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At last... (Audiolab) - part V

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I've heard the CDQ in analogue and pre mode and it was certainly no better than the Young. The MDAC in digital pre mode was significantly better though, so much I'm looking for a new pre-amp until John comes up with an MDAC Q version.

Hi Sq,
All this talk of the much improved jitter attenuation on the optical and coax inputs has got me considering the MDAC again. Did you happen to compare the spdif with usb during your listening session? If so, I'd be really interested to hear your conclusion.

Also, John:
Another question regarding the MDAC. I don't know how well you know the 8000AP, but are you able to comment on whether it's possible to use its digital out to improvise a bypass for the front L/R with this combo (8000AP -> MDAC -> 8000X7) ?

Edit: Actually, I think you may have already answered this with you comments about using the TV digital-out unless there is a more elegant solution ?

Cheers,
Tim
 
If you have a digital output which contains stereo only signal then your sorted.

I have just checked the same on my Marantz Av7005 , the only down side is that the digital out is used for connection to a digital recording device (on mine). And is set in the input assignment to a single digital input. Which is fine if you say only have sky as a digital source , but in order to say switch another means manually changing the input settings.

I also picked up on that comment regarding the digital pre-amp comparison making the MDAC better than the Young. So it sounds like its worth configuring it that way.
 
Hi Sq,
All this talk of the much improved jitter attenuation on the optical and coax inputs has got me considering the MDAC again. Did you happen to compare the spdif with usb during your listening session? If so, I'd be really interested to hear your conclusion.

Also, John:
Another question regarding the MDAC. I don't know how well you know the 8000AP, but are you able to comment on whether it's possible to use its digital out to improvise a bypass for the front L/R with this combo (8000AP -> MDAC -> 8000X7) ?

Edit: Actually, I think you may have already answered this with you comments about using the TV digital-out unless there is a more elegant solution ?

Cheers,
Tim

Hi Tim,

Sorry, I don't know the AP well enough (Never even used one) to know if you can send Processed L/R out via a Digital Output - I wish I could be of more help.

But I tell you what - been thinking about the obvious need to be able to select between MDAC output and some Analogue pass though mode - we could added the feature to the external PSU box - so that its a PSU + Audio Pass though selector - there is a Comms Bus link on the PSU connector to facilitate this - I'm guessing this would be ideal?

John
 
Kudos to Dominik and JohnW for their online forum response speed (excluding Johns PM boxfrom which I've not had the same response, although I bet he is bombarded).

Hi Bottleneck,

I don’t recall seeing any PM from you - but then I only have space for 50 PM's and my box is normally always full. I'll be the first to admit that I'm the worst when it comes to having to write anything. I have a truly terrible hard time to be able to express my thoughts into words - then forget being able to spell them.

It’s been a constant hardship and has effected me since my very first school days. Now with Internet being so entrenched in our daily lives, not being able to express ones thoughts into word or even spell them becomes so debilitating.

I hated to attend school as I was at the very bottom of my class (not being able to read or write), yet I remember building a crude B/W television from an old Russian Mini CRT I found sticking out of a skip in Streatham high street the summer before I attended secondary school – it had no AFC and kept drifting off station as it warmed up, would loose Sync on "Dark" pictures (No PLL to keep its timebase going when it briefly lost Sync) - yet it worked... I learnt a lot about driving a CRT that summer – I really learnt about televisions. I still remember the “White Dot” that would remain in the centre of its screen once it was switched off for a few minutes – like a fading star….

Yet still I was considered "Stupid". I was really a classic case of a Child who thought very differently, and really did not fit within the “standard teaching model” and desperately needed special education. What I cannot understand is how you can have a child who before secondary school had self thought himself to build his own two way radios, televisions, “computers” & robots etc – yet could not read nor write well and yet nobody stopped for a moment to think that it was just a little odd?

My school years still haunt me today - I can truly say they where the darkest days of my life – a real shame really, as I often hear how our "childhood years" are when we where free and happy....

I remember my great "Break" in learning to spell (and thus read) came when I built a speech synthesizer for my ZX81 using the GE SPO256 speech IC, during the evenings of my first year of secondary school - it was a "phonetic" based speech system - which I had to "split” words into sounds - thus I learnt my basic spelling skills by programming this Speech synthesizer to “speak”. Even today I only "read and spell" by recognizing words rather then being able to break a word into "phonetics" to spell it out.

When I encounter a "new word" I don’t recognise, then by “reading” the first few and last letters I understand its basic “sound” – and then by understanding its context within the sentence – I can guess the word… I’m still that bad…

Really, its very hard for me to write – Pls. take this into consideration if I don’t answer, I have over 1200 unopened E-mail’s in my folder… I atleast try to keep my input here on this forum "up to date"... :)

John
 
What about USB cables. Do they make a big difference?

Hi Mark,

They might with some other DAC Designs, but as the MDAC operates in Async USB mode and is internally powered - the USB cable will make VERY little difference.

There is a very good chance on the other hand that the USB Isolator will be beneficial,

John
 
Hi Bottleneck,

I don’t recall seeing any PM from you - but then I only have space for 50 PM's and my box is normally always full. I'll be the first to admit that I'm the worst when it comes to having to write anything. I have a truly terrible hard time to be able to express my thoughts into words - then forget being able to spell them.

It’s been a constant hardship and has effected me since my very first school days. Now with Internet being so entrenched in our daily lives, not being able to express ones thoughts into word or even spell them becomes so debilitating.

I hated to attend school as I was at the very bottom of my class (not being able to read or write), yet I remember building a crude B/W television from an old Russian Mini CRT I found sticking out of a skip in Streatham high street the summer before I attended secondary school – it had no AFC and kept drifting off station as it warmed up, would loose Sync on "Dark" pictures (No PLL to keep its timebase going when it briefly lost Sync) - yet it worked... I learnt a lot about driving a CRT that summer – I really learnt about televisions. I still remember the “White Dot” that would remain in the centre of its screen once it was switched off for a few minutes – like a fading star….

Yet still I was considered "Stupid". I was really a classic case of a Child who thought very differently, and really did not fit within the “standard teaching model” and desperately needed special education. What I cannot understand is how you can have a child who before secondary school had self thought himself to build his own two way radios, televisions, “computers” & robots etc – yet could not read nor write well and yet nobody stopped for a moment to think that it was just a little odd?

My school years still haunt me today - I can truly say they where the darkest days of my life – a real shame really, as I often hear how our "childhood years" are when we where free and happy....

I remember my great "Break" in learning to spell (and thus read) came when I built a speech synthesizer for my ZX81 using the GE SPO256 speech IC, during the evenings of my first year of secondary school - it was a "phonetic" based speech system - which I had to "split” words into sounds - thus I learnt my basic spelling skills by programming this Speech synthesizer to “speak”. Even today I only "read and spell" by recognizing words rather then being able to break a word into "phonetics" to spell it out.

When I encounter a "new word" I don’t recognise, then by “reading” the first few and last letters I understand its basic “sound” – and then by understanding its context within the sentence – I can guess the word… I’m still that bad…

Really, its very hard for me to write – Pls. take this into consideration if I don’t answer, I have over 1200 unopened E-mail’s in my folder… I atleast try to keep my input here on this forum "up to date"... :)

John

Hi John

I hadn't realised any of that.
As mentioned - yours (and Dominik's) approachable and friendly postings on PFM are a good model that others could follow. At no point do you belittle competitors, and you always want to help.

My hope, is that one day soon you and Dominik will make your own products, the way you want to make them - selling direct. I think that day will come. Let's see :)

NB
You need an assistant to help you with your emails! :)
 
Thanks for the answer John. I ordered the isolator today :) By the way I also suffer with writing and spelling. Computers and spell checkers are great. Well unless you have no idea how a word is spelt. I have spent ages trying to put a word in and then just changed the whole sentance after failing miserably. I try to work it out mathmatically but it doesn't always work and I'm left handed to boot!!
 
Thanks for the answer John. I ordered the isolator today :) By the way I also suffer with writing and spelling. Computers and spell checkers are great. Well unless you have no idea how a word is spelt. I have spent ages trying to put a word in and then just changed the whole sentance after failing miserably. I try to work it out mathmatically but it doesn't always work and I'm left handed to boot!!

You and I both - I can tell when a word looks right, so I just play around until it looks close - then use the spell check. Sometimes still not close enough for the spell check :rolleyes: :D Oh dear... so you can often hear me asking Dominik, Renata (Who are both Czech) or even my 11 year old French Son!!! embarrassing...
 
Hi John picking up on your earlier message about potentially unread pm's then wanted to check whether you'd got my pm re getting on the list for a silver MDAC from bartletts in islington? if i missed the boat then np - will just give me some time to save up for a couple of additions at the same time :)

i've basically been out of proper hifi for quite a few years now. i intially made do with a pioneer cd and A400 amp with some technics sbm300 stand mounted speakers that an emigrating mate gave me for a few quid. Even this has been largely unused for 3 or 4 years now.

Recently i've been getting back into music via a an ipod and some good headphones and now am thinking of building back up - but taking it one step at a time to spread the cost.

My initial plan was to have a cd source, but more thinking is directing me towards an old pre intel iMac as a source for my reripped cds (planning FLAC), this into an MDAC - reusing the A400 and SBM350 untill i can build up more funds.

I'd replace the A400 first - was thinking about trying to demo a valve replacment - maybe some monoblocks. Would be happy to go 2nd hand and maybe look at something from icon audio.

Finally replace speakers - think this could be some time away tho - money likely to be in short supply after the above changes!

If anyone has any thoughts on the above - i'd be happy to benefit from another viewpoint.
 
Hi rtrt,

Your on the list :) as is everyone who has PM/Emailed me so far.

As a "Cheap" second hand power amp thats often overlooked, try a Quad 606 - these can be had quite cheap, and will work well with the MDAC.

I'm not sure how good a "Cheap" valve amp would be - Valve amps need qood quality transformers - these do not come cheap... Valve amps can be VERY good (if not some of the best) - never heard a bad thing about EAR sound quality...

I'd worry about the "Cheap" Chinese valve amps that are flooding the market... But others will know better...

Quads are a safe bet, but maybe there are some good Valve amps around the Quads SH price (GBP300), Steven Toy and others might be your best bet for advice...

Re-reading your Post, I believe that your speakers are the weakest link!!!

Leave the A400 for now, and start off by getting much better speakers (I could be wrong, but a quick search was not promising. Nowdays "Technics" just sets the alarm bells ringing.) - I'd say spend as much as you can on the speakers, then think about the MDAC - then the power amp last.

George or Simon at Bartletts can help - or again even second hand... (Speakers can be damaged easily, and as they are Mechanical devices there performance can deteriorate over the years, so there’s more of a risk in buying second hand speakers then say Amplifiers).

If the speakers are as poor as I imagine, then I really recommand sorting them out first,

John
 
Thanks for the quick reply John - good to know that my silver machine is on it's way along with everyone elses :)

I suspect the speakers are a bit better than you imagine (tho I can understand why you'd think otherwise) Had already found that HiFi World had a 1 line review on their site - pasted below.

Technics SB-M300 £350 Nov 95 A great sound with solid bass from a compact and well priced 'speaker.

Must admit when i was looking for info I didn't realise they'd been around quite that long!

So in my mind the A400 and speakers were of similar capability, but the amp occasionally crackles thro one channel - so that was probably the main reason for putting it in for replacement first.

Re valve amplifiers and avoiding chinese direct - been reading hifi world recently and theyd said pretty much the same.

I might see how the MDAC sounds thro the a400/sbm300s for a while and who knows christmas might bring a surprise and let me look at replacing the amp and speakers together early in the new year ;)
 
Chinese valve amps can be good but they need to be looked at by a UK-based engineer who specialises in valve amps to ensure that they are safe to operate on UK voltages - up to 253 Volts. Chinese valve amps are barely safe at 220 Volts. I can recommend Anthony Matthews of Tube Distinctions.co.uk who built my amps and will be modifying them again in the near future.

Nick (lurcher) of audio talk and AOS is also a good bet.

Some of the World Audio Designs amps are also very capable and are often available ready-built s/h.

Personally I am a fan of KT 88 output valves and their derivatives (6550, KT 90 and KT 120) for their "real world" capabilities in terms of being able to reproduce all kinds of music and drive a wider range of speakers.
 
John,
Thanks for the recommending the USB isolator. The difference the Danish model makes to the foobar/ASIO4ALL feed from an old Thinkpad X41 is marked - loads more detail and timing. No question it's worth the Euros 46.79 to have it delivered from http://www.electronics-shop.dk/galvanically_usb_isolation.htm?currency=EUR

Thanks again, Duncan

ps. The quality and degree of your communication on here is fantastic. It's a good job for all of us that the failures of the London education system didn't manage to deprive us of your talent, intelligence and generosity.
 
John/Dominik - Is the volume control on the MDAC analogue or digital? If it is digital, would it be better to run it into a separate pre-amp, especially for low level listening, or is it best connected straight to a power amp (or active speakers)?
 
The volume control is in digital domain. Considering the dynamic range of 115dB on unbalanced and 122dB on M-DAC's balanced outputs, you are not likely to realize any benefit noise-wise by attenuating in analog domain. The power amplifier / active speaker has it's inherent input noise which will be dominant, no matter you drop the level in digital or analog domain.

If you're worried about reduced resolution, that would be a valid concern in 16 bit age, not so with the whole DSP datapath at 32 bits - ie. 192dB headroom. Just like with an analogue volume control, resolution is preserved but it sinks into the thermal noisefloor. The M-DAC's CROSS output stage is a full blown Class A preamplifier sporting near zero output impedance. There is really no reason to daisy chain another preamp, just like you wouldn't consider running two separate preamps in a typical system.

Think of it this way - the whole SACD format is only using 1 bit, yet does not suffer from lack of resolution. Thanks to the concept of dithered quantization and noise shaping. M-DAC's digital volume control preserves resolution in the same way as DSD does with just 1 bit, although M-DAC has the advantage or many more bits.

Dominik
 
Hi Tim,

Sorry, I don't know the AP well enough (Never even used one) to know if you can send Processed L/R out via a Digital Output - I wish I could be of more help.

But I tell you what - been thinking about the obvious need to be able to select between MDAC output and some Analogue pass though mode - we could added the feature to the external PSU box - so that its a PSU + Audio Pass though selector - there is a Comms Bus link on the PSU connector to facilitate this - I'm guessing this would be ideal?

John

Hi John, no problem, I think I was being a bit lazy with that question anyway (probably a case of RTFM!) :)

I guess the simple answer is that if I can get a PCM (is that the right term?) front L/R digital signal from "somewhere" into the MDAC, then it's possible to do the pass-through? Can the volume setting on the digital inputs on the MDAC be trimmed independantly like the CDQ analogue inputs? You might remember I have an issue where I need to use attenuators from the CDQ to the X7 which causes the knock-on effect that there is then not enough range in the trim settings on the AP for me to raise the level of the fronts sufficiently to match the surrounds.

Your PSU / pass through idea does sound like the perfect solution though.

Thanks for the reply
 
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