D-LA2A Support Thread

[offthewallstudio]

Anyone know the value of the resistor for the vu meters?  3.6k but how many watts mouser part number?

 

[[silent:arts]]

1/4W is fine

 

[offthewallstudio]

1/4W is fine

thank you so much Volker. Radio Shack here in the United States is a local store the only thing that carry is 3.3 K resistor quarter Wat. Now if this is going to do anything that the device that  it shouldn't do I would have rather spend the money on shipping in order through mouserr but if this one works perfectly fine I will get it either which way I would like to know your professional calling this Thanks

 

[offthewallstudio]

just about done with the device although I have one wire here from the transformer power that is yellow with a green stripe its not connected to anything where does this go? I cannot seem to figure it out thanks it is the sowter transformer

 

[saxmonster]

Usually that color is ground check the sower schematics

 

[troubleous]

Hello Volker and everybody on the board!

I'm finishing my build here (enjoying it a lot by far + learning loads of things while I go) and everything is working soundwise.

I have only one peculiar meter related problem: I can't get the zero adjust calibrated (on zero) on neither on the meters. No matter of how and what I adjust, it stops at pointing "1" on the left of zero.  I have neon bulbs installed (will replace with zeners as soon as they arrive) and I have installed 100k trimpots on R125/225 position. Also installed 3.6K resistors on meters.

Otherwise the unit & the meters seem to work fine, pulsing nicely with music and also registering peak reduction as supposed.

Does anyone have any idea what could be the culprit here? I went through all the resistors twice and found no wrong ones installed (did the same with capacitors, and all seem to be correct). Maybe this is some very stupid wiring mistake that I am having, but I just can't figure out what and where to look at.

Cheers and thanks in advance!
/Jarkko

PS. Thanks for all fellow builders who have been posting and asking and suggesting! Made my journey by far a blast

 

[offthewallstudio]

Hello Volker and everybody on the board!

I'm finishing my build here (enjoying it a lot by far + learning loads of things while I go) and everything is working soundwise.

I have only one peculiar meter related problem: I can't get the zero adjust calibrated (on zero) on neither on the meters. No matter of how and what I adjust, it stops at pointing "1" on the left of zero.  I have neon bulbs installed (will replace with zeners as soon as they arrive) and I have installed 100k trimpots on R125/225 position. Also installed 3.6K resistors on meters.

Otherwise the unit & the meters seem to work fine, pulsing nicely with music and also registering peak reduction as supposed.

Does anyone have any idea what could be the culprit here? I went through all the resistors twice and found no wrong ones installed (did the same with capacitors, and all seem to be correct). Maybe this is some very stupid wiring mistake that I am having, but I just can't figure out what and where to look at.

Cheers and thanks in advance!
/Jarkko

PS. Thanks for all fellow builders who have been posting and asking and suggesting! Made my journey by far a blast

hey there. Id love to help you. I need to get my vu working.  I need to find out how to wire the LED  + -  part. Could you post a few photos of yours and maybe a run down on how you did it? Ill then trace my work and see if i can help
Thanks!

 

[offthewallstudio]

and here is a shot of the pots them selves, you can see also the VU meter with the 3k6 wired up and the gain pot is the 25k/75k mod

hey looks great! how did you connect the LED part? i cant seem to get it right. pls help!

 

[offthewallstudio]

I took a quick pic of mine that I finished a few months back.  I built it to be more of a buss comp but I have found it works just as well as my other LA 2A for tracking.  I really like this compressor.  Great sound and great build.

I did stepped gain switches, and a few other nice little mods.  The center switches are a stereo attenuator (0, -2, -4) and the other two toggles are 3 positions with different output load resistors.  Thanks everyone for your help!

hey looks great! i have the same set up as u. 2 questions for you. the vu meters. the LED  +- part. how did you wire yours and also the fender light amp. how did you wire that up? i am haveing trouble with those 2 and then im done!!!

 

[offthewallstudio]

The VU Meters are rated at 3.6v-5.2v 20mA (Hairball Audio Meter). I also get the relays ticking over of there own free will when i have the VU meters LED connected and i have been working the compressors for a while.

have other people taken the 5v for their VU Meter LED's from the 5v supply on the board that is meant for the relays?

hey there i am in the same boat now. how did you end up wiring your LED on the vu?

 

[Rocinante]

Your relays are only a tad bit on the high side.  Throw a resistor in between if its too much for your liking.  Daisy chaining them to end at an indicator led is what I did. Still a bit bright so ill probably bump up the resistor a tad.

 

[troubleous]

hey there. Id love to help you. I need to get my vu working.  I need to find out how to wire the LED  + -  part. Could you post a few photos of yours and maybe a run down on how you did it? Ill then trace my work and see if i can help
Thanks!

Hey again! Of course, being a newbie, I forgot to mention that I haven't either figured out the meter leds + pilot light part yet myself. I tried daisy chaining leds + resistor on the +5V relais output, but the leds (no matter what combination I tried) are too dim to be used. Tried all kinds of things from 5V ultra bright white ones to regular red and yellows. By far nothing works.  I feel stupid

/Jarkko

 

[offthewallstudio]

hey there. Id love to help you. I need to get my vu working.  I need to find out how to wire the LED  + -  part. Could you post a few photos of yours and maybe a run down on how you did it? Ill then trace my work and see if i can help
Thanks!

Hey again! Of course, being a newbie, I forgot to mention that I haven't either figured out the meter leds + pilot light part yet myself. I tried daisy chaining leds + resistor on the +5V relais output, but the leds (no matter what combination I tried) are too dim to be used. Tried all kinds of things from 5V ultra bright white ones to regular red and yellows. By far nothing works.  I feel stupid

/Jarkko

dang

 

[troubleous]

hey there. Id love to help you. I need to get my vu working.  I need to find out how to wire the LED  + -  part. Could you post a few photos of yours and maybe a run down on how you did it? Ill then trace my work and see if i can help
Thanks!

Hey again! Of course, being a newbie, I forgot to mention that I haven't either figured out the meter leds + pilot light part yet myself. I tried daisy chaining leds + resistor on the +5V relais output, but the leds (no matter what combination I tried) are too dim to be used. Tried all kinds of things from 5V ultra bright white ones to regular red and yellows. By far nothing works.  I feel stupid

/Jarkko

dang

I'm guessing this is some kind of grounding issue (?) - when I measure voltage on the 7805, the leds get brighter (when touching the voltage regulator with multimeter).

Otherwise the voltages around the board seems to fine. The relais output that I'm using for the leds is giving me around 5.5V at the moment, yet I can't make my leds bright.  Dang Dang

Hopefully someone with better brain cells tells us what is the obvious problem...

/Jarkko

 

[Rocinante]

Check your connections. I used hairball tn-73 meters and its the same suggestion in the thread given by a few people. It's a tight fit in there so it took me a minute to make a good connection. I believe I went to ground with "-".

 

[[silent:arts]]

The 5V PSU isn't connected to ground on the PCB, it is floating.
No problem if you connect the Meter / LEDs / Relais to the + and - from this PSU.
If you connect the - from the LEDs etc to ground somewhere else make sure to set the jumper on the PCB

 

[offthewallstudio]

hey there. Id love to help you. I need to get my vu working.  I need to find out how to wire the LED  + -  part. Could you post a few photos of yours and maybe a run down on how you did it? Ill then trace my work and see if i can help
Thanks!

i just got some notes:



Stereo Link Switch

    Use yellow Mogami cable.
    Wire a 2 pin Molex connector to attach to the “Stereo Link” connector on the left channel of the PCB: Looking at the board with the front of the case facing you (as shown on page 7 of the PDF), strip back the shield of the Mogami cable and wire the right pin of the Molex connector to the copper drain wire and the left pin to the red wire. Leave the clear wire unconnected (making sure it doesn’t short to the red wire).
    The Mogami wire should be long enough to reach the Stereo Link switch on the front panel.
    Cut the other end of the wire, leaving it unterminated.
    Follow steps 2-4 to prepare an identical cable for the right channel.
    Looking at the Stereo Link switch from the back (as shown in the picture you texted to me), you will want to use the left pin of the middle row and the left pin of the bottom row. The top pin on the bottom row and all three pins on the right side will be unconnected.
    Connect the red wire from the left channel Mogami cable to the left pin in the middle row of the switch. Cut back the shield and leave the copper drain wire unconnected (and make sure they don’t short to the switch).
    Connect the red wire from the right channel Mogami cable to the left pin in the bottom row of the switch. Cut back the shield and leave the copper drain wire unconnected (and make sure they don’t short to the switch).


5V Relay Hookup

    Wire a 2 pin Molex connector with regular, single-connector wire to attach to the “relais” connector on the far right of the PCB.
    Crimp two black wires (or another color, just be consistent) to the top pin of the far right Molex connector, as shown of page 7 of the PDF. One black wire should be long enough to reach the right channel “Relais” connector with a little slack and the other should be long enough to reach the left channel “Relais” connector with a little slack, as shown on page 7 of the PDF.
    Do NOT wire either the left or right channel “Relais” Molex yet; just cut the wire to length.
    Crimp two red wires (or another color, just be consistent) to the bottom pin of the far right Molex connector, as shown of page 7 of the PDF. One red wire should be long enough to reach the right channel Bypass switch with a little slack and the other should be long enough to reach the left channel Bypass switch with a little slack, as shown on page 7 of the PDF.
    Wire the right channel “Relais” Molex connector. The black wire on the top pin will come from the far right Molex connector, as shown on the PDF. The red wire on the bottom pin should be long enough to reach the right channel Bypass switch.
    Wire the right channel Bypass switch. Use an SPDT switch (this is the kind with three terminals). The middle terminal will be attached to the red (i.e. bottom) wire from the right channel “Relais” Molex connector, as shown on the PDF. The bottom terminal will be attached to the red (i.e. bottom) wire from the far right “Relais” Molex connector, as shown on the PDF. The top terminal is left unconnected.
    At this point, we will diverge from the wiring shown on the PDF.
    Wire the left channel “Relais” Molex connector. The red wire will go to the bottom pin of the Molex, as shown on the PDF, and should be long enough to reach the left channel Bypass switch.
    However, TWO black wires will be attached to the top pin of the left channel “Relais” Molex connector. The first will be the black wire from the far right Molex connector, as shown on the PDF. The second will be another black wire, which will be long enough to reach the “LED -“ terminal on the LEFT VU meter.
    Wire the left channel Bypass switch. Use a SPDT switch (this is the kind with three terminals). The middle terminal will be attached to the red (i.e. bottom) wire from the left channel “Relais” Molex connector, as shown on the PDF. The bottom terminal will be attached to the red (i.e. bottom) wire from the far right “Relais” Molex connector, as shown on the PDF. However, ALSO attached to the bottom terminal of the switch will be a red wire that is long enough to reach the “LED +” terminal on the LEFT VU meter. The top terminal of the switch is left unconnected.


VU Meter LED Hookup

    Solder two black wires to the “LED -” terminal on the left VU meter. One black wire will be the second, unused black wire from the left channel “Relais” connector. You will also solder another black wire that is long enough to reach the right VU meter to the “LED -“ terminal on the left VU meter.
    Solder a 100 or 150 ohm resistor (or similar, could be from 100 to 200 ohms) to the “LED +” terminal on the left VU meter.
    Solder two red wires to the other end of this resistor. One will be the red wire from the bottom terminal of the left channel bypass switch. The other red wire will be long enough to reach the right VU meter.
    Solder a 100 or 150 ohm resistor (or similar, could be from 100 to 200 ohms) to the “LED +” terminal on the right VU meter.
    Solder the black wire from the “LED -“ terminal on the left VU meter to the “LED -“ terminal on the right VU meter.
    Solder the red wire from other side of the resistor attached to the “LED +” terminal on the left VU meter to the other side of the resistor attached to the “LED +” terminal on the right VU meter. Basically you should have 5 volts, which comes from the red wire attached to the bottom terminal of the left channel bypass switch, going to the “LED +” terminal of both VU meters, each passing through a resistor before hitting that terminal on the VU meter. (The resistor prevents the LED from drawing too much power and burning out.)

Hey again! Of course, being a newbie, I forgot to mention that I haven't either figured out the meter leds + pilot light part yet myself. I tried daisy chaining leds + resistor on the +5V relais output, but the leds (no matter what combination I tried) are too dim to be used. Tried all kinds of things from 5V ultra bright white ones to regular red and yellows. By far nothing works.  I feel stupid

/Jarkko

dang

I'm guessing this is some kind of grounding issue (?) - when I measure voltage on the 7805, the leds get brighter (when touching the voltage regulator with multimeter).

Otherwise the voltages around the board seems to fine. The relais output that I'm using for the leds is giving me around 5.5V at the moment, yet I can't make my leds bright.  Dang Dang

Hopefully someone with better brain cells tells us what is the obvious problem...

/Jarkko

 

[dmp]

I've powered mine up and it has a significant mains hum.
I think I grounded according to the recommendations.
I connected a separate 5v supply on the relays and when I turn off the mains power, the noise disappears and the audio is transmitted without flaws for a few seconds until the tubes power down (gain works, etc).
Could it be transformer proximity? PSU is Rondo, OT is Edcor, IT is Jensen JT-11.
Note I had the transformer mounted to the side - in the picture I unbolted it and laid it down. No change to the hum by changing the orientation.
Ideas?

 

[[silent:arts]]

I see a lot of unshielded wires next to the mains switch ...
Unmount the mains switch from the front and move it outside, or next to the PSU transformer - better?

 

[dmp]

I'll try that and report back.
I will  put in shielded wire to the pots and stereo link too