aleph 5 Help!

dhole · 9th May 2005, 10:25 AM

Hehe So Ive put together an aleph 5 using the Recent BrianGT mini aleph boards. I dont even know if I should ask for help as I have probaly made a stupid mistake.

Anyway. I now have a single mono amp that when connected unbalenced gives a terrible distorted but amplified signal at its outputs. I have measured voltages and they seem to be very close to the a5 schematic apart from........ The 0.5v across -V and -s which is non existant!

If there isnt an obvious bunder I am going to stuff another board and double check things. then try with that board. Any advice in the mean time would be much appreciated.
regards
dave

MikeW · 9th May 2005, 11:08 AM

Check the bipolar in the current source and make sure the pinouts are correct.

dhole · 9th May 2005, 11:45 AM

cheers Mike, would that be C10 (B 2 ) on the A5 schematics ?

dhole · 9th May 2005, 12:51 PM

I have checked there and the polarity is correct. Perhaps I have blown the ztx450 I used on Q5 ?.....

dhole · 9th May 2005, 01:41 PM

well replaced the ztx440 and no difference.....

MikeW · 9th May 2005, 02:24 PM

Q5 is what I was refering to. Check R19, 221K. If this is lower you will get less current. If it is taken out you should get a .7 volt drop across your source resistors.

dhole · 9th May 2005, 06:10 PM

FIXED

R19 changed from 221r to 221K !!!!!!!!!!
hehe
My mistake.......

Now lets hope the heatsinik is big enough... its getting warmer.....

Dave

9th May 2005, 10:25 AM	#1
dhole diyAudio Member Join Date: Jul 2004 Location: Brighton	aleph 5 Help! Hehe So Ive put together an aleph 5 using the Recent BrianGT mini aleph boards. I dont even know if I should ask for help as I have probaly made a stupid mistake. Anyway. I now have a single mono amp that when connected unbalenced gives a terrible distorted but amplified signal at its outputs. I have measured voltages and they seem to be very close to the a5 schematic apart from........ The 0.5v across -V and -s which is non existant! If there isnt an obvious bunder I am going to stuff another board and double check things. then try with that board. Any advice in the mean time would be much appreciated. regards dave

9th May 2005, 11:08 AM	#2
MikeW diyAudio Member Join Date: Sep 2002 Location: North of Boston	No Bias Check the bipolar in the current source and make sure the pinouts are correct. __________________ MikeW

9th May 2005, 02:24 PM	#6
MikeW diyAudio Member Join Date: Sep 2002 Location: North of Boston	Q5 is what I was refering to. Check R19, 221K. If this is lower you will get less current. If it is taken out you should get a .7 volt drop across your source resistors. __________________ MikeW

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9th May 2005, 11:45 AM	#3
dhole diyAudio Member Join Date: Jul 2004 Location: Brighton	cheers Mike, would that be C10 (B 2 ) on the A5 schematics ?

9th May 2005, 12:51 PM	#4
dhole diyAudio Member Join Date: Jul 2004 Location: Brighton	I have checked there and the polarity is correct. Perhaps I have blown the ztx450 I used on Q5 ?.....

9th May 2005, 01:41 PM	#5
dhole diyAudio Member Join Date: Jul 2004 Location: Brighton	well replaced the ztx440 and no difference.....

9th May 2005, 06:10 PM	#7
dhole diyAudio Member Join Date: Jul 2004 Location: Brighton	FIXED R19 changed from 221r to 221K !!!!!!!!!! hehe My mistake....... Now lets hope the heatsinik is big enough... its getting warmer..... Dave

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