Carlos, USE THIS RESISTOR! The 10ohm previne the terra's loop
Carlos, usa o resistor! Ele previne o loop do terra.
The terras loop cause very big problems in signal. In special the High Frequency signals
O loop de terra causa um grande problema no sinal. Em especial nas altas frequências.
Thanks.
Carlos, usa o resistor! Ele previne o loop do terra.
The terras loop cause very big problems in signal. In special the High Frequency signals
O loop de terra causa um grande problema no sinal. Em especial nas altas frequências.
Thanks.
So, you suggest me to keep the resistor, thank you Mod evil.
To finish with the ground loop.
It is OK!... it is already installed, and to change is easy..just to make a jumper over the 10 ohms resistor and ready!
Quaaaack!
I think they gave one on Charlie...well i think they did..sure they did
regards,
Carlos
To finish with the ground loop.
It is OK!... it is already installed, and to change is easy..just to make a jumper over the 10 ohms resistor and ready!
Quaaaack!
I think they gave one on Charlie...well i think they did..sure they did
regards,
Carlos
The 10R resistor
Carlos,
keep the resistor, but protect it as shown on attached image. I recommend 1N5408, 3Amp diodes. At least 1N4007, 1Amp.
Based on experience and burnt speakers resulting from resistor failure (peak power energy destroyed the resistor, or repeatively degraded until it failed).
I am 50 years old, if you wanted to know
Carlos,
keep the resistor, but protect it as shown on attached image. I recommend 1N5408, 3Amp diodes. At least 1N4007, 1Amp.
Based on experience and burnt speakers resulting from resistor failure (peak power energy destroyed the resistor, or repeatively degraded until it failed).
I am 50 years old, if you wanted to know
Attachments
Sheldon said:
ungrounded equipment combined with emi filter caps between L and GND on powerline side of equipment. Current is really small, couple milliamps max, not going to lethal but can supprise nastily.
About 110VAC unloaded as it is capacitive divider between L-N. Or around 55VAC in us.
And yes, properly grounded equipment helps 100%
Well...hehe.... never is too much late to learn new things.
I have noticed that this kind of connection result noiseless related hum captured....but did not know those secondary problems that can happen.
I am 54 years old Pavel, and i thank you by your explanation, it is good that you are here with us, with this good will to give us informations about doubts we have...many other guys knows those details,but use to say that:
"Belf book, page 41, he used this approach to avoid capture of photonic energy from Andromeda"... well .... those things, that really do not turn things clear.
I think that hundreds will thank you, because there's a lot of things we do not know, and we go living ashamed to ask questions about that.
Great Mod Evil, you evoluted very fast....now you will turn my teacher, already elected for this job!...unless you are repeating what you have read perfectly memorized...ahahahaha!
regards,
Carlos
I have noticed that this kind of connection result noiseless related hum captured....but did not know those secondary problems that can happen.
I am 54 years old Pavel, and i thank you by your explanation, it is good that you are here with us, with this good will to give us informations about doubts we have...many other guys knows those details,but use to say that:
"Belf book, page 41, he used this approach to avoid capture of photonic energy from Andromeda"... well .... those things, that really do not turn things clear.
I think that hundreds will thank you, because there's a lot of things we do not know, and we go living ashamed to ask questions about that.
Great Mod Evil, you evoluted very fast....now you will turn my teacher, already elected for this job!...unless you are repeating what you have read perfectly memorized...ahahahaha!
regards,
Carlos
mzzj said:
Thanks. Ah, didn't think about emi caps. Fortunately the only caps of that nature I have in any of my gear are small ones, not enough juice to fry a 1/4 watt 10ohm resistor, I think. And all my stuff is grounded and no cable connection, so I think I'm safe for now. I'll go naked until I have another reason to open things up. By the way, I lifted the power ground from earth and chassis in this amp by using a 150 ohm resistor, protected by diodes as described above.
Sheldon
PMA said:Or emitter degeneration in the input BJT diff pair?
To bad that i had not planned it when i made the pcb...
anatech said:
Yes, there is something about jfets, in theory a degenerated bjt would
be better, but there is more, maybe it has to do with different dynamic
behaviour ? (dynamic capacitance and that stuff)
Gladly, the sk170 is a simple drop in for the mpsa18 !
Mike
Hi Mike,
I'll have to pick some 2SK170's up. I can mount degeneration resistors without too much trouble. Just yank the emitter leads up and stick them in series.
Okay, I'll be nice and pull the entire transistor when doing this. It's neater that way.
At this point this is a prototype. If there is a big difference, the artwork can be modified. I wouldn't worry too much about it. Besides, I still have to make the PCB's. I wonder if I can sneak them in.
-Chris
I'll have to pick some 2SK170's up. I can mount degeneration resistors without too much trouble. Just yank the emitter leads up and stick them in series.
Okay, I'll be nice and pull the entire transistor when doing this. It's neater that way.
At this point this is a prototype. If there is a big difference, the artwork can be modified. I wouldn't worry too much about it. Besides, I still have to make the PCB's. I wonder if I can sneak them in.
-Chris
MikeB said:
Hmm, interesting, with 22ohm REs in input-LTP it would get unitygainstable
with a safetymargin of 44° and 122° overall...
Don't know if this would change the sound ?
Mike
Actually that's why I posted (phase margin)....
According to our listening experience with another amplifiers, emitter degeneration has almost always improved the sound ... should be tried, and I might do it ...
MikeB said:
To bad that i had not planned it when i made the pcb...
Mike
There are degeneration resistors in both stages in my version. So the open loop gain is much lower. But the amplifier is rock solid, and very stable. It can drive pure capacitive loads, without any oscillation, or overshot...
sajti