dr. benway wrote:1) Why do the 16 and 4 ohm outputs not seem to be wired up? The 8 ohm is a-okay, but nothing from the other two.

I checked on my Sovtek to make sure that the 4 and 16 werent designed only for hooking the head up to more than one cab (i.e. switched off of the 8 ohm tap in some way), but I saw nothing to indicate they were. Thus, I dont know why that they wouldnt work, but nevertheless you should only hook your cab up to the one that matches the load of the cab. Since the load of your cab is more than 8 ohms, it shouldnt present any immediate problems, but you should probably find a way to get the other two taps working, if that's possible.

2) There was a blue flash that seemed to come from somewhere around the leftmost (as you look at the back of the amp) tube and what I assume to be the capacitors when it was first switched on. I read this thread but that doesn't seem to nail down whether this is a bad or okay thing--it should probably be noted that I was running the 8 ohm output into my 16 ohm cab for reasons noted above.

It was probably from one of the power tubes, but there's really no way to tell from that description for sure what caused the spark.

I would have the amp looked at by a tech, tubes checked and replaced where needed, power tubes biased, and possibly the filter caps replaced. I tend to do that every time I buy a used tube amp, the spark and the two non-working outputs just gives you more reasons.

3) The leftmost tube glowed a hell of a lot more than the right one for a while, and continued to increase its glow until we chickened out and cut the power. After that it acted normal from that point. What was this phenomenon and is it related to number two above?

I imagine it could be. There could be an intermittent short in one of the power tubes. Or it could be something else.

Get it checked out.

4) possibly the most stupid question of all: what's the deal with the standby switch? I assume it's to warm the tubes or something? Should I play with this switch on or off?

It's for warming up the amp before playing. When the amp is in standby, you wont be able to get any sounds out of it, but the amp will be warming up.

Thanks for the tips. I'll try and find an amp tech in the local area and see if they'll take a look at it for me. Sucks though as I've been waiting for it for weeks and wanted to just play, dammit.

I own a mig60 which is an okay amp by me but nothing like a plexi or whatever. I was def. unhot for the higher gain levels so I ripped out the tubes and put some fresh Svetlana's (what else) in. It's better now.

One thing to remember is that these things are bass-y so if klang is what you're looking for I'd avoid [them].

Hey there!

See my post above from almost five years ago... holy crap, I've been here a long time...

Which 50 is it. Master volume, on non master volume?

A bright blue flash makes me thing you have a bunk tube, which also would explain why one is running hotter.

So it could just be a warn out tube, or it could be an issue with bias. If a tube loses its negative bias supply, then it will overheat in a matter of minutes.

Try swapping the power tubes, turning the amp on, and see if the bright glow follows the tube or the socket. If the same tube in the alternate socket glows, it's the tube, if the other tube glows after switching (the bright tube in in the socket where the other one glowed bright), then it's a voltage or bias issue.

let us know.

Ben

It's a non-master volume. I won't be back with it until tomorrow evening, but after the initial red-plating (as I have been informed it is called) it didn't happen again--no glow from that tube and amp seemingly fine. I'll keep an eye on it.

I have been in contact with the guy who assembled the amp. Supposedly the 8 ohm tap is the only one connected. His English was pretty bad, but from what I can tell he's not sure whether the transformer in there is even capable of supplying the 4 & 16 ohm taps, and from research it seems very difficult to find out. I may be wrong. It does mean that I have to keep running from the 8 ohm tap into the 16 ohm cab for now (and possibly forever if this transformer issue makes things as complicated as it seems to).

dr. benway wrote:I have been in contact with the guy who assembled the amp. Supposedly the 8 ohm tap is the only one connected.

My thought was that maybe the transformer had been replaced with a model that only had an 8 ohm out.

Also, feel free to take it out of the chassis and snap some pics. It probably won;t help, but there may be some telltale signs in there of what's going on.

ben