Interesting stuff

[xerxes]

Some interesting stuff: www.ecdesigns.nl/index.html

I've been following a thread at DIY Audio Forums: www.diyaudio.com/forums/showthread.php?s=&threadid=79452&perpage=10&pagenumber=1, where he is discussing the creation of some DACs using either 8 time delayed TDA1541As or 16 TDA1543s, to produce a NOS Dac with "hardware oversampling". Most of it goes over my head, but it looks impressive none the less.

[rickcr42]

Some interesting stuff:

scary looking if you ask me man.

"beam me up Scotty !"


I HATE tubes lit by LEDs because it is an effect that has less to do with "the look" than any sonics.these are usually the same types who toss a tube into a solid state opamp circuit to
warm it up" even though the marriage is not usually a good one.Different strokes man

where he is discussing the creation of some DACs using either 8 time delayed TDA1541As or 16 TDA1543s, to produce a NOS Dac with "hardware oversampling".

??

Have to read into this more after work.My initial take would be why ?

If you want an OS DAC there are plenty of good digital filter chips available and if "hardware OS" ceases to become a Non-OS DAC anyway.

Then there is interchannel matching.Scewing the time domain of 16 chips sounds to me like the end result would be a very jittery stereo image.One that wanders to the chip perspective and not what is on the disc though again i may be wrong and will have to read the thread through later.

[jelosno]

BLOODY HELL!

I went thourgh this thread

Well you can't really say it is a OS DAC and I am not sure whether it is NOS. The creator of that things says it is NOS and, well, yeah, could be.

And he does NOT like to use filters and he DOES NOT use FILTERS.

Thas was why I went through it. Had to skip some pages when things wen off topic which never will happen here ;D

Can be very interesting when he will sell PCBs. The thread had more teh 22.000 hits id I am not mistaken. There seems to be a rush for TDA1541As already...

LEDs with tubes. Not ok. But if you read through it is quite nice since he was a hardcore SS guy and just because others suggested it he included tubes and loved them right from the start.

[jelosno]

A entirely different fish: THE 1543.

This is considered to be the awful version of the 1541.

After some nagging in the 1541A thread the guy build a version with 4x4 1543s and was quite impressed.

@ www.dddac.de/ you will find the simple and short and CHEAP version of the multi 1543 DAC.

He sells PCBs but the information provided is good enough so some folks have made their breadboard version.

Interesting site, not too deep. Enough understandable technical info.

One comment on the 'feedback' page was the following:

• His 1541 DAC sounded much better on detail, texture, tonality and soundstaging. This was clearly heard on jazz and seductive female vocals. It was a very smooth sounding DAC (almost sleep inducing).
  
• The DDDAC1543 design was far superior on dynamics, solidity and the "space between notes". This was clearly heard on headbanging rock music. Bass guitar and percussion sounded excellent - the DAC passed through the drive of the music.

The solution could be biasing and/or other caps says the designer of that DAC.

The weird thing is that, depending on how many 1543s are stacked and combined he will acchieve 2v output.

Again NO FILTERS - NOS

USB and SPDIF input available to be converted to I2S. With a CDPRO the signal can go directly 'into' the DAC

What I don't like is the battery solution but that could be changed.

Links found on the site:

www.geocities.com/TDAC1543/

didnt.doit.wisc.edu/audio/dddac1543/dddac1543.html

www.diyparadise.com/8x1543dac.html

didnt.doit.wisc.edu/audio/dddac1543/00_new_DAC/build_pix/

[xerxes]

I HATE tubes lit by LEDs because it is an effect that has less to do with "the look" than any sonics.

Well, you know my take on tubes, the opposite to that of children, wherby they should be heard, but not seen.

I really like things to be quite plain and understated, the bare minimum of indicator lamps, no flashy chrome, and no "Manhattan skyline at night" bunch of tubes sticking out of the top of the box!

All in all, I'm not too keen on the guy's aesthetic, if I wanted that many lights on my hi-fi I'd buy an Aiwa, but I think the attention to detail and the build quality is very impressive none the less. I'm also quite intrigued by the omni directional speakers on his web site, which incidentally, I do rather like the look of.

[rickcr42]

Thas was why I went through it. Had to skip some pages when things wen off topic which never will happen here

Nope ! We run a tight ship 'round these here parts

Again NO FILTERS - NOS

with digital you NEED a filter somwhere no matter what the design or you end up with aliasing.Originally all CP players were Non-OS but so they followed the DAC stage with multi-pole brick wall filters that were serious sonic butchers affectionatelymown as "ringing bastards".This led to the digital filter which was created to "oversample" the digital stream placing the aliasing at a higher frequency.This in turn allowed for either higher F3's (the -3dB point of the low pass filter) in the filter hence less intrusive on the audible frequencies or slower rate filters that are more listener freindly but that would still be as far down in the stop band by the time it reached the digital crap that it would be as inaudible as the former brick wall filter

Filters have a rate of attenuation that is based on "per octave" with each filter pole being -6dB.
So if three poles will be -18dB per octave meaning if the F3 is at 20khz will be down 18dB by 40khz,36 db by 80khz,72 by 30 etc.
So if it begins above 20khz but must have a very sharp attenuation of everything above 40khz you need a lot of poles to get there and that means ripple.

Well, you know my take on tubes, the opposite to that of children, wherby they should be heard, but not seen.

Wish my wife was of that mind.My opinion is there is zero reason to have small signal tubes "sticking out" and would prefer mine under wraps at all times except when it was time to change them as was done in the "Golden Age of Audio" (Fishers,Scotts,Marantz,etc.).

My wife is of the "if i can't see the damn tubes glow what is the point ?" mind and it drives me frikkin' nutso because to me it is about how I get to the sound I am after and has zip to do with the "look" of the active devices used

I really like things to be quite plain and understated, the bare minimum of indicator lamps, no flashy chrome, and no "Manhattan skyline at night" bunch of tubes sticking out of the top of the box

with you on that one bubbameven to the circuitry.Plain & Simple when i can,complicated if I must,wrap it all up in a chassis to protect it from harm (and from prying fingers BZZZZZZZZZT !!!!!!!!! ) and put the sucker in system and fegetaboutit

I'm also quite intrigued by the omni directional speakers on his web site, which incidentally, I do rather like the look of

I take the polar opposite track on that and prefer controlled dispersion so I can lock in the lateral image.I did once own a pair of Dahlquist DQ-10s that radiated almost as much energy to the rear as fron but those suckers liked a lot of room to breathe before sounding right.Any side or rear walls were like poison but get them pricks out in the open and they too opened up.....if you hit them with 200WPC or better anyway

BLOODY HELL!

I went thourgh this thread !

Takes a bit of stamina yes ?

entirely different fish: THE 1543.

Some very highly regarded DACs use the 1543

www.wavelengthaudio.com/preamps.html

something of possible interest here

www.tubecad.com/2006/07/blog0072.htm

[xerxes]

I take the polar opposite track on that and prefer controlled dispersion so I can lock in the lateral image.I did once own a pair of Dahlquist DQ-10s that radiated almost as much energy to the rear as fron but those suckers liked a lot of room to breathe before sounding right.Any side or rear walls were like poison but get them pricks out in the open and they too opened up.....if you hit them with 200WPC or better anyway

Indeed, I they'd be a much use as a chocolate tea pot in my cramped listening room, but I'd like to hear them in the correct setting. I've only ever personally owned fairly conventional stand mounts.

I did once hear a pair of flat panel electrostatics, which also need plenty of space, in a demo and was really impressed. I think what was really intriguing was that having only ever heard conventional, bulky, coned speakers, getting so much sound, and fairly punchy too, from a pair of speakers no more than an inch thick was somehow slightly unbelievable, they also imaged really well.

[rickcr42]

Indeed, I they'd be a much use as a chocolate tea pot in my cramped listening room, but I'd like to hear them in the correct setting. I've only ever personally owned fairly conventional stand mounts

.

Loudspeakers are a serious pain in the ass if compared to headphones.With cans all you need to do is match up the power drive and gain but with loudspeakers that plus you need to consider not only the room but where you will be listening from as well.Use a speaker meant for near field listening and you get "shouty" sound when trying to drive it load enough for distant listening.Use a speaker meant to be listened to from three meters away and you get "gaps" when sitting too close.no winning.

Flat panel speakers need to be large to fill a large space with sound yet need to be narrow or the high frequencies roll off rapidly and why you see ribbon tweets added at times to assist the top end (higher end maggies,the old QUAD ESL with Decca Ribbon Tweeter)

The early QUADs can be considered a near field speaker of sorts even though they sound fine 10' away due to the limited excursion of the membrane and why some used doubled up "stacked" QUADS in large rooms.Looked at as a mid range cabinet about as good as it gets when mated to a dipole subwoofer and a ribbon tweeter though don't expect eye blinking impact.Clean as hell yes,powerful dynamics no.

The DQ-10 mentioned previously was a cone driver attempt at the QUAD ESL sound with the ad copy more or less saying they were QUADS with a little more bass,a little more treble and a lot more power but that power ! Baby,you don't KNOW what power hungry is until you own a pair of DQ-10s but get them moving with a "proper" amp (Bryston or Ampzilla back in the day,the Hafler DH-500 was a wimp even though 200WPC rated ) and get ready to rock !

(I likely will own another pair one day.That or a set of ESL57's which have so far have eluded me even though I am an admirer.I own both dynamic and electrostat cans so why not dynamic and electrostat loudspeakers in the same house ?)

In your situation the Dahlquists would sound like pure sh*t,the QUADs could be weasled to work (see below) while the best way to fast/bipolar would be a small cone driver mated to a flat panel or ribbon tweeter AND having another tweeter mounted on the back of the cabinet playing at a lower volume than the front mounted tweeter.By having a phase flip/tweeter mute toggle+variable Pad you can dial in the sound to match any room provided you pay attention to first reflections both front and rear.

I currently have a pair of rear firing "Orange Squeezer" tweeters on top of my main left/right speakers that I switch in when playing movies that for some reason add to the enjoyment level even though I never use them for music only use.something to do with the psychoacoustics thingy and since movies are larger than life the sound system needs to be just as dramatic to keep up


possibly an experiment to see if you like/want bipolar speakers in your room would be to purchase a couple of these $5 wonders and play with them as rear tweets.Totally against the "if you want to be cool/high end audiophile rule book" but fk it man,your money,your system,your life.Rules are made to be broken dude

I did once hear a pair of flat panel electrostatics, which also need plenty of space, in a demo and was really impressed. I think what was really intriguing was that having only ever heard conventional, bulky, coned speakers, getting so much sound, and fairly punchy too, from a pair of speakers no more than an inch thick was somehow slightly unbelievable, they also imaged really well

Bipolars can be "fooled" into thinking they are in a larger acoustic space if you deaden the back wall with acoustic tiles such as Sonex panels.Used in a "2X2 Grid" with a couple of inches between each grouping of four (again you gotta play with positioning in your own room on your own system) can give a proper reflective/absorptive back wall that will allow placement closer to the back walls.Same with side walls in really cramped rooms.

You can't make a mini monitor fill a large hall with sound,neither can you play a "long throw" Horn or P.A. system in a small room but everything else is fair game if you work at it ;D

[jelosno]

they should be heard, but not seen

Well, if they do have a nice glow I don't mind seeing them... ;D


The Tentlabs CDP kit without the chassis is around EUR 1500,- net excl shipping.

Not bad but since I do own a LUA Cantilena which is the way overpriced sibling of the Jolida JD100A that cost 'round a EUR 1100 some five or six years ago.....
Rather stick with my old CDP.
There are some infos on how to 'upgrade' the Jolida and they seem to be reasonable. I might go that route first and change the clock to one from Tentlabs. Let's see how this turns out.

Might also build one of those interesting 1543 megatower DACs. I am no big fan of battery powered units but it makes sense pricewise.
The DDDAC seems not to have an digital filters. Pretty much of a very clean audio signal path. Only a coupling cap per channel at the very end before the RCA jack.
I could use the LUA/Jolida DAC with the tube end buffer and it's digital out to feed the 1543 DAC. There is a Tentlabs clock that has a extra signal out for external DACs...

Can anyone have a looks at the tentlabs.com/Products/cdupgrade/shunt/index.html site and check whether these shunt regulators for the power supply make any sense?

I am also quite lost between the XO-2, XO-3 with shunt regulator and the XO-x and the XO-supply and the XO in single form....

Stefan

[rickcr42]

just so you know a shunt regulator does not have bandwidth or speed limitation because none of the voltage actually passes through it being a "shunt" which means in parallel with the load.

A series regulator is just that,in series which means ALL voltage passes through it (in series with the circuit DC voltage input rather than across it)

On paper the series regulators whip major ass and do everything right while the shunt reg has limitation but in the real world of audio circuits the shunt regulator SOUND better though I would be hard pressed to explain why.

Is it the bandwidth ? The constant impedance (higher than a series reg so should suck) ? The fact that it can not be overloaded or run out of steam but will just stop regulating when the voltage falls too low ? Recovery time ? The way transients are handled ?

Every one of my digital and analog monolithic chips has and independant TL431 based shunt reg right at every voltage pin with a small CLR filter for each which are ALL fed from a simple DC Supply with a Pi filter for the feed with the only thing "built by rick" using a series reg being my Szekeres Amp and that uses a mongo LM350K V-reg running 28 VDC @ 3A

read this "crash course on voltage regulators"

www.tnt-audio.com/clinica/solidstate.html

am also quite lost between the XO-2, XO-3 with shunt regulator and the XO-x and the XO-supply and the XO in single form..

each is for a very specific end use that is explained on the pages