Hi guys!
I have problem with output transformer on SE TH100 monoblock amp. Transformer is James Audio.
Sometimes it starts buzing,long,short,quiet,loud...there is no rule to the patern. But now i find out that buzing get much quieter when i put my hand on transformer.
Any idea what is problem?
Everything is nicly connectet,ther is no poor conection insida amp. I give it to some guy who "fix it",he change so resistors on power transformer,but problem stay.
I have DALLAS II speakers with fostex 206s so they are very sensitive,so buz its too too loud forbmuzic listening.
I try to put new tubes,change tubes from one monoblock to another,but nothing changing the ptoblem. Second monoblock work with no problem,perfectly.
So,any idea?
I have problem with output transformer on SE TH100 monoblock amp. Transformer is James Audio.
Sometimes it starts buzing,long,short,quiet,loud...there is no rule to the patern. But now i find out that buzing get much quieter when i put my hand on transformer.
Any idea what is problem?
Everything is nicly connectet,ther is no poor conection insida amp. I give it to some guy who "fix it",he change so resistors on power transformer,but problem stay.
I have DALLAS II speakers with fostex 206s so they are very sensitive,so buz its too too loud forbmuzic listening.
I try to put new tubes,change tubes from one monoblock to another,but nothing changing the ptoblem. Second monoblock work with no problem,perfectly.
So,any idea?
If an output transformer buzzes, it can only do it during a signal passage. It shouldn't do it when no music signal is present. Could the amp be oscillating?
Hm,then its not output transformer,becuose buzz is always there. With conectet something on in or without,so then probaly is not output transformer.
Any idea what else could it be?
Strange thing hapening when this monoblock is turnd on. Fllor belove me,old pioneer tuner also start to play buzz,also in unpredictive waves. And only when bad monoblock is on. With other there is no problem with tuner.
Any idea?
Any idea what else could it be?
Strange thing hapening when this monoblock is turnd on. Fllor belove me,old pioneer tuner also start to play buzz,also in unpredictive waves. And only when bad monoblock is on. With other there is no problem with tuner.
Any idea?
The ac plug has a ground?
If both ac cables have a gnd conected can be a loop
Try to disconnect momentainly only one ac ground of one channel
Walter
Yes,both connected to ground. I will try this.
Now i find somthing new. Its always chang in buzz when you touch iterconnect cable. I try to swich from one to another 100 times. Always left one makes buzz,right never.
Now i try to change cable to diferent one and now is working good. For now at least. Is it posible that this monoblock have some problem with this type of cable? Becuose on second one works normaly.
It is anti cable.
Here are pics from one wich i change for another.
Now i find somthing new. Its always chang in buzz when you touch iterconnect cable. I try to swich from one to another 100 times. Always left one makes buzz,right never.
Now i try to change cable to diferent one and now is working good. For now at least. Is it posible that this monoblock have some problem with this type of cable? Becuose on second one works normaly.
It is anti cable.
Here are pics from one wich i change for another.
Why you don’t use same type of cables with a good shield?
Then can be some difference also on internal wiring
Walter
Then can be some difference also on internal wiring
Walter
I'm listening now for 2,5h with new cable,and it buzz only one time,shortly,maybe for half minute,and quaetly,not loud like before.
Is it posible that AC 220V input have voltage drop some times and that this drop couses buzz?
Is it posible that AC 220V input have voltage drop some times and that this drop couses buzz?
You may have made an oscillator. If you're wrapping a bunch of feedback around that output transformer, that could cause quite some instability.
I dont have shematics,i buy this amps.
For now with new cable plays ok. Maybe they need extra good shielded cables. I will try to get pair of extra good cables to be sure that its not from them.
For now with new cable plays ok. Maybe they need extra good shielded cables. I will try to get pair of extra good cables to be sure that its not from them.
If the amplifier is oscillating and disturbing nearby tuners, there is more than likely something fundamentally wrong with the design that needs to be addressed.
Try putting an 8 ohm resistor on the speaker terminals instead of a speaker and run the amp for a while under these conditions. If you get absolutely no appearance of the problem, that would tend to support my hypothesis.
Try putting an 8 ohm resistor on the speaker terminals instead of a speaker and run the amp for a while under these conditions. If you get absolutely no appearance of the problem, that would tend to support my hypothesis.
I make new interconnect,even solder it directlly inside without rca plug. Same problem.
Buzzig get quiter when i grab output transfor.e shield into my hang,or when i grab intervonnect cable in my hand. Cable is now star quad shielded,4x 1.5mm so its not to the cable. But i dont understand what and how to messure curent on 100th tube,can anyone help?
Buzzig get quiter when i grab output transfor.e shield into my hang,or when i grab intervonnect cable in my hand. Cable is now star quad shielded,4x 1.5mm so its not to the cable. But i dont understand what and how to messure curent on 100th tube,can anyone help?