Problem with Input on Tube Amp
Ok, heres whats goin on:
I broke one of the input jacks on my sovtek mig-100, so I decided to just replace both of them. I wired it up the way it was originally wired up but now I am having a problem.
The low input gets sound but it is very low and not what it is supposed to sound like. The high input does not work at all and i just get a really offensive buzzing. Both channels buzz when I insert the tip of the plug.
My guess is that I messed up with the little jumper cables that connect the two inputs. Can anyone help? I could provide pictures if that would be better.
thank you very much for any help!
-RJ
Ok, heres whats goin on:
I broke one of the input jacks on my sovtek mig-100, so I decided to just replace both of them. I wired it up the way it was originally wired up but now I am having a problem.
The low input gets sound but it is very low and not what it is supposed to sound like. The high input does not work at all and i just get a really offensive buzzing. Both channels buzz when I insert the tip of the plug.
My guess is that I messed up with the little jumper cables that connect the two inputs. Can anyone help? I could provide pictures if that would be better.
thank you very much for any help!
-RJ
Ok, heres whats goin on:
I broke one of the input jacks on my sovtek mig-100, so I decided to just replace both of them. I wired it up the way it was originally wired up but now I am having a problem.
The low input gets sound but it is very low and not what it is supposed to sound like. The high input does not work at all and i just get a really offensive buzzing. Both channels buzz when I insert the tip of the plug.
My guess is that I messed up with the little jumper cables that connect the two inputs. Can anyone help? I could provide pictures if that would be better.
thanks so much
-RJ
I broke one of the input jacks on my sovtek mig-100, so I decided to just replace both of them. I wired it up the way it was originally wired up but now I am having a problem.
The low input gets sound but it is very low and not what it is supposed to sound like. The high input does not work at all and i just get a really offensive buzzing. Both channels buzz when I insert the tip of the plug.
My guess is that I messed up with the little jumper cables that connect the two inputs. Can anyone help? I could provide pictures if that would be better.
thanks so much
-RJ
are you sure you got the same type of jack?
There are shorting vs. non-shorting...etc...different brands use different types.
-maz
There are shorting vs. non-shorting...etc...different brands use different types.
-maz
Take it to a tech. You might have used the wrong type of sockets... A decent tech should be able to fix something like that in 10 minutes flat.
Also be damn careful, those migs have around 500 volts on their output tubes!!! And the caps stay charged for a while...
Also be damn careful, those migs have around 500 volts on their output tubes!!! And the caps stay charged for a while...
The schematic of your amp tells me that it uses mono jack inputs. Stereo inputs look the same, but are wired differently. You should get mono jacks.
Heres a picure of what I did. That white jumper wire is going from tip to tip. The red one is going from the tip of the low input (the one on the left side) to the sleeve of the high. Thank you very much!
ooops, forgot the links.
http://www.ftwcw.net/amp1.jpg
http://www.ftwcw.net/amp2.jpg
http://www.ftwcw.net/amp3.jpg
http://www.ftwcw.net/amp1.jpg
http://www.ftwcw.net/amp2.jpg
http://www.ftwcw.net/amp3.jpg
I'm sorry I don't know what's going on in your amp. I looked at the sovtek schematics and all sovtek amps use mono jacks.
So me thinks your amplifier is modded in a way I have never seen before.
Please let me know how you fixed it and maybe what the input switching is like. Good luck!
So me thinks your amplifier is modded in a way I have never seen before.
Please let me know how you fixed it and maybe what the input switching is like. Good luck!
I think its more of an issue of a SHORTING VS. NON-SHORTING jack than it is the stereo v mono thing.
i could be completely off-base, though.
-Maz
i could be completely off-base, though.
-Maz
Not Stereo Jacks
They are not stereo jacks. They do have 3 connections but 1 of them is a shorting switch that contacts the tip connection when a jack is not inserted. Have a look at the schematic and you will see this- http://www1.korksoft.com/~schem/newamps/sovtek_mig100h.pdf
The reason you don't have any sound out of the "High" input is because you have not closed the circuit to your first potentiometer. A good musical instrment store should be able to sell you a couple of the correct jacks and then it's just a matter of tracing the wiring in amp and soldering away!
As stated beore, please be very careful while working on this one. They have power supply caps in series to handle the high voltage and that means you could expect to find >450 volts on the B+ rail! Even in standby mode, the first pair of caps are going to be charged and the 220K equalizing resistors on the second pair will not be in the circuit. If none of this makes sense to you, please take this to a qualified tech to have it repaired. It's just not worth risking your life to save a few bucks.
T
They are not stereo jacks. They do have 3 connections but 1 of them is a shorting switch that contacts the tip connection when a jack is not inserted. Have a look at the schematic and you will see this- http://www1.korksoft.com/~schem/newamps/sovtek_mig100h.pdf
The reason you don't have any sound out of the "High" input is because you have not closed the circuit to your first potentiometer. A good musical instrment store should be able to sell you a couple of the correct jacks and then it's just a matter of tracing the wiring in amp and soldering away!
As stated beore, please be very careful while working on this one. They have power supply caps in series to handle the high voltage and that means you could expect to find >450 volts on the B+ rail! Even in standby mode, the first pair of caps are going to be charged and the 220K equalizing resistors on the second pair will not be in the circuit. If none of this makes sense to you, please take this to a qualified tech to have it repaired. It's just not worth risking your life to save a few bucks.
T
It is fixed but now I am experience like a crackling problem as the sound is decaying, I had this before and it was a bad solder joint. anyone know where to start?
Does it do this in both inputs? If it's only on the High input, look at the shorting portion of the Low jack. Other than that, you might try cleaning the tube pins and sockets. If the tubes are ones that have been in there a while (or just really old...I mean vintage, like in my case) they could have some oxidation on the pins. It's simple, and cheap. If you can tap the tubes and get the noise to occur, it's time to replace that one. I have more than my fair share of old triodes that are just plain noisy. I hope it solves your problem!
T
T
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