AC15 reverb

sinjunkie · Post by **sinjunkie** » Fri Dec 23, 2005 4:10 am

I have a Korg AC15 TB i think it's a '98.
it seems to me that the reverb is kind of weak. compared to my 72 princeton reverb.
it works but just adds a little fullness when the knob is maxed out, I have new JJ ECC83s tubes in it now and have tried swapping tubes with no change.... is this normal for this amp?
also what are the tube locations functions for this amp .... which one is the phase inverter?
the tubs closest to the rectifier looks grayish toward the top and the others still look new with no coloration to the glass, all these tubes have very low hours maybe 5 total run time.
sorry to bounce to different issues in the same post.
thanks ~

triode · Post by **triode** » Sat Dec 24, 2005 9:11 pm

The tubes should all be tested with a calibrated tester. Many vendors sell bad tubes, they do not even test them before they sell them. Also, you may have a bad reverb tank. The transducers get worn out or broken due to vibration or rough handling.

Lastly, you may have a defective reverb recovery transformer. I am not exactly sure if that model uses one as I have not seen the schematic. When the reverb is bad, there are several things to check.

sinjunkie · Post by **sinjunkie** » Mon Dec 26, 2005 5:26 am

found it I have a bad cable to the reverb tank.

admin · Post by **admin** » Mon Dec 26, 2005 6:10 am

Great. Don't you just love it when the fix is user friendly.

sinjunkie · Post by **sinjunkie** » Mon Dec 26, 2005 9:59 am

yes, I guess I was looking for something major, I'm glad it was just the cable.
I'm still looking for the tube location functions for this amp.... like which one is the phase inverter, if any one can help.
Thanks~

jps · Post by **jps** » Mon Dec 26, 2005 10:13 am

The phase inverter should be the tube closest to the power tubes, after the preamp and reverb tubes.

sinjunkie · Post by **sinjunkie** » Wed Dec 28, 2005 11:48 am

thanks , but the Vox tubes are not laid out like a fender Amp there are two rows of tubes the pre-amp tubes in one row and the power tubes and rectifier in the other.
I am guessing that the pi tube is the last pre-amp tube, I was just looking for verification from someone who knows.

jps · Post by **jps** » Wed Dec 28, 2005 4:55 pm

I would still think it should be the closest to the power tubes for layout purposes, just a guess however.