10 pieces aleph x and non of theese working - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 28th April 2006, 01:51 PM   #11
diyAudio Member
 
elviukai's Avatar
 
Join Date: Apr 2003
Location: EU- Electronic Union country
BTW voltage rails are +26 and -26 from zero potential.and if measuring across + and - I get 52volts. seems normal power suply..
__________________
natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..
  Reply With Quote
Old 28th April 2006, 01:56 PM   #12
diyAudio Member
 
Join Date: Nov 2000
That does not help :-(

Where is the measured rails?

You should have +26V on the postive rail.
And -26V on negative rail.

This when you connect the black measurement lead to ground.
red measurement leadto a targeting point.

You fail to specify the rails? Why? (Asked in post
Is there no negative voltage in your circuit?

Then what does your powersupply look like?
What schematic did you use for the powersupply?

Seems I am repeating my self. And based on the second set of
measurments there is a serious powersupply mistake. And or
misplacement of the ground
  Reply With Quote
Old 28th April 2006, 02:18 PM   #13
diyAudio Member
 
Join Date: Nov 2000
I just had a look at kristijan's PCB.
see kristjian's pcb

I was unable to locate a ground connection,
other than the input grounds.

If your input connector is isolated, this input-ground (and
circuit ground) will never be connected to the powersupply,
hence no negative voltages, and the circuit will not function
properly.

Do you have a groundwire running from the amplifier PCB
to your powersupply ground?

My previous post crossed yours. Sorry about that


  Reply With Quote
Old 28th April 2006, 02:34 PM   #14
diyAudio Member
 
elviukai's Avatar
 
Join Date: Apr 2003
Location: EU- Electronic Union country
in this picture you give link is small area of 4 inputs. and one of theese(actualy two,but second one is for line input ground) called GND to this gnd I conected my zero potential ground(one cap plius is plus,then the same cap minus conected with other caps plus and here we have zero potential)and the last pin minus is minus to PS I conected this zero potential to gnd NOTE that I did folowing power suply with 2 bridges(both secondaries goes to bridge AC legs ,and from one bridge I take plus, the same bridge minus conected to another bridge plus and have zero potential, and last pin is minus whee it minus of PS
__________________
natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..
  Reply With Quote
Old 28th April 2006, 02:51 PM   #15
diyAudio Member
 
Join Date: Nov 2000
Based on your previous description the powersupply seems OK

But the measurements don't show any negative voltages.
Howcome?

Measurement 3
If you measure the -PWR on the amplfier board,
so red probe on -PWR and black probe on GND,
you should see -26,5V.
Is this the value you see?

Measurement 4
With black probe on ground:
Measuring on the gate off the "gain transistor"
shows "Gate +25,7" but it should be around -20V
can you confirm this?
  Reply With Quote
Old 28th April 2006, 03:01 PM   #16
diyAudio Member
 
elviukai's Avatar
 
Join Date: Apr 2003
Location: EU- Electronic Union country
Based on your previous description the powersupply seems OK

But the measurements don't show any negative voltages.
Howcome?

Measurement 3
If you measure the -PWR on the amplfier board,
so red probe on -PWR and black probe on GND,
you should see -26,5V.
Is this the value you see? Yes Sorry its MINUS 26,3 not plus

Measurement 4
With black probe on ground:
Measuring on the gate off the "gain transistor"
shows "Gate +25,7" but it should be around -20V YES ITS MINUS SORRY AGAIN. i ENTER WRONG VALUES ,I WILL MEASURE NOW CAREFULLY AGAIN ALL AND WRITE BACK
can you confirm this?
__________________
natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..
  Reply With Quote
Old 28th April 2006, 03:20 PM   #17
diyAudio Member
 
elviukai's Avatar
 
Join Date: Apr 2003
Location: EU- Electronic Union country
HERE IS CORRECT VOLTAGEs.

here is some measured values maybe this helps-
Reference to ground(one mulrimeter end connected to zero potential power supply lead and other at targeting point)
Most measurements are identical in both balanced sides of pcb

Gain mosfets Gate -25,7, Drain +20,8 Source -26,5
CSS mosfets +25,3 +25,3 +21,4

irf9610 (both) +20,5 -25,5 +24,1
irf 9610 (single) +16, +24,1 +24,1


values measured at transistors-

Gain mosfets GD +46,8 DS -47,5 GS -0,5
CSS mosfets-0V(??) -4,2 -4,1


Irf9610 (pair) GD +46,8 DS -49,5 GS -3,4
Irf9610 single +8,1 0V +8
__________________
natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..
  Reply With Quote
Old 28th April 2006, 03:25 PM   #18
diyAudio Member
 
elviukai's Avatar
 
Join Date: Apr 2003
Location: EU- Electronic Union country
referce to ground
BC 550c transistors
(Pair near 220uf electrolytic in schematic) E +21,2 B +21 C +25,1

(other pair) -26 -26,1 -25,5





between pinns of bc550c eb 0,18, bc -4,13, ec4,3
other pair eb 0, bc 0,5, ec 0,55
__________________
natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..
  Reply With Quote
Old 28th April 2006, 04:18 PM   #19
diyAudio Member
 
Join Date: Nov 2000
Given +PWR = 26,5V and -PWR = -26,5V
Measurements ground referenced

>Gain mosfets Gate -25,7, Drain +20,8 Source -26,5
That's not good. Should be around:
Gate -21V, Drain 0V, Source -26V. In this case your source resistor
would be dropping |0,5V|.

>CSS mosfets +25,3 +25,3 +21,4
That's also not good. Should be around:
Gate +4,5V, Drain +26,5V (rail), Source +0,5V

>irf 9610 (single) +16, +24,1 +24,1
Also not good. Should be around:
Gate +16V, Drain +4V, Source +20V
Way off, as you can see.

>BC 550c transistors
>(Pair near 220uf electrolytic in schematic) E +21,2 B +21 C +25,1
No good. Should be around
E = 0V, B = 0,7V, C = 4,5V
There have been a lot of problems around these BC550C.
Given these measurements, this would be my prime suspect.
What brand did you use? Do you have the datasheet from the
manufacturer? Check the orientation again? Do not let the
markings on the PCB silkscreen, determine the correct position.
There are two types of bc550. Leads inline and Leads in triangle.
Pinning CBE for type one EBC type two. Which one do you have?
Fairchild, Zetex, Philips, Siemens? Allocate the proper sheet and
determine the correct lead out. Cross check with board pads.

Use a simple transistor meter to get an indication of gain
BC550C should have a hfe of 400 - 800. This way you know
which leg is C, B and E

The measurments on the diffpair are inconslusive.
two parts with exactly the same figures for G, D and S.
Not possible. Sources are connected, so they give same reading.
Drains should differ a little bit. Same goes for the gates.
Please repeat measurements around these.
  Reply With Quote
Old 28th April 2006, 09:21 PM   #20
diyAudio Member
 
elviukai's Avatar
 
Join Date: Apr 2003
Location: EU- Electronic Union country
bc550 transistors are conected right way(I think) because I mached them to pairs with digital multimeter hfe function to mach. this function wouldnt work if i do not conect to right pins.

is it posibly problem in some resistors? could it be that resitors from same tape can be diferent,lets say 4,7kohm and accidently 47kohm, because I did not measure all resistors.

the firs thing waht i will do tomorow is recheck all resistors, I am 100%sure that mosfets gain and css conected OK,and 90%posibility that bc550c conected ok mine is all legs in line,probbaly from philips or siemens, did not searched for irf9610 pins but its is the same as in irfp240. just soldered in places where threy belong.

what a headache..
__________________
natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
One Aleph-X working, One to go wuffwaff Pass Labs 102 5th August 2005 06:36 AM
My Aleph-p isn't working PatPet Pass Labs 11 24th August 2004 11:04 AM
Pass Aleph-3 one channel not working? meaw Pass Labs 5 26th January 2004 05:21 AM
Aleph 2 Working!! Mark A. Gulbrandsen Pass Labs 14 17th December 2002 01:56 PM
My Aleph 5 isn't working DJG Pass Labs 26 7th December 2002 10:49 PM


New To Site? Need Help?

All times are GMT. The time now is 06:56 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2