Odd C+ Reverb problem (FIXED - Doh!)

[Restless Rocks]

Now in a headshell the reverb tank is much closer to the Power Tranny and it's magnetic feild. Also you might try undoing the "one wire" ground mod since you have a new tank and shouldn't need it. Be sure to use the Metal cover for the tank and that it is making metal to metal contact with the tank itself.

 

[Boogiebabies]

The cap should be a small 400V .01 Orange Drop next to the 1W 100K plate resistor off V3A.
The red wire to the reverb knob comes off this cap. Just to the right of the orange drop there should be a 15uf 15V small black
cathode cap with a 15K resistor to ground near the red jumper wire. Off the L junction these two parts make, should be a blue wire
that goes to the foot switch.

I have two amps pulled out right now if you need anything else verified.

 

[CudBucket]

It's always the simple things.

The 9AB2A1B Accutronics tanks are meant to sit open side facing down.
When put in a head cab the open side faces up.

Sometimes this requires the little springs that hold/ suspend the reverb springs to the tanks case be moved.
If not the part inside the tank that suspends the springs might bottom out. Inmy case it was bottoming out.

I hate knowing about something but forgetting. Hopefully I'll never forget this one again!

Fwiw I've swapped some tanks into a head without moving the holding springs and there hasn't been a problem.
So it's not always needed.

Lastly, Technically speaking Accutronics specifies a 9AB2A1A model for tanks mounted open side up.

Are you forking kidding me? I have a Mark IV with the 9AB2A1B in it and of course it's mounted face up. When I turn the Reverb on, I hear a wierdness in the tone almost like the strings are fretting out. I bet this is the issue. I was going to bring it to a tech on Friday. What holes did you put the springs in? A pic would be great. It's at the very least, worth a try.

Dave

 

[CudBucket]

Thanks. I can't see the pics at work but I'll do so as soon as I get home. I guess the object is to raise the floating assembly so it doesn't touch the bottom of the pan. I know it's a pain as I've dealt with reverb issues on both the Lonestar and Studio Pre I had. At least with the Studio, you just take the spring assembly out of the pan and attach the springs to the chassis. Anyway, I'm rambling...

Dave

 

[Henz]

I recently had the exact same issue with my new verb tank. Every time I turned the verb pot up I would get this hum. Well, it turned out that the spring carriage was bottoming out on inside of tank and picking up cooling fan noise. I changed mounting springs around so now it floats. Hum gone. According to model number, the open side should be down but seems impossible in a head.