D-LA2A Support Thread

[[silent:arts]]

congratulations to all the new builds, welcome to the family
it is banner time ;D

... Finally i finish the two D-LA2A !!! (one is mine and the other i builded for my friend)
I have noticed two problems ...

I'm sure you will sort the last few issues out soon

... Here is my new baby. A new DLA2A is born and is sound very nice. I love this comp ...

I'm sure this love lasts long

Yes!!...it's working!  

8) 8) 8)

... My first tube project...and yes i felt a shock...so i was careful after that!...

you wanted to learn it the hard way? good to know you are still alive, stay careful in the future!

 

[creal]

thanks you Volker for this great compressor and the nice banner.
Now it's time to finish the PM670
Cheers
Cyril

 

[Audioman]

Thank you for the Banneeeeeeeeeeeer !!!
And obviously for the great support !!!
your collegue ;D ;D ;D ;D ;D ;D ;D ;D ;D
Fabio

 

[desol]

Thanks Volker.  8) Cool banner..

 

[desol]

taken from the UA Teletronix® LA-2A Manual:

Stereo Balance Adjust (RV103/RV203):
...
The interconnecting wire should be less than 2 feet in length and should be shielded.
...
To calibrate the units for stereo operation:
- Connect the units together as described previously.
- Turn the Peak Reduction knob counterclockwise (no compression).
- Set R3 on each unit to a clockwise position.
- Set each meter to read Gain Reduction.
- Adjust the Peak Reduction control on the left channel until approximately 5dB of gain reduction is achieved.
- Adjust R3 on the unit that shows the greatest amount of gain reduction until the gain reduction indications are equal.
- When operating, set the Peak Reduction controls to the same setting on both channels.

I'm stumped. Following this, i turn the trimmers on both channels(137 and 103) all the way clockwise and i get no GR dual or stereo..  :-\

 

[[silent:arts]]

I'm stumped. Following this, i turn the trimmers on both channels(137 and 103) all the way clockwise and i get no GR dual or stereo..  :-\

I don't know what can cause this but your RV103 works reverse ???

 

[desol]

:-\

 

[Borja Lopez]

Hi, this is my unit finished. We are using the compressor in our studio, one month ago, and it works fine, sounds great! 
Thanks Volker and thanks to all members of this forum!

 

[mativas]

Hi.



1. I am new in the league and i finishing to get the pieces for my D-la2a but i need to get the 22uF / 450V NICHICON> in the moser website  and the delivery times are very  very far  . So I need to know if you guys know  another  store that can have them in stock.. also I am watching these nichicon in ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200541624054&ssPageName=STRK:MEWAX:IT

these can eventually replace the 22uF / 450V NICHICON from the boom list? Has the same specs but these looks smaller than the cap in the mouser list.

2. already exists a replacement for the  WIMA POLYESTER 10nF / 630V cap? the people of mouser will be having it in stock in more than six months!! I have seen caps with the same specs in ebay but i don't  know if really will works with the project..


3. I am close to pay the order in tubedepot and I picked up four sovtek 12ax7 because Is the same tube used in mesaboogie and i like it. Is necessary to get it in matched pairs? or not matching pairs will be perform well?


THANKS FOR YOUR HELP.. THIS IS MY FIRST! ;D


Mativas.

 

[creal]

Hi mativas

I've order the caps at banzai
http://www.banzaimusic.com/home.php

3. I am close to pay the order in tubedepot and I picked up four sovtek 12ax7 because Is the same tube used in mesaboogie and i like it. Is necessary to get it in matched pairs? or not matching pairs will be perform well?

Maching pair is better but not matching perform well, if the tube are in good condition.
Make your test
Hope that helps.

Cyril

 

[mativas]

Maching pair is better but not matching perform well, if the tube are in good condition.
Make your test
Hope that helps.


Thanks Cyril  I will try not matching!!

any one can help me with this  issues?... thanks a lot!

1. I am new in the league and i finishing to get the pieces for my D-la2a but i need to get the 22uF / 450V NICHICON> in the moser website  and the delivery times are very  very far  Sad . So I need to know if you guys know  another  store that can have them in stock.. also I am watching these nichicon in ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200541624054&ssPageName=STRK:MEWAX:IT

these can eventually replace the 22uF / 450V NICHICON from the boom list? Has the same specs but these looks smaller than the cap in the mouser list.

2. already exists a replacement for the  WIMA POLYESTER 10nF / 630V cap? the people of mouser will be having it in stock in more than six months!! I have seen caps with the same specs in ebay but i don't  know if really will work with the project..

 

[[silent:arts]]

there are a lot of 22uF/450V caps in stock at mouser:
don't know if this link expires

 

[desol]

I found i had the pots wired incorrectly.  :  

Now it's compressing much more.. More like i was expecting, would be normal.

The way it was wired before it was just barely compressing, which is why it was hard to tell.
I'm getting more voltage off of the t4b now as well..

I'm working through the schematic, trying to see what else i've done....

 

[mativas]

there are a lot of 22uF/450V caps in stock at mouser:
don't know if this link expires

Thanks Volker.. I thought that  only the capacitors from the boom list will be doing the work.. In don't have experience in this kind of works...

So.  Should I Do the same for the  WIMA POLYESTER 10nF / 630V cap ?

 

[desol]

Volker, i just want to thank you again for offering this project. I've confirmed that everything is working as it should,
and it is compressing beautifully.

Awesome project.

 

[briomusic]

Nearly done with my DLA-2A: I have audio and lovely compression on both channels.

one of the NE2's has an intermittent fault and only lights up when I tap the PCB - probably best swap it for a spare one.

a bigger problem is the fact that the right channel meter is not showing any gain reduction. it works perfectly as a VU meter and can be biased to 0dB in GR mode but then the needle won't move. It's NOT the T4Bs fault (swapped with other channel) so that only leaves the R227 or a bad solder joint I guess? I did replace Rx25 with a trimmer but unfortunately it is mounted in a way that makes it very hard to adjust. Still this shouldn't lead to 'no movement at all from the 0 set' at any value should it?

Also I find the VU meter to be too sensitive, it shows 0VU at about -20dBFS. I would prefer -14dbFS or so. How do I make it less sensitive? Resistor in series or parallel to the meter?

Thanks Volker and everyone, can't wait to get the Frontpanel done and claim my banner  ;D

 

[Kingston]

NE2? if that's the neon, swap it for a 60-70V zener and enjoy metering that does not generate noise and lasts forever.

 

[briomusic]

What Wattage Zener? Is this one cool?
http://www.banzaimusic.com/62V-Zener-Diode-5W.html

cheers
Brio

 

[Kingston]

That'll work fine. A good idea to have it high wattage like 5W.

 

[Randyman...]

a bigger problem is the fact that the right channel meter is not showing any gain reduction. it works perfectly as a VU meter and can be biased to 0dB in GR mode but then the needle won't move. It's NOT the T4Bs fault (swapped with other channel) so that only leaves the R227 or a bad solder joint I guess? I did replace Rx25 with a trimmer but unfortunately it is mounted in a way that makes it very hard to adjust. Still this shouldn't lead to 'no movement at all from the 0 set' at any value should it?

So your CH2 does compress, but doesn't show any GR on the meter?  I have a similar issue and can also "zero set" the meter, but I'm not getting any actual compression on CH 2 (passes audio, slightly distorts when Peak Reduction is dimed but no GR to speak of).  I re-flowed all tube and T4B solder joints, and swapped tubes and T4's between channels.  Ch 2 still won't compress.

If I link the channels, Ch2's Peak Reduction does have an effect on Ch 1's GR, so it appears I'm getting sidechain audio through the Ch 2 detector (that I can tell).

Any further clues on what to check next?  I've been stuck here for over a month now - I'm somewhat timid around high-voltage and don't mind taking this as slow as I need to.


Also - On the Neons - Is it generally recommended to replace them with the Zeners mentioned above?  Will a zener really make these units quieter and more reliable?

Thanks for any input  8)