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-   -   new layout for lfa 50a (http://www.diyaudio.com/forums/elektor/147415-new-layout-lfa-50a.html)

JEP 12th July 2009 10:47 PM

new layout for lfa 50a
 
2 Attachment(s)
A few years ago I fully redid the layoutdesign for my elektuur lfa50a.
the componentplacement is about the same but there is more room voor biggercaps and foil c's. I also made a large board for the big powercaps. As you can see on the attachment. So there are almost no wires anymore. I think that looks very cool. And the best thing is its sounds really great too.

I have an 2sk389 as inputdifamp because 2sk146v was not avaliable anymore. And no inputcap. Because my preamp has outputcaps. But I can always put room for one on the layout if you want one.

Let me know, Roy

To me the lfa50a is a great amplifier

scanspeakman 13th July 2009 01:42 PM

Re: new layout for lfa 50a
 
Quote:

Originally posted by roy algra
A few years ago I fully redid the layoutdesign for my elektuur lfa50a.
the componentplacement is about the same but there is more room voor biggercaps and foil c's. I also made a large board for the big powercaps. As you can see on the attachment. So there are almost no wires anymore. I think that looks very cool. And the best thing is its sounds really great too.

I have an 2sk389 as inputdifamp because 2sk146v was not avaliable anymore. And no inputcap. Because my preamp has outputcaps. But I can always put room for one on the layout if you want one.

Let me know, Roy

To me the lfa50a is a great amplifier

Looks great! I have the LFA50-OA as well, but in the original configuration. Great sounding amp!

Scanspeakman

JEP 13th July 2009 02:32 PM

Hi scanspeakerman,

I have it for 15 years now but never had a thoughd about replacing it. A friend of mine Who has worked for an highendstore who has had a lot of amplifiers in his system had them on loan for a while said that overal the lfa50a was the best amp for his system.

Its a real great amp.

Thanks roy

scanspeakman 13th July 2009 03:05 PM

Hi Roy,

I am using the amp for about the same period I guess. Seems indestructable. Only other amp I am considering is the Elektor Extrama but I am not able to find any topics on the net displaying the results of some who has build the Extrema.

I am planning to give the LFA50-OA an overhaul in the next few months (slitfoils for the big powercaps, some panasonic fc's in other positions etc). I'll probably post some pictures when I am done.

What kind of pre-amp are you using with the LFA50-OA?

Scanspeakman

jan.didden 13th July 2009 03:16 PM

Quote:

Originally posted by scanspeakman
[snip] Only other amp I am considering is the Elektor Extrama but I am not able to find any topics on the net displaying the results of some who has build the Extrema.[snip]Scanspeakman

So, you can be the first here to build it!

Jan Didden

jacco vermeulen 13th July 2009 03:59 PM

Quote:

Originally posted by janneman
So, you can be the first here to build it
Dream on

scanspeakman 13th July 2009 08:59 PM

Quote:

Originally posted by jacco vermeulen


Dream on

Why? Design too difficult to build? Or are some parts used in the design not available anymore?

Scanspeakman

jacco vermeulen 14th July 2009 03:21 PM

The parts are not that hard to find, there's still someone active overhere who offers a replacement for some of the CRD's you need.

Major issue with the design is the heatsinking for power levels above 50W, my strong advice is to use fan operated high performance heatsinks.
A big help is the availability of Kerafol insulating foil, 7.5'' x 7.5'' sheets can be ordered from Conrad. (one of EUVL's great pointers)
I originally used thin aluminum oxyde TO247 insulators, adapted to size to fit under the big Sanken cases.
The Kerafol sheets are easy to slice into MT200 case sizes with an office paper cutter, saves quite a few temperature points compared to Mica, any other insulator sheet make is not to my liking.

Second item would be what preamp to use with this power amp.
Logically speaking, the preamp deal would also have to be a balanced package, very low on distortion, high on dissipated watts.

You wouldn't be the first overhere to build it, but the first to comment on it.

scanspeakman 15th July 2009 01:45 PM

Hi Jacco,

I have send you a message.

Scanspeakman

WALTER BURKHARD 2nd October 2009 04:44 PM

Hi , i have build LFA_A 50W and 8 2SK146V Toshibas still in my stock.
And 14pieces 2SK146GR all NOS.
All are fore sale.

br Walter


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