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-   -   Aleph 3, P 1.0 , P 1.7, help for newbies (and confirmed…) (

Miles Teg 17th August 2001 09:55 PM

Here, we can found some questions and answers (I hope…) for the people who is not habit with DIY audio parts.

First for the Aleph 3:
-It’s really recommended to build separated alimentation for each canal ?
-For this (or these) alimentation we need a toroďdal transformator, how many VA for this ? (in minimum because everybody know that it’s better when the transfo is bigger or overkill…)
-How many is the power dissipation for each transistor of the Schematic ? (very useful for choosing heatsinks)
-The equivalent for the IRF9610 are : 9510, 9620, 9520, 9110, 9210 right ?
for the IRF 244 are : IRF140, 240 , P140, P240 isn’t it ?
- In a lot of Pass project we can see the use of thermistor for grounding and thermic protection : what is the species and reference ? The principle of the use of a thermistor for grounding ?
- It was recommended to make the bridge diode (monoblock) with diodes alone ? The species and ref of the diodes that you use ? It’s recommended to put on parallel of each diodes a caps ? How many µF the caps ?
-I have heard that we can use two diode bridge rectifier per channel. How it works ? It’s really recommended ?

And for the poor young electronic man I am, what does it mean “Front end” (I’m a little shame, I’m sure I know it under a French name).

For my part I draw PCB with good PC program (P-CAD 2000) and I learn to use it in school, so send me the maximum informations you can for the drawing of Aleph 3 and P 1.0 1.7 hybrid.

I’m a little afraid with the volume selector of the P 1.7, I think too it was overkill to use a microcontroller. I already worked for optical interrupters (like Three channel Optical Incremental Encoder Modules HEDS-9040) coupled with Quadrature Decoder/Counter interface IC’s (HCTL-2000 series) who is providing binary code directly (that we can use for command a lot of relays).
That is a hope ? For made it I need to know :
- What it’s is the precise reference or species for the optical interrupters used in Pass P 1.7

For this decoder I need to build a 14 MHz clock generator, I think it will be easy.
I think we can abort the use of the IR telecommand…
For the channel select a simple commutator will be more indicated (with or without relays, cheaper…).

For the others can we say about the things to know when we put a heatsink on a FET. What is the best way to isolate ? to thermic conduct ? more and more…

I notice one thing. We talk never enough about the simple electronic, it’s was we are expect to use in the Nelson Pass philosophy, isn’t…?

I wish this thread became a reference for who is going to build is Aleph project. Today I ask a lot of questions, but for the further time I will answer to others.
I’m going to holiday for the next two week, so make good response, not only for me (the half of this question I’ve got the answer) but for make a center of the Aleph build.

Take good time, I stay on beach for two weeks and I will be back for finish the PCB I have promise.

I you have other questions take place bottom, it was make for this…

Petter 17th August 2001 10:34 PM

Absolute value encoder
Consider using an alps ACE -- absolute contacting gray code encoder -- 128 steps. You need a converter to binary (and logarithm unless you factor the log into resistor values).

At least you don't have to worry about quadrature encoders + you get absolute position (powers up at same volume as when you turned it off).

I think I have seen one with true binary direct out, but have not found it since, so that may have been a misunderstanding.

Good luck.


Miles Teg 17th August 2001 10:41 PM

Yeh petter my decoder/counter give me a real binary code usable directly, but your encoder interest me. Can you be more precise? Can you send me your mail adress by my mail?

Freddie 21st August 2001 04:29 PM

Do you know where to find the alps ACE -- absolute contacting gray code encoder ?

Petter 21st August 2001 06:07 PM

Sorry, it was Bourns,1162,373,00.html

So, there seem to be plenty options out there. Do a search on Google if you are interested!


Miles Teg 22nd October 2002 09:17 AM

If I can ? just : Up

I know, I know, very long up :D

guido 22nd October 2002 10:55 AM

using ACE

I am using an ACE in my preamp to read the position of a normal ALPS pot. Check out the website if you are interested. If it still interesting drop me a mail.

PS, The output of the ACE is not 'logical'. You need a table (in eprom or in the code) to convert it into the something usefull.

Also saw on the net that there is a 'formula' to calculate it.
But that takes time and code-space in a controller.



AuroraB 22nd October 2002 02:04 PM

Gray-to -Binary can be done with X-Or gates...

guido 22nd October 2002 03:40 PM


From the link above:

The classical way to convert Gray to Binary is as follows:

Feed the Gray MSB directly through to be your Binary MSB.
Then make an XOR of the the Gray MSB and 2.MSB. Output will be your Binay 2.MSB.
Then XOR this output with your Gray 3rd. MSB.
Output is now your 3. MSB Binary.
Proceed with XORing each output with your next following unused Gray bit until your all done.
That's all there is to it.
On the other hand, - generating a LUT in a PROM might do it in one chip,
as 8 bits will need two XOR DIPs. One DIP will suffice up to 7 Gray bits...........

But the output is not "normal" gray code:

Gray Code 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 1
2 0 0 0 0 0 0 1 1
3 0 0 0 0 0 0 1 0
4 0 0 0 0 0 1 1 0

0 0 1 1 1 1 1 1 1
1 0 0 1 1 1 1 1 1
2 0 0 1 1 1 1 1 0
3 0 0 1 1 1 0 1 0
4 0 0 1 1 1 0 0 0

Since it is possible to 'compute' the binary (with a microprocessor), so i agree it should also be possible
with logic. But i have the routines at home somewhere (for a pic16f84) and they are many lines...
I guess this 'translates' into much logic.
A table (eprom or inside a microprocessor) seems easier.

Or am i (and the person who did those routines) wrong ?

AuroraB 23rd October 2002 07:12 AM

Sorry,--I was quite in a hurrry yesterday...

Of course code conversion can be done in LUTs, - be it bare EPROM or with processors, but somehow there is a resistance within the audio community to use processors within amplifiers, so the X-Or converter is fully asyncronous. Many people also don't have the tools for programming PROMs or CPUs, and only need the Gray-to-Binary convertion to drive e.g. a relay based attenuator.
The beauty of the microcontroller i of course that it gives the possibility of remote control as well, without any extra counters etc.

Another thread under Solid state amplifiers set out to make a "universal amplifier", and the different parts were divided into sub-threads, but the thread for the control system seems to be dead.....??

I am working on the ideas for a microcontroller based control system for volume, input selection etc. but my spare time is farly limited, and will be for some time to come. I have even launched the idea into a BSc project at a local college, but there will be no results from here until june, - if at all.

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