Hi
I have found 3 UK suppliers of ON Semi MJL21193/94 transistors.
Farnell ~ £5.09
Digikey ~ £4.55
RS ~ £2.37
Now, here's the thing. RS is a reputable supplier and although their price is rather attractive, I don't want my pants pulled down over fakes.
Does anyone think that RS' price is "too low" for these devices?
It does say that they are supplied by ON Semi, but you just can't be too careful these days.
I have found 3 UK suppliers of ON Semi MJL21193/94 transistors.
Farnell ~ £5.09
Digikey ~ £4.55
RS ~ £2.37
Now, here's the thing. RS is a reputable supplier and although their price is rather attractive, I don't want my pants pulled down over fakes.
Does anyone think that RS' price is "too low" for these devices?
It does say that they are supplied by ON Semi, but you just can't be too careful these days.
New version of Lynx?
Hi, anyone that knows the difference between Lynx 3.0 and Lynx 3.01. I'm about to order parts for the Lynx 3.0 boards and want to know what I miss in the new version before ordering.
/Andy
Hi, anyone that knows the difference between Lynx 3.0 and Lynx 3.01. I'm about to order parts for the Lynx 3.0 boards and want to know what I miss in the new version before ordering.
/Andy
Hi,
anyone know how critical the value of the zener resistors are.
I have got 35 volt transformer primaries which gives about 49 volts dc so according to the QAG the zener resistors should be; (rail voltage-ZV/ 0.02= R) 49-15/0.02= 1700R
I am having great difficulty finding 2 watt resistors of this value; only 1.6 and 1.8k so far, although Digikey have 1.75k but want £12.00 postage!? I have tried Farnell and RS Components and ebay. Any help would be appreciated.
Also has anyone tried the Burson discrete op-amp plug in's?
Cheers
anyone know how critical the value of the zener resistors are.
I have got 35 volt transformer primaries which gives about 49 volts dc so according to the QAG the zener resistors should be; (rail voltage-ZV/ 0.02= R) 49-15/0.02= 1700R
I am having great difficulty finding 2 watt resistors of this value; only 1.6 and 1.8k so far, although Digikey have 1.75k but want £12.00 postage!? I have tried Farnell and RS Components and ebay. Any help would be appreciated.
Also has anyone tried the Burson discrete op-amp plug in's?
Cheers
Jerryo,
go back to your formula and insert first 1k6 and then 1k8 and find out what current passes these alternative resistors.
Check power dissipation of the resistors.
Check power dissipation of the Zener.
go back to your formula and insert first 1k6 and then 1k8 and find out what current passes these alternative resistors.
Check power dissipation of the resistors.
Check power dissipation of the Zener.
So here we are;
1.60k = 0.02125 amps/0.722w
1.70k = 0.02 amps/0.68w
1.75k = 0.0194 amps/0.65w
1.8k = 0.0188 amps/0.63w
The zener is 1 watt so I guess it would not make much of a difference. In any case the resistors available have a tolerance of 5% which gives a margin for overlap of resistor values. I only asked as I am building the Lynx with exactly the right components as the BOM gives in order to avoid any problems.
Cheers
1.60k = 0.02125 amps/0.722w
1.70k = 0.02 amps/0.68w
1.75k = 0.0194 amps/0.65w
1.8k = 0.0188 amps/0.63w
The zener is 1 watt so I guess it would not make much of a difference. In any case the resistors available have a tolerance of 5% which gives a margin for overlap of resistor values. I only asked as I am building the Lynx with exactly the right components as the BOM gives in order to avoid any problems.
Cheers
SOA protection calculation
How to calculate R124 and R125 - HELP HELP HELP
if i use 2SC5200 and 2SA1943 i have problem... because if the supply voltage is +-55V collector current is about 2,5 A
and if i use emiter resistor 0r22 i get 2,5*0,22=0,55V how do I subtract 0,6V ??
what emitter resistors and R124, R125 use ??
supply voltage will be about +-55V, transistors 2SC5200 and 2SA1943
How to calculate R124 and R125 - HELP HELP HELP
if i use 2SC5200 and 2SA1943 i have problem... because if the supply voltage is +-55V collector current is about 2,5 A
and if i use emiter resistor 0r22 i get 2,5*0,22=0,55V how do I subtract 0,6V ??
what emitter resistors and R124, R125 use ??
supply voltage will be about +-55V, transistors 2SC5200 and 2SA1943
correction:
supply voltage will we about +/-55V DC and exactly 2x40V AC but maybe better 2x38V AC ??
supply voltage will we about +/-55V DC and exactly 2x40V AC but maybe better 2x38V AC ??
Last edited:
A BJT amplifier will get a real 200W into 4r0 from a 35+35Vac transformer if built properly.
A source follower stage (=mosFET version of EF) will need more voltage to get to that target.
A CFP based on FETs should at least match the BJT power.
A source follower stage (=mosFET version of EF) will need more voltage to get to that target.
A CFP based on FETs should at least match the BJT power.
Hi all.
I finished my amp.these are several picture of my amplifier:
there are some protection circuit in my amp.DC detection,delay and temperature protection.
But there is a problem in my amp.there is Oscillation in my amp:
without any input signal:
with input signal at around of mid level with 12.7VRms output voltage:
so I several tested on this amp.but I couldn't adjust exact R114.because the
voltage across R128 doesn't go down less than 60mA.
so the voltage between tp A and tp C doesn't go down less than 2.30V.
but I can adjust R114 when I replace 100pf capacitor instead of C102
and C103(33pf).
but there is oscillation in output of my amp yet.I attached picture of
this test.(you can see it in picture above)
so I added a 33pf cap from pin 2 to pin 6.but still some oscillation.
I use OPA134.
thank's
I finished my amp.these are several picture of my amplifier:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
there are some protection circuit in my amp.DC detection,delay and temperature protection.
But there is a problem in my amp.there is Oscillation in my amp:
without any input signal:
An externally hosted image should be here but it was not working when we last tested it.
with input signal at around of mid level with 12.7VRms output voltage:
An externally hosted image should be here but it was not working when we last tested it.
so I several tested on this amp.but I couldn't adjust exact R114.because the
voltage across R128 doesn't go down less than 60mA.
so the voltage between tp A and tp C doesn't go down less than 2.30V.
but I can adjust R114 when I replace 100pf capacitor instead of C102
and C103(33pf).
but there is oscillation in output of my amp yet.I attached picture of
this test.(you can see it in picture above)
so I added a 33pf cap from pin 2 to pin 6.but still some oscillation.
I use OPA134.
thank's
sorry, you are right.
but I asked this question for two week ago to Mr Jan.but unfortunately he is sick.
but I asked this question for two week ago to Mr Jan.but unfortunately he is sick.
I tried with NE5534,OP27 and LF256(because LF356 was not available for me.but all of them were the same.
but OP27 was better then the other.so I tried all of value for C102/103 and C109 from 27pf to 220 pf.but non help.
Dear PMA,masteramp and others...
could you please do me favor and help me.
I attached picture of my power supply and.I don't think,oscillation be related to power supply.there is enough capacitor on this.
so you can see my wire in the green circle.
thank,s
but OP27 was better then the other.so I tried all of value for C102/103 and C109 from 27pf to 220 pf.but non help.
Dear PMA,masteramp and others...
could you please do me favor and help me.
I attached picture of my power supply and.I don't think,oscillation be related to power supply.there is enough capacitor on this.
An externally hosted image should be here but it was not working when we last tested it.
so you can see my wire in the green circle.
An externally hosted image should be here but it was not working when we last tested it.
thank,s
I found it out.
I replace a 27pf for C109 and so I place a 33pf form pin 2 to 6 and it was my solution.
now my amp doesn't have any problem.
I wish health for Mr jan.
I replace a 27pf for C109 and so I place a 33pf form pin 2 to 6 and it was my solution.
now my amp doesn't have any problem.
I wish health for Mr jan.
I tested my amp and all of thing was ok.at first I apply a low level signal 100mv and my output was pure 2.69v.as this amplifier has a gain of 25 ,this value was good.
this is a picture of input than output:
so this is maximum power without bar:
and this is maximum power with 10R bar:
but I'm in doubt about power of this amp.32V on 10R is 102W and on 8R is 128W not 150W.why?
os please help me about SOA of my amp.
I used 2SC5200 and 2SA1943.so R128 to R135 is 0.51R.I have gotten 150R for it.
is it right?
till this time,all of thing was ok.
I tested this amp with 1khz signal.but as soon as I raise frequency to UP…(80khz for test)suddenly my amp blew!!!
please help me about this situation that why ?
because frequency response of this amp is 300khz.
is it logical?
who's here?
this is a picture of input than output:
An externally hosted image should be here but it was not working when we last tested it.
so this is maximum power without bar:
An externally hosted image should be here but it was not working when we last tested it.
and this is maximum power with 10R bar:
An externally hosted image should be here but it was not working when we last tested it.
but I'm in doubt about power of this amp.32V on 10R is 102W and on 8R is 128W not 150W.why?
os please help me about SOA of my amp.
I used 2SC5200 and 2SA1943.so R128 to R135 is 0.51R.I have gotten 150R for it.
is it right?
till this time,all of thing was ok.
I tested this amp with 1khz signal.but as soon as I raise frequency to UP…(80khz for test)suddenly my amp blew!!!
please help me about this situation that why ?
because frequency response of this amp is 300khz.
is it logical?
who's here?
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