Official LYNX Power Amp builder’s thread

[PMA]

Jan, if you do not mind, I would also show OPA627 step/square response. We can see that the OPA627 is much better balanced device in terms of rise and fall edges, and more stable, than the OPA134. Both reponses taken with generetor with less than 10ns rise and fall time.

 

[tinitus]

Or the logical conclusion could be problems with data spread cosistency on opamp ... I say this without much knowledge on the issue

 

[Jan Dupont]

You are most welcome, Pavel 😉

Yes your measurement pictures shows clearly the difference, but the puzzle is still there.

 

[Jan Dupont]

Please share your knowledge with us, tinitus 😉

 

[argofanatic]

Re. OPA134 oscillations

I don't know if it matters but these are the capacitors I used for C102, C103

33pf Silver Mica 500V

Argo

 

[Jan Dupont]

argofanatic;

I have used those to. No problems....

I'm more into that it could be a wiring issue

 

[argofanatic]

I'm more into that it could be a wiring issue

... as in PCB layout ?

I used your beautiful boards x 4, all with the same behavior.

 

[Jan Dupont]

argofanatic;
No in the signal and power wiring to and from the PCB

 

[EMX_125]

CCS

Hi.... Jan....

Good Afternoon.... Jan I Ask You What the Meaning of CCS For Active Differential Input stage? 😕

 

[Jan Dupont]

What the Meaning of CCS For Active Differential Input stage?

I'm not sure what mean 😕

 

[tt.tt]

Hi I am new to this forum. The only reason I joined is the Lynx thread. I like this amp very much. Next week I will do the PCBs for it. Because I am a student - I have to build it as cheap as possible. I found some metal plates - but can not figure out how I should build the heatsink out of it. Is the mass of used metal also important, or just the surface to radiate the heat? What kind of heatsink do others in this thread us, and of what dimensions are they? greets

 

[Ragnwald]

Hi tt.tt

To saw heatsink out of a block is a very interesting thought.
Someone did it and dokumented it on a site i now can´t find.
He made it with a circlesaw with a blade spec. for metalsawing, mounted on a sawingtable.
Someone remember the site?

A good prifile i am using, is Junior JK-1188.
300mm x 150mm x 83mm
http://kuehlkoerper.de/cms/images/pdf/jk1102-jk1190.pdf
EUR 51:20/ piece.

I think it is the same profile Brystone use in 4b SST, witch use the same output device, for instance. 😉

 

[bigpanda]

I might be able to get hold of some 2sc5200 + 2sa1943, are they qualified for this project? Tks

 

[tt.tt]

Hi Ragnwald,
thank you for this hint. I will build my heatsink about 20 cm x 28 cm as a basis. I found somebody that will help me with the metal work. I will post some pictures, if you like. ciao and thank you

 

[bigpanda]

genuine 2sc5200

Hi,

I got hold of the 2sc and 2sa and I cracked open 1 of the 2sc. I manage to do it without hammering on my thumb (Is that a good sign? The tougher it is, the better chance of being a genuine one). A job that I thought was suppose to be easier (or maybe I don't have the experience) Anyway I wasn't able to clear the epoxy off the face of the die, just manage to break the whole die with epoxy still sticking to the front off the metal backpanel The die measures about 5mm x 5mm

Am I lucky enough to have got hold of the real ones?

Another method of check them rather destructive ones?

Tks

 

[AndrewT]

which is stronger?
A good solder joint from die to copper backplate or epoxy casing to front of die?

If the die came free from the backplate, what does that say about the 2sc?

 

[bigpanda]

Hi Andrew

Maybe I am making up excuses to comfort myself, but what happen if you hit in the right place? How would you do it if you are trying to crack them open?

Tks

 

[crt]

I might be able to get hold of some 2sc5200 + 2sa1943, are they qualified for this project? Tks

Yes, shoot it!

i build this amp with those toshiba too.

 

[bomellberg]

Is Jan's homepage gone? I only get the ISP "cliche" page when I try to reach http://www.audio-circuit.dk/

/Bo

 

[xaudiox]

yeah same here...🙁