#1
I have recently been able to acquire a studio preamp for a rather low price (lower then the general used market) and while it is working just fine there are some kinks that I would like to iron out before fully installing it in my rig.
Since I don't have a camera with me right now I am not able to make any photos of the amp today but I will surely post some tomorrow afternoon.

The amp itself looks just a little beat up but the sound (as far as I can tell) is what it should be. I had a little issue with the reverb tank (one spring that kept the tank in place was loose and stretched) but I worked my way around this problem and was able to fix it.

Now the first thing that I would want to ask is regarding the dust that has settled on most of the electrical parts inside the preamp. I used to use isopropanol to clean my graphics card (I had a little leak in my water cooling system and I had to get rid of some nasty goo that had settled on the pcb) but since I have never had to clean an old preamp I don't know if there could be some kind of problem with this kind of method.
My thinking is that, since isopropanol is volatile, that there are no liquids left on the main components to cause a shortage.
Could there be a problem that the alcohol might react with the old parts or is it completely harmless and doesn't need any additional attention when it is used in this context?

The other thing is that the transformer seems to be having a humming problem that worries me a little bit. I have done some research on the matter and have found contradicting comments. Some say that there is nothing to be worried about and then there are the folks who tell you to immediately replace the transformer or the the preamp itself will take some damage. Since the last comment was made on an audio electronics forum I guess that that's the comment to go by.
As far as I know these humming noises can be caused be DC that flows through the transformer. Cheap and or Old transformer will suffer from this phenomenon more and thus should be replaced because the transformer itself is giving of vibrations that could damage the tubes for example.
I have tried to seek out the transformer that would be needed to replace my old one but so far I have found nothing that could be useful.

What I do know is that the transformer which were used in the US and European versions are practically the same (they are only wired differently).

Does anyone know if there are still ways to get a hold of these transformers and/or if this problem that I am having is just a minor flaw that doesn't need my attention.

To be clear, the humming noise that I am hearing comes directly from the transformer and is present in every possible configuration. It is not a loud humming noise but definitely noticeable if you focus on it.


Now the last thing that I want to know is, if there are any replacement parts for the graphic eq? It is not broken and doesn't need fixing but I just would like to know a place that I could use for future reference.

The other problems that I see with the preamp are minor. Some input jacks may need a replacement (although they still work - they just, let's say lost their grip) and some potentiometers show some signs of age.


As I said before, the amp itself sounds perfect. The cleans are crisp and the distortion screams Metallica.
The preamp itself is a bit noisy but I attribute that to the nature of an overdriven amp.


Lastly I apologize for my rather lengthy thread and for my english skills (I am from Germany). I know that some questions might seem stupid but i just try to keep this little beauty from breaking down.

I know that I already started a thread about this very subject but I felt that these questions might fit this environment a little bit better. The old thread is gone and I appreciate any answer or hin that you could give me.
Last edited by swedish_chef at Apr 10, 2011,
#2
Last edited by swedish_chef at Apr 11, 2011,