Krell KSA 50 PCB

[sierrafan]

I measured Ic, in accordance with that scheme in the picture. The temperatures were the same for all transistors.

 

[AndrewT]

what is the operational current of your output transistors?
That is the test current at which you should measure the Vbe of the transistor. This will match Vbe at Iq.

If you require better matching then take matched sets of Vbe and measure the base current when Vbe for each DUT is identical and the Ic is within 5%. This will give transistors that match for hFE AND Vbe.

 

[robson fulco]

Hello good evening to all friends
mount the amplifier Krell 50 and even pecebo that much heat the transistor q110 eoq 109 where they are to sink ...
could someone give me a force there!

 

[dwieck]

How do you order the group buy boards?
Thanks
Dennis

 

[jacco vermeulen]

where they are to sink ...

Robson,

=> sink

 

[troystg]

How do you order the group buy boards?
Thanks
Dennis

Mark G had some left over that he gave to another person (Bob) to continue selling. I will look up that person and get back to you. I think this is the post...

http://www.diyaudio.com/forums/showthread.php?postid=1665767#post1665767

Bob was also doing a good a job and was easy to get along with too.

 

[bobgroger]

Yes, I still have some. Same deal as in the previous post. I don't want to make any money, just send it to DIYAudio and email me a copy of the PayPal receipt, I will send a pair of boards.....

Bob G.

Mark G had some left over that he gave to another person (Bob) to continue selling. I will look up that person and get back to you. I think this is the post...

http://www.diyaudio.com/forums/showthread.php?postid=1665767#post1665767

Bob was also doing a good a job and was easy to get along with too.

 

[Harry3]

Yes, I still have some. Same deal as in the previous post. I don't want to make any money, just send it to DIYAudio and email me a copy of the PayPal receipt, I will send a pair of boards.....

Bob G.

It's refreshing to see that ther are honest and good people still left in this world!

 

[dwieck]

Thanks Bob and Troy. I am sending a paypal donaion tonight. Bob I tried to emil you but I dont have enough posts to email directly yet
Dennis

 

[Adi2009]

Hi.
I bought heatsink for ma ksa50. Is it enough? Dimension 42cm x 17,5cm x 3,4cm.

 

[Adi2009]

It'll be one heatsink for one channel.

 

[jacco vermeulen]

Not enough if biased for 50W with 37.5Vdc rails.

Your heatsink is in the whereabouts of 0.4C/W, and likely even a bit higher than that, for the numbers above you'll need 2 of them per channel.
And only if you can think up a way to use both sides of your symmetrical heatsink effectively.

 

[troystg]

Not enough if biased for 50W with 37.5Vdc rails.

Your heatsink is in the whereabouts of 0.4C/W, and likely even a bit higher than that, for the numbers above you'll need 2 of them per channel.
And only if you can think up a way to use both sides of your symmetrical heatsink effectively.

Make it a KSA-25... 25 WPC Class-A is still a lot.

 

[Adi2009]

But I'm going to use only 4 transistors per chanel (not 6) - 2xPNP and 2xNPN and U=50V - like in KSA-50MKII. One user from audiostereo.pl told me that it'll be enough so I ask;-)

 

[Adi2009]

I can buy something like this: 27cm x 13,5cm x 12,5cm, but onlyone heatsink for two channel.Is it ok or not?

 

[Adi2009]

sorry

 

[Adi2009]

pictures

 

[AndrewT]

that long sink will do nicely for one channel.
If you cut it in half and use both parts, it will run less hot on one channel.

I doubt you can run one channel on one half.

 

[Adi2009]

Look at this Picture. this heatsink is enough. Are you sure that my heatsink is too small?This from site 315 (the black one)

 

[Adi2009]

This is the last idea. I have 4 heatsinks. Two on a chanel. If I put 2 PNP transistors on the first heatsink and 2 NPN transistors on the second heatsink, probably I'll have problem with offset. I can do something like on a photo. I will put aluminium 4 x (2cm x 4cm x 10cm) between two heatsinks. Will it be enough for one chanel?