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Elektor's "Ulti Amp"

Measurement Ultiamp

Hi Piersma,

No problem, I hope you had a good holiday. I haven't had much time in the meantime also.
Regarding the Ultiamp project:
I've purchased some poti's to replace R13, R14, R15 and R27. In this way I hope to get the DC-settings in the correct range.
I've noticed that sometimes one channel doesn't produce any audio although the security PCB indicates everything is switched on and OK.

Do you have any suggestions? Do you have some detailed pictures of your modifications?

Thanx!

JackV
 
Problems

hi Jack,

Check the idle current stability over at least one hour and see what happens, it might be the cause of the problem you mention. I would strongly suggest, as mentioned earlier in this threat, to use 0,1% resistors in the front end stage to resolve the DC offset.

regards,
Piersma

Jack V please sent me a private message
 
I have had a look at the component layout (p.74 -elektuur 12/92) and it looks to me that diode D8 has the wrong orientation. On the layout there is a trace that runs from the anode of D8 to pin 2 of IC3. I think the trace should run from the cathode of D8 to pin 2 of IC3 according to the schematic.
 
As requested by PM.
 

Attachments

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