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?
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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?
You got it.
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.
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!
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:)
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.
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.
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.
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?
I seem to recall pointing that out as well. I even abandoned my own battery psu design when I noticed that problem.Quote:
Originally Posted by lovejoy
The TC-7520 psu was designed for me by someone who makes a living out of designing these things.Quote:
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.
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.Quote:
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.
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.Quote:
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?
Stan
Well, in that case, all I have left to do, is sort out my music library..
Thanks Stan.
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.Quote:
Originally Posted by Covenant
Stan
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!
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.
[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?
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.
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
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?
...but USB is a computer interface using a hand shake protocol and CRC data protection.
http://www.faculty.iu-bremen.de/birk..._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
would it be overkill to get diy an linear transformer psu?
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
I'd still like to know if anyone has used USB repeaters for lengths over 5m....
Are the Maruta's going in the Cayman Stan?Quote:
Originally Posted by Sensimilia
Yes I have used one and it works fine, whether it degrades the sound is another matter but there are no strange noises.Quote:
Originally Posted by webby
I can't afford them!Quote:
Originally Posted by Covenant
Good job I kept the Maplin PSU then :cool:
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 ;-).
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
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)
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
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
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
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
Something that I have been saying all along.Quote:
Originally Posted by leo
Quote:
Originally Posted by Sensimilia
Bit of Ground Hog day:eyebrows:
i notice, my SLA battery drain off even though the dac is off
anybody?
The DAC is in standby mode when the power LED is off.
Same with the TC-7510 too ?Quote:
Originally Posted by Sensimilia
Chris:)
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.
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;).Quote:
Originally Posted by Stratmangler
Ah !!! (touches nose and winks knowingly)Quote:
Originally Posted by Sensimilia
Chris:)