A vote for galvanic isolators

[Clive]

I run an unusual addition to my system sometimes; it's an amp fed from my bass amps, this extra amp feeds a pair of Aura Sound bass shakers attached to my listening chair. I've been having trouble what sounds like a mid bass oscillation at a low level. This was fixed with a galvanic isolator between laptop and 7520 dac. The sound overall has improved a little but it's interesting that the isolator has killed some form of oscillation, ground loop or switched mode interference. Whatever....it's fixed now, it shows the potential for benefit from these devices, albeit in my peculiar system with bass shakers!

The shakers are this type: http://www.amazon.com/Aura-AST-2B-4-Pro-Bass-Shaker/dp/B0002ZPTBI

[Clive]

I've had more time now to listen to my PC audio setup with the galvanic isolator in place. When I moved to my current music laptop I found the quality dropped a little. The isolator has brought back the tightness & dynamics which had gone somewhat AWOL, soundstage & imaging is better too.

I've also tweaked windows to run fewer processes, there are only 26 started now, I could be more drastic and probably will be over time.

Listening to Rodrigo y Gabriela, sounding really good, even after listening to Dave Grusin on vinyl, though Grusin still wins the dynamics competition.

[John]

I heard the shakers and was impressed by what they do I know most people will just see this as a effect and perhaps to a degree they right but they fun and seem to add to the overall enjoyment of the music

[Clive]

I heard the shakers and was impressed by what they do I know most people will just see this as a effect and perhaps to a degree they right but they fun and seem to add to the overall enjoyment of the music
They can be fun for sure! I think you need good bass in the first place otherwise your seat moves to notes you can't hear, it doesn't work the same like that! Let's call it an enhancement :)

It works a little better with a wooden floor than it does with my solid floor. With a wooden floor the whole room vibrates but you have to re-plaster after a while.....

[John]

It works a little better with a wooden floor than it does with my solid floor. With a wooden floor the whole room vibrates but you have to re-plaster after a while.....

:lolsign:

[Reid Malenfant]

Hi Clive, I looked at this yesterday but forgot to reply :rolleyes:

If you have more than one SMPS feeding any front end stuff it's quite possible that they are running fairly close frequency wise, though others could be 100KHz out ;) However, if they are close you can get a beat set up that is at a frequency which is the difference between the two PSUs...

So assuming you have a switcher at 40KHz & a second at 40.04KHz the beat frequency will be 40Hz...

When I used to work with SMPS a lot of the more complex supplies were synchronised by running the master faster than the others & then synchronising the others to the clock of the master which brought them up to the same clock frequency.

The same was done with all SMPS with active power factor correction to avoid this problem ;)

It's not something that happens with standard PSUs connected to the mains as they are effectively all in sync :eyebrows:

[Clive]

Hi Clive, I looked at this yesterday but forgot to reply :rolleyes:

If you have more than one SMPS feeding any front end stuff it's quite possible that they are running fairly close frequency wise, though others could be 100KHz out ;) However, if they are close you can get a beat set up that is at a frequency which is the difference between the two PSUs...

So assuming you have a switcher at 40KHz & a second at 40.04KHz the beat frequency will be 40Hz...

When I used to work with SMPS a lot of the more complex supplies were synchronised by running the master faster than the others & then synchronising the others to the clock of the master which brought them up to the same clock frequency.

The same was done with all SMPS with active power factor correction to avoid this problem ;)

It's not something that happens with standard PSUs connected to the mains as they are effectively all in sync :eyebrows:
Could be! One switcher for the laptop, another for the dac....I'll check later by running the laptop from it's battery.

[Reid Malenfant]

Quite a good possibility then ;) Most low power commercial SMPS will operate at very near the same frequency, 50KHz oscillator which results in a 25KHz switching frequency with a half bridge (the most common form). Higher power stuff tends towards much higher frequencies & possibly resonant (zero voltage switching) full bridge supplies to reduce losses & make a compact supply as possible.


I'll check later by running the laptop from it's battery.
Good idea, however there will still be an SMPS inside the laptop that converts the input PSU to various voltages used by the laptop PC itself ;)

[Welder]

Yep, they get my vote :)

http://www.circuitsathome.com/products-page/usb-interfaces

This is the best implementation I’ve tried. It’s flexible, reasonably cheap and suitable for a Linear Power Supply.

The next step then Clive is to get rid of your laptop and build yourself a server with a LPS. That should sort out all the SMPS problems.

You’ll want one of these for the best USB data transfer.
http://sotm-audio.com/sotm/products/tX-USB.htm

Oh and Linux.
Hopefully once done you’ll be reporting that you find you prefer file audio after all ;)




Vinyl more dynamic than redbook; tut tut man what are you like :doh::lol:

[Clive]

Good idea, however there will still be an SMPS inside the laptop that converts the input PSU to various voltages used by the laptop PC itself ;)

I must admit that had crossed my mind too, anyway at least the isolator is doing it's job!

[Clive]

Yep, they get my vote :)

http://www.circuitsathome.com/products-page/usb-interfaces

This is the best implementation I’ve tried. It’s flexible, reasonably cheap and suitable for a Linear Power Supply.

The next step then Clive is to get rid of your laptop and build yourself a server with a LPS. That should sort out all the SMPS problems.

You’ll want one of these for the best USB data transfer.
http://sotm-audio.com/sotm/products/tX-USB.htm

Oh and Linux.
Hopefully once done you’ll be reporting that you find you prefer file audio after all ;)




Vinyl more dynamic than redbook; tut tut man what are you like :doh::lol:
Hi John, the vinyl is a Sheffield Labs direct cut recording, it's pretty extreme in the bass, the deck, arm and cartridge are extreme too. Far more so tan my digital gear. Above all else though it's about the recording pushing the dynamics. I don't have it on digital (it's pure analogue anyway....). BTW it's been overloading my DSP units on the bass amps....bloody digital, no headroom! :ner:

A pc server/tranpsort would be great, it's just the time involved to do it. There's guy in Macclesfield selling them, I wonder what he's charging...way too much I expect.

[dave2010]

Hi Clive, I looked at this yesterday but forgot to reply :rolleyes:

If you have more than one SMPS feeding any front end stuff it's quite possible that they are running fairly close frequency wise, though others could be 100KHz out ;) However, if they are close you can get a beat set up that is at a frequency which is the difference between the two PSUs...

So assuming you have a switcher at 40KHz & a second at 40.04KHz the beat frequency will be 40Hz...

When I used to work with SMPS a lot of the more complex supplies were synchronised by running the master faster than the others & then synchronising the others to the clock of the master which brought them up to the same clock frequency.

The same was done with all SMPS with active power factor correction to avoid this problem ;)

It's not something that happens with standard PSUs connected to the mains as they are effectively all in sync :eyebrows:
Fascinating. Didn't think of that, or indeed that there could be a real problem. So - in theory, feeding a laptop into a Caiman and then into a Bantam Gold, all with SMPSs, or feeding a Squeezebox ->Caiman -> BG could give problems.

Whether it's really likely - not sure, but the fact that you've considered it, and made sure that any potential problem was minimised, is interesting.

[technobear]

Using headphones, I can clearly hear the difference a USB isolator makes. I can hear computer related noises without it. I can hear the noises change as I move the mouse around for example. The isolator stops this completely. I use this one:

http://electronics-shop.dk/galvanically-usb_isolation :)