Wiring help

[MarkMcQ]

Hi, I bought a Studio Preamp last week, and I had the top off so I could fix the input jack, which a previous owner had kindly chewed the thread on and left loosely attatched, and I noticed this wire hanging loose inside, and it appears to have just been cut and left.
http://www.skinplant.com/hippy/wire.JPG
On the right side, I've highlighted a metal tag (The lower of the 2) which seems to have the remains of a wire soldered to it, and it looks like it may be part of that white one. Can anyone shed any light on this?

The reverb is also non functioning as well. I noticed a tag on that too which looks a wire had been soldered to it at some point, but is no longer there (Centre one):
http://www.skinplant.com/hippy/reverb.JPG

Thanks
Mark

 

[ytse_jam]

hi i own a studio preamp but i'm not at home these days... when i'll come back i'll take a look!

 

[ytse_jam]

well, now i'm able to help you. Concerning the first problem and the first image, i can tell you there are 3 wires soldered to the upper tag, which are a green&yellow one, a black&white one and a black one. There is only one wire soldered to the lower and it is brown. There are no remains of a wire soldered to the lower tag at all. In my studio pre also there isn't that white wire i can see in your picture, but there are very little remains of a wire soldered to the starting point of yours (you can see the soldering iron - do you call it so in us english?? however it should be tin, or tin bronze, sorry for my technical terms, i'm italian - and also about 2mm of wire remains). It looks like my pre had that white wire but it was cut (i hope it was made during production at mesa, since it doesn't seem to be of use).
Concerning the second problem/picture, in my one there are the same remains of a wire soldered to the center tag. There should be one more spring, though, even if it is not the reason for which reverb does not work in your case...
i don't know what's wrong with your studio pre, i can tell you mine works right and sounds great, and reverb works perfect too. I'm gonna post some pictures, but i must wait for my sister who has to come back home from her job, since she's the only one able to use our new digital camera (i even don't know where the power button is :lol: )

 

[MarkMcQ]

Thanks, it's greatly appreciated.

I've ordered a new set of valves for it, one of which is the one for reverb, I'm hoping that might be why it's not working. If not, I'll probably get a local tech to give it a look over.

 

[ytse_jam]

Here are the pictures:

Point #1

Point #1 more zoomed

Point #1 another view

Reverb Section

Reverb Section more zoomed

Point #2 (this is the one you have the white unuseful wire soldered to)

Just a whole view...

Just a view of the circuitboard

 

[ytse_jam]

On the right side, I've highlighted a metal tag (The lower of the 2) which seems to have the remains of a wire soldered to it, and it looks like it may be part of that white one. Can anyone shed any light on this?

Even if it was so, it wouldn't have changed anything but worsening the circuit, since both wire conjunctions would have been put to earth and the presence of the wire could have generated ground loop problems. I'm not a very expert technician, and i'm finding it difficult to express these technical considerations in english since i speak italian, so i hope to be right and to have expressed the right concept. :wink:

The reverb is also non functioning as well.

As you said, you might change the 12AT7 tube which is the one for reverb if i'm not wrong. The first time i looked inside my pre I discovered that all 12AX7s were Mesa tubes (probably still the originals!) but the 12AT7 was an Electro Harmonix, so it could be possible that the reverb tube is the one which more easily fails. But i must say i'm not such an expert, so if you don't mind you could try changing the 12AT7, but if you don't want to buy it being not sure of what the problem is, i suggest you to write a PM to anyone of the forum veterans who surely know much more than me about these things!bye and good luck

 

[MarkMcQ]

Thanks for taking those pics for me. I owe you one.

I'll probably just unsolder that white wire and bin it.
My new valves arrived this morning. Got Electro Harmonix gold ones, they have a nicer sound that the Mesa ones that were in it. Not sure if it's a characteristic thing, or if the Mesa ones were just needing replaced. But it definitely sounds somewhat better than it did a few days ago when I got it, although it's still not exactly as I had hoped.
Now I need to pick up a new cab, and sometime soon a valve poweramp too. My Marshall VS120 is solidstate and seems to colour the sound. Hopefully once I have both of those, the pre-amp will start to sound a bit more to my liking.

Reverb is still dead though. Maybe I'll try and track down another spring for it to replace the missing one. Maybe even have an amp tech check this over to see if it's a fault. I never use reverb, plus I have a TC Electronics M300 in my setup which has some decent ones, should I ever want to, but I'd like to get the reverb working anyway, so the pre-amp is fully functioning.