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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: April 18, 2013, 01:57:34 pm
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Nick - What spec of transformers did you order in the end? rating? any ES screen? any special windings?
Paul
Hi Paul They are 625 va AirLinks with 4 x 22 v secondaries. They were custom wound, as you know standard they have 2 secondaries. I did not bother with the primary secondary shield or GOSS emi shield options, your AirLinks seem to work rather well without these options  . The price for the custom wind was close to the standard 625 va with 2 secondaries. Cheers, Nick. |
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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: April 17, 2013, 05:52:13 pm
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Hi Paul,
I had seen Peters Daniels comments some time ago when I started with the bi-amp build. Peter comments do sound very promising for bridged / bi-amped though don't they.
My speakers are quite hi nominal impedance, I think at least 8 ohms and could be higher IIRC. Although bridged modules see half the nominal impedance of the speaker they do only have to deliver only half the output voltage level compared to single ended. Also because our amps are bi-amped they must be seeing higher impediance than the overall nominal speaker impedance because they drive the individual speaker drivers which will have a higher individual impedance than the speaker overall.
My main concern is driving so many modules ("8") directly from the NOS1 outputs. In theory the loading of the bridged design per NOS1 output op amp phase should be the same as our current bi-amped builds. I guess that question will have to wait for listening tests.
I have made some progress with the amp, I took the option to join the two cases to route the transformer secondary’s to the rectifiers (option 2 above) and it looks very nice and neat. Next step is wiring up individual modules to pair them into low DC output offset pairs and then start final the wiring up. I think it may take quite a while to wire up but I am keen to take my time and get it nicely done. Have to say I am REALLY interested to hear the end result.
Cheers,
Nick.
Edit fix unwanted smiley
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408
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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: April 13, 2013, 03:09:24 pm
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Is it a most stupid idea to put the rectifiers and all in the Supply case ?
Peter hi, I had stayed away from putting the rectifies in with the transformers in part because of the reasons Paul gave regarding the earthing but also because of a problem I had with my current amp build. In my current amp, the rectifier boards are close to the transformers also when I built the rectifier boards I fitted the 10µF capacitors that Peter Daniel supplies (they are optional). Well, I spotted that PauIs amp dosen't have the 10µf capacitors fitted so I snipped them out of my amp. What a difference it made to SQ, much better. I figured that the 10µF capacitors were either resonating very badly, which seems unlikely, or they were picking up hum field from the transformers. The clincher for the transformer hum theory was when I tried moving the physically large Mondorf input capacitors in my amp off of the aluminium case bottom (just placed them onto some 8mm foam) this gave a MASSIVE lift in SQ and fixed an oscillation problem when the amp was on without anything connected to the inputs. So within reason I'm very keen to keep the transformers well isolated from the amps. A long explanation but hopefully it may prove helpful if anyone is doing a build. Cheers, Nick. EDIT I quoted the capacitor size incorrectly as 47uf above. Now changed to the correct value of 10uf. |
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409
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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: April 13, 2013, 12:43:33 pm
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How is the power going to enter the amplifier module? Theresoes not seem to be a lot of space left on the "backpanel"?
Coen hi, You made me smile asking this, I have two options worked out and I'm trying to decide which to go for. Option 1 is to run an umbilical into the back of the amp module. I left space to mount a cable gland on one side of the speaker posts. Internally i was going to run the 16 ac power lines to the rectifiers through 15mm plumbing copper tube (earthed to PE ) and under the amp modules. The issue is the possibility of ac hum from the wiring so close to the modules and the cable run is long at 1m in total from transformers to rectifiers. Option 2 is to run the ac psu wires through the side of the PSU and amp cases just behind the front panels. To do this i would link the two cases with bolts and spacers (bolts are in the pictures). This approach gives a very short and direct run for the ac wiring away from the modules. If i take this option was planning to insulate the fixings that join the cases, I don't want case hum being transferred from the PSU Case to the Amp case, Iv had a real problem with case and transformer induction fields in my current one box amp. The two cases will be electricly connected but only via their binding points to PE. Option 2 is my favourite at the moment. Nick. |
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410
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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: April 13, 2013, 12:13:36 pm
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Hey Nick - Looking great so far - those lumps of copper (?) look good!! Balanced amps should be better from a noise point of view. When finished maybe you could bring them here and we could have another session.
I have spare 4 amp modules so I have all the parts (also the same amp cases) to build a balanced myself. Perhaps you could bring them here when you are finished and we could compare balanced versus the stock version?
P
Paul, Im definathy up for a visit when the amp is finished. It would be great to try it though your system, provided it dosen't sound awful, there are a lot of assumptions in the design right now  Nick. |
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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: April 13, 2013, 12:08:20 pm
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PS: Do I see 8 secundaries in total in there ?
Hi Peter, Thanks for the encouragement and the advise on offsets. I had been giving them some thought it looks like i have to setup a test harness to power up each module measure offsets and match pairs of modules. Yes there are 8 seconderies overall, I was keen on having each output electricly a monoblock as far back as the transformer iron. The ratio of two modules to a supply seems to work very well so to keep to this and limit the transformer count to 2 I had these custom wound with four secondaries. They are 625va which keeps the ratio of 300 va for each pair of modules. Of course this is just a load of theory until i can take a listen  Cheers Nick. |
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Ultimate Audio Playback / Playback Tweaks and Source related subjects / Re: PCI supply rail noise
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on: April 12, 2013, 10:33:24 pm
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Jud hi,
The NOS1 is connected to the pc via a usb interface. In my case I use a usb pcie card (eg not a mobo usb port) and the x-sound capacitor card works very.
The x-sound card has the potential to help your dragonfly setup provided that you are using a usb port on pci or pcie usb card. If you are using a mobo usb port it is unlikely to help.
It may be worth installing a usb 3 pcie card if you are not already using one. Many folks on the forum find this works better than mobo usb. Cards with the NEC usb 3 chipset seem to work very well. These cards are fully compatible with usb 2 devices.
Cheers,
Nick.
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413
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Ultimate Audio Playback / Playback Tweaks and Source related subjects / Re: PCI supply rail noise
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on: April 12, 2013, 03:12:02 pm
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Maybe there is noise but perhaps less spiky and more evenly distributed who knows - for sure it sounds good though. Paul, maybe you didn't get it; Suppose your PCI bus draws such, that there's a (just making up something) 20MHz frequency, a 23.1MHz frequency and a 70MHz frequency hammering on everything. If you now add 20.1MHz, 20.2, 20.3, 20.4, etc. and fill all up up to 70MHz, there is no frequency anymore and it has become "flat noise". The capacitors will sort of do this because of their (uncontrolled) frequency of loading. No original peaks will drop because of this and the smoothening happens because the original frequencies can not be profound anymore. But notice that this means of attacking noise is one big wild guess, because nobody tells how high the amplitudes of the original frequencies are and how high the added are. And you can bet that they are not evenly high by some sort of coincidence; Now something else happens (has to happen to let it work out) and that is that the added noise must be higher in amplitude than the original. So, more noise really and it could be harmful theoretically. Higher noise but more random (more "real" noise). To get the real picture (of what I mean and for what's *that* worth !), think about false harmonics (the THD figure); So, your NOS1 has a few and they are ~110dB down. Do we hear them ? possibly. How to solve it ? Add so much noise that the false harmonics vanish in the noise. And now they're really gone. Smart trick. After another night SQ has improved further. Yea ? I wouldn't count on that. Or better said : I wouldn't count on anything working really when that is the case. Thus, you are burning in capacitors and now the sound improves. Well, then it is only a matter of waiting until it degrades. And improves again, and degrades. If you understand the theory (my theory) than you will agree that this is nothing to base your music reproduction on. You blame the washing machine on Monday morning, but actually a bank of caps is in a wild mood. And nicely resonate with eachother at an interval of a minute (slow judder). But keep in mind, it is you who implied that described process is going on because sound improved. So which psychological way do you want to go ? haha Mine won't burn in. I forbid them.  Peter PS: Alain, -thus- Yes. Peter The cards have a set of sized capacitors linking +rail voltages to PCIe ground. The caps do not seem to adopt the bypass with a 1/10 to 1/100 of the the next largest vale rule consistently which I why I mentioned them being somewhat randomly chosen values, but given to smallest values used I would expect them the present a low pass filter effective to high frequencies on the supply rails (made less effective by track lengths etc). I figured that this would both attenuate fundermantal noise frequencies and smooth transient current draw on the rails. The caps might also fire back their own resonant noise onto the rails, but surly there main effect will be attenuation and smoothing of transient current demands. My card also significantly changes (improved) with burn in. Not difficult to hear the difference at all with use. I have ordered a second card just to try two out at the same time. Proberbly the result will be resonance between the banks of caps but you never know Cheers, Nick |
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Ultimate Audio Playback / Playback Tweaks and Source related subjects / Re: PCI supply rail noise
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on: April 12, 2013, 08:51:53 am
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Is the Sotm USB PCIe doing the same ?
Alain hi There will be an overlap in what the sotm and x-sound cards do. To an extent the Sotm applies the same approach in that the supplies taken from the pcie bus are better built on the card from a noise point of view than on a standard usb card. These supplies are designed to supply the sotm card itself though and not to generally reduce noise on the pcie power rails. The x-sound will have more of an effect on the pcie bus rails generally this may help reduce noise from video cards and other parts of the pc. Nick |
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Ultimate Audio Playback / Playback Tweaks and Source related subjects / Re: PCI supply rail noise
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on: April 11, 2013, 08:04:19 pm
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It's a passive bank of capacitors that bypasses the power 3.3 and 5v rails on the PCIe bus. Bypasses ? Does it shunt the rails to ground or something ? (that looks like leading to a shortcut). Wouldn't it be merely so that it's (the caps) just attached in parallel to the rails to smoothen the supply ? Regards, Peter Peter hi, Your right they are connected across the rails to smooth and reduce noise. Each 3.3 and 5 v rial (there are quite a few of them on the bus) has its own bank of caps. Cheers, Nick. |
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417
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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: April 11, 2013, 07:56:31 pm
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Hi,
I finally got around to starting a gainclone MK II build and thought I'd post some pics of the build so far.
As you can see the modules and rectifiers are built (sourced from Peter Daniel) and I'm close to completing the case fit out. Next stage is wiring up then testing.
The final result will have balanced inputs and bridged and bi amped outputs, so it used 8 gainclone modules in all driving 4 output channels with each output having a pair of bridged modules. It's dual mono back as far as the mains input lead.
Really looking forwards to seeing how it all sounds.
Cheers,
Nick
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Ultimate Audio Playback / Playback Tweaks and Source related subjects / PCI supply rail noise
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on: April 11, 2013, 07:45:27 pm
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Hi, I'v experimented in the past on the power supplies and clocks of pci and pcie usb cards used to drive audio devices, oftern the results have been very posertive other times more "interesting". what is for sure is that pci and pcie power rail noise has a BIG effect on SQ and I think the periodicity (think buffer sizes) of the data being placed onto the PCIe bus also interacts with PCIe supply rial conditions to effect sound. This card looked like a simple, fun way to experiment without having to mod my usb3 card. It's a passive bank of capacitors that bypasses the power 3.3 and 5v rails on the PCIe bus. The aim is to reduce rail noise for your sound critical PCIe cards. In my case i have a USB 3 card that connects to my NOS1 DAC, but it it should work for SPDIF cards or sound cards in other systems. You just place the card into a vacant slot and that's it. The capacitor size choices look a bit odd but despite this IT WORKS..... and how ! Sound quality changes in my system comprise; + Wider deeper higher sound stage + Much more life like tone (voices strings etc) + Ability to track ver complex passages and not become confused (like a powerful amp or upgrading to a cartridge that track much better) + Bass goes down lower become more taught and very tuneful. Quite a list I know, but the difference was heard in my system from the first note. This may spark conversations about "filters" but right now I think it moves the PC a big step forwards as a front end component. It might be that the cap values could be better tuned but card works. I know Paul's card arrived recently and he may want to add more. Available here and at cheap-fi money http://www.ebay.co.uk/itm/ApeXi-Power-Filter-Card-for-Computer-Audio-Enhancement-For-PCI-and-PCI-E-Slots-/251232340488?pt=AU_Components&hash=item3a7e9d4a08Cheers, Nick. |
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419
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Ultimate Audio Playback / Chatter and forum related stuff / Re: Gainclone heaven ?
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on: March 26, 2013, 09:55:54 am
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Hey Georg
Sounds great and built with some nice components. A couple of things that came to light here that may be be of interest.
I changed the caps next to my modules from 1000uf to 1500uf and was supprised at the improvement in balance and control of the sound.
Also I suspected field interference from one of my transformers which are R-Core types and currently in the same box as the gainclone modules. The transformer was turned 180 degrees and the sound was really improved.
Might be worth playing about with these variables whilst the soldering iron is hot
keep is posted on how you system sounds as it runs in.
Cheers,
Nick.
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Ultimate Audio Playback / Your thoughts about the Sound Quality / Re: 0.9z-8-3a
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on: March 16, 2013, 03:04:01 pm
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Btw ... I think I already announced pre-0.9z-8-3 that the SFS doesn't matter so much anymore. So, besides the more holographic sound (I think) at the higher settings, the detail remains at the higher settings (my 120 and I never tried higher). This seems to be a good thing (sort of : one dial less).
If I am right at all on this.
If I still had a preamp, the volume would be set to "11" al la Spinal Tap |
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