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Question: Preamp question

Razor1976

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Jul 21, 2021
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Melbourne, Australia
Is there a way of knowing what year this stingray preamp is? I've had it for years and might use it for a project. I'm assuming it's from mid 80's or early 90's? Cheers

MM Stingray preamp.jpg
 

Rod Trussbroken

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cache_7192980.JPG


Above is a 1985 Ernie Ball 2EQ Sting Ray preamp.

Your preamp is also a 1985. Note the 3 grey and 2 blue electrolytic capacitors. Putting aside capacitor colours, it's the same as a Pre-EB preamp from c.1982 onwards. EB and Pre-EB use the same circuit boards which are designated "B3" on the underside copper track. The only difference between EB and Pre-EB is that EB soldered the IC chip "LM4250CN" direct to the circuit board. The Pre-EB has the IC mounted to the board via an IC socket.

Before soldering the preamp into circuit it should really have a 1K Ohm protection resistor added to the end of the white lead-out wire (bottom right). EB included this resistor on the board in c.1986.I have the wiring schematic if you need it.
 
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Razor1976

Member
Joined
Jul 21, 2021
Messages
8
Location
Melbourne, Australia
cache_7192980.JPG


Above is a 1985 Ernie Ball 2EQ Sting Ray preamp.

Your preamp is also a 1985. Note the 3 grey and 2 blue electrolytic capacitors. Putting aside capacitor colours, it's the same as a Pre-EB preamp from c.1982 onwards. EB and Pre-EB use the same circuit boards which are designated "B3" on the underside copper track. The only difference between EB and Pre-EB is that EB soldered the IC chip "LM4250CN" direct to the circuit board. The Pre-EB has the IC mounted to the board via an IC socket.

Before soldering the preamp into circuit it should really have a 1K Ohm protection resistor added to the end of the white lead-out wire (bottom right). EB included this resistor on the board in c.1986.I have the wiring schematic if you need it.

Awesome. Thanks Gav, I appreciate it. Could you please send me the schematic? Thanks again.
 

Razor1976

Member
Joined
Jul 21, 2021
Messages
8
Location
Melbourne, Australia
cache_7192980.JPG


Above is a 1985 Ernie Ball 2EQ Sting Ray preamp.

Your preamp is also a 1985. Note the 3 grey and 2 blue electrolytic capacitors. Putting aside capacitor colours, it's the same as a Pre-EB preamp from c.1982 onwards. EB and Pre-EB use the same circuit boards which are designated "B3" on the underside copper track. The only difference between EB and Pre-EB is that EB soldered the IC chip "LM4250CN" direct to the circuit board. The Pre-EB has the IC mounted to the board via an IC socket.

Before soldering the preamp into circuit it should really have a 1K Ohm protection resistor added to the end of the white lead-out wire (bottom right). EB included this resistor on the board in c.1986.I have the wiring schematic if you need it.

Cheers Gav. Much appreciated. Could you pls send me the schematic? Thanks again.
 

kevins

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Feb 13, 2005
Messages
454
Travis is that you?

I bought one identical to that from a guy named Travis lol
 
Last edited:

kevins

Well-known member
Joined
Feb 13, 2005
Messages
454
cache_7192980.JPG


Above is a 1985 Ernie Ball 2EQ Sting Ray preamp.

Your preamp is also a 1985. Note the 3 grey and 2 blue electrolytic capacitors. Putting aside capacitor colours, it's the same as a Pre-EB preamp from c.1982 onwards. EB and Pre-EB use the same circuit boards which are designated "B3" on the underside copper track. The only difference between EB and Pre-EB is that EB soldered the IC chip "LM4250CN" direct to the circuit board. The Pre-EB has the IC mounted to the board via an IC socket.

Before soldering the preamp into circuit it should really have a 1K Ohm protection resistor added to the end of the white lead-out wire (bottom right). EB included this resistor on the board in c.1986.I have the wiring schematic if you need it.
How likely is the preamp to blow without it anyways?
 

Rod Trussbroken

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How likely is the preamp to blow without it anyways?

The resistor is to protect the preamp IC from being destroyed if the guitar lead becomes short-circuited (even momentarily). Easy to happen.

All MM Sting Ray and Sabre Basses have them factory-fitted. Initially they were an outboard component. They became an on-board component c. 1986. The above 1985 preamp doesn't have the resistor on the circuit board. It, and earlier preamps will have to have it added manually.
 
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