the shelf linear power supplies can produce those types of figures at a low price'.
No disrespect to Leo but when the designer makes a comment like that it seems reasonable to be to look at alternatives.

No worries, I just try and help, not trying to force things on people;)

Normally a linear is better but thats without it seeing large uf on its output, regs in linear regs don't like to see that:)

StanleyB
05-05-2009, 08:57
In the words of Stan himself:
'What it needs is a low ripple voltage and current. So far only off the shelf linear power supplies can produce those types of figures at a low price'.
No disrespect to Leo but when the designer makes a comment like that it seems reasonable to be to look at alternatives.
The TC-7520 uses a two stage power supply design that is unconventional, and is of my own invention.
I am not going to sit here arguing with people and picking at words. You have had my say, I produced the two parts of the TC-7520 power supply, I wrote about it on my site,and I leave it at that. If people wish to ignore my time and effort and want to go their own way, well that's their choice. Just don't expect me to take part on discussions or offer advise on such issues. You are on your own.

Stan

StanleyB
05-05-2009, 08:59
Normally a linear is better but thats without it seeing large uf on its output, regs in linear regs don't like to see that:)
You are wasting your time Leo. A few posts from now and your words of wisdom would have been forgotten. It is the 2nd time you have mentioned this, and the first time was not even noticed:doh:.

STan

technobear
05-05-2009, 09:21
Does this mean the 7520 is or is not suitable for use with a 12V system driven by a large lead acid battery :scratch:

I would have thought the battery wouldn't care about the capacitance.

lovejoy
06-05-2009, 09:21
A battery would be fine. In fact, that's exactly what I am going to try on my TC-7520 this week. I used to have one of Doede Douma's fantastic 1543 based DDDAC kits which I found sounded best powered by a sealed lead acid battery, but as the thing drew in excess of 1A at 12V I ended up buying a golf cart battery (20Ah) and having to charge it once a week which was a bit of a pain. The Beresford as I understand it only draws around 100mA, so a modestly sized 12V SLA battery will last a good while.

I've been playing with power supplies for a while with both the 7510 and the 7520. I found the original wall wart OK, then tried the Maplin supply but didn't find it significantly better and returned it. I then got Stan's new supply and found that to be a good improvement over both the standard supply and the Maplin, but nothing to my ears even approaches my discreet supply which I built using a toroidal transformer outputting 18V - 0V, feeding a low ESR electrolytic, going into one of Teddy Pardo's TeddyReg boards from PFM. To me this just raises the DAC to another level (especially if you've changed the op-amps to your liking). The usual disclaimer about your mileage may vary applies. I'll be interested to compare it with a battery supply and will report back if anyone is interested.

Covenant
06-05-2009, 09:42
I am really interested in your approach Lovejoy and would be grateful if you would publish details and piccies of your PSU in the DIY section. Isnt 18v getting a bit much?
I dont think Stan approves of talk about alternative PSU which is understandable given the effort he has gone into producing his new one. Its likely that very few people would go down this route however given the time and cost involved.

lovejoy
06-05-2009, 09:58
Completely agree. From Stan's point of view, he's trying to make the best DAC available for the best price, which in my mind he's achieved and then some. It would make absolutely no sense to make this kind of power supply to sell as even an option as it would be heading towards doubling the outlay. I've been lucky in that everything I've built has come from parts I either had lying around or cannibalised old dead projects.

Yes, 18V would be too high to feed straight into the DAC. The 18V AC from the toroid gets rectified and smoothed and ends up at about 25V which feeds the TeddyReg board which in turn outputs the 12V to feed the 7520. This solution is by no means perfect. Ideally a toroid which gave me something in the region of 12-0-12 so I could perform full wave rectification and a higher value low ESR cap would probably improve things further, but apart from the TeddyReg board itself I've not bought anything new.

The battery experiment will be funded by the £20 credit note I have from Maplins from when I returned their power supply.

Covenant
06-05-2009, 10:22
Would it cost that much? The Super TeddyReg board built and shipped is only about £40.

lovejoy
06-05-2009, 10:35
The Super TeddyReg is £40 (I wish you hadn't mentioned that as that's another experiment for another day ;-)). Then you have to add the cost of a transformer and a bridge to feed it with. I guess you could use a simple mains transformer which wouldn't cost you much more than a fiver but I can't vouch for them. Toroids (which I am using) after a quick look at the Maplin website are around £20 and generally considered a better bet for audio. Then add a good quality low ESR (this bit is important) smoothing cap which is another few quid and either a bridge, or diodes (pennies) and a nice box to put it all into. The cost soon stacks up, not to mention all of the time gone into designing such a thing.

StanleyB
06-05-2009, 14:01
If you feed more than 15V into the DAC be prepared for an internal explosion inside the DAC. The power cap is rated at 16V.

leo
06-05-2009, 15:15
It maybe worth editing the above post and the one on here http://theartofsound.net/forum/showthread.php?t=2658 which mentions 15v , as Stan says if the caps are max rated at 16v running them over 15v will make em go bang, running near max voltage is at least going to greatly reduce the lifespan may even leak,bulge and go noisy if run 24/7
Your best off giving them some headroom, 12v would be the best imo

Covenant
06-05-2009, 15:35
Its funny Leo mentioning that. I was always a little bit wary of the comments about running the Maplin PSU at 13.5v. I wouldn't want to go any higher than the designed voltage.

StanleyB
06-05-2009, 16:42
The Maplin PSU was only recommended for the TC-7510 up to the MK5. From the MK6 upwards the internal PSU design was changed. That pronounced midrange boost on the higher voltages is due to the inability of the Maplin PSU to charge up the Virtual DC power supply high capacity capacitor inside the TC-7510 & TC-7520 within less than the minimum frequency one expects to reproduce. That means that the lower bass energy requirements are not fulfilled by the Maplin PSU.
In the case of lead acid batteries: these are unable to perform adequately once they are partially discharged. Their off load voltage might be 12V or more, but once on load they can drop below 12V. I did many measurements and even ended up abandoning my attempt to make a battery PSU. The sub woofer I bought off Dave_C clearly showed up a softening of the bass as the battery got discharged.

Stan

Dougr33
06-05-2009, 18:48
Stan, aren't you basically saying (said I think) that there's little or no audible gain to be had with a different power supply on the 7520 due to your current design?

StanleyB
06-05-2009, 19:06
You got it.

Spod
06-05-2009, 20:55
Just goes to show, everyone hears differently.
Hate being contradictory, but I definitely hear an improvement using the 7250+4032 when powering it with the Maplin (at 12v) over the supplied 2nd-gen PSU (music seems to have more solidity to it). But I'm quite willing to believe I just hear "a difference" and on my system I just happen to prefer it with that difference.

Dougr33
06-05-2009, 22:44
Well, my statement he agreed to was "little or no" audible gain... People pay $$$ for that last little bit!! So if you can hear it, it's a good thing!

Covenant
07-05-2009, 06:41
I think its a good thing to put the improvement in context though. Paying a lot for an upmarket supply doesnt make sense if you can get better performance through changing an op-amp for a tenner (or the other improvements that Stan has yet to tell us about :eyebrows:)

lovejoy
07-05-2009, 07:18
I'm afraid I have to be contradictory here too. I guess it's all completely system dependent and a sprinkle of voodoo going on, but I found my discrete power supply over the standard wall wart to be as big an improvement as replacing the op-amps. I'm extending an open invitation to anyone passing through Swindon to drop in and hear it (although avoid Swindon this weekend as it's Radio 1's big weekend).

I did purchase a battery on my way home from work last night. The jury is currently out. I'd concur with things sounding softer. At the moment I think I will probably go back to my discreet supply, but I'll give it a week and see how it goes.

Covenant
07-05-2009, 07:58
If Swindon was a bit nearer Ormskirk I would take up that kind invite Lovejoy.
As you said yourself though, you already had most of the parts for your PSU so it cost you very little. I am all for getting the best from my Standac but realise that costs in the region of £150 do not make sense (to me). YMMV.
Stans battery comments were interesting-if I read it right you may get an improvement at first which rapidly tails off.

lovejoy
07-05-2009, 08:14
Yes, depends how big your battery is and how long your average listening session is. I bought a 2.2Ah battery from Maplin and as the DAC apparently will only draw in the region of 100mA, that's plenty for a good day of music without allowing the charge in the battery to get too low. Then once I've finished listening, I switch the battery over to a trickle charger which keeps it topped up while not in use.

The trick with batteries is not to get into the habit of allowing it to fully discharge and then completely recharge it. They don't like it very much. When I had my DDDAC, this happened a couple of times as the thing was drawing so much current and I noticed that after a couple of full charges the sound quality was noticeably worse, even when the battery was fully charged so it had to be replaced. As Stan's DAC only draws a small amount of current, I thought it was worth a try as I can have an evening of entertainment and then trickle charge during the day, comfortably replacing the energy I've used.

lovejoy
10-05-2009, 09:31
Well, I've had a good weekend of experimentation with various power sources and I seem to have settled on a setup I'm very happy with now.

The battery approach isn't the best. Too soft, dynamics get squashed, there's just no excitement and it doesn't take long to get bored.

I took the battery out and put Stan's new supply back in and it was immediately much better. The dynamics are back, focus is much better and everything gets cleaned up.

I've come to the conclusion that the law of diminishing returns kicks in with anything above Stan's new power supply and I think the difference between the original wall wart and the new one is bigger than that between the new supply and my own discreet supply.

One thing I did pick up on this weekend is how much I prefer the sound of a USB connection from my PC to using either optical or coax. Strangely, I can tell no difference whatsoever if I'm using a Mac between optical and USB but on the PC, USB brings more realism to instruments like piano and guitar. It's one of the only digital setups I've ever heard where you can actually feel the amount of weight going into a played piano note. There's much more of a sense of being able to look into a recording too. It's thoroughly engaging.

So to sum up my findings so far (of course I'm not going to stop playing), first and foremost, digital source is paramount and for me it's got to be a PC running Foobar through ASIO with a USB connection. I'd love to use a Mac as the interface and music management is so much better, not to mention quieter and faster to load, but (and I know people will argue that iTunes gives bit perfect output - but there's so much more to it than that) I find the sound from a Mac flat, lifeless and lacking in any ability to stir the emotions. So I'll stick with the PC until I find something that is as good if not better in a smaller box - maybe something along the lines of an SB3 possibly.

Then Stan's new supply is a no brainer if you haven't already got one. For the outlay, it's a big improvement. Yes, you can get better, but unless you've got lots of bits lying around that you can construct your own supply with, it's going to cost a fair bit for a modest improvement.

A nice new op-amp or two in the output stage is also a no brainer. I can't think of anything else you can spend a tenner on and get such a huge improvement, except for maybe a nice bottle of wine, but the op-amps are a more permanent upgrade.

Then, if you're on a PC, have a play with a USB connection and if you're using Foobar use the Kernal Streaming plugin. I guarantee you'll be listening for hours.

This poses a question.. I see that the USB input has a crystal for clocking the data coming in. Would there be anything to be gained by swapping this standard crystal out for a low jitter alternative like a Tent Labs clock?

StanleyB
10-05-2009, 10:16
The battery approach isn't the best. Too soft, dynamics get squashed, there's just no excitement and it doesn't take long to get bored.

I seem to recall pointing that out as well. I even abandoned my own battery psu design when I noticed that problem.



I took the battery out and put Stan's new supply back in and it was immediately much better. The dynamics are back, focus is much better and everything gets cleaned up.
The TC-7520 psu was designed for me by someone who makes a living out of designing these things.



One thing I did pick up on this weekend is how much I prefer the sound of a USB connection from my PC to using either optical or coax. Strangely, I can tell no difference whatsoever if I'm using a Mac between optical and USB but on the PC, USB brings more realism to instruments like piano and guitar. It's one of the only digital setups I've ever heard where you can actually feel the amount of weight going into a played piano note. There's much more of a sense of being able to look into a recording too. It's thoroughly engaging.
Many have tried and failed in their attempt to design a DAC with a USB input that could give SPDIF and optical a stiff challenge. I myself consider the DAC1 from Benchmark to be the only serious competitor with a USB input that can rival the TC-7520. Everyone else is way behind us on USB performance. My feeling is that maybe other designers see USB input on a DAC as a gimmick that does not require professional design commitments, or they haven't got a clue how to design a professional USB circuit.



This poses a question.. I see that the USB input has a crystal for clocking the data coming in. Would there be anything to be gained by swapping this standard crystal out for a low jitter alternative like a Tent Labs clock?
The crystal I use is good enough for the purpose. I tried more expensive ones, but the jitter in PPM is even lower than the jitter from the receiver IC I use. So I couldn't get an improvement.

Stan

lovejoy
10-05-2009, 10:23
Well, in that case, all I have left to do, is sort out my music library..

Thanks Stan.

StanleyB
10-05-2009, 10:24
(or the other improvements that Stan has yet to tell us about :eyebrows:)
More soundstage, firmer bass on the LM4562NA. But they require soldering skills, which is why I only gave a brief glance of them. I am in negotiation with someone who can take over the job of doing the mods for the soldering challenged.

Stan

Covenant
10-05-2009, 10:46
Your research is much appreciated Lovejoy you have saved me the cost and effort of experimenting with different supplies. I am now certain that Stan's new supply is the best way forward. I tried a battery supply too and was underwhelmed.

So the money saved can go towards Stans upgrade which sounds intriguing.
Whatever it is, I know it will be the best comprimise between performance and cost.

Please keep us all informed Stan!

lovejoy
10-05-2009, 16:26
More than happy to be of service. I'm sure there'll be more experiments to try in time too. With the utmost of respect to Stan, he's always a great help and seriously knows his stuff, but I always like to try these things for myself, no matter if you end up spending a few pounds, and it's always good to have the odd third party recommendation.

ReachtheSky
10-05-2009, 23:28
[QUOTE=lovejoy;45139]
One thing I did pick up on this weekend is how much I prefer the sound of a USB connection from my PC to using either optical or coax. Strangely, I can tell no difference whatsoever if I'm using a Mac between optical and USB but on the PC, USB brings more realism to instruments like piano and guitar. It's one of the only digital setups I've ever heard where you can actually feel the amount of weight going into a played piano note. There's much more of a sense of being able to look into a recording too. It's thoroughly engaging.

Thanks for your great report. Very informative.

Do you know if USB cables have an impact on sonics in the same way as normal interconnects? Are you using “special” USB leads to get your favourable results?

lovejoy
11-05-2009, 08:02
I don't have any special USB cables. I have a load of spare ones lying around of all different shapes and lengths both with and without RF chokes. At the moment I'm using one which was sat on the end of an old printer for years. A task for this week is to see if there are any differences between them.

I read a report by someone a while back that there was a benefit in a good quality USB cable which I found quite hard to believe at the time, but knowing that there are indeed differences between optical and coax cables, it's an avenue that should be investigated.

ReachtheSky
11-05-2009, 08:37
Hi Rich

Yes I remember that comment a while back and asked the question of you for that very reason.
I’ve located and attached those USB comments by kbutch below.

Rich have you used the “repeater USB” extension type cables for over 5m lengths? I imagine there would be many people interested in using USB from a PC located ~10m away from the audio gear (to isolate noise, convenience, another room, etc)

Quote:
#7, kbutch, 22/3/09:
Try upgrading your USB cable used to connect the 7520.

I know digits are digits, and USB uses a "handshake" to confirm data is sent. NEVERTHELESS, I changed a perfectly fine standard USB cable for a U.S. $30 Belkin Gold Series USB Shielded 2.0 cable, which is well-shielded, 20 AWG wire, that has gold-plated connectors and is yet very flexible .

Hooked the A end up to my Mac computer , and the B end to my Beresford TC-7520. My Lord. What a difference. It is much more easy to listen to at higher volume without any strain. Notes are richer, and it is easier to pick-out the musicians in the soundstage. Things sound effortless now, and must have been a bit strained/distorted with the standard cable. Cheapest darn upgrade yet for me.

Granville

lovejoy
11-05-2009, 09:54
I don't think that was the same post I saw. That's really interesting, thanks for that. Just goes to show that the term 'bits is bits' only applies if you're a computer. Time for a bit of research on high quality USB cables then.

It would be very boring if it all behaved predictably wouldn't it?

NRG
11-05-2009, 10:09
...but USB is a computer interface using a hand shake protocol and CRC data protection.

http://www.faculty.iu-bremen.de/birk/lectures/PC101-2003/14usb/FINAL%20VERSION/usb_protocol.html

I don't think it was really envisaged as a storage interface but its widely used as such without apparent data loss or problems. I can understand it sounding different to SPDIF which is more akin to FM.

...as to cables...maybe there is something in keeping the cable as short as possible and with proper shielding to keep correctable errors low. IE less strain on the receiving node correct circuit (if it has one!) but keep it real guys when choosing USB cables. :)

***EDIT***

Ah! Unless the transfer is isochronous in which case there is no defined format used...but CRC is still used...hmmmm

dikyllis
02-07-2009, 13:42
would it be overkill to get diy an linear transformer psu?

StanleyB
02-07-2009, 14:17
It's likely to be. I spent some time looking at this and I couldn't get a better performance from it. The TC-7520 PSU can charge up that massive 10,000uF cap inside the TC-7520 case far faster than any linear PSU out there.
If you really want to improve on the TC-7520 PSU you could start by replacing the regulators with some of the Murata SR versions.

Stan

webby
02-07-2009, 14:19
I'd still like to know if anyone has used USB repeaters for lengths over 5m....

Covenant
02-07-2009, 15:23
It's likely to be. I spent some time looking at this and I couldn't get a better performance from it. The TC-7520 PSU can charge up that massive 10,000uF cap inside the TC-7520 case far faster than any linear PSU out there.
If you really want to improve on the TC-7520 PSU you could start by replacing the regulators with some of the Murata SR versions.

Stan

Are the Maruta's going in the Cayman Stan?

Clive
02-07-2009, 15:27
I'd still like to know if anyone has used USB repeaters for lengths over 5m....

Yes I have used one and it works fine, whether it degrades the sound is another matter but there are no strange noises.

StanleyB
02-07-2009, 15:35
Are the Maruta's going in the Cayman Stan?
I can't afford them!

trailer
02-07-2009, 18:15
Good job I kept the Maplin PSU then :cool:

lovejoy
03-07-2009, 17:32
I've been playing again...

Regular readers will know that I run my 7520 off a 'teddyreg' regulator circuit powered by a toroidal transformer which I think works very well..

Well, the thought occurred to me earlier - "If I have very nicely regulated 12Volts coming into the 7520, why do I need a reservoir cap in the internal power supply?"

So just to be on the safe side, I thought I'd try it first in my old 7510 as a test bed. I just removed the reservoir caps and powered up as usual. No smoke, no nasty noises - good start.

That was 3 hours ago and was only meant as a quick test. It's made quite an improvement to the 7510 - Dynamics have gone through the roof. Drums now have a REAL kick to them, but it's also amazingly tight and controlled. Cymbals are sweeter and there's loads more air around everything. It's now digging way down into the recording and pulling out the best from even the poorest recordings.

It has been one of those afternoons of lots of grinning. I should go and try the same trick on the 7520, but I'm enjoying the 7510 way too much to bother for the time being ;-).

chrism
03-07-2009, 19:02
Hi,

Just wondering when you removed the caps how did you complete the circuit? I have a Maplins 13.8v 5 amp supply but justs a bit scared to try it without the 10,000 cap I have added into my 7510.

Regards

Chris

leo
03-07-2009, 19:20
If the Maplins 13.8v one is a SMPS I seriously would not recommend removing the big caps on the DC input, if its a linear it may be worth a try, linears will struggle keeping the big caps charged as well as a stiff SMPS, its one of the reasons a Switcher works better with these dacs (as they are)

chrism
03-07-2009, 19:23
Hi Leo,

It is the linear one - a bench supply (13.8v 5a) with a cheap trafo and simple regulator in it. Sounds way better than any switching one I have tried to date. So, shall I whip out the 10,000 cap and have a go?

Regards

Chris

leo
03-07-2009, 20:10
Well you can try it, its easy to put back in if you prefer it with the cap
The output of the bench supply is probably well filtered

StanleyB
03-07-2009, 20:24
Bypassing the power supply in that fashion could take out the input selector IC, the LEDs IC, and the headphone IC on the TC-7510. They are rated at 12V.

Stan

leo
03-07-2009, 21:40
Ah, so the 7510 is different to the 7520 in this case?

Just proves you should wait until the designer comments before trying anything like this;)

If its not recommended to go higher than 12v input to the TC-7510 and Chrism is determined to try the Maplin job its probably best to adjust the output voltage which shouldn't be too hard

Or easier still leave it all as is

StanleyB
03-07-2009, 21:48
Ah, so the 7510 is different to the 7520 in this case?
Something that I have been saying all along.

leo
03-07-2009, 22:16
Something that I have been saying all along.


Bit of Ground Hog day:eyebrows:

dikyllis
06-07-2009, 16:52
i notice, my SLA battery drain off even though the dac is off

anybody?

StanleyB
06-07-2009, 17:01
The DAC is in standby mode when the power LED is off.

Stratmangler
07-07-2009, 13:19
The DAC is in standby mode when the power LED is off.

Same with the TC-7510 too ?

Chris:)

lovejoy
07-07-2009, 13:42
Batteries will naturally lose their charge over time. IME a sealed lead acid battery should never be left for longer than a couple of months without a full charge and never deeply discharged in use. If you're using one for a DAC then best to have a trickle charger to hand that can gently top it back up when it's not being used.

StanleyB
07-07-2009, 14:47
Same with the TC-7510 too ?

Chris:)
Yep. It's my secret 'operational temperature maintenance circuit' that needs the trickle juice so that the DAC doesn't need too long to warm up;).

Stratmangler
07-07-2009, 16:10
Yep. It's my secret 'operational temperature maintenance circuit' that needs the trickle juice so that the DAC doesn't need too long to warm up;).

Ah !!! (touches nose and winks knowingly)

Chris:)