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Old 11th March 2006, 04:18 AM   #1091
jajabin is offline jajabin  United States
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A question about aleph-x.

On Wiki, I found this paragraph.
"You may want to install everything except Q1, Q2, Q10 and Q11, then power it up to see that the diff pair and it's current source work properly."

How can I know the diff pair is working properly or not?

Thanks
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Old 11th March 2006, 05:22 AM   #1092
lgreen is offline lgreen  United States
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Default good question

Yes, i'm going to fire up mine as soon as my variac arrives next week and reading that part of the wiki left me scratching my head. Please, more instructions on starting this up for the 1st time.

What should one look for when gradually increasing the line voltage? If I could put 2 DMM's and a scope on the circ, what spots should I have them on and what should I see?

Also, I want to check the output mosfets beforehand to make sure they are ok, can this be done with a dmm?
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Old 11th March 2006, 07:28 AM   #1093
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Hi,

the only thing you can check is if the current source for the diff pair is working and if the fets are matched properly by looking at the voltages at the 392R resistors.

William
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Old 11th March 2006, 04:51 PM   #1094
jajabin is offline jajabin  United States
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Quote:
Originally posted by wuffwaff
Hi,

the only thing you can check is if the current source for the diff pair is working and if the fets are matched properly by looking at the voltages at the 392R resistors.

William

Hi William,

If they are working properly, what's the voltage drop across 392R?
Should I connect to any input when I check it?
Thanks.

Wing
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Old 12th March 2006, 11:06 AM   #1095
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Hi,

at aprox. 10mA per input fet you should be able to calculate it

0,01 x 392 = 3,92V above the -rail.

input shorted to ground

William
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Old 23rd March 2006, 12:50 AM   #1096
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Default Conrad Heatsinks

Anybody from Scandinavia who's interested in Conrad Heatsinks Group Buy, please take a look at: Heat sinks from Conrad Heatsinks
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Old 9th April 2006, 06:36 PM   #1097
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Default again q about keistijan aleph-x

after 140 replies I have chickened a bit idint find info what I need. my 10 pieces aleph-x pcb reaDY TO GO.. except few things.

I am using Kristijan boards, but slightly modified-thicker traces.

http://www.kk-pcb.com/alephx.html

questions
1. I have excelent vishay dale carbon 1% tolerance 10w resistors. 1ohm. if conect 2 in paralel I get 0.50ohm, this is more, original schematic uses 0,47ohm x4 5w is paralel. can I use 8x 10w 1ohm instead originals.


2. bias Left, right and bias q?what values I should use, can i put resitors there, or pot is needed to achieve some voltage points(like in zen v4) if I put pots from waht position start amp? I am sure I will fire first if set pot to incorect value..
what rssitors is the most critical? I used 1% tolerance 0,6w , but they are not the same. irf 240 and irf9610 are mached at 0,01V

my transformers is 18V secondaries.

also Iwant to use one amp on speakers which has 2 ohm impedanse at 70 and 30hzhz . what modification I shopuld do, to make amp that controls loww region well enought.
note I am speaker designer and not a expert on amps, variac, bias etc .

will wait any input..



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Old 21st April 2006, 04:29 AM   #1098
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Default supply voltage aleph-x

Hi

This is my second project about aleph.
I want to change the supply voltage +/-22V to +/-18V.
What parts should I change on circuit?

Thanks
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Old 26th June 2006, 10:24 PM   #1099
DACMan1 is offline DACMan1  South Africa
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Default PCBs

I can't figure out why no-one is sharing their board designs for this project. Its a very simple board, took me less than an our to draw, so i'm willing to share it if anyone is interested. Unfortunately, my traxmaker won't prind to adobe, so the files are still in traxmaker format... Let me know if you are interested. I made boards for 4 channels with press and peel blue, and it all worked out to less than $20.
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Old 13th July 2006, 11:08 AM   #1100
Luke is offline Luke  New Zealand
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Quote:
The only thing you can check is if the current source for the diff pair is working and if the fets are matched properly by looking at the voltages at the 392R resistors
Hi Wuffwaff,

isnt it easier to use 392 ohm resistor on one leg, and a pot on the other to get the voltage across the resistors equal?

cheers Arthur
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