Just some pics of the latest build 😉
24 valves in total. 8 EY500A rectifiers
6 6N6P's in driver duties
10 EL84's in push pull.
Modular construction. Waiting for output bottles and transformers.
The whole thing will be mounted in a 19" 4U case
Photos here:
Dolby AC3 ... with vacuum tubes | Facebook
24 valves in total. 8 EY500A rectifiers
6 6N6P's in driver duties
10 EL84's in push pull.
Modular construction. Waiting for output bottles and transformers.
The whole thing will be mounted in a 19" 4U case
Photos here:
Dolby AC3 ... with vacuum tubes | Facebook
Oh...
I thought with a title like that, you had built the DECODER in valves...
So, youv'e done a 6 channel Power Amp, not a Dolby AC3, or Dolby-Stereo/Pro-Logic Decoder.....
I did a Dolby Stereo Decoder in Chips and discretes, from the original Dolby research docs...
I used summit like 20 odd dual op-amps, and four VCA chips.....
Still got it round here somewhere, Worked pretty well, but the Dolby Pro-Logic has its limitations. Far Prefer Circle-Surround, MUCH better spectral representations--Even of Dolby recorded stuff....
Sorry, personally dont like Digital AC3, way too 'lossey' Much prefer Analogue decoding done Properly, But--Thats just MO!
I thought with a title like that, you had built the DECODER in valves...
So, youv'e done a 6 channel Power Amp, not a Dolby AC3, or Dolby-Stereo/Pro-Logic Decoder.....
I did a Dolby Stereo Decoder in Chips and discretes, from the original Dolby research docs...
I used summit like 20 odd dual op-amps, and four VCA chips.....
Still got it round here somewhere, Worked pretty well, but the Dolby Pro-Logic has its limitations. Far Prefer Circle-Surround, MUCH better spectral representations--Even of Dolby recorded stuff....
Sorry, personally dont like Digital AC3, way too 'lossey' Much prefer Analogue decoding done Properly, But--Thats just MO!
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Could you picture it! I suspect there's more computing power in the Dolby decoder than put a man on the moon!
There are 5 power amps and one line amp. The firmware is my own.
There are 5 power amps and one line amp. The firmware is my own.
Err....
Not being funny, But...
If the 'Firmware is your own' (and I'm assuming the decoding algorithm) Then it cant be Dolby AC3....
Dolby AC3 is a Propriety algorithm of Dolby Laboratories....
TBH if it IS your own, Its prolly a damnd site better than AC3!
Not being funny, But...
If the 'Firmware is your own' (and I'm assuming the decoding algorithm) Then it cant be Dolby AC3....
Dolby AC3 is a Propriety algorithm of Dolby Laboratories....
TBH if it IS your own, Its prolly a damnd site better than AC3!
The firmware that is used to talk to Mr Dolby's IC.. it drives the LCD display/remote control etc. Basically only reads and writes to the relevant registers.
Oh, Yes!
They are a very 'funny' company that way! You wouldnt believe how much I had to go through to get the design notes for the then, 'Dolby-Stereo' decoder used in Cinemas. --What the CP-50 and CP55 were based on....
This was before they released 'Pro-Logic' on the scene for the domestic market....
Everything is guarded most securely!
Even the actual 'Dolby-Digital' sound-track between the sprocket-holes on a movie 35mm print has the Dolby Logo in its centre, on each and every one of the millions in a release 35mm print!
Out of curiosity, what DSP are you using? Years ago, A.D. had a pretty nice one that AC3 would run on.....
And all finished at last... sounds great ... need to fabricate a top that's more ventilation than cover. Dolby AC3 ... with vacuum tubes | Facebook
That's pretty awesome! I've always wondered about doing something like this; its way beyond my skill level at the moment, but it's still cool to dream.
Is this for a home theater setup or a multi-channel music setup? What speakers are you using? Power output is 15 watts per channel?
Is this for a home theater setup or a multi-channel music setup? What speakers are you using? Power output is 15 watts per channel?
The PCB at the back right of the case takes SPDIF or AC3 optically or coaxially (is that a real word?) and does the decoding, and gives 6 outputs. So it will work as 2 channel stereo or 5.1 surround. Power output is about 10 watts.
Each power amplifier is based on the diyparadise "simple EL84". If I did it again, I'd use a bigger case and have a better power supply, but I'm made up with the results. This is the first time I've used Edcor iron, and I'm suitably impressed. Bass is really tight and controlled.
Front Speakers are Rocket audio. Centre is a JBL something-or-other. Rears are some JVC speakers from a nasty "hifi". Sub woofer is a Cabasse. I've not done home theatre before, and speakers were not a concern. Now I'm so pleased with the results, I may go and get some "proper" home theatre speakers, then again, I'm yet to build my own speakers ... many amps/preamps/DAC and even my own CD .. but never a speaker ... now, where's my saw ?
Each power amplifier is based on the diyparadise "simple EL84". If I did it again, I'd use a bigger case and have a better power supply, but I'm made up with the results. This is the first time I've used Edcor iron, and I'm suitably impressed. Bass is really tight and controlled.
Front Speakers are Rocket audio. Centre is a JBL something-or-other. Rears are some JVC speakers from a nasty "hifi". Sub woofer is a Cabasse. I've not done home theatre before, and speakers were not a concern. Now I'm so pleased with the results, I may go and get some "proper" home theatre speakers, then again, I'm yet to build my own speakers ... many amps/preamps/DAC and even my own CD .. but never a speaker ... now, where's my saw ?
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Sir do you have a circuit for this? I created a hafler matrix decoder but without vca's. Think I can improve my DIY surround.
thanks in advance.
Well--Probably Somewhere!
Ive moved house a couple of times since then, Not even sure where the prototype board is anymore.....
--I only built it more as an experiment than to use properly, and was a great learning experience!
TBH, IF you can get hold of one, The Circle-Surround chip from A.D. will knock spots off any Dolby Stereo (Pro-logic) circuit, and is fully compatable with music/non-encoded media,--Unlike Dolby, which sounds hideous with non Dolby encoded media!
Circle-Surround has a three band steering matrix as opposed to Dolby's single-band, and surround isn't limited to 7kHz like the Dolby matrix.
As I recall, the AD Chip is the SSM 2005A while the 'pro-logic' Dolby chip is SSM 2125/6 Both these chips use simple logic control, so no micro or codes to write, just tie certain pins to gnd or supply to set modes....
Ive moved house a couple of times since then, Not even sure where the prototype board is anymore.....
--I only built it more as an experiment than to use properly, and was a great learning experience!
TBH, IF you can get hold of one, The Circle-Surround chip from A.D. will knock spots off any Dolby Stereo (Pro-logic) circuit, and is fully compatable with music/non-encoded media,--Unlike Dolby, which sounds hideous with non Dolby encoded media!
Circle-Surround has a three band steering matrix as opposed to Dolby's single-band, and surround isn't limited to 7kHz like the Dolby matrix.
As I recall, the AD Chip is the SSM 2005A while the 'pro-logic' Dolby chip is SSM 2125/6 Both these chips use simple logic control, so no micro or codes to write, just tie certain pins to gnd or supply to set modes....
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