D-LA2A Support Thread

[[silent:arts]]

5mm standoffs + 250V Anode Voltage = Problem? But I get your point, will try to build a suspension ring for the upper part of the tube.

if I recall correctly I used 5mm standoffs.
add some insulation material between the case an PCB (some plastic or cardboard stuff, like you find it in some commercial units to prevent you to touch PSU parts)

 

[[silent:arts]]

Hi all,

Here is a link to my mostly complete BOM for US guys.

ftp://ftp.tradingtechnologies.com/tam/eric/BOM/USABOMLA2ASilentArt.xls

If anything is cheaper someplace other than in the new file let me know and I can get it changed.

ops link don't work   
any new link somwhere?

regards

with your amount of posts you should know how the internet works  ;D ;D ;D
this forum adds http:// to any uncoded link. http://ftp:// will never work
but this will work:
ftp://ftp.tradingtechnologies.com/tam/eric/BOM/USABOMLA2ASilentArt.xls

 

[mjproc]

After final wiring last night, 4 times checking everything looks visual ok...... I finally fired up my dla2a !!! nothing blew, no smell, bulbs glows

Have some small puzles to solve, but this is the fun part....  Sooooo nice to seee them tubes glow

I have to read the theory of operation now......

(I'll post some pictures when I move it to the new 3U case (it's still inside the behringer case, with the behringer frontpanel) I tell you,,,, this behringer is heavily modded

 

[SIXTYNINER]

with your amount of posts you should know how the internet works  ;D ;D ;D
this forum adds http:// to any uncoded link. http://ftp:// will never work
but this will work:
ftp://ftp.tradingtechnologies.com/tam/eric/BOM/USABOMLA2ASilentArt.xls

thanks so much for the link,
also http://www.nrgrecording.de/nrg/viewtopic.php?t=405
and many others links of nrg site
don't "run" properly
....probably updating site
regards

 

[[silent:arts]]

non working links can always happen in this internet.
might be someone used a time-limited host for pics,
the domain went down (most of my older broken links are down since I gave up silentarts.net)
and this project (and most of the links etc) is more than 4 years old

if you need any missing link previous hosted by me just ask.
nobody will go thru all those pages fixing links
(while I did exactly that once I moved my host ...)

 

[mjproc]

I have some problems I hope someone can help me with..

My dla2a dosn't seem to compress correctly.  I set the gain knob to approx the same gain as under bypass, then turn the peak red know clockwise.  Near full clockwise I can hear distorbtion applied and gives a rather nasty fuzzy output.  This applies to both channels.

Same thing happens when running the dla2a without T4B's.  So my unit works as an amplifier.

I've wired the heaters, measured the voltages on the tubes (tho a bit higher than the reference voltages from Silentarts)

Any1 seen this before?

 

[mjproc]

checked if the T4B received any signals (mounted the T4B without cover)

The T4B leds seem to work, at least the light "pumped" in sync with the signal and were influenced by the pots.

Tried to use a flashlight to see if there were any respobse on the vu in GR mode.  the VU moved "a bit" when lit upon.

Still fuzzy output.

I've tries several different tubes for V1 and V2, from Behringer to Telefunken.  Differs in gain, but no combinations seem to resolve the "fuzz"

Ahhh my head implodes

 

[mjproc]

Hope someone who knows the nature of la2a can help me...

Is it "normal" to have small amounts of "fuzz" / "hiss" when GR is full CW?  I've tried to turn Limit/response CCW and it seem to quiet up a bit the more ccw I get.

When I run signal through with small amount of gain, 45-50% GR it sounds quite good, and does compress.

Running drums through can be from nice warm -> hard, pumpin "trashy" sound.

What I fear is that I'm trying to tame the nature of this beast, thinking this and that is too much...
(I've never tried/heard an Original LA2A)

Brgds
Ole Peder

 

[RedNoise]

Hi all !
Cannot remember if this question's already been asked but :
Would 2W 5% Carbon resistors (ie : A.Bradley) sub 3W 1% metal film resistors???
Thanks!

 

[oilcanstudios]

its a drip, but she came out nice

Big KNOBS

 

[[silent:arts]]

nice, but mono & needs too much rack-space ;D ;D ;D

 

[Soeren_DK]

Anybody know if these tubes? Will they be a good choice for this project?

NEW Electro Harmonix 12bh7 Gold pins
Balanced Tungsol 12AX7 used readings 91/91
NOS Procomm 6aq5a

Cheers
Soren

 

[Soeren_DK]

Can I use this trafo?

Cheers
Soren

 

[stereokillah]

hi Soeren_DK , i've used Electro Harmonix 12bh7 in my 3 units , i 've tried Tungsol 12AX7 , sovtek 12ax7lps and 12ax7 JJ,
after some test i keep sovtek and JJ and let tungsol that give me a noise more important,

i don't know Procomm 6aq5a but like it's the good reference it's fine

 

[[silent:arts]]

another one is born, look here[/quote]





[quote author=crisotop]Volkers infamous d-la2a design (building was a breeze + works perfectly after 1st power up). Used "original" Sowter clones (1009 + 1010) and stepped Elma switches for easier recall. (25k pot + 75k resistor is a must on these things and brings the gain in a useful range). Matched tubes, matched T4 cells = close to perfect stereo tracking. This unit is also quieter and has less hum than my mono 3RU La2a build (what a waste of rackspace). It's tough to fit the tubes in a 2U case, but it can be done.[/quote]


;D ;D ;D

 

[Soeren_DK]

hi Soeren_DK , i've used Electro Harmonix 12bh7 in my 3 units , i 've tried Tungsol 12AX7 , sovtek 12ax7lps and 12ax7 JJ,
after some test i keep sovtek and JJ and let tungsol that give me a noise more important,

i don't know Procomm 6aq5a but like it's the good reference it's fine

Thanks... 

Cheers
Soren

 

[crisotop]

In my case it's the opposite, Tungsols give me the best noise performance, they have slightly more 50/100Hz hum, but "beatiful" with noise in the upper spectrum, whereas the JJs (regular + gold) tend to buzz in the higher frequencies (especially the higher priced gold edition).

My power trafo gets hand-warm (safe to touch), hope this is normal (probably already addressed somewhere in the thread)

cheers
christoph

 

[mjproc]

I'm having a problem with phase error ???
I initially thought it was related to my mixer setup, but after assembling some insert cables last night I still have phase error.  When inverting the return on my mixer, it seems to be "normal".  I've tripple checked my wiring and cables, measures and looks ok.

Could it be a faulty trafo wiring?  I use sowters, and in mono all seems fine, phase problem is only under stereo operation.

I'm soooo close now, please help me some1.....

Ole P

 

[crisotop]

Can't quite follow your problem? You've got phase cancellation between your left and right channel? Let's say you send a 1k sine into both channels they null out on your (equally loud) mixer return channels?

 

[pacemaker]

Hi Guys,
might be a dumb question ,
but is there a BOM for Volker D-LA2A ?
regards,
Francois