a Dual LA2A - the [silent:arts] version

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

[silent:arts]

Well-known member
Joined
Jun 4, 2004
Messages
5,231
Location
Berlin, Germany
Gentlemen, may I present you the [silent:arts] D-LA2A:

IMG_3984.jpg


it was not easy to fit the two channels in a 2U rack, but with a little care it worked:

IMG_3980.jpg

IMG_3981.jpg


it was my first self designed double sided PCB, and my first Tube project.
I'm glad everything is working :grin:

IMG_3982.jpg


I have had problems with gain over "7" (may be this grid stopper thing), but I changed the gain pot to a 22K log in series with a 75K resistor to get an easier to adjust gain range (still 26dB gain - enough for a compressor / limiter).

hope you like it (since this LA2A is NOT ptp) :twisted: :green:  :green:  :green:
 
As always, a very pro looking job :thumb:
Love the blue PCB's in there.....and the sub panels to mount the pots on so you will not have bolds on your main frontpanel. I guess it can't get much better than this!
 
Awesome! I see on the PCB's you marked left and right that means the unit is a Stereo? or dual mono?
Really cool!
 
Nice!

How did you do the pot pcbs mounted to the back side of the front panel (what kind of hardware).

Is it a short screw sunk into the front panel, or...?

Regards

ju
 
[quote author="3nity"]Awesome! I see on the PCB's you marked left and right that means the unit is a Stereo? or dual mono?
Really cool![/quote]
it is dual mono or stereo - just press the button in the middle.

[quote author="fum"]How did you do the pot pcbs mounted to the back side of the front panel (what kind of hardware).[/quote]
there is no pot pcb, only the pots and the switchs. they are mounted to 2mm Alu panels, connected to 8mm threaded bushes.

thanks for the kind words everyone :grin:
 
Very nice work :thumb:
I'm also in the process of making a dual mono/stereo unit.

Is this some standard power transformer you are using?
I actually bought the one from edcor, it is not a donut though.

Have you checked if the matching is satisfactory? Did you somehow match the t4b's?

Coolness,
hejsan
 
Volker,

VERY cool looking, amazing you got it into the 2U rack. You now have more space for other gear!!!! As always you never cease to amaze and I'm impressed :thumb:

I love the choice of colour as well, black panels are far to safe :green:

Matt
 
OK, STOP IT!!!

I'm constantly trying to convince myself I don't need an LA2A, and you and matta aren't helping at all :wink: .............. ha ha

Sheesh, I've never even heard one in real life, yet for some reason I lust for one. :roll:

Fantastic Work :thumb:
 
While I'm still trying to get mine working I've been doing pre-production at another studio and the scratch vocal mic is running though one. Holy moly! It sounds fantastic and it's a reissue.

I have a reissue LA3A and it sounds great but totally different than the LA2A. I can definately hear the price differnce. Not sure if it's $1300 worth of differnce but it can be heard.

Cheers,
 
Hi hejsan,
you know the transformers ? :grin:
thanks again
[quote author="hejsan"]Is this some standard power transformer you are using?[/quote]
no. it is custom wound from Mueller Rondo. really nice company!
[quote author="hejsan"]Have you checked if the matching is satisfactory? Did you somehow match the t4b's?[/quote]
I didn't match the T4b's (since I only have two of them :green: )
but I matched all resistors for both channels.
the tracking is fine - oddly better without the stereo link switched in :? , but still within 1dB.
the gain reduction Metering doesn't track fine, but who cares ...

[quote author="matta"]VERY cool looking, amazing you got it into the 2U rack. You now have more space for other gear!!!![/quote]
thanks - and yes, place is an issue in my place. more to come of my "blue series" tube gear collection ... :green:

[quote author="Lowfreq"]I'm constantly trying to convince myself I don't need an LA2A[/quote]
everybody needs a LA2A. you will know when you have heard one :green: :green:

[quote author="wmb"]I have a reissue LA3A and it sounds great but totally different than the LA2A. I can definately hear the price differnce. Not sure if it's $1300 worth of differnce but it can be heard.[/quote]
for a little more of that money you can build a dual version ...
 
gotta say this build looks friggin amazing! Did you design the circuit or is it from a schematic? I've looked on the net for a pcb layout of the L-ay-2-ay but cant find anything
 
no, I'm not the designer of this circuit :green:
it is just a standard LA2A
I can send you the schematic and PCB layout in as a Target file. Other formats have to wait until my new MacBook Pro arrives, since my Virtuel PC installation is lost in the land of bad blocks :roll:
 
thanx very much silent that would awsome....i PM you with my details....cheers
 
Back
Top