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All high end and low output

Posted:
Sun Nov 05, 2006 6:07 pm
by docvlak
My A12 works but it has low gain and nothing but high end. Sounds like a high pass set at about 700hz . Any ideas?

Posted:
Tue Nov 07, 2006 1:58 pm
by tpryan
Try re-flowing all the solder joints at the input transformer. Verify that the output transformer is wired correctly. Is there any significant DC offset at U1, pin 6?
phase switch cuts signal

Posted:
Wed Nov 08, 2006 12:13 pm
by docvlak
I resoldered the input trans. and all the wires on the output tran are correct. When it comes to checking for DC offset Im getting out of my league again. i dont know if this is correct but I set my multimeter to 20v DC and with the negative probe grounded and the pos on pin 6 I get a reading of.003. It still has very low output with no low end. One thing I discovered ,though is that when I switch the phase the signal is gone . I hope this points to something.
J6 the culprit?

Posted:
Mon Nov 13, 2006 11:54 am
by docvlak
In the assembly instructions it mentions the J6 jumper(which there wasnt one in the kit) has a 1/2 amplitude signal available there(something like that). And no instructions to jumper it (so I didnt). I took the kit in to my local tech and he called me and said when the J6 is jumpered everything is fine. Should J6 be jumpered? This is my first A12 so I dont have one to compare it to. Only J99s.and if so the the assembly sheet should state that for not so savvy guys like me. If It is wrong please let me know. Thanks