a Dual LA2A - the [silent:arts] version

[silent:arts] · Apr 7, 2007

Gentlemen, may I present you the [silent:arts] D-LA2A:

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

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

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:

radiance · Apr 7, 2007

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!

Purusha · Apr 7, 2007

I see those racks finally arrived :grin:

HOWEVER, VERY IMPRESSIVE WORK VOLKER :thumb: :thumb: :thumb:

3nity · Apr 7, 2007

Awesome! I see on the PCB's you marked left and right that means the unit is a Stereo? or dual mono?
Really cool!

fum · Apr 7, 2007

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

Stagefright13 · Apr 7, 2007

HOLY SMOKES! That's just awesome. Congrats!!

John

[silent:arts] · Apr 7, 2007

[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:

hejsan · Apr 8, 2007

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

matta · Apr 8, 2007

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

Lowfreq · Apr 8, 2007

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:

Stagefright13 · Apr 8, 2007

The LA-2A sounds like nothing else. It has a lusty sound! :green:

wmb · Apr 8, 2007

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,

[silent:arts] · Apr 9, 2007

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 ...

bernbrue · Apr 9, 2007

Cool and sexy, Volker, as I mentioned before.
regards
Bernd

Handcrafted Tone · Apr 9, 2007

Seriously bad ass

You've convinced me, I need to make an LA2

gerardmanvuca · Sep 1, 2007

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

[silent:arts] · Sep 1, 2007

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:

gerardmanvuca · Sep 1, 2007

thanx very much silent that would awsome....i PM you with my details....cheers

[silent:arts] · Sep 2, 2007

*** removed ***

bernbrue · Sep 2, 2007

Thanks a lot, Volker. Good to have this one.
regards
Bernd

a Dual LA2A - the [silent:arts] version

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