LA-4 Help Thread!

[mac]

Does anyone have the physical dimensions of the PCB ?

Cheers. 

Mac

 

[culteousness1]

See Reply #190:

Eurocard: 160 * 100 mm

Distance between holes: 150mm and 90 mm
The holes are roghly 5 mm from the edge.

I would wait to get the cards before drilling though...

Best,
Carsten

 

[atticmike]

anybody got an la3a in their studio and was able to compare those units with each other?

Mike

 

[gyraf]

..la3 and la4 are very different beasts...

Jakob E.

 

[mac]

I just re-read this thread and I know that through much trial and error, the consensus is that the VTL5C4/2 is the way to go.... But here in Aus, two of these will cost me $70 delivered...(here's hoping they perfectly match for stereo pair!)....

Is there a general "second best" option....NSL32 I am guessing?

Mac

 

[dirtyhanfri]

http://es.farnell.com/jsp/search/productdetail.jsp?id=1652520

4€ each

 

[culteousness1]

http://es.farnell.com/jsp/search/productdetail.jsp?id=1652520

4€ each

Yes, but mac is in Australia:

http://au.element14.com/excelitas-tech/vtl5c4-2/no-of-channels-1/dp/1652521?Ntt=VTL5C4/2

So, 28 Aus$ each...

 

[mac]

Hey guys,
How many of you with working units actually find yourself changing the input range (pad) switch?

I am making up my mind if it needs to be on the front panel or on the rear like the original.

Or perhaps with modern signal chains it it unnecessary and I can just jumper on the board to the low position and be done with it?? I know there is a chance for noise here and particularly as my recycled enclosure will need longer wire runs I am considering just an internal Jumper.

Keen to know how often you need to flick the switch?

Mac

 

[dirtyhanfri]

I Always have it in Low position. Both In tracking or mixing, (feeding it from the output of a mic pre or a DA)

 

[mac]

Anyone else have any experience to share???

;D

Mac

 

[ilfungo]

Hi
I use high position sometimes for some strange distorted drums....
Ciao

 

[shredup]

Hi

I built 2 LA4, they're sounding very, very good, but I've still got 2 problems:

- The panel meter displays only GainReduction, but not +4 or +8... I checked 50 times the wiring, all's good. Any idea???
- When I switch the stereo link, the fuse blows !!! My transfo is a 2x18V-30VA and fuse is 375mA. I'm using one PSU for two LA4... Any idea too ???

Thanx

Mathias

 

[shot]

I have just built 3 units!
They're still on the bench, not racked but...
They all pass signal, they compress, no hum or anything, they respond good to calibration!
Though I did not go through a real calibration procedure.
But they all work! Yesss! They all work without a glitch!

Now I'll have to build them an enclosures, front panels, mount them into their enclosures, sort some messy wiring and calibrate them.
More fun! hehe!

me happy!


I'll put two LA4 in a single enclosure and try to calibrate them to be able to work in a linked mode (read that it's tricky to calibrate stereo operation... keep my fingers crossed).
For the third one I was thinking to do a few mods.
First I'll try to replace R13 resistor (timing resistor) with a 100K fixed value plus 100K linear pot. Maybe it will work as a timing potentiometer and provide some variable attack/release times! Had this just as an idea. I'll have to check if it actually works.
And the second thing I was planning to do is to combine it with Studer 169 EQ (audiox's project). My idea was to install it right before LA4's transformer and calibrate EQ's makeup gain to fit LA4's 1:2 transformer. Of course, EQ would have it's own bypass.
In next weeks or months, when I have spare time, I'll try it... we'll see if it'll work...

Anyway,
Gigantic THANK YOU goes to Luny for making this project possible!
And thanks to Davo for posting very easy to read wiring diagram!
And all others on this thread that contributed with very valuable information!


me happy!

 

[sage]

I finally put my Stereo LA4 in the rack and realized after a test that the unit was outputting signal OUT OF PHASE - Obviously I checked my XLRs and the PAtchbay but INDEED it was the UNITS _ so....

IF YOU ARE USING A CINEMAG CMOQ-2S OUTPUT TRANSFORMER THIS IS the correct wiring:

YELLOW to + on PCB FROM TRANSFORMER
BROWN to - on PCB FROM TRANSFORMER
GREY to + TO TRANSF.
GREEN to - TO TRANSF.
ORANGE and RED connected TOGETHER to each other
VIOLET and BLUE connected TOGETHER to each other

ALWAYS CHECK YOUR PHASE !!!!

sage

 

[sage]

Finally me and Marson put up in the studio the gear built in the past few months and here is a FB page with pictures, thanks to all on this Forum that have helped with these great projects:

http://www.facebook.com/marsonaudio

sage

 

[Greg Dixon]

Finally got around to finishing mine. Sounds great. No issues. Transformers are from Hairball and I used the VTL5C4/2. Meters are used Sifam AL29s I picked up a few years back. The front panel didn't work as planned and then sat under my bench for a couple of years. I don't mind it. Like those pre-relic'd guitars. Maybe I'll start a new trend........ :-\

 

[irfrench]

What an ace project!

I'm thinking I'll build a couple using Gustavs boards but cut down to fit in a 51x rack.

Couple of questions if you don't mind:

[list type=decimal]
[*]In the UK the VTL5C4 (single version) is readily available, is there any advantage in using the double version instead of a pair of single versions?
[*]Are there any guidelines/specs to look out for with the VU meter?
[/list]

Any help would be very much appreciated.

Thanks,
Ian

 

[Script]

[list type=decimal]
[*]In the UK the VTL5C4 (single version) is readily available, is there any advantage in using the double version instead of a pair of single versions?
[/list]

Should work just fine. Double opto uses only one LED, so you might end up with very slight mismatches between gain reduction opto cell and metering opto cell -- but there will be anyway in the opto cell's resistance (buy a couple and try to get as close as possible). If you need extremely high-precision paranoia(!) metering, I suggest you drop the VU meters altogether and go for IC-based LED metering. But not necessary for this project at all, cos it's about sound... Most VU meters are not very precise anyway (ballistics), unless you spend a lot of money and I mean a lot. In my world VU meters are more like eye candy, they are there just to let you know that something is happening -- and then you listen.

 

[irfrench]

Script,

Thanks for the advice, I'll have to see how it compares with the single or double VTL.

My thought's exactly with the VU meter, eye candy it is!


I guess all that sits between me and a pair of LA4's is, er, me!

Thanks!

 

[irfrench]

Ta da!

Gotta say it.  I love you guys!  This thing is awesome, and I haven't even calibrated it yet! 

The wiring was a nightmare - this is a tough 500/51x project for sure.  But it sounds GREAT!



Thanks again.  One last one in the rack...

Ian.