Spring reverb tank input grounding change

[rock soderstrom]

Hi guys, I want to change the inputs on two 9AB2A1C tanks. The second A indicates a grounded input, but the circuit of my choice wants a floating input.

https://sound-au.com/project34.htm
Therefore, I would simply install an isolated RCA jack and thus make the input ungrounded on each pan.

Is that right?

The second photo shows a 4FB3C2C with a isolated input.

 

[user 130681]

Correct.

 

[rock soderstrom]

Thanks Jon, I wanted to be sure before drilling holes in my precious tanks.

 

[Tubetec]

I often just put in a TRS Jack socket in that location , so now depending on connector I can have balanced or unbalanced connection on TS or TRS jack and choose the most appropriate cable .
You do have to watch out for the depth of the jack socket though as it might come into contact with the reverb sub chassis . An old fashioned switchcraft metal TRS works well , also be carefull if you have to enlarge the mounting hole , you dont want to contaminate the magnets/pole pieces with metal fillings , so best remove the spring sub unit before attempting the mod .
One more thing , a drill bit can easily snag up while enlarging the hole ,I found this out for myself ! , a good round file will get the job done without any chance of F-ups.

Its mostly the recovery side I've swaped out to TRS ,but I have used tanks with drive impedences of around 200 ohms off your usual balanced op amp mixer out , aux out etc , its a bit tough on the op amps , but you needent drive it balls to the wall either . A mixer headphone out if you have one to spare out usually does a much better job of driving the tank(s) .

 

[user 130681]

Thanks Jon, I wanted to be sure before drilling holes in my precious tanks.

I would remove the old sockets and fit isolated sockets in the orignal holes.

 

[rock soderstrom]

I would remove the old sockets and fit isolated sockets in the orignal holes.

Initially I wanted to leave the original RCA socket installed but the more I think about it, this is the best solution.

 

[CJ]

Mod pans have a small PC board with provisions for jumpering grounds with a solder bridge, that is, two solder pads that are close enuff to negate surface tension of molten solder. Of course that does not help you out so what was I thinking, I should be committed,

 

[TwentyTrees]

Mod pans have a small PC board with provisions for jumpering grounds with a solder bridge, that is, two solder pads that are close enuff to negate surface tension of molten solder. Of course that does not help you out so what was I thinking, I should be committed,

Helps me out though, as I'm planning a build with Mod spring tanks. Thanks!

 

[rock soderstrom]

Mod pans have a small PC board with provisions for jumpering grounds with a solder bridge, that is, two solder pads that are close enuff to negate surface tension of molten solder

You're right, this is a good solution, in fact all manufacturers should do it this way.

MOD pan grounding solution, see photo.