Hi tinitus, the toroids that I will be using have 35v secondaries. I doubt whether I "would" hear any difference with the increased bias, but I suppose it might be worth trying just for the experiment. ( whilst monitoring the temperature of everything ). It would be perhaps nice to have 10-20 watts in class A.....we shall see. Cheers.
Overload protection
ACD,
Just want to know why you only get output current from one transistor only in the output protection.
I mean , you are measuring Q112/113 output current and based on that one protection starts.
Should not you be also measuring all output transistors ?
if that's the case , is it enough to repeat resitances for all transistors and do a parallel connecting (the other end of R) to the join R128/124?
Cheers
Zenon
ACD,
Just want to know why you only get output current from one transistor only in the output protection.
I mean , you are measuring Q112/113 output current and based on that one protection starts.
Should not you be also measuring all output transistors ?
if that's the case , is it enough to repeat resitances for all transistors and do a parallel connecting (the other end of R) to the join R128/124?
Cheers
Zenon
In this case it was a choice I made due to the layout. If you look at other schematics some measure only on one output pair (as on the LYNX) and others on all output pairs. The best is of course to measure across all output pairs.
If you want do measure across all output pairs, you can "duplicate" R124 and connect one end of each of these to R130/132/134 and the other end to the point R124/126.
Just calculate R124 and R126 as normal, and then multiply R124 and the 3 extra added resistors with 4 (as they are seen as in parallel from the protection circuit).
Q. for crt
Hi Crt,
It seems you fabricated your own board so they are not plated-thru, right? How did you manage to solder the outputs to the pcb where the soldering has to be done on the non-component side (or even both sides) also. Any special tools or setup you have to use? Did you solder on the component side first with the heatsink in place and take the heatsink off and solder on the soldering side again?
Always wonder how to do soldering for outputs on a signle side board when we had them layout simiiliar to this situation. Any input from anyone? Tks
Hi Crt,
It seems you fabricated your own board so they are not plated-thru, right? How did you manage to solder the outputs to the pcb where the soldering has to be done on the non-component side (or even both sides) also. Any special tools or setup you have to use? Did you solder on the component side first with the heatsink in place and take the heatsink off and solder on the soldering side again?
Always wonder how to do soldering for outputs on a signle side board when we had them layout simiiliar to this situation. Any input from anyone? Tks
Hi Pingrs,
Heard of that befoe but can never figurre how for TO-3P leads. Do you mean there are rectangulars rivets too?
Hi tinitus
I am thinking about that too, That would be a sheet of AL with a hole cut out so that your solder gun can go 'thru' it. But that sounds quite a bit of work and waste of material. That's why I am asking if there is an easier way.
Heard of that befoe but can never figurre how for TO-3P leads. Do you mean there are rectangulars rivets too?
Hi tinitus
I am thinking about that too, That would be a sheet of AL with a hole cut out so that your solder gun can go 'thru' it. But that sounds quite a bit of work and waste of material. That's why I am asking if there is an easier way.
Re: Q. for crt
yes, i have to modified the original layout, because in my town, no shop can make a thru-holes. and some parts which i cannot solder on component side (like some caps).
i solder on both side for output transistor. yes like you said
"Did you solder on the component side first with the heatsink in place and take the heatsink off and solder on the soldering side again"
sorry for my bad english
if cannot really understand what your mean.
bigpanda said:
yes, i have to modified the original layout, because in my town, no shop can make a thru-holes. and some parts which i cannot solder on component side (like some caps).
i solder on both side for output transistor. yes like you said
"Did you solder on the component side first with the heatsink in place and take the heatsink off and solder on the soldering side again"
sorry for my bad english
if cannot really understand what your mean.
whoandcar:
"Where can I get those rivets?"
One source I know of:
http://www.intertronics.co.uk/products/eyelets.htm
argofanatic:
As Mikeks would say "elementary my dear Watson"- it has to be if I use it.
Brian.
"Where can I get those rivets?"
One source I know of:
http://www.intertronics.co.uk/products/eyelets.htm
argofanatic:
As Mikeks would say "elementary my dear Watson"- it has to be if I use it.
Brian.
OPA134 Issue
Hi all,
This is just a notice that there may be a capacistance issue using the OPA134 opamp in the LYNX amp.
I have not my self experienced this problem, but I have had some feedback from others, who has experienced this.
The symptom is either fast oscillation or very very slow "motor boating" at app. 1 Hz.
Please report your experiences back to me.
I will look into the problem and report back here, when I hopefully have some answers.
Thanks
Hi all,
This is just a notice that there may be a capacistance issue using the OPA134 opamp in the LYNX amp.
I have not my self experienced this problem, but I have had some feedback from others, who has experienced this.
The symptom is either fast oscillation or very very slow "motor boating" at app. 1 Hz.
Please report your experiences back to me.
I will look into the problem and report back here, when I hopefully have some answers.
Thanks
Power Transistor substitutes
Before I solder them in I would just like to confirm that I can substitute MJL4281/MJL4302 for the MJL21194/MJL21193 without modification.
From my interpretation of the spec sheets, the 4281/4302 seems to have a slight advantage in the power handling.
I just happen to have several left over from my other projects.
Thanks,
Argo.
Before I solder them in I would just like to confirm that I can substitute MJL4281/MJL4302 for the MJL21194/MJL21193 without modification.
From my interpretation of the spec sheets, the 4281/4302 seems to have a slight advantage in the power handling.
I just happen to have several left over from my other projects.
Thanks,
Argo.
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