Spring reverb tank input grounding change

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

rock soderstrom

Tour de France
Joined
Oct 14, 2009
Messages
3,402
Location
Berlin
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.
 

Attachments

  • 20220523_221327.jpg
    20220523_221327.jpg
    125.9 KB · Views: 28
  • 20220523_221346.jpg
    20220523_221346.jpg
    111.1 KB · Views: 28
Last edited:
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) .
 
Last edited:
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,
 
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! 👍🏼
 
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.
 

Attachments

  • 20220525_120713.jpg
    20220525_120713.jpg
    133 KB · Views: 13
Last edited:

Latest posts

Back
Top