[SlimDevices: Audiophiles] New home for SB2!
Hi, My proposed new home for my SB2 arrived yesterday. Some pictures here: http://gallery.robinbowes.com/v/Electronics/DACMagic/ It's a dead Cambridge Audio DACMagic 1! I've not powered it up yet but it apparently blows fuses when switched on. I've not finalised my plans yet, but I'll probably do some or all of the following: - replace front panel and mount SB2 VFD in centre - power the SB2 from one or more of the existing power supplies - replace the SB2 digital supply with a Super Regulator - Bypass the SB2 output stage (drive direct from DAC) - Use the DACMagic output stage, including balanced outputs - upgrade the DACmagic analogue stage (caps, opamps, etc.) - Power which ever analogue stage I use with a SuperReg - connect up the digital inputs to the SB2 DAC for use with other sources. - connect the pretty lights to the SB2 DAC some how :) I'm waiting for a Service Manual for the DACMagic so I can work out how to hack the circuit but I've drawn a blank so far. If anyone's got one I'd appreciate a copy. What do you think? Maybe slimdevices should consider making something in a box like this? Cheers, R. -- http://robinbowes.com If a man speaks in a forest, and his wife's not there, is he still wrong? ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: Purpose of the BigASS cap?
Purpose of the BigASS cap? I thought it improved your bottom end :) Andy. -- Andrew L. Weekes ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Re: What kind of Burr-Brown does SB2 have?
seanadams a écrit : There isn't a simple answer to this. SB2 uses the PCM1748, but the DAC chip alone does not dictate the performance of the whole system - it can be somewhat better or much worse than the data-sheet specs depending on the design. Since the DAC chip is only one component of the whole clocking + power + DAC + amplification process, the only way to really do a head-to-head is to listen blind, or measure the complete systems under identical test environments. However, even then, there is no such thing as an exhaustive test. Do you think that the SB2 could be improved by replacing (not as a mod, for the SB3 for instance) the PCM1748 by a more expensive model from Burr Brown? The PCM1748 is quite cheap, according to TI web site (http://focus.ti.com/docs/prod/folders/print/pcm1748.html), so I guess it's only a small part of the price of the SB2, even if you don't pay it 1.3$US ;-) (listed price for 1000 units). The PCM1792A (http://focus.ti.com/docs/prod/folders/print/pcm1792a.html) has for instance much better specs (on paper) than the PCM1748, but it costs 10 times more (less than 14$US for 1000 units). It is used in the Denon DVD player DVD-A1XV, for instance. The PCM1794A seems also nice. To say differently, according to your measurements, do you think that going to this type of high end chips will be possible without a much higher price and with a direct improvement, or do you think all the rest of the SB2 should be improved to match the specs of the PCM1792A, driving up the price (e.g., by including a PSU like Andrew's one)? Fabrice ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: Purpose of the BigASS cap?
Andrew L.Weekes wrote: Purpose of the BigASS cap? I thought it improved your bottom end :) Bum bum! (Basil Brush, anyone?) R. -- http://robinbowes.com If a man speaks in a forest, and his wife's not there, is he still wrong? ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB2: reduce analog out voltage by 10x?
Still on the subject of dBu. My power amp has a power-save function. If the input signal is less that -74dBu, the power amp will automatically switch off after 5 mins. If it detects a signal louder than -74dBu, it will automatically turn back on. My problem is that when I connect the SB2 directly to the power amp, the power amp never turns off. This would seem to indicate that even when the SB2 is turned off, its noise floor is louder than -74dBu. Is this to be expected, or do I have a duff unit? Cheers Chris -- cbemoore ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB2: reduce analog out voltage by 10x?
cbemoore wrote: Still on the subject of dBu. My power amp has a power-save function. If the input signal is less that -74dBu, the power amp will automatically switch off after 5 mins. If it detects a signal louder than -74dBu, it will automatically turn back on. My problem is that when I connect the SB2 directly to the power amp, the power amp never turns off. This would seem to indicate that even when the SB2 is turned off, its noise floor is louder than -74dBu. Is this to be expected, or do I have a duff unit? Sean can probably answer this better but 74dBu is approx. 150uV rms, i.e. not much so it's possible that there may be some residual noise that is keeping your amp switched on. R. -- http://robinbowes.com If a man speaks in a forest, and his wife's not there, is he still wrong? ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: What kind of Burr-Brown does SB2 have?
All, FWIW, I recently began replacing the stock PCM1748E with the PCM1748KE. The KE version has 6dB improved Dynamic Range and SNR, as well as improved THD and channel separation specs. I now do this on all SB2s that I mod (except for those who do not want to use the analog output). I posted about it yesterday over here: http://www.audiocircle.com/circles/viewtopic.php?t=21539 I'm not sure if there are any other dac chips that can be used in place of the 1748 w/o a board respin and/or SW changes. Sean? Thanks, -- Vinnie R. Vinnie Rossi Red Wine Audio, Inc. www.redwineaudio.com ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: What kind of Burr-Brown does SB2 have?
I haven't actually tested the KE - what I found was that the measured performance of the E consistently exceeded the specs for both the E and the KE. I'm guessing it's the same as CPUs, which can be marked with different speed grades to address different price points even if they all test the same. As far as putting other DAC chips in there - it depends on the chip but generally no, it is not really practical - may as well make/buy an external DAC. A DAC with current outputs for example would probably require a completely different power supply for both the DAC and the IV conversion. -- seanadams ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB2: reduce analog out voltage by 10x?
That is a really low threshold. I'd have to measure what the noise floor is in absolute terms - I've only looked at it in the frequency domain which isn't going to indicate an exact pk-pk figure needed to determine if it's always below 150uV. -- seanadams ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: What kind of Burr-Brown does SB2 have?
I'm using the KE. I reckon I can hear the improved dynamic range, but it's probably not worth doing unless you improve the PSU and the clock first. I don't actually think there's that much wrong with the PCM1748 - cheap or not! -- Patrick Dixon www.at-view.co.uk ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Re: What kind of Burr-Brown does SB2 have?
On Wed, 2005-09-14 at 10:08 -0700, seanadams wrote: I haven't actually tested the KE - what I found was that the measured performance of the E consistently exceeded the specs for both the E and the KE. I'm guessing it's the same as CPUs, which can be marked with different speed grades to address different price points even if they all test the same. Most (many? all?) semiconductor devices are mass produced and then measured and labeled. By engineering standards, the specs have to be limits, minimum gain, maximum noise, maximum departure from ideal, etc. Of course, the manufacturers won't tell you for sure. The idea is that you can design a circuit and get at least the specs, maybe better. This lets the designer (Sean and others in this case) design the end-to-end performance. There is no guarantee at all that removing one part, and replacing it with another that is labeled better, will actually deliver an improvement. I remember going through a bucket of transistors measuring the beta (gain) and putting all below 100 in one bin, to be $0.25 each, all over 100 in another bin to be $1.00 each, and all that measured 100 on the button in another bin for $10.00 each. It wasn't the beta value that made them more valuable, it was that they were all the same. The common example of this is CPUs, where the clock rate determines price, and makes a huge difference, but all the parts start out the same. All you can be sure of is that the KE version meets higher specs than the E version, and costs about ten times as much. Not that any given KE is ten times better than any given E. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: What kind of Burr-Brown does SB2 have?
Pat, Actually the KE version is just a few pennies more than the E version. $2.93 vice $2.70 at Digikey. However, your point is a good one. Regarding the devices and how they meet specificationsand how they are markedand which hopper they came fromand whether the designs were slightly differentor whether they perform similarly in the larger circuit...etc. It all matters not when the evaluation method is subjective only. You can throw all the numbers or objective testing right out the window. :) Cheers, Davey. -- Davey ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: What kind of Burr-Brown does SB2 have?
is that it was built with audiophiles in mind. The Burr-Brown is 'good enough' to get by on. The folks at SlimD gave us something workable with the ability to port output to whatever DAC we want if the internal DAC falls short in our system. I suppose that is an argument against doing much more with the DAC if it keeps the price of the mechanism's function to give an intuitive and sturdy presentation of internet radio and hard drive music. I strongly sense that this device and ones like it are the future of hi fidelity stereo. The SB is on a compatible track for the MP3 masses who don't do hi fi. It is nice that it works as well for them as it does for audiophiles. -- GreenMan ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Re: SB2: reduce analog out voltage by 10x?
seanadams wrote: Hmmm looks like using 128x (instead of 64x) oversampling brings the out-of-band noise way down, mostly under -115dBu all the way up to 96KHz. wonder what are the pros/cons of using 128x all the time. the noise is low level and out of band, but could be interacting with signal, no? is the level still that much lower when processing signal? --rt ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: External DAC?
WK446 Wrote: I run the SB2 to a Monarchy Audio DIP Classic to an Audio Mirror D1 NOS DAC, all via digital coax. I also own a Benchmark DAC-1, but I prefer the sound of the non-oversampling DAC. I have also used (and owned) the following DACs with my setup as well: - Museatex Melior Bitstream - Channel Islands VDA-1 combo I'm considering the Benchmark DAC-1. Why do you prefer the Audio Mirror D1? As an owner of the D1, have you ever heard about the DAC-Ah available from Poth Audio? It's supposedly essentially the same dac, but at a much smaller price. I'd like to know if anyone has done an A/B on the Audio Mirror and the DAC-Ah. -- GreenMan ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Initial Squeezebox2 sound impressions vs my luck and a NAD C 541
So, finally got my squeezebox on Friday, after waiting 10 days for Dabs to get them in and one to me. Already had slimserver/softsqueeze up and going. Plugged it in, and seems I was unlucky at first. Everything worked except for the actual decoding of the audio. I connected to the server OK, could browse my music, add to the playlist and set it playing. At this point the spectrum analyzer would not show any activity, nor once I'd enabled it via the server, did the time counter increase. After making sure I wasn't doing anything stupid, I decided to post my problem on the slimdevices forum. 10 minutes later I had a suggestion from Sean Adams, of Slim Devices, which had me up and going in around 2 minutes. Turns out somehow the FPGA programming had become corrupt, and I needed to get the box to reprogram it. Brilliant. So, 2 minutes setup time assuming you've not been unlucky enough to get one with a corrupt FPGA. For the sake of completeness, I should add that I did have another minor issue in that I couldn't enter my full length WPA key with the supplied firmware (software for the processor - different from program for the FPGA) - it wouldn't scroll along once I reached the edge of the screen. The latest firmware almost fixed this - it now scrolls along, but if seems unhappy once I enter the final character. No matter, I'm sure shortening my key by one digit won't be too insecure. OK, so I'm up and running, I'm sat in my chair, and I'm quickly thinking that having access to every CD I own via a remote control is pretty much as revolutionary as going from cassettes to CD's. Great, brilliant, what could be better? Well, it doesn't sound half bad either, but I happen to have a pretty decent CD player, so lets see how it sounds compared to that. Initial test system (prices are retail - I don't think I managed to pay quite this much for anything) NAD C 541 CD player ~ 3yrs old (£330) + QED silver spiral ~5yrs old (£90) - 0 Ohms measured resistance vs Squeezebox2 (£190) + home made 3m network cable interconnect - 0.2 Ohms measured resistance. Both playing through a Musical Fidelity X-A2 ~5yrs old (£500), and some BW DM601 speakers ~6yrs old (£200) biwired with some variety of QED silver speaker cable (~£7/m). Impressions: Foo Fighters, in your honor, cd2 Play Squeezebox, play NAD, OK, the NAD is louder, going to have to try to compensate for that. back to Squeezebox and nudge the volume control is there a difference? NAD (nudge volume) - I think this sounds better, Squeezebox (nudge volume so its definitely louder) - OK, the NAD has it. To summarize, after struggling at first to make out a difference, the NAD sounds smoother / fuller with vocals vs the sqeezebox which has a sightly grainy character, and symbols seem to have more energy. There's possibly more dynamic range, with the symbols hitting you from a quieter background. In terms of bass, the NAD does have a fatness to it, which pretty much always sounds good, but I suspect it may be adding a touch of distortion here. OK, possibly unfair to not check out the difference to the cables, give the squeezebox the QED interconnect, the differences are still there. Compare cables on the NAD only. Its very difficult to notice a difference, exacerbate by the time it takes me to plug, unplug and restart the track, but the QED might just have a slightly smoother mid upper and more detailed, or simply louder treble. This is all straight out the box for the squeezebox, so I left it playing for a few days, having added every cd I own to the playlist. This is where I discover that after ~ 1 day of playing it stops, and I need to go back to the network config, to get it to see my wireless network connection. DOH! Have yet to investigate this properly, but I'm on the best channel I can find, getting 70-80% signal strength. 2nd Test System OK, 5 days on, lets have a listen through some headphones, specifically some sennheiser HD650's (~£230) powered by a WNA (White noise audio) MkII headphone amp, with a few tweaks (~165 for the DIY kit). I've only recently got this setup, but it turns out it was a mistake. It makes my musical fidelity amp, and BW speakers that once sounded excellent, now sound far too much like a cheap ghetto blaster. I really don't want to spend 2k on a full size system to match the quality offered by this headphone system. NAD - oh wow, I really need to stop wasting my headphone system by attaching it to my pc (but that's what I got it for). Squeezebox - OK this is good too, but the step down from the NAD is now more obvious (possibly because I know what I'm looking for), but unchanged in character from previously. Cheap liteon divx/dvd player - far worse than either of the above. I can't even begin to describe how its worse, its too far away to make any sensible comparison. Conclusion. Squeezebox concept is brilliant. Going from cassette to cd meant you could pick your track with ease. This is the next
[SlimDevices: Audiophiles] Re: Initial Squeezebox2 sound impressions vs my luck and a NAD C 541
Also posted this on headfi. Hope it is of some use/interest. -- bludragon ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB2: reduce analog out voltage by 10x?
fuzzyT Wrote: seanadams wrote: Hmmm looks like using 128x (instead of 64x) oversampling brings the out-of-band noise way down, mostly under -115dBu all the way up to 96KHz. wonder what are the pros/cons of using 128x all the time. the noise is low level and out of band, but could be interacting with signal, no? is the level still that much lower when processing signal? --rt well it does have a marginally higher noise level in the audio band. here they are overlaid: http://www.seanadams.com/64_128.gif These jive with the data sheet (page 28) - note that their scale goes all the way to 8 times fs and mine only goes to 2x. -- seanadams ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Re: SB2: reduce analog out voltage by 10x?
seanadams wrote: well it does have a marginally higher noise level in the audio band. here they are overlaid: promising. for the few db in the audio band and for the potential harmonic interactions of the slightly higher band stuff. hard to say what the ears will make of it, but we'd sure love to find out. --rt ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: External DAC?
GreenMan: I am guessing that you are known as Im_all_ears on Audiogon. Yes I have heard of the DAC-Ah. It is sold by a company in Hong Kong called DIYclub. It is the same version as that being sold by Poth Audio. The Audio Mirror DAC has a few internal and cosmetic changes. There is an entire thread on this mystery on Audiogon - the thread was removed from Audiogon after complaints by the creator of the Audio Mirror DAC. Audio is entirely based on subjective and internal preferences. I suppose once you get a chance to listen to a number of DACs, you start to identify pleasing sonic characteristics. It's like the tubes vs. solid-state debate. Cheers, Dennis GreenMan Wrote: I'm considering the Benchmark DAC-1. Why do you prefer the Audio Mirror D1? As an owner of the D1, have you ever heard about the DAC-Ah available from Poth Audio? It's supposedly essentially the same dac, but at a much smaller price. I'd like to know if anyone has done an A/B on the Audio Mirror and the DAC-Ah. -- WK446 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: New home for SB2!
Hi Robin, this is a very good idea to re-cycle some of my DACMagic II ! I suggest you to replace all three transformer, they are not very reliable. If you remove the tape around the tranfo you fill a little fuse or thermistor, you may try to replace them but in my case I prefer to replace them all. One two of my unit I replace the all the 10 filtering capacitors. Some of them was starting to leak. I got the service manual if that help. I'm leaving in Montreal,Canada. I guess I could scan it. -- mftech ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: External DAC?
WK446 Wrote: GreenMan: I am guessing that you are known as Im_all_ears on Audiogon. Yes I have heard of the DAC-Ah. It is sold by a company in Hong Kong called DIYclub. It is the same version as that being sold by Poth Audio. The Audio Mirror DAC has a few internal and cosmetic changes. There is an entire thread on this mystery on Audiogon - the thread was removed from Audiogon after complaints by the creator of the Audio Mirror DAC. Audio is entirely based on subjective and internal preferences. I suppose once you get a chance to listen to a number of DACs, you start to identify pleasing sonic characteristics. It's like the tubes vs. solid-state debate. Cheers, Dennis Yeah, I could understand the Audio Mirror guys being unhappy if what I've read elsewhere is true, namely that the technology was copied after a DAC was shipped to China. Since you've heard both, how do they compare sonically? Do they sound comparable, or even the same, to one another? I've heard neither. -- GreenMan ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
