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Old 30th May 2008, 05:50 PM   #491
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Quote:
Originally posted by housing
can't go to the US for I have lost all my finger print on my thumbs
You can have mine for $5 and a set of heatsinks, $50 more and i'll throw in a thumb.

I'd appreciate a temperature measurement when you're ready to feed the boards with juice, interesting to see what they're worth in C per W without a fan.
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Old 30th May 2008, 06:32 PM   #492
housing is offline housing  Hong Kong
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Quote:
Originally posted by jacco vermeulen


You can have mine for $5 and a set of heatsinks, $50 more and i'll throw in a thumb.


No, thank you. These junk heatsinks need a lot of metal working.


Quote:
Originally posted by jacco vermeulen


I'd appreciate a temperature measurement when you're ready to feed the boards with juice, interesting to see what they're worth in C per W without a fan.
I have tested the pair at an ambient temperature of about 29 degree Celsius, still air. Everything goes fine and the heatsinks on the Shunty are warm to the touch only. That one on the Pumpkin is hotter but still don't burn my fingers.

Don't have thermal couple for my Fluke 189 for temperature measurement but may buy one some day. Will let you know the ¢XC/W then.
 
Old 30th May 2008, 06:48 PM   #493
Manu is offline Manu  Europe
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Quote:
Originally posted by Zen Mod


"buffer for Blues" or Borbely buffer ( two N Jfets in toob fashion )
Can any of you smart people explain me what is a buffer exactly, and what is it for?
Like Adriano, I want to know.

Manu
 
Old 30th May 2008, 09:14 PM   #494
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by Manu
Thannks Jacco.
Any hints about litterature on this subject?
Manu

pooftaaaahhhhh , puffer , stossdampfer



I dunno exact number or name of the pdf - go to Borbely's and look for "new Jfet frontiers"

naaaah ......... just download all pdfs , and you'll find mucho dobrih stvari

on the other thought - look for "Borbely " and "Papa" on these DVDs I sent you .
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Old 30th May 2008, 10:25 PM   #495
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by Manu
Thanks Saša,

I didn't find nothing about pooftah at Borbelys but some lines on Buffers. I hope I can understand.
Did Nelson wrote something about buffer?
I recall there was a "Buffer for blues" thread but not a paper.


Manu

dvds - folder "Borbely" and folder "Pass"
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Old 31st May 2008, 11:36 AM   #496
Vix is offline Vix  Yugoslavia
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Hi Manu,


Papa said that he will publish a buffer article. In the meantime, look here:

http://www.diyaudio.com/forums/showt...43#post1520943
More precisely, you will need only this:
Attached Images
File Type: jpg buffer.jpg (12.1 KB, 525 views)
 
Old 31st May 2008, 11:54 AM   #497
Manu is offline Manu  Europe
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Ah... Yes.
Thanks crazy cat.

The perpective of Papas Buffer-paper is a good news for me.
Its always amazing how this great artist manage to adress in one same article both smart e-ingénieurs and stupid french monkey. With good results I think...

Manu

PS
(Is it hot in Dutch-land as it is in Ostrija these days? ... We have hochsummer time ... I don't complain. Just that Aleph needs some additional cooling)


Steen : Are you sure you have to change to metal-case? A pity considering your beautiful wood-work. More air flow inside could mebbe cure the heatproblem? No?
 
Old 31st May 2008, 01:42 PM   #498
juma is offline juma  Serbia
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Quote:
Originally posted by Vix
Hi Manu,
Papa said that he will publish a buffer article. In the meantime, look here:
http://www.diyaudio.com/forums/showt...43#post1520943
More precisely, you will need only this:
You can read a lot about that buffer circuit in the zipped PDF (figure 16 b) in attachment
Attached Files
File Type: zip jfet-2.zip (90.3 KB, 96 views)
 
Old 31st May 2008, 03:01 PM   #499
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Default Cook Book - few more lines

as always - Cook Book supplemented with few more lines ;

they are :


"- My mistake was that I wrote ZY10 zenners in Shunty (D1 to D5, D1ato D5a)
; all you need is ZF , which are just generic 400mW ones ; now corrected in parts table .

- In case that you are fluffy with setting absolute offset (DC voltage between plus and minus
outputs of Pumpkin ) , you'll have replicated DC on both INPUTS of Pumpkin ........ exactly
divided by ratio of feedback net .
That will result in screechy noise during volume pot turning .....
cure is simple - Papa-like ....... just include 2u2 good cap on each input leg (both + and -)
between pot and inputs ; that will block DC to reach pot .
Hehe - that cure is certainly less evil than using any kind of Servo"


regarding these caps - Holger (HB) already sez long time ago that he even will not try his without input caps .........

as usuall , Cook Book can be found HERE


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Old 1st June 2008, 04:59 PM   #500
steenoe is offline steenoe  Denmark
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Quote:
Originally posted by Manu

Steen : Are you sure you have to change to metal-case? A pity considering your beautiful wood-work. More air flow inside could mebbe cure the heatproblem? No?
All ya guy's are nut's I know I asked for F4 preamp, and I really like the sound of it.... Well, I will simply build the psu into a seperate case, just like the one my Pumpkin is in right now Surely, two cases dissipates double up on the heat, right? I have ordered the wood for it allready. BTW its Erocco-teak. Just hope I didnt butcher a rainforest

 

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