Ok, I'll go the lazy way 
It was doing fine with the ACA, so probably/hopefully will behave with others...
In the meantime, I'll spend the time with mechanics (mounting the pots, heatsinks etc.)... instead of finally take the deep plunge and work on the AVC... which I still feel not confident/thought through.
It was doing fine with the ACA, so probably/hopefully will behave with others...
In the meantime, I'll spend the time with mechanics (mounting the pots, heatsinks etc.)... instead of finally take the deep plunge and work on the AVC... which I still feel not confident/thought through.
Just another question:
I'm configuring my build with 2 led: a power-indicator, and channel-indicator. This will be done through the second channel of the rotary-switch (just like you laid out in the i-select docs...).
Is there a better way than feeding both leds from the power-indicator-led? Like, feed the pwr-indicator and channel-indicator-led with its own 2K2 resistor? ...
Thank you again!
I'm configuring my build with 2 led: a power-indicator, and channel-indicator. This will be done through the second channel of the rotary-switch (just like you laid out in the i-select docs...).
Is there a better way than feeding both leds from the power-indicator-led? Like, feed the pwr-indicator and channel-indicator-led with its own 2K2 resistor? ...
Thank you again!
The 2k2 power LED feeder resistor on the DCB1 pcb gets voltage from the local 7812 reg rail. The input position LEDs if engaged are fed voltage from the 7812 reg on the I-Select pcb. Better don't use a common power on LED's feed and input position LEDs feed. Just adjust the 2k2 power LED limiting resistor value for equal brightness with the input position indicator LEDs.
Dear Salas
I'm not sure wether I'm good:
DCB1 turn on, all LEDs are lit.
Can't hear the relays on power-on, switching channels is good, and some 3 seconds after turning it off it clearly clicks
I first measured a DC-offset 1.1VDC and 0.7VDC (*), but now—after a few measurement at TP / across the 18r it's 0.00 and doesn't move...
I'm measuring at TP 9.75V / 9.82V
Voltage drop at 18r 1.67V / 1.35V
...
What do you think?
*) [EDIT: I am really not sure about the DC-offset I was able to measure, as my first thinking was "a little highish but still ok", but I didn't write it down]
I'm not sure wether I'm good:
DCB1 turn on, all LEDs are lit.
Can't hear the relays on power-on, switching channels is good, and some 3 seconds after turning it off it clearly clicks
I first measured a DC-offset 1.1VDC and 0.7VDC (*), but now—after a few measurement at TP / across the 18r it's 0.00 and doesn't move...
I'm measuring at TP 9.75V / 9.82V
Voltage drop at 18r 1.67V / 1.35V
...
What do you think?
*) [EDIT: I am really not sure about the DC-offset I was able to measure, as my first thinking was "a little highish but still ok", but I didn't write it down]
Attachments
Last edited:
DC offset you measure at each signal output RCA between center and barrel. It must not be more than 5mV is our spec. Use the DCmV range of your meter.
Rails look good nearing the 10V goal and close enough together. Drops across each 18R parallel pair suggest 185mA and 150mA i.e. certainly more than enough spare current is created in the master constant current sources.
To check if the output relay does its job see whether a couple of seconds are passing until DC offset appears i.e. it engages with a delay after power on. Since inputs are selected the other relays surely do their job.
Rails look good nearing the 10V goal and close enough together. Drops across each 18R parallel pair suggest 185mA and 150mA i.e. certainly more than enough spare current is created in the master constant current sources.
To check if the output relay does its job see whether a couple of seconds are passing until DC offset appears i.e. it engages with a delay after power on. Since inputs are selected the other relays surely do their job.
I repeated the measurements today, but with the uotput-wire disconnected:
Offset is
R ≈ 1.5mV
L ≈ 0.4mV
So it looks the switch or the connection switch to plugs is fishy (it was a struggle and it’s continuities are weird. Removing this now)
Here’s the drawing for the front-plate just because I like its „proportions study“
Today was a not good day.
I had 2 minor issues and still have them!
The more serious issue after the gossip part...
// ===================== GOSSIP =====================
Issue 1: the last LED, a blue one, does not light up when it should. I checked everything, the led is placed correctly, and when I check it with the DMM in Diode-mode, it lights up just like the others in the row. (Connection is as in post #2785 ). I remade the connectors, all connections and wiring seem good (measures continuity, led lights up when checked w/ DMM from every accessible junction/connection ... it goes on every time EXCEPT through the selector-thing. headbonker!
Issue 2: I went for a switched 2 output-config. All went fine, looked good, measured good, so I put everything in place, plugged it in, played some music—nothing. Argh. (Coffee + other sedatives needed by then). So I accepted my faith, unsoldered the switch, hardwired one output, replugged everything and played music again—nothing.
...
NO WONDER, AS THE POT WAS ZEROED!
Headbonkers 2. Ok, played around a little bit, and realized the channels aren't activated in line with the switch-positions, but it is playing. IT IS PLAYING!
===================== GOSSIP ===================== //
Then I possibly made a more serious mistake: As I wanted to find out the channel's switch-positions, I forgot to turn off DCB and hot-unplugged a connector (the 3 pole connector on the board) and this (I believe) kinda muted the output. Again, I'm not sure what happened, but I believe the output-relais does not turn back on...
Had to stop here anyway, so no real music-joy today.
In the meantime, if you (or anyone else) have a hint for me, I'm very grateful.
TBC...
I had 2 minor issues and still have them!
The more serious issue after the gossip part...
// ===================== GOSSIP =====================
Issue 1: the last LED, a blue one, does not light up when it should. I checked everything, the led is placed correctly, and when I check it with the DMM in Diode-mode, it lights up just like the others in the row. (Connection is as in post #2785 ). I remade the connectors, all connections and wiring seem good (measures continuity, led lights up when checked w/ DMM from every accessible junction/connection ... it goes on every time EXCEPT through the selector-thing. headbonker!
Issue 2: I went for a switched 2 output-config. All went fine, looked good, measured good, so I put everything in place, plugged it in, played some music—nothing. Argh. (Coffee + other sedatives needed by then). So I accepted my faith, unsoldered the switch, hardwired one output, replugged everything and played music again—nothing.
...
NO WONDER, AS THE POT WAS ZEROED!
Headbonkers 2. Ok, played around a little bit, and realized the channels aren't activated in line with the switch-positions, but it is playing. IT IS PLAYING!
===================== GOSSIP ===================== //
Then I possibly made a more serious mistake: As I wanted to find out the channel's switch-positions, I forgot to turn off DCB and hot-unplugged a connector (the 3 pole connector on the board) and this (I believe) kinda muted the output. Again, I'm not sure what happened, but I believe the output-relais does not turn back on...
Had to stop here anyway, so no real music-joy today.
In the meantime, if you (or anyone else) have a hint for me, I'm very grateful.
TBC...
Good evening Salas and all listening friends
It’s good you ignored my previous post—it’s not as bad as I thought, DCB1 is playing as it should.
Problem was I lost control, because I just messed up the channels (1 is not one and the LEDs aren’t in the same order etc.). So the only things I have to o is redo the output-switch, and sort out is the sort order for the used channels and the corresponding leds. And a non-working led as a little bonus.
Apologies for my previous wining, you may shake your heads upon me!
It’s good you ignored my previous post—it’s not as bad as I thought, DCB1 is playing as it should.
Problem was I lost control, because I just messed up the channels (1 is not one and the LEDs aren’t in the same order etc.). So the only things I have to o is redo the output-switch, and sort out is the sort order for the used channels and the corresponding leds. And a non-working led as a little bonus.
Apologies for my previous wining, you may shake your heads upon me!
Thank you,Salas.
Already thought it would go this route. But since this is a position I don't even use in the moment (could accommodate a Jack input from the front or something like this), I swapped it with another red one. Less hassle. (might have been different if I'd added a USB-DAC or something, but just a fourth input ...)
Already thought it would go this route. But since this is a position I don't even use in the moment (could accommodate a Jack input from the front or something like this), I swapped it with another red one. Less hassle. (might have been different if I'd added a USB-DAC or something, but just a fourth input ...)
DCB1 is up and running!
It is doing very well, connected to ZM's Old Soul (and kef 101.2). Very transparent, very "punchy"
There's something not perfect though: the output relay seems to be very sensitive and has sort of a behavior: It doesn't trigger on turn-on, but after a few seconds and switching outputs output is here. But after ~20 minutes it went mute. This was 10 minutes ago (more or less) and after a turned-off pause it did not come back. Bummer. Back to the bench.
It is doing very well, connected to ZM's Old Soul (and kef 101.2). Very transparent, very "punchy"
There's something not perfect though: the output relay seems to be very sensitive and has sort of a behavior: It doesn't trigger on turn-on, but after a few seconds and switching outputs output is here. But after ~20 minutes it went mute. This was 10 minutes ago (more or less) and after a turned-off pause it did not come back. Bummer. Back to the bench.