D-LA2A Support Thread

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drgrateful

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Mar 31, 2010
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Hi Volker,

Happy New Year and thanks for your help!

I am about to wire the xlr connectors to the board. From the pictures posted, I see that people use different solutions here: some use three wires twisted together, others use shielded two-conductor wire, with shield going to pin 1 and connected both to the XLR connector and the PCB. You seem to have used a three-conductor wire (at least this is what I think from the pictures of your build). Is there a preferred way to go here?

Thanks, Matteo
 

[silent:arts]

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Hi Matteo,

yes, I used shielded cable and connected the shield at the XLR and PCB side.
not the way I do it normally.

each audio channel on the PCB has its own ground connector,
directly located next to the "input" Molex.
 

telefunk

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Feb 16, 2010
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Hi everybody.

Just finished my D-La2a. Used Edcor 600:15k and 15k:600 transformers and Kenetek T4b's. Everything worked really nicely immediately but there is only one problem: I NEED MORE INPUT GAIN! It works nicely when i put both channels in series, then i get fantastic compression.

What can i do to increase the input gain? Other than change the input transformer...And yes, i already adjusted the Lim Resp to full.

And other thing: why isnt everybody taking the power for the 12v VU lamps directly from the 10v AC of the Rondo Transformer?

Oh, and btw, thanks Volker! You get my full respect for doing this! Thanks!

 

Randyman...

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What are you driving the LA2A with?  (What's the preamp sending out level-wise?).  

My Edcors should be here soon (same ones as yours) - so I hope this isn't an issue with these particular transformers in the D-LA2A (seems to work fine for others - including Azone and his fantastic BOM  :D ).  Do you have the taps wired correctly?  I know all of my pre's can spit out +26dBu to +30dBu or more - so I don't think level will be an issue on my side  ;)


8)
 

telefunk

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I do have HUGE amounts of output gain but not enough input gain to get enough compression.

I feed the La2a inserted to my Harrison console that has nominal level of -6dBm. (channel insert point)

Can the Rondo Transformers 10Vac take also two 12v VU lamps?
 

[silent:arts]

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my first guess: compression potentiometer is wired wrong.

telefunk said:
Can the Rondo Transformers 10Vac take also two 12v VU lamps?

if the "In/Bypass" works everything is fine on this side.
it is 9V btw, feeding the 5V "utility PSU".
however, it is not in the audio path.
 

telefunk

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When i turn the gain pot i get more output gain, not input gain!

I other words, turning the Gain pot I do not get more compression...

is there something wrong?

EDIT: sorry did you mean the peak reduction pot?
 

Biasrocks

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I'm not familiar with this build, but the High Frequency compensation and Stereo Balance pots will affect the threshold.

Make sure they are fully clockwise to start.

Mark
 

telefunk

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SOLVED!

I had my stereo adj trim pot wrong way around. So, when i turned it fully counter-clockwise, it started to work.But it seems to make difference even when not in stereo link mode?!?!
 

drgrateful

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Hi everybody.

In my Rondo transformer I also have a yellow-green wire coming out of the transformer. I can't see it in other people's builds (the other wires are exactly as those in Volker's build: see http://www.silentarts.de/DIY/D-LA2A/IMG_3981.jpg). Should this yellow-green wire be connected to the star ground?

Thank you, Matteo
 

electrisizer

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Dec 26, 2008
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germany near frankfurt
hey there  :)

one question... im in wiring action right now...

do you have original shilded molex pin cables (the grey ones in pic above) or do you cut the original molex and solder them with shilded cables together?

if there are some original shilded molex cables please give me an (german) ordering source...
 

electrisizer

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Dec 26, 2008
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thanks volker!

and another question i fired the unit up and voltages are ok but i dont find a source for t4 voltages...

the only thing i found says pin 5 is 7.5v - when i trim this value with RV 104/204 the NE2 glimmer goes out - is that right?
 

helterbelter

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Jan 26, 2006
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Zevenaar, The Netherlands
Hi all,

I "finished" my La2a about 6, 7, maybe more months ago. (yes, a D-LA2a board, but just one channel populated).

Back then I've tested it and it works, but it doesn't pass low frequencies. At that time I didn't have much time to continue searching for the mistake, and I kinda thought the Edcors (15k/600 and 600/15k) were to blame for the lowcut, but by now I think this isn't the reason.

I've read the whole thread again, looking for similar problems, but I didn't find any. Does anybody here have a clue what might be wrong ? I'm 99-100% sure there's no short somewhere, and all voltages measure fine. (I had another problem to solve earlier, so I already checked this stuff).
 
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