Having trouble installing East mid Sweep preamp - have I broken it?

[Dolando]

Hello, I need some help! I have a basic understanding on wiring, but I'm now out of my depth...

I have got an East mid sweep that I planned to put in my passive jazz thats wired with a blend pot. (Diagram attached)

When wiring up the preamp I managed to wire it upside down which meant the 9v battery was going into both hot and cold inputs. Will this have damaged the preamp? Also, the bass worked but the EQ didn't.

Secondly, I wired it up the right way and nothing is coming through at all.

I was told that the mid sweep output should feed the jack Hot output, so I have the input coming from the middle tone lug to Hot input. The ground is coming from tone casing, then the output goes to the hot jack tip output. The ground for the jack comes from the tone casing as well. Is this correct and i've ruined the preamp, or am I just doing it wrong?

Oh here's the East Wiring diagram;

http://www.east-uk.com/pdf/midsweep01.pdf

 

[stratamania]

The wiring as described seems as though it is workable, unless I misunderstood the description.

What happens if you remove either the wire to the cold input or the ground as they seem to be linked internally ?

It is possible that sending the voltage directly through the circuit could have damaged it.

But I think possibly the best thing to do would be to contact East and get their input.

 

[Dolando]

Thanks for the reply. Yea thats what I'm afraid of. Its a silly mistake I had it upside down in the control plate, but still read the diagram like it was the right way up!

When I plug the battery in, it gets really hot in a few minutes which seems a little odd. A couple of things I'm not sure on is the difference between hot and cold inputs? Never seen cold input before, I was going into the hot.

Also it says 9-18v +VE, not sure what VE is? I had the battery going straight into the preamp, am I missing something?

I'm going to give them a call Monday, just wanted to see if anyone would have an idea whats wrong. I'll see what happens when going into the cold, what happens when I remove the wire.

 

[stratamania]

+VE just means positive.

Hot and cold in this case just mean the hot is the  positive or live wire of the circuit and cold the negative.

In guitar circuits the ground or earth tends to be joined to negative but in other circuits you will usually have, live or hot, cold or negative and an earth such as you find in a UK power socket.

 

[Dolando]

Thanks for the help Stratamania, you're always very helpful.

I contacted John East and he was very helpful, he even replied to me on Sunday. Anyway, he hasn't said if I have damaged it, but he did draw out a diagram for me to use to wire it up properly. I thought I'd share it for anyone else that may need it.

I'll let you know how it goes when I wire it up.

 

[stratamania]

Great, that's good service on a Sunday.

Hope it works out...

No problem I just try to help out where I can even if it's just an idea.  :icon_thumright:

 

[swarfrat]

I'm just guessing from my own electronics experience, but if the battery got hot rather than the circuit, there's probably a reverse polarity protection diode that shorts out the battery if connected backwards. Its not the most elegant solution but cheap and it works

 

[Dolando]

Thanks for the help and knowledge guys. I've just fitted it and it works and it sounds awesome. I'll post a pic when I get a chance.

 

[stratamania]

Good to hear it's working...