Dual La2a - [silent:arts] version

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Postby jcpanizza » Thu Jul 21, 2011 12:15 pm

Hi,

I am a new member on this forum and i've been making diy audio stuff for4 years.
I've started to build a d-LA2A with volker's board and i'm almost finished.
My unit is wired and I made some tests last week, everything works fine except there is no peak reduction at all.

I'm wondering if my drip 'T4b' could be faulty? because the same thing happens if the t4b is out of the board. I opened one of my drip t4b to look inside but i'm not sure what it should look like.

any thoughts?
jcpanizza
 
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Postby jensenmann » Thu Jul 21, 2011 1:11 pm

Did you try to swap both T4Bs? Does it happen in the second channel, too?
Check the PCB fpr solderblobs again.
Jens
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Postby jcpanizza » Thu Jul 21, 2011 1:45 pm

it happens on both channels so i didn't try to swap both T4B's. I tried to run the unit without T4B's and the same thing happens (obviously!).
I'll double check my PCB.
thx for your answer ;)
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Postby jensenmann » Thu Jul 21, 2011 1:53 pm

bypass wired wrong?
Jens
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Postby jcpanizza » Thu Jul 21, 2011 2:13 pm

The bypass is fine, i measured it and i can hear it too because de "gain" control works fine on both channels.
I also checked the "link" molex's as i was not sure how to wire it.

Now i am checking all the gain reduction stage looking for mistakes on my build...
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Postby [silent:arts] » Thu Jul 21, 2011 2:28 pm

disconnect the stereo link first.
if wired wrong no gain reduction will ever happen.

RV 103 / 203:
try it at both extreme settings (clockwise / counterclockwise)
volker
olafmatt wrote:Strom kann tot machen
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Postby jcpanizza » Thu Jul 21, 2011 3:08 pm

i just disconnected both "stereo links"
now i have peak reduction on channel right!

the left channel is still not compressing though. and it has a little hum (right channel is hum-free)

i tried what volker said about RV 103 & 203, but there is no difference.
I'll try to find mistakes in my build, i guess it will be easier now that i have a working channel.

thx for your help guys!
jcpanizza
 
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Postby jcpanizza » Thu Jul 21, 2011 3:37 pm

I just noticed something else:
when I power up my unit with the meter in GR mode, le left channel vu meter indicates a "negative" gain reduction (+3 dB) for about 15 seconds and then it goes back to 0... the right channel (the one that is working perfectly) stays to 0 when i power up the unit.

Does this give you any idea?

I just finished checking my board for solder bridges or missing solder and everything looks fine to me... i'll keep looking!
jcpanizza
 
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Postby [silent:arts] » Fri Jul 29, 2011 9:43 pm

doesn't sound like a problem, but might be the neon lamp
volker
olafmatt wrote:Strom kann tot machen
[silent:arts]
 
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Postby jcpanizza » Fri Aug 12, 2011 4:08 pm

Hi Volker, thx for your answer.
The Neon lamp is shining, does this mean it works normally?
I'm gonna see if I have a spare neon lamp in my stock and replace it.
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Postby Organisator » Mon Nov 14, 2011 8:26 pm

Darf ich hier auch auf Deutsch schreiben?

Ich habe statt der Neon Lampen 62 V Zener Dioden geholt, allerdings sind die zu dick für die Durchkontaktierung.
Aufbohren geht da ja schlecht, mir fällt sonst aber nur ein einen dünneren Draht z.B. Reste von Widerständen dran zu löten.
Spricht da was gegen?
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Postby [silent:arts] » Mon Nov 14, 2011 8:53 pm

Organisator wrote:Darf ich hier auch auf Deutsch schreiben?

eigentlich nicht, aber machen andere ja auch.

Organisator wrote:Ich habe statt der Neon Lampen 62 V Zener Dioden geholt, allerdings sind die zu dick für die Durchkontaktierung.
Aufbohren geht da ja schlecht, mir fällt sonst aber nur ein einen dünneren Draht z.B. Reste von Widerständen dran zu löten.
Spricht da was gegen?

fällt mir nichts ein (aber was für Zener hast Du denn? 10W???)
volker
olafmatt wrote:Strom kann tot machen
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Postby Organisator » Mon Nov 14, 2011 9:16 pm

Ist ne 5 W/62 V Zener.
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Postby [silent:arts] » Mon Nov 14, 2011 9:22 pm

5W hat dickere Drähte, richtig.
5W braucht es aber auch nicht.
Nur zu.
volker
olafmatt wrote:Strom kann tot machen
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Postby Organisator » Mon Nov 14, 2011 10:50 pm

1,3W reicht auch?
Dann hole ich mir lieber neue Zeners als ne Frickellösung zu machen.
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