Aleph p 1.7 questions?

[bbakota2000]

Hi,
I want to start working on P 1.7 preamp, but I have few questions for which I didn't found an answers. First, did Nelson used stepped attenuator? If not, can I use stepped attenuator for a volume control. If yes, which one? I'm trying to find an "ultimate" attenuator, but I'm not shure what to look for. Which resistors in attenuator?
Second, what about micro controller Phillips 87c752? It has been discontinued. Which one I can use instead? I don't know anything about micro controllers.
Last question. Is it possible to make it sound better than the original? I just want tons of transparency and musicality.
It is going to be connected to my almost done Aleph 5.
Thanks

 

[Kongen]

volume...

look at this page... it is a copy of the original volumecontrol. The only difference is the number of steps and the function of the volume control. This one has more steps (256), where the original only used some of the 256 steps (i can't remember how many). I'm going to use this one i think... i'm also doing a aleph p1.7 with kristjians(?) (http://web.vip.hr/pcb-design.vip/) boards... good luck...

kongen

 

[bbakota2000]

You probably forgot to put a link for the page. Try again please.

Master; Which one did you use in the original?

 

[Alain Dupont]

bbakota2000,

>> Phillips 87c752

A new chip exists LPC762

see http://www.semiconductors.philips.com/news/content/file_454.html

I am looking at these for a CCS-X-BOSOZ with remote and stepped attenuator with relays...

I will need help to redesign a remote ...

Regards.

Alain.

 

[Kongen]

forgotten link...

Sorry about that... the link is http://home.tu-clausthal.de/~tpa/relais/relais.html...

kongen

 

[bbakota2000]

Ok thanks for the link.
What is the best stepped attenuator to use if I don't want to have a comfort of remote control and display? What kind do I have to use (balanced or no), and what are the pros and cons of the stepped attenuator versus let's say Alps Black Beauty?

 

[Kongen]

one argument for the stepped attenuator is the precision... Imagine the precision of each step if you are using 0.1% resistors compared to a potentiometer...

 

[nbaula]

If you havent seen this already check them out http://www.apoxcontrols.com/apox.htm

 

[bbakota2000]

For Aleph p 1.7 I need 2K and lowest one they offer is 5K. Does that make any difference?
One more question. What can I use instead of Wima MKS4 10uf/100V in P 1.7? I'll use kristijan's boards and I'm limited with space. Can I use Black Gate N series?

 

[Kongen]

Caps...

Yeah i had the same problem... either they were damn expensive or there weren't room for them. I ended up using some intertechnik, which i bought directly from their website... http://www.intertechnik.de/ go to the webshop and find the 100v mkt radials... about 3 euros per cap...

kongen

 

[till]

The site linked in #5 is mine, and the circuit is the cheap diy version , whereas the apox is a luxorious kit version http://www.diyaudio.com/forums/showthread.php?s=&threadid=12186&highlight=. The precision of the relais volume circuits depends only on the resistors you choose. I would not choose a microcontroller for such a project depending on what the template for what i´m building used, but choose a MC thats easy to obtain, cheap and programmers easy avaiable.

For the PIC a remote control is easy to implement, as RC5 code for reciving signals from an Philips remote controll is allready to be found in the net.

One day i´ll find the time to implemet a remote funktion for the circuit.

 

[bbakota2000]

So if I want to use Goldpoint Mini-L attenuator http://www.goldpt.com/compare.html , they offer lowest value of 5K and I need 2K. Can I just buy a kit of high quality and low tolerance 2K resistors and solder them in? BTW What do you think of price ($171), is it too much?