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Step 38 Questions.

PostPosted: Fri Nov 16, 2007 6:12 pm
by Garagedays
This is the first kit I have ever built so I am proud to say I am only off a little bit :-) On Step 38, it is telling me to measure R8. It should be between 13v and 14v. Mine is measuring 12v. Can someone get me past this part please :-)

Also, need to say thank you to Tim and Seventh Circle for putting together a very organized and well thought out kit. I have only used a couple of cheaper kits to see if I had the conifidence to tacke these kits. I am definately impressed with how well things went :-) I have 2 N72's and 2 A12's to start work on over the weekend and I can't wait to put these to use.

Tim Davis

PostPosted: Sat Nov 17, 2007 11:01 am
by tpryan
12v should be fine, depending on the power supply settings. As you use higher voltages, the voltage at R8/R9 increases. Another test is to measure the voltage at the junction of R29 and R30, which should be very close to 0v no matter where the regulators are set.

PostPosted: Sun Dec 02, 2007 10:34 pm
by Garagedays
Tim,
Thanks for the reply, I have been fairly busy and haven't gotten back to this C84. I think my final question before I rack this C84 is...

U1, U 5, and U 6 are running fairly hot.

U1, I can only touch for about 4-5 seconds before it is too hot. I dont see smoke, I dont really smell anything but how hot should this opamp get?

U 5 and U 6 are fairly hot as well... How hot should these to get?

I completed my 2 A12's and 2 N72's and they are now all working :-) I want to get this one ready for some acoustic recording I have coming up :-)

Thanks,
Tim Davis

PostPosted: Mon Dec 03, 2007 8:11 pm
by tpryan
It's normal for the op-amps to run hot, especially U1. We haven't killed one yet.

PostPosted: Tue Dec 04, 2007 3:57 pm
by Garagedays
Thanks Tim. I installed it in the chassis and it is working great! Did some quick recording of acoustic guitar and do like it on that. I have heard that the J99 sounds great on acoustic as well. I love putting these together so hopefully I can order 2 J99's and 2 more A12's without upsetting the balance in my checkbook and my marriage :-)


Thanks for your help. As always, it is appreciated.


Tim Davis