Yet another Volume controlers and source selections

Can you briefly explain why? Thanks.

That last one is the inter-stage attenuator and it is like in my schematics if you want the whole attenuator to work properly for our years !
It is like this :
R5----------R4--------R3-------R2--------R1-------R0
-32dB --- -16dB ---- 8dB ---- 4dB ---- 2dB ---- 1dB
stage attenuation
at 63dB all are off
at 62dB only R0 is on rest off
at 61dB R1 on rest off
at 60dB R0 and R1 is on rest off
.......
at 0dB all R are on.
As for the 1dB stage is like that for smoother transition between stages .
 
That last one is the inter-stage attenuator and it is like in my schematics if you want the whole attenuator to work properly for our years !
As for the 1dB stage is like that for smoother transition between stages .

OK, now it is clear why is the first relay connected with resistors in this way. Its seems that always we must have resistor in series with signal for this type of attenuation. Thanks.
 
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Still have a few things missing but going to start with what I have...
One question:
Some were in the tread danzup mentions a soft for the 8515 to read the codes from the remote controls (to identify codes) but I read the complete tread twice and I can find it.
Can anyone tell me were it is ?

Thanks
Ric
 
I will post here a new project : an Atmega IR remote transmitter that is 100% compatible with any project , that way you must not search for an compatible IR remote transmitter .
@RS232 : i will check and if there is not I will post again that firmware .
 
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Hi everyone,
I connect the first relay with resistors as shown in datasheet and the situation has improved. Attenuation of the signal now goes noticeably better, does not even have any unwanted overtones in the signal coming out of the attenuator (the signal gnd is connected to ground of Atmega). But the clicks are evident during the amplification / reduction, from 32 to 63 steps. With signal amplification, the clicks are more pronounced. You can hear them from loudspeakers . I dont have any DC from the source. Probably the clicks are present throughout the scale, but till the 31 step they are hidden with attenuation of the last relay (390k resistor on the signal line). Question, is the relay clicks present in your system after step 31? Thanks.
 
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R2R Audible Clicking

I didnt solder my R2R VC version but reading russian audio forums I would like to say that there is a solution for this problem and there are some resons for this problem to be.
1. Resistors values match.
2. High input resistance of the next stage after VC.

1. Check all resistors values you are using.
2. If input resistance of the next stage higher then 10k try to reduce it.
 
Audible Clicking

Why not so easy?
1. Routing ground on PCB in a right way.
2. Recalc all Res values to make Rin and Rout lower down to 600 Ohm (for example)
3. Use RC circuit for each relay (for coil contacts)
4. Make a delay for relais switching (if you have a source code)
5. Avoid capacitive load (I think this is the hardest part of this problem)
 
In the design of the RelaiXed2 this effect was significantly lowered by:
●having a PCB ground shield between the digital relay control lines and the audio circuits on
top
●using 5V relays, instead of the otherwise probably more desirable 12V relays. Still, the effect
still remains.

So if it is so easy then why "the effect still remains"? And this man was an engineer by Philips, so if he cannot solve this problem ,then it must be very hard to solve.
 
how did you manage the time when you increasing or decreasing the volume and the other functions.

My problem is when i increasing or decreasing the volume, the clock is show up between the numbers, when the rc5 remote control sends a low pulse.

this is the subroutine for the Time:
Sub Datetime:
Do
Locate 1 , 5
Lcd Time$
Locate 2 , 5
Lcd Date$
Waitms 1
If Command > 128 Then
Exit Do
End If
Goto Begin
Loop
End Sub
 
In my preamp the clock is shown only when in standby mode.
But in your case you must do some code optimisation.I need to see the complete code or the whole main loop to say you exactly how to do it.This is only one procedure which is called and there are also other procedures wich interfere with it.
This procedures and commands are executed one after another.
But I'm not experienced in this language.
Maybe you must simply change the order of execution and the problem disapears.
 
Well,
today I soldered relay board and wrote some BAS-code for R/2R VC, only vol up/dn, on/off and input sel subs, connected each other and started testing about audible clicking.
I can say that I heared only ONE click at -31dB in full range (from -127dB to 0dB) but only when volume does UP from -32dB.
When volume goes down from -30dB to -32dB - no click.
Then I solder WIMA-0.1 on signal input and that click is disappeared (may be a little bit DC were in audio channel).
Now I have R/2R clicks-free VC...