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Digital that sounds like analog

Posted 10th December 2012 at 03:18 AM by abraxalito
Updated 15th February 2013 at 05:11 AM by abraxalito

For those who missed Frank (fas42)'s link on a thread I started then here's where I'm continuing my minimal oversampling DAC developments for the time being : Digital that sounds like analog
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Google+ DIY Audio community.

Posted 7th December 2012 at 10:06 PM by rjm
Updated 14th April 2013 at 11:14 PM by rjm

There was no DIY Audio community on Google+.

So I made one.

Google+ has always been a "quiet room" where like-minded people got together to talk about things, away from the noise and chaos of facebook.

The problem was that it was difficult to find said like-minded people. They were there, but for the majority you had no way of knowing that.

Well, now Google has fixed that by introducing "communities". It's a user-created hub, a digital meeting room ~ salon ~ lounge ~ front porch, a designated gathering place associated with a certain hobby, interest, or topic.

This feature is brand new, so I have no idea whether it will work. It could, like facebook, devolve into noise and spam... or it might be useful and worthwhile. I think its worth a shot, anyway.

I created the group, but it is free and open. It's not mine in the sense I don't intend to use it as a platform. I have my own G+ page for...
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Amplificador SubZero-Dr Jacobid

Posted 2nd December 2012 at 09:17 PM by SERGIODS


Hello fellow forum would like to know if anyone har Zero sub amplifier, is an amplifier that caught my Atencio.
It is the famous Dr Jacoid
> Output power (RMS) 180W into 8 ohms -------------
> Output power (RMS) 230W into 4 ohms -------------
> Output (music) --------- 220-230W into 8 ohms
> Output (music) --------- 270-300W into 4 ohms
> Check osetljivost/impedansa----0, 6V/47koma (by 200Wrms ohms /
> ----- 7 Hz 112KHz-/-3dB frequency response (to less than 0.01% distortion)
> ------------------- THD <0.003% (a 130WRMS into 8 ohms)
> ------------------- THD <0.005% (a 180WRMS into 4 ohms)
> S/N------------ noise> 95 dB (compared to 100Wrms)
> ------- Damping factor> 300 (in 150WRMS into 8 ohms)

Notice of Copyright. Everything on this website is copyrighted by Dr. cheekbones Borivoje. Reproduction or re-publication by any means, electronic,...
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6C33C OTL - Construction Journal Continues -Cutting the aluminum

Posted 1st December 2012 at 02:00 AM by wlowes

I am keeping this journal for my own record. There is no new engineering in this project. This is just my own journey while building my first tube amp.

Major milestone achieved today. I finally took the plunge and cut the aluminum. I am very happy with the results. Each and every part fits perfectly.

I planned this project around Front Panel Express. I used their tool designing and redesigning the lay out until I was confident in my layout and fit. Problem is FPE is expensive. Then I saw some comments from other builders that the edge FPE leaves is not really finished. I went searching for a more cost effective solution. I landed on cutting using WaterJet while searching for local CNC shops. There is a company in Toronto close to where I work that has an advanced waterjet cutting machine. I exported my FPE file and sent it in for a quote. Given I need a left and a right panel for the 2 mono's I got them to cut both panels...
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Upload of design documentation for ADAU1442

Posted 20th November 2012 at 11:55 AM by googlyone
Updated 20th November 2012 at 12:02 PM by googlyone

I have had a few people ask for the CAD files and software for the ADAU1442 DSP. I have tried uploading the whole lot as a series of ZIP files - I hope this works OK.

There are a few things that warrant comment, and if you try to untangle this lot, I am sure a few questions to me. Feel free to ask away...

- The sigmastudio file is simply there to generate the code for the DSP. All the actual values for filters etc are calculated by the microcontroller under user control.

- SigmaStdio generates a bunch of export files, my software uses the *.h files, both to load the DSP code, and also to get the addresses in the ADAU1442 of registers for biquad coefficients etc. The microcontroller code pretty well loads these in straight, but there is a tiny bit of tidying up the sigma generated files first...

- The microcontroller is a PIC18F4560 (from memory) the CAD file has a PIC18F5420 in the schematic - these are pin...
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File Type: pdf ADC.pdf (88.0 KB, 333 views)
File Type: pdf DAC.pdf (86.6 KB, 347 views)
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The Front End

Posted 19th November 2012 at 04:26 AM by rjm
Updated 22nd November 2012 at 05:18 AM by rjm

The most disruptive audio technology since the CD, since the advent of stereo actually, is ... the iPod. You can lump in mp3, iTunes, and digital distribution in there if you want, but it’s the iPod, the physical device, which has more than anything re-defined what we think of as an audio system in the twenty first century. Shelves of physical media and a playback unit, or, if you preferred, broadcast content, has been displaced by a handheld, personal, portable jukebox. The audio component system of the 1970’s (media, sources, preamp, amp, speakers) has faded into obsolescence, replaced by powered speakers, headphone amplifiers, desktop audio, compact “speakers+amplifier” systems the ubiquitous "dock" fronting a traditional amplifier-speaker system.

Audio is missing the front end.

Because it isn’t an iPod, I’m sure of that. Its day is done. No, it's pretty clear to me that the front-front end of the future is settled: Its the internet. The cloud....
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Current output...

Posted 15th November 2012 at 09:05 PM by hbc

I think I may be getting it..?? (well something anyway). I have been living happily with the 3w ECL86 amp (current output reigned in by feedback) for some months, and am accustomed to its sound now. A friend has recently returned my Class A hybrid digital amp and I thought I would try it out again. I instantly noticed a sort of grungy ness and colder “transistory” sound, even though this is a no feedback design with a transistor emitter follower output. It is curious how the little IB two way speakers don’t like transistor amps.

I got to thinking about current output amplifiers, I was intrigued a few months ago by some comments on an article in the EE times Consumer audio: Is accurate sound overrated? where the poster "Cookie Jar"  stated “One day on a whim, I hooked up my distortion meters to the actual speaker terminals of my living room stereo, and I was in for a rude awakening. The distortion readings were a couple of orders higher than for...
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My Nexus 7 Tablet

Posted 12th November 2012 at 06:54 AM by rjm
Updated 18th November 2012 at 04:03 AM by rjm

The Nexus 7 is cheap. I paid 19,800 yen for my 16 GB model, shipping and tax inc., and it came with 2,000 Yen credit to buy apps and movies and such in the online Google Play store. And yes, its plastic, even the silver metallic trim around the edge is just a silver-coated plastic part. It is solid, however; sturdy, well-built, and good-looking. The back is covered in grippy, dimpled rubber that feels like leather. The screen is a little dim, but high resolution (800x1280) ~220pi, pretty to look at and easy to read.

With a 7" screen and default portrait orientation the device is closer in spirit to a large smartphone than a small tablet. A giant, wi-fi only smartphone. It's a handy size for reading paperback-format books, comics, and news articles, but not so hot for magazine format publications and A4-formatted journal articles. Browsing the web is generally fine, but the experience varies widely depending on the individual layout of the web page. As you might expect,...
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OTL update - tube power supplies Done!

Posted 4th November 2012 at 02:14 PM by wlowes

Over the past few weeks I continued to build out and test the power supplies. I really am pleased with the decision to make each supply as a module that can be fully developed and tested outside the box.

After the success with the first supply for small tubes, I moved on to the power tubes. After abandoning the large Sangamo can caps, I ordered in 8 2200uf snap in caps.. 2 per rail, 4 per monoblock. After they arrived I realized that these things are pretty big. The question was how to securely mount them. I settled on another wood block so they can be mounted securely under the chokes. As before, I mounted them through the wood using some silicon cement. There are some nice mills wire wound bleeder resistors. The B+ power supply design calls for a single center tapped 230v transformer. I had scored 2 pairs of 120v 500va Toroidal transformers. I must admit it took a lot of research and a couple of helpful posts before I was sure that I really had this figured...
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Need Realistic HK 210/Acrosound Stereo 120 Amplifier Schematic

Posted 28th October 2012 at 08:13 PM by 1972youngstown

recently aquired Realistic HK-210/Acrosound Stereo 120 amplifier. would like to restore but can not locate schematic or operating/owner's manual(instructions for biasing tubes). does anyone have schematic and/or manual or direct me where i can be find them?
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