I comment that both RelaiXed pre-amplifier and UcD power amplifier are design of product innovation. (i.e. audio relay attenuator, digital microcontroller control technology, power electronics, etc...) Since I just use my hobby leisure time to do it, the original schedule was postponed. I plan that I shall complete these two audio DIY projects later.
In order to present a better understanding for the design of RelaiXed pre-amplifier, I sketched a block diagram of RelaiXed pre-amplifier as attached. After discussion with the designer, Jos van Eijndhoven by email, he commented that my sketch was correct. Listed as belows are the emails about technical discussion between Jos van Eijndhoven and me for your reference.
Those audio DIYers who think RelaiXed pre-amplifier interesting can contact Jos van Eijndhoven directly at http://www.eijndhoven.net/jos/relaixed/index.html .
B. regards,
alant
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Reference Emails as below
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----- Original Message -----
From: "Jos van Eijndhoven" <jos@vaneijndhoven.net>
To: "Alan" <smtam@ieee.org>
Sent: Friday, April 25, 2008 5:52 AM
Subject: Re: Block Diagram of RelaiXed Balanced Pre-amplifier (Dwg Rev#3)
Hi Alan,
thanks for your kind message.
Indeed, sometimes a post is made regarding the relaiXed, or my earlier passive attenuator, in a newsgroup without that I ever see that. Thanks for linking me to that. Myself, I am also busy currently with building a Hypex UcD-HG amplifier, but my progress is also limited due to lack of time.....
I have heard the combination with my relaixed already (builtin combination by someone else) and I can say that the result is stunning!
To keep you interested :-) I attach a small text that someone recently posted in a British DIY forum about the passive attenuator. (The DACT switches are -here in Europe- well-known as the ultimate high-end volume control, and is a manual rotary switch with discrete resistors.)
Greetings,
Jos
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06-03-08
My point is, this is a very good stepped attenuator indeed, it beats the DACT CT2 by quite some margin, which I've been using for some time (2 years). And its fully remote with 64 steps on the gain and 4 inputs all via little relays which are quite audible. (but its no problem, a faint click is all that one hears)
It takes about 1 hour to build (if you take your time, small tip on the iron) and a doddle to install. (follow the simple instructions) Which I did and left overnight as time was running out last night.........today have had a good listen and well well well, very transparent, as if a thin layer of mist was wiped way.
It drives an AD815 chip pre amp very well
Graham
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07-03-08
Will post more pics over the weekend............it truly is a very transparent device. Now everthing has warmed up again I'm now getting a much clearer picture of the low level information on the CD's. Very good indeed and for less than the price of a 'handomatic' DACT CT2.
The 64 steps on the gain is a bit of a wind by hand, 2.5 turns to my listening level. Hav'nt counted how many clicks
Graham
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10-03-08
What stands out other than already stated is the low volume level reproduction pin sharp imageing and no loss of detail........
Graham
----- Original Message -----
On Thu, Apr 24, 2008 at 10:16 AM, Alan <smtam@ieee.org> wrote:
Dear Jos van Eijndhoven,
You are welcome! The motivation is based on my interest to your design which is regarded as an innovative product. Hope that every audio DIYer will enjoy it. I am a music hobbyist located in Hong Kong. I discovered your RelaiXed pre-amplifier over internet. After review, I recommended your design at the discussion forum in "HiFifever" organization at http://www.hififever.com/forum/viewtopic.php?t=1783&sid=7f05ce06c2274e97019231d8caff4f55 . My username in "HiFifever" is "alant". "HiFifever" is the biggest and reputable DIY organization in Hong Kong and he is the sole agent of UcD (http://shop.hififever.com/index.php?cPath=41_38) in Hong Kong. My goal is to complete the two audio DIY projects of RelaiXed pre-amplifier and UcD power amplifier on or before mid of year 2009. For UcD power amplifier, I shall join the local DIY training course conducted by HiFifever, but RelaiXed pre-amplifer is really a "Do It Yourself" project. Since I just use my hobby leisure time to do it, I cannot start it immediately due to personal reason. It is now under review and preparation process. If I am ready, I shall contact you to purchase the PCB, pre-programmed microcontroller, etc... later. Thank you for adding my name into your potential customer list, please keep me information updated if any.
Hope that every music hobbyist will enjoy your design!
B. regards,
Alan
----- Original Message -----
From: "Jos van Eijndhoven"
<jos@vaneijndhoven.net>
To: "Alan" <smtam@ieee.org>
Sent: Thursday, April 24, 2008 6:59 AM
Subject: Re: Block Diagram of RelaiXed Balanced Pre-amplifier (Dwg Rev#3)
Dear Alan,
yes, all correct. I think it has become a really nice and clear picture!
Greetings,
Jos
----- Original Message -----
On Wed, Apr 23, 2008 at 10:55 PM, Alan <smtam@ieee.org> wrote:
Dear Jos van Eijndhoven,
One more point, as just want to say more clearly as below:
1) IR remote control indirectly sends instruction to Front microcontroller (U2D) via Photodiode/IR receiver (U3D), but
2) Rotary switch directly sends instruction to Front microcontroller (U2D) without passing through Photodiode (U3D)
If need to present more concisely, I revised to drawing "Block_diagram_ver3.vsd" (Version #3) as attached to illustrate the difference between instruction sent from IR remote control and rotary switch to front microcontroller (U2D).
B. regards,
Alan
---- Original Message -----
From: "Alan" <smtam@ieee.org>
To: "Jos van Eijndhoven" <jos@vaneijndhoven.net>
Sent: Thursday, April 24, 2008 1:48 AM
Subject: Re: Block Diagram of RelaiXed Balanced Pre-amplifier (Revised dwg)
Dear Jos van Eijndhoven,
I provide you a second choice of drawing with separation of 2 microcontrollers within the Microprocessor Control Unit (MCU) as per attached file "Block_diagram_ver2.vsd". As per this drawing as below, please note:
The Microprocessor Control Unit (MCU) mainly consists of five electronic components:
1) Two microcontrollers, including Front microcontroller (U2D) and Relay microcontroller (U1D)
2) Two IC arrays (U4D, U5D)
3) One photodiode as IR receiver (U3D)
In modelling the logical processes within MCU, it can provide the following six processes:
1) Instruction is activated by either IR remote control or rotary switch by manual option to Front microcontroller (U2D) via photodiode/IR receiver (U3D)
2) Front microcontroller (U2D) directly handles the operation of LCD display unit (L1D, L2D)
3) Front microcontroller (U2D) directly sends instruction to relay microcontroller (U1D)
4) Relay microcontroller (U1D) indirectly drive command to relay in Volume control unit via IC array (U4D)
5) Relay microcontroller (U1D) indirectly drive command to power relay via IC array (U4D)
6) Relay microcontroller (U1D) indirectly drive command to relay in Input channel selection unit via IC array (U5D)
In the logical flow of above processes: when step #1 is activated, both steps #2 & #3 will be proceeded. Depneding on the result on step #3, only one of three steps #4, #5 & #6 will be performed.
In conclusion, you can choose either previous drawing file "Block_diagram_rev1.vsd" or this drawing file "Block_diagram_ver2.vsd". It is subject to your final decision.
B. regards,
Alan
----- Original Message -----
From: "Jos van Eijndhoven" <jos@vaneijndhoven.net>
To: "Alan" <smtam@ieee.org>
Sent: Wednesday, April 23, 2008 9:53 PM
Subject: Re: Block Diagram of RelaiXed Balanced Pre-amplifier (Revised dwg)
Hi Alan,
nice drawing!!!
yes, it is correct, you properly understood how it works. It is nice to see the separation of the power-lines.
The only missing thing might be matter of taste or chosen abstraction....
The diagram does not show the 2nd microcontroller and its responsibilities. - the 'front' microcontroller handles the switch, the IR, the display, and sends results to: - the 'relay' microcontroller which receives commands from the front, and drives all relays (volume-, channelselect- and power-relays)
Greetings,
Jos
----- Original Message -----
On Wed, Apr 23, 2008 at 7:50 AM, Alan <smtam@ieee.org> wrote:
Dear Jos van Eijdhoven,
Forgot to add a 5Vdc power line supplied to LCD display unit. Revised as attached file "Block_diagram_rev1.vsd".
B. regards,
Alan
----- Original Message -----
From: Alan
To: Jos van Eijndhoven
Sent: Tuesday, April 22, 2008 11:42 PM
Subject: Block Diagram of RelaiXed Balanced Pre-amplifier
Dear Jos van Eijdhoven,
After a preliminarly review of your design, I sketched a block diagram as attached in order to capture my understanding. Hope that you like it too. If any error, feel free to advise me. Besides, I attached the source file "block_diagram_source.vsd" to you which is drawn by Microsoft VISIO software. You can edit it directly or use for other purpose, such as attach to your user guide if applicable.
B. regards,
Alan |