thoppa

Hi, Anyone know any technical info about DVD dual disc stereo audio ? I think it is 48Khz 16 bit but I dunno. Do you ? http://www.dualdisc.com/faq.html I'm listening to the DVD side - it says the audio is better than the CD side. My DAC says it is getting 48Khz but I set my DVD transport to 96Khz hoping to get DVD-A audio quality. I don't think I am sadly. Cheers, Tom. http://www.dualdisc.com/faq.html''>http://www.dualdisc.com/faq.html' title="dualdisc" target="_blank" mce_href="http://www.dualdisc.com/faq.html">

So it's quite straightforward then eh ? :-) Thanks for posting this info - it is just what I was trying to find out and gives me a much better idea. I haven't had a chance to use the battery cos I finished off my bi-amping today. I'm really not convinced about bi-amping in the real-world but I didn't try the active route so maybe that's why. The power filter I borrowed is a line conditioner designed for hi-fi, it says. It has turned the 'odd' noise into a slightly quieter but pure hiss only, which I trust is the system. I haven't heard a click all day even though the neighbours have been in and obviously switching stuff on and off as usual. It seems to work so I'll probably buy one - they are about US$50 which seems pretty reasonable. There's a website : http://www.chongqinglongyu.com/product.aspBut altavista babelfish can't translate the data page and the English tab doesn't work so it's not much help. Like so many things made in China, the assembly and finishing is poor. I had a bit of a shock when I connected up the cap to the tweeter today - the compression driver does not fit flush to its mounting on the horn because the horn moulding is just a few fractions of a millimeter too big over a bout a third of its outer diameter, so it sits at an angle of maybe 10 degrees and ther plastic surround bends to allow the screw to fully tighten. Both speakers had the identical problem so obviously the factory die is out of spec. I doubt it affects sound output though. Anyway, says made in China on the back of the speaker. I had a pair of Dynaudios once - they said 'carefully made in Denmark' on the back. Zeiss have recently tried to produce a 16-80 lens for Sony in China but the lens' release has been delayed by six months because apparently Zeiss were not satisfied with the quality control in China and so moved production to Japan. Lens comes out in March. http://www.ecat.sony.co.jp/alpha/lens/lens.cfm?PD=24680Cheers, Tom

Er...scratch that...quite wrong . The woofer uses a 2nd order crossover and the values indicate it is Linkwitz-Riley for 4ohms at 900Hz, half the stated crossover frequency. The values don't fit any other model. I have replaced this with a 2nd order passive line level crossover set at 1800Hz and matching the amps input impedance of 20Kohms and this works well it seems. The tweeter crossover has me at a complete loss. It is 3rd order; the cap values fit Butterworth but the coil value doesn't, by a factor of 6. I have given up trying to work it out and have used another passive line level crossover similar to the above and also 1st order butterworth in line with the tweeter. Initial impressions is that the unmodded speaker sounds very similar to the modded one so I think maybe I have got lucky with the maths. If someone reading this decides they want to mod their RF52s I would actually say don't bother unless you are into the fun of it. Positioning the speakers for the room acoustics has made more of a difference IMO. BTW I ran looped mono test tones through the speakers and switched from left to right and back again to test output and response. As far as musical performance goes, however, it is too early to say if all this effort has proved worth it. In fact, I have become very doubtful about the real world benefits of bi-amping. I certainly don't have ears capable of appreciating the subtle differences or pockets deep enough to really gain from it. Cheers, Tom

Hi, Thanks to this excellent post : http://www.silcom.com/~aludwig/Sysdes/Crossove_Design.htm#Bi_ampingI have found out the tweeter uses a 3rd order 'dual' series crossover. Not my earlier assumption about compensation - I see light ahead ! Cheers, Tom

Thank you so much - very informative ! Sound (sic) advice too ! It's hiss but not a pure tone hiss. 50cm from the speakers it's quite inaudible. I also notice that my neighbours' light switches (I think) cause tiny clicks that are not so tiny with the volume up. My laptop uses smps power, as does the external hard disk so I switched these off and played audio from the 80Gb internal drive and ran on the battery. No real difference. I can also power the amps from a motorcycle battery but as yet I haven't had a chance to do this. They have smps or linear supplies - I have both. I also have a 5V/12V 60A/60A supply intended for servers - it is super smooth with surge protected output etc but its fans are so noisy it's impractical. It was gift from a friend who works in a company over the border. A great bit of kit but sadly unused. I digress. The DAC is a linear supply (sadly not toroidal so while looking inside I started thinking about replacing it...one thing at a time ...). Anyway, I'll play around and let you know. I won't be checking the mains voltage. The first amp I built many years ago was great but the power supply shorted to the case when I was moving it - the shock made my hands grab the case even tighter for a second or so before the amp and I parted company with some force. I laugh about it now but wouldn't wanna do anything that might make the last few bits of hair I have on my head fall out. I have a Chinese LongYu power thingamy on loan. I am still testing this with various connections and I'll post about it tomorrow. Gotta work today ! Shucks... Cheers

Hi, Thanks for posting this. You have so much spare time ! Lucky man.... I have tried to do some research on power filters and I have discovered two basic types - ones that use a transformer to isolate and others that use regulators to produce a pure sine wave. Apparently the second type is better for audio as the former don't react fast. Any idea what your Belkin and no-brand use ? Cheers !

Hi ! It sort of makes sense to me - all components degrade or create a loss because none are perfect, not even OFC wire. I don't think the argument is that 1st order crossovers are always better - as you say it depends on the speaker. But if a speaker set-up is great with a 1st order then this is better than a higher one. So I'm coming back to this idea that the last thing I want to do is use an active line level crossover because op amps colour the sound, and add noise and distortion. I can't afford one that doesn't suffer these problems. So I'd really appreciate your opinion on this idea : I would like to reduce the bandwidth going into the amps to improve their performance, especially the woofers, and, if possible, I would like to remove/minimise all components connecting the power amp to the woofers for better damping. So I was thinking about a passive line level 2nd order low pass filter. It's easy - two capacitors and 2 resistors matched to the frequency and amp input impedance (20Kohm). There's an insertion loss but my DAC has a very high output and my amps have high gain too. It seems to me to be the best solution for my set-up. I will always have to have a capacitor in line with the tweeter, even if only for protection, so it might as well be part of a high pass filter. So I think it will suit my set up (and my lack of knowledge*) just to leave the HF section alone and add a slight attenuation at the pre-amp level if needs be. I don't think I'll need one because the insertion loss on the LF might be compensated for by the loss of the coil in series with the woofer. Can you see any matching problems with this ? Is my theory cockeyed ? Thanks, Tom *The high pass filter is not 'standard' - there is an attenuation resistor, 11ohms, then a capacitor 2.2uF, then a coil to earth 0.36mH, then a final series capacitor of 6.8uF. It seems to me that the 6.8uF cap is the correct value for 1800hz and the rest is a compensation and attenuation circuit, which I do not know how to analyse.

Hi, Well I don't have this but you have given me an idea ! Thanks ! I have just realised my class-T amps will run from a car battery. I will give it a try tomorrow morning.....thanks. Tom

Hi ! It's a bit weird really, it sounds like someone miles away is running a water pump ; I can hear the pump faintly whirring and water softly whoosing. It is very quiet and I only hear this with my ear right against the speaker. I'm not in the habit of listening so close (dur !) but I was trying out comparsions re my bi-amping and DAC testing and during this I switched back to my old Onkyo and noticed the exact same noise. So I tried my Sony - same noise. In fact the noise is the same between very different amps (2 class AB, class T) and power supplies (linear and smps) and inputs (DACs, soundcard, DVD etc) it only varies in volume and slightly in tone. I even went to the extreme of shorting out the inputs on one amp's circuit board so it was a closed circuit amplifying nothing - and yes, you guessed it - same noise. The quality of the noise changes slighty when I switch on the bathroom ( flourescent ) light so I'm as sure as eggs are eggs that is coming out of my wall. I am going to try out a Chinese-made power filter bar designed for audio over the weekend but because I don't know how these things work I won't know how it is affecting my amps - noise may go - but this might just be a dirty great big capacitor that doesn't discharge fast enough to supply an amp's transient demands so quality might be affected. Any idea how they work ? Cheers, Tom

Curiosity killed the clicks....let me know if it works and what the make and manufacturer are please ! Thanks, Tom

Thanks ! Unfortunately, I already have tried your suggestions. No difference. Boo hoo. You have a good supply - lucky dude ! My supply is being affected by the house wiring, my neighbours and the grid generally. I could ask the neighbours to switch everything off but that's not gonna make me popular at the next BBQ. It isn't loud at all and I am definitely being fussy, but if I can reduce it that would be very satisfying. I think I have to get a simple filter for spikes and noise - for about 8 amps (2KW) max I reckon. Cheers, Tom

Apparently so - reduced phase issues, constant output over the crossover frequency, fewer components enabling better damping. Not a great difference I imagine , but better. Tom.

Hi, Your system is sorted eh ? No fuss.... I have set up my system with one channel "fool's" bi-amped and the other running both HF and LF through one channel. I have listened and listened and tried test tones too but I cannot hear a difference. I believe my ears. If I can't hear it, it may as well not be there right ? So now it is time to think about the crossovers. The speakers use a 2nd order - but 1st orders are much better - so how about a passive line level crossover (for 6dB per octave and only using capacitors and resistors - no awful coils) and then another passive first order crossover at the exit of the power amp - will this give 12dB per octave overall ? Is there any way to build a speaker crossover without using coils, as there is for line level crossovers ? Any / all help welcomed !! Thanks, Tom

Hi, I have noticed, by switching amps and power supplies about, that there is noise in my system that can only be coming from the AC power coming from the wall. So I'm looking for a better mains filter but I don't know how they work, what to look for, and why some are recommended for power amps and some are not (something to do with dynamics and the filtering....). Anybody help me out ? Cheers, Tom

Hi, My Musiland is NOS I think - and accepts bit streams up to 24/192. Is this the kind of thing you are after but at a reasonable price ? It doesn't upsample to 24 from 16 bits either; you select it from a menu. This matches the Edirol output which also allows the user to select the sample frequency by switches on the unit, so I am really trying to maintain a bit-perfect stream. In the US it sells for between US$270-US$300 which is only a bit more than I pay here - normally this price difference is the other way round ! If you buy in the US you have sales protection, here there is nothing - a 100-yard guarantee - actually, in HK if anything goes wrong after more than a week it is a warranty issue not a vendor one, which can then take months. I would be happy to pay US$20 more for some sales protection. So don't irk at the price difference, demo one and pray you get a reliable one if you go for it. I really believe that you have to live with a product for a while to know it's character, unless it's vastly different from what you know, or spend $$$ for a product that is fully developed and trust in your wealth. My favourite DAC is the Musical Fidelity XDAC-V3. Refined sound. Very sweet to my ears. But US$750 incl the power supply so way out of my budget. Hey ho. Also not vastly better than the Musiland but where the Musiland has faults, the Musical Fidelty seems to me to be flawless. Have you demo'd one ? They had one in the speaker shop where I bought my Klipsch but I did not demo it fully as I was thinking speakers not DACs. Most of the DACs I demo'd used CS chips and they were all very similar. The most technologically advanced, the DIYEDEN Great March 2, was the most sensitive to data stream errors - yet it claims to be jitter free. There's huge amounts of technical BS going around I think and many more adjectives than data. So I think you just have to believe your ears - it doesn't sound like you need a new DAC urgently so how about getting a good portable headphone amp and headphones and get used to them (if you haven't already); then take them along to connect to a DAC with a CD of your favourite tunes in due course when technology has moved the goalposts again ? I reckon this is the best way to discover if a DAC is for you. I will do this next time for sure. (So now I'm in the market for a decent headphone amp...it never stops...haha) I'm back to using my Edirol soundcard. Lacks the deep punch and is brighter than the Musiland and lacks the hidden detail too, but it is okay. It uses an AKM 192/24 DAC which is pretty decent. It is the op amps in it that suck. This is true of many DACs , hence all the guys out there modding them. The DIYEDEN Great March is a perfect example - great performance for the money and easily tailored to individuals listening tastes. Here is a link to some basic specs of chips : http://blog.zol.com.cn/48/article_47521.html Hope this helps, Tom

Hi, I have heard good things about the Beresford (or TCC) TC-7510 but only on the web and that might not be reliable...I saw one post questioning the credibility of the people posting good reviews. Anyway, you can get it on ebay for US$150 in the US so shipping shold be low. What are you using now ? Do you need oversampling ? If it isn't essential but you want good sound and are handy with an iron then check out DIYparadise.com - they've dubbed their NOS DAC "Monica". I would have gone with this but I am hoping to start into SACD and DVD-A in the near future... Cheers, Tom My Musiland is fine when it works. The bass has a deep punch but is a bit lighter further up in the cello region. The detail is there but it isn't overbright. I would be very happy but it is back in a box and I have to exchange it again - 4th time lucky ?!

Hello again, I do NOT recommend the Musiland MD-10 DAC - why ? This is now the third unit I have had in a week and it has gone wrong - it still plays but the display doesn't work now. Clearly poorly built units. Stay away ! Tom.

Hi, Forgot to say - the service is both of these shops is very good - you can be quite confident about buying from them but be patient with their English. If you ever try to learn Cantonese you will discover that these guys have done very well to learn a language that is so different from their own. My comment above got edited even though it wasn't a rude word, so how about this - the Musiland scuffs faster that you can say scuff backwards ! Cheers, Tom

Did I say Musiland MD-10 ? My notes tell me it was a modded DIYEDEN Great March. Actually, I am embarrassed to say I could hardly hear any difference. Hmm. Certainly nothing that would encourage me to invalidate the warranty on a made-in-China product. I didn't write down the mods but it was quite extensive. MD-10 US$250. First of all I noticed it was much louder. It has more pre-amping, and also has its own digital volume. I played with this but couldn't discern any difference between a loud pre-amp and a quiet MD-10 and vice-versa. Looks like it it works and is worth having, especially for me as I want to feed two amps (see the Bi-amp thread in technical questions). I then found I had to 'play' with it as it has two buffers - under a 'style' setting on it's display - one of which is "Hifi" and the other "AV". I admit my ignorance about this and so set it for Hifi. It also has a bit-depth setting - 16, 20, 24 - which it says to match to source. I have no idea if it upsamples so I set it to 16 bit for the CD. The manual is in English but actually contains no real information of value. Finally, I sat back and started to listen. The highlights were the breaking glass and screams on Prodigy's Break and Enter, the vocal tone and swirling background details of Evanescence's My Immortal, the timpani drums and organ on Sunrise from Also Sprach Zarathustra (spelling?) and the vocals and percussion on Norah Jones and Ray Charles's Here We Go Again. Finally, my acid test, my all time favourite song Sunscreem Love U More. A good system reveals the delicious warbles and growls in the vocals, this did, and the staging was spot on too. I know this track so well it's ridiculous, and the Musiland was fine - not amazing I must admit but the best so far. Plus its quite attractive. I started to think that if I got the case enamelled white and the face plate rubbed down and polished to a mirror it would look lush. Chris had modded one - removed the power supply and fitted this into an external box. My imagination had been tweaked and so I knew I would be happy to leave with ths in my bag but I had to remain objective - perhaps a better sound was waiting for me. Next up was the Zhaolu after a trip across Hong Kong to another equally dingy district. I was interested in the better model - the Zhaolu 2.5C using the same chip as the Musiland. This DAC is modular so I could easily add a second pre-amp for my bi-amping. However, it looked cheap and nasty and I must admit failed to excite me. I think it is as equally competent (but not stunning, I don't think either of them are) as the Musiland, and cheaper at US$200, but it didn't grab me. So now I am listening to my own Musiland MD-10 at home. I am moderately content. I must admit I want better but for now it is perfect for my needs. I think it's gonna sell well but buyers beware - the first one out of the box had a display fault, the next had a volume fault (turned itself down for no reason after a few minutes play) and the headphone amp socket was too far recessed to take a plug. Third time lucky. Other criticisms; the USB output doesn't have its own driver and won't run kernel streaming through Foobar so Windows is messing up the sound and nothing can be done about this. The power cable has the world's thinnest wire, and the optical cable looks cheap. The brushing is light and can scuff faster that you can say fcuk. Overall though, it's worth the money I think. Happy DAC hunting ! Tom.

Hi all, I live In Hong Kong so I have the opportunity to demo an endless number of DACs; but my budget is US$300 so that restricts my choice a lot. Given that, and not being a tube-dude, (warm-up times and short-ish life), that restricts my choice to a more reasonable number. I thought I'd share my experience with you. I tried two shops : http://www.diykits.com.hk/ and http://vocativeaudio.com/ I went to Vocative first. His setup was all about vocals and so his system sounded sharp but had awesome staging. I immediately regretted leaving my Sennheisers at home. Dumb. Don't you make the same mistake.... First up was the DIYEDEN Great March 2. US$320. Upsampling, reclocking, oversampling, take away the numer you first thought of....very heavily processed signal basically. My demo CD's first track is Madonna's Hung Up cos it can cut ears to ribbons if it isn't well-managed and helps me listen for distortion and dynamics. On Chris' system it sounded awful. Instant dislike; metallic and 'ghosty'. Skip to track 2, Handel's Water Music, selected for the blaring horns. Surprising well-controlled but where is the orchestra ? They can't all be sitting in the middle surely ? Um. Quickly moved to track 3 Natalie Grant's Held. The high end simply overwhelmed me I was getting tired of listening already. Natalie's voice can sound clear and soft but on this she was a little hoarse, which made me realise the Great March 2 is a donkey. A good looking donkey but I'm no ***....neither is Chris. He only keeps one in stock, the demo model, because he knows no-one is gonna buy one. I tried one last track to check it's accuracy - the pronunciation of "fifth avenue" by Rebecca St James in Don't Worry (great stereo effect on ths track). She sang, "firffff". Try it yourself before you commit to buy - I think you'll find it lacks bass but sounds clean and bright, however, it also smudges some details too. Not my cup of tea. Expect it to get heavily modded.... Next up the DIYEDEN Great March (unmodded). I was stunned that this US$125 'old' model breezed through the first three tracks with some aplomb, relative to it's younder and more expensive sibling. I went on to listen to my whole demo CD and at the end decided that it was a real bargain. It made a mess of the background crackle on Massive Attacks' Teardrops but it wasn't that bad. It also seemed to fudge some of the multiple bass lines in the Prodigy tracks I selected. But overall, amazing for the money. It looks okay too. Plus it can be easily modded and there's lots of people out there doing it so I'm sure it could deliver a pretty good sound with tweaking. Very tempting.... Next was the Musiland MD-10 - actually another DIYEDEN product....but I'll post this now and wrire about that in a sec....

Hi Is the Audigy PCI or USB ? 6 channel ? Do you have any problems with the driver ? And are you using optical or co-ax connections ? Seems to me you might have a v sweet setup going there ! No wonder you plug Denon eh ? Cheers,

Hi, Yes, a plan...love making plans....but is it a good one ? DACs are everywhere in Hong Kong and, as you say, choosing can be hard. I'm off today to visit vocative audio and diy kits to demo some. The DAC in my Onkyo FR-V77 goes into its "discrete" amp stage and the two together sound very brittle compared to the DAC in the Edirol UA-1EX "Eddy" combined with the DIY Paradise "Charlize" class-T amps. I also have an old Sony MD313 which is balanced but flat sounding. Also have a Soundbaster Extigy USB card which is okay but I have some issues with it. I saw Dr Who is using an Audigy 2 - how is it Doc ? Unfortunately the USB in the Extigy has been very temperamental since an electrical storm a few months back so I also have a cheap CM106 USB card that I've been using to pass through AC3 into the Soundblaster since the storm. Of all the combinations above, Eddy and Charlize are the happiest couple, despite the atrocious op amps in Eddy (given in an earlier post). So, yeah, DACs.....hmm.....tricky. I'll post my findings on Sunday probably and in another thread ; and unless I fall in lust with one (e.g. the Musiland MD-10) I'll try them all (Zhaolu (said Jow-loo with a slight z in the J ! in Putonghua) 2.5C, Great March 2, Great March modified, Musiland MD-10 and the Lite models too maybe.)) I won't listen to the tube ones. I have never been into tubes for two reasons - they need to warm up and they have a short(ish) life. They do sound really good but simply don't appeal to me. So how is the passive bi-amping you use with your MacIntosh ? Any noticeable improvements or problems ? Cheers, Tom

Ah, the quote was by Dr Who....! I hope the studies go well. All the best and thanks again.

Thanks - good to know it's not my maths, but it is a bit of a headache. Here is an article on passive line level crossovers : http://www.t-linespeakers.org/tech/filters/passiveHLxo.html And another two on crossovers generally : http://www.silcom.com/~aludwig/Sysdes/Crossove_Design.htm#Bi_amping http://sound.westhost.com/lr-passive.htm So, after much reading I've decided to keep Klipsch's RF52 crossovers and replace the iron core inductor with an air core (on order from Solen in Canada). I plan to vertical bi-amp (separate the left channels from the right channels competely with separate amps) and use individual filters for all amp channels. The amps are small so they will hide behind the speakers and have very short cables to the speakers. The combination of short cables and a much better coil should make a difference to the LF section especially. I'll use a first order passive line level filter on the exit of the DAC and bi-wire from the DAC pre-amp output to the amps with some tasty cables. I'll do my best to match the desired op amp output to the crossover frequency and input impedance of the amps. Although the gains will be not be as good as an active filter without a high level crossover, there are no real drawbacks either, except a slight reduction in the pre-amp level into the amps. It also avoids the horrors of another set of op amps dragging down the noise and distortion performance before it gets amplified. The amps will still receive a narrower bandwidth and also have to drive a less complex load. It is also far far far simpler and I don't have to re-engineer the crossover Klipsch has designed, which would require test equipment almost as expensive as the amps it seems. I saw someone's quote after their post was "it's all about compromise". How true. Many thanks to Dr Who and Speakerfritz for your help and pointers. Great guys ! Thank you. Cheers, Tom

Here's the foobar link again for digital bi-amping. http://xover.sourceforge.net/ The only decent soundcard I can find for my laptop is the Creative professional E-MU 1616 US$399 or E-MU 1616M with better DACs for another US$100. This is out of my budget so the digital bi-amp option is too sadly. Should have got a desktop.... Here are some links for the pros and cons of bi-amp with and without an active crossover. Opinion is divided and it seems that, to broadly generalise, tube-dudes maintain it's almost pointless and linear-lovers seem to think it's worthwhile. Although there are theories, no one has posted any hard data to support it seems. And no class-T anywhere..... http://www.soundstage.com/synergize/synergize031998.htm http://www.fluance.com/wiring.html http://sound.westhost.com/bi-amp.htm Man I love my Klipsch RF52 s ! I haven't done much else except work, eat and listen, listen, listen....who would have thought I'd be ust as happy to listen to Michael Jackson as Also Sprach Zarathustra as Norah Jones as ....the list is endless ! Cheers Mr Klipsch ! U R A * ! Tom