Explendid amplifier designed by Michael Bittner, our MikeB

[anatech]

Hi keantoken,
Yes, the coil is wound on the resistor. Click on the "www" button under one of Mike's posts.

-Chris

 

[jarkaa]

Caps on rails

Hello

Possibly a line of 1-470uF, a couple 100 uF and some 10's and 1 uF plus the 0.1 uF. That should present a nice low impedance across the band. Of course, it would eat up board space too!

I have utilized a RC snubber on the rails after the 1kuF caps, which should present a smooth and low impedance curve in a compact size.

There was a quite hot discussion about it last year.

Thorsten Loesch simulated this and the results can be seen here
http://www.diyaudio.com/forums/showthread.php?postid=546197#post546197]

Here are the real world measurements of the circuit:
http://www.diyaudio.com/forums/showthread.php?postid=548002#post548002

Jarno

 

[loek]

Does this actually give the correct inductance?

I did 15 turns on a 6mm tube, that gives exactly 0.5 uH.
Loek

 

[sandro600]

Folks ,

In May this year i ordered samples of MJL0281 andMJL0302.
The 0302 arrived in 5 days , the 0281 were put on back order then
onsemi cancelled the order without saying why in July. Then they wouldnt answer emails . A couple of days ago I tried one more time to reach them and today I received this reply.

Hello Paul,

We are sorry but we don't have this MJL0281A device in our sample stock
so you will not receive this order.
We don't have this part on our program.
We apologize for any inconvenience that this has caused.
Regards,
Stanka


Stanislava Simoncikova
Technical Administrative Assistant
Tech. Support Dept.
ON Semiconductor Slovakia a.s.
Phone: 00421 33 790 2994
E-mail: stanislava.simoncikova@onsemi.com


Have others not been able to obtain samples of MJL0281 ?
The 0302s arrived from Singapore. and I'm getting a reply from Slovakia. I know these companies are global but does the left hand know what the right is doing?

Mjl 0281 is still listed on their website as available

Grateful for any suggestions

 

[wputera]

😕 Could anybody help me find the layout n pcb track of this Explendid amplifier?so many post to read this thread .Thank you guys🙂

 

[MikeB]

You find most important infos here:

http://www.lf-pro.net/mbittner/Sym5_Webpage/symasym5_3.html

Mike

 

[roender]

Hello Mike
Please take a look at this amp
http://www.diyaudio.com/forums/showthread.php?s=&threadid=88669
What do you think about?

 

[keantoken]

In May this year i ordered samples of MJL0281 and MJL0302.The 0302 arrived in 5 days , the 0281 were put on back order then onsemi cancelled the order without saying why in July.

🙄

They may be having a problems with a lot of sample orders for these devices. Though I doubt it because transistor variety is so hunourmous.

 

[anatech]

Hi sandro600,
Use MJWxxxx, same die but smaller package. Enough for the Symasym.

-Chris

 

[sandro600]

Anatech, I was leaning that way so after the email from onsemi,
I'll follow your recommendation

 

[MikeB]

Sandro, the difference between MJL and MJW is here only 180 to 150 watts.
I looked on the onsemi site, MJL0281 is listed as unavailable, only MJL0302 on stock. MJW is completely out of stock....

I have no idea what is going on. Not the best way to introduce a new device ?
At least digikey has the MJWs on stock.

Mike

 

[MikeB]

Once more looking at Onsemi's site i realized that the MJW is rated 1.4$ and the MJL 2.4$. No wonder that the MJL is dying...

Mike

 

[-_nando-_]

Hello !!

I was searching the component's prices, and I found that the Mica capacitors are incredible expensive!

C14 10pF Mica = 2USD
C2, C7 100pF Mica = 1USD
C3,C4 330pF Mica = 4,5USD

Cornell Dubilier capacitors...

Can I use it polyester or ceramic ? Specially the C3, C4... ?


Thanks !


Kind Regards,

Fernando

 

[MikeB]

That's really overkill ! Yes, go for polyester/styroflex, not ceramic for c14.

Mike

 

[-_nando-_]

Hahahaha Mike this smile is really funny ! 😀


Yeah, so I'll get away with poliester caps, and pay the expensive mica for C14 ! Should it degrade the sound or would be something that a human will not perceive?

 

[MikeB]

Hahahaha Mike this smile is really funny ! 😀

My favourite, right after

Yeah, so I'll get away with poliester caps, and pay the expensive mica for C14 ! Should it degrade the sound or would be something that a human will not perceive?

Filmcaps are also available with 10pf. At least using a standard ceramic for c14 is audible. That's because distortions from c14 will be amplified by the amp and are not correctable by the feedback, as the feedback signal itself gets distorted.
I think 2USD for a 10pf cap are unacceptable.

Mike

 

[jacco vermeulen]

www.thel-audioworld.de/bauteile/glimmer/glimmer.htm

Michael,
you were saying ?

 

[MikeB]

www.thel-audioworld.de/bauteile/glimmer/glimmer.htm
Michael,
you were saying ?

😀

Would YOU pay 498€ for one 6.8µF mica cap ?

I think, these few caps should not cost more than the rest of the amp (excluding psu and heatsink)

Mike

 

[-_nando-_]

As the 10pF is critical, I'll pay, I do think that it isn't acceptable, but at the final cost it don't weight that much 🙂

The others will be polyester ! Is the WIMA capacitors expensive? There's no price in the farnell site


Cheers !

 

[MikeB]

Hmm, i can't tell you, as WIMA is a german company, these caps are quite cheap here ! 😀
But, they are definitely very far from the prices of Cornell Dubilier.

Mike