do your own homework.
Reading is not impossible when google gives all the links.
Try looking at some of these ...
#234 - apassgear,
#344 - barko,
#585, 559,619, 633,1105, etc - jackinjj,
#867, 963, 1999, etc -juma
#897,926 - goffe
#1156 - spind
#1665 - Brian
#1799 - kheko
#1840,1861 - opc
#2047 - estman
#2097 - mongo
#2100 - cviller (see his blog on this site)
#2127, 2287 - culture
# ........
... plenty designs to cover nearly all variations.
#234 - apassgear,
#344 - barko,
#585, 559,619, 633,1105, etc - jackinjj,
#867, 963, 1999, etc -juma
#897,926 - goffe
#1156 - spind
#1665 - Brian
#1799 - kheko
#1840,1861 - opc
#2047 - estman
#2097 - mongo
#2100 - cviller (see his blog on this site)
#2127, 2287 - culture
# ........
... plenty designs to cover nearly all variations.
i know you are helping me, But i want a simple single layer pcb layout of at least 3 pairs of trannies. double layer will be a bit difficult for me as double side pcb not available here only single side.
If i want double side i have to travel 60 kms . If no option then i will make a double side version.
Also ther are so many versions i am a bit confused. i need output of 200 watts at 8 ohms.
If i want double side i have to travel 60 kms . If no option then i will make a double side version.
Also ther are so many versions i am a bit confused. i need output of 200 watts at 8 ohms.
I thought I understood, but I am puzzled again:
My jfet are not matched, as I was told to use just a pair that did not have big difference. But EUVL adviced to match them. And if you match them (for idss) you do on the value after or before your calculation ?
Just a tip to search the thread. View it in advanced printing format in a single page, you can even save it...111 Mb
You can quickly skip to the interesting post.
D.
Well Viki,
As Tinitus said - I think you would be better looking towards a different cct design for a 200W/8R class A amp.
Even with the 3 output pairs driven from a cascoded front end and symmetrically balanced topology, it's going to be a bit difficult and none of the 25watt pcbs designs will be at all suitable.
As Tinitus said - I think you would be better looking towards a different cct design for a 200W/8R class A amp.
Even with the 3 output pairs driven from a cascoded front end and symmetrically balanced topology, it's going to be a bit difficult and none of the 25watt pcbs designs will be at all suitable.
Why ? Just match 10 devices n and 10 p and use two 3000VA toroids per channel.
Dissipation around 300 W per channel at idle. You can have a multi-functional amp, boiler at the same time.
D.
I don't know whether you read about this amp, it's power and class of functioning etc. You will not be able to do this design for 200W at 8 ohms. Also the amount of transformer and heatsinks that you may need to provide even if it is possible makes it simply unviable. You are better off looking for Class B amps.
Referring to post # 10073,
If you were to use a 5.1R degeneration resistor between Source of 2SJ74 and the feedback node, then
R2=10ohm and corresponding feedback 50ohm
R1=10ohm and 50ohm feedback
You only use 15R /75R if you connect the source of the 2SJ74 directly to the feedback node, as you are then combining the 5R and the 10R into one resistor.
Patrick
If you were to use a 5.1R degeneration resistor between Source of 2SJ74 and the feedback node, then
R2=10ohm and corresponding feedback 50ohm
R1=10ohm and 50ohm feedback
You only use 15R /75R if you connect the source of the 2SJ74 directly to the feedback node, as you are then combining the 5R and the 10R into one resistor.
Patrick
I didnt understand,do you mean Krell KSA50 will be enough for my speakers.
what is the output of Krell KSA50.
can you guide me to the pcb layout if possible.
Now this is clear, what about the matching story? I understood that the 5 ohm give an asymmetry to the circuit to compensate the difference of the devices. Then, how to choose them ?
Thanks,
D.
dear viki
maybe a good idea to start your own thread, with a debate about what kind of amp you need
Im sure you will get lots of suggestions
i am already overwhelmed with all the replies i got, I never really thought i will be replied.
there are so many members, and most of them are very Knowledgeable.
i am a new diyer with no engineering background, Except i can solder exceptionally well.
Thank you to all the diyers for such support. It really has upped my confidence.
I will now be looking for krell ksa 50/100
there are so many members, and most of them are very Knowledgeable.
i am a new diyer with no engineering background, Except i can solder exceptionally well.
Thank you to all the diyers for such support. It really has upped my confidence.
I will now be looking for krell ksa 50/100
The choice of Toshibas outputs doesn't make compulsary to use the 4 ohms degeneration Patrick's trick. The amp will work as nice as stock F5 without.
This is a step towards perfection considering distortion.
That's nice, but, to keep the spirit, it implies also a thorough matching of output mosfets, emmitor's and feedback resistors.
This is a step towards perfection considering distortion.
That's nice, but, to keep the spirit, it implies also a thorough matching of output mosfets, emmitor's and feedback resistors.
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