i finaly set my bias right....
at 54V rail, it worked to set it at 1.8 mA...
the amp is working fine but,boy is it getting hot..., and i don't mean the final transistors, because i have a huge heat sink, and a big fan...
but the mje340/350, and the mje 15030/31 are getting hot..., i supose i will put them a bigger heat sink...
the amp, sounds good, easy to build...nice sound, cheap...
i can hardly wait, to test it on a osciloscope, to see how it preforms there...
at 54V rail, it worked to set it at 1.8 mA...
the amp is working fine but,boy is it getting hot..., and i don't mean the final transistors, because i have a huge heat sink, and a big fan...
but the mje340/350, and the mje 15030/31 are getting hot..., i supose i will put them a bigger heat sink...
the amp, sounds good, easy to build...nice sound, cheap...
i can hardly wait, to test it on a osciloscope, to see how it preforms there...
For any persons Interested, I have Cleaned up and Re-Drawn the Schematic.
http://www3.telus.net/chemelec/Projects/Misc-PCB
I Agree with: amplifierguru, Especially on the Supply Rails.
The Amp that I Designed and currently use is Less Power than this one and I used a Decoupling circuit on its supply rails.
So I plan to make a Few Revisions on this one in the near future.
Probably also a revised board at some point.
But it is Becoming Gardening Time so that may be awhile.
Take care...........Gary
PS: I'll give it another week and than Anounce the Winner.
http://www3.telus.net/chemelec/Projects/Misc-PCB
I Agree with: amplifierguru, Especially on the Supply Rails.
The Amp that I Designed and currently use is Less Power than this one and I used a Decoupling circuit on its supply rails.
So I plan to make a Few Revisions on this one in the near future.
Probably also a revised board at some point.
But it is Becoming Gardening Time so that may be awhile.
Take care...........Gary
PS: I'll give it another week and than Anounce the Winner.
Before committing myself to ordering all the parts I need, I have a few questions for those that have already built them or are in the process of building theirs. BTW: I live in the US.
1. I know of several places to get most of the parts (Avnet, DigiKey, Arrow). What places do you people recommend?
2. Where can I get a heat sink of such large proportions (like the one pictured on the author's web page)?
3. Since there is a huge variety of parts, what kinds of capacitors are used? (I'm used to seeing the ceramic and electolytic...not the square ones that are pictured.)
4. I'm planning to build a dual-channel amp. Will the power supply be sufficient to run both channels? (I will be using a 500VA 2x37 Torid).
Thanks in advance.
1. I know of several places to get most of the parts (Avnet, DigiKey, Arrow). What places do you people recommend?
2. Where can I get a heat sink of such large proportions (like the one pictured on the author's web page)?
3. Since there is a huge variety of parts, what kinds of capacitors are used? (I'm used to seeing the ceramic and electolytic...not the square ones that are pictured.)
4. I'm planning to build a dual-channel amp. Will the power supply be sufficient to run both channels? (I will be using a 500VA 2x37 Torid).
Thanks in advance.
desert00rat said:
500W is sufficient for both channels only at 8 ohms... for 4 ohm, you should use a bigger transformer...
also, i think a 37V ac is a bit low...(50V cc)
i am using a 550W normat transformer, 44V ac, 58 cc...
C3,4 -normal, electolytic
C2,5,8-ceramic
C1,6,7-have to be non-polar,non-electolytic , and also non-ceramic ... there are lots of other types(i just don't know how they are called....), for ex: mkt, film , multy-layer...
and C7 has to be at least 200V...
the transstors, 15030/31 work in class A or class AB...???
could someone please tell me if the prefinals(MJE 15030/31) work in class A or class AB ???
i believe that they work in class AB, but someone told me that they work in class A, and only the finals work in AB....am i right or wrong...???
i believe that they work in class AB, but someone told me that they work in class A, and only the finals work in AB....am i right or wrong...???
My Number was 66 , So I Believe "csl113" has won these Boards as his number was 56.
I Don't want to screw-up on this, So can someone else chech the past postings and Varify This.
PS: I Also Believe those drivers work in AB.
Take care............Gary
I Don't want to screw-up on this, So can someone else chech the past postings and Varify This.
PS: I Also Believe those drivers work in AB.
Take care............Gary
so, how can i contact you....so we can talk...???
i tried to send email, but it appears that it's confidantialy...
caold you send me a mail at csl1131@yahoo.com
i tried to send email, but it appears that it's confidantialy...
caold you send me a mail at csl1131@yahoo.com
Hi, Send me an Email at: chemelec@hotmail.com
You MUST Put the Words: "Electronic Free PCB" in the Subject Line.
And give me your Name and Address so I can get these Mailed out to you.
Take care...........Gary
Those Boards were Mailed to "csl113", Yesterday.
Hopefully he will get those amps assembled and post his results on here.
Thank to all the persons that submitted a number.
But I am Surprised there were not more.
Take care all.............Gary
Hopefully he will get those amps assembled and post his results on here.
Thank to all the persons that submitted a number.
But I am Surprised there were not more.
Take care all.............Gary
m250
is anyone have tried using MJL4281A(NPN)/MJL4302A(PNP) as the output transistor instead of MJ15024/MJ15025.
is anyone have tried using MJL4281A(NPN)/MJL4302A(PNP) as the output transistor instead of MJ15024/MJ15025.
it sets the bias.. the idle curent ...
at first it should be set to it's maximum position....is it is set to it's idle position.. you may burn the output transistors..
at first it should be set to it's maximum position....is it is set to it's idle position.. you may burn the output transistors..
Excuse! Did not read everything, likely wrote R 6, 7 - 100, D1 - D4 - are unnecessary, the shunt 0,1uF, R16,17 - 3k. And I would change a feedback.
It only my opinion, and is more than anything)
Excuse for my English.
It only my opinion, and is more than anything)
Excuse for my English.
See on the schematic- p1- it's the only pot on the schematic!!!
let me know if there are any other problems in the schematic
And the final question is:
is it absoloutely essential that the amp runs off a dual rail power supply. it's just that i've found a tordial transformer in RS which has 2 55 volt outputs and if i use it as a dual rail it will give me an output of 110v- the same as in the us
is it absoloutely essential that the amp runs off a dual rail power supply. it's just that i've found a tordial transformer in RS which has 2 55 volt outputs and if i use it as a dual rail it will give me an output of 110v- the same as in the us
there is NOTHING wrong in the schematic....
it works fine...
the amp run's on dual power suply...
a simple power can NOT be used...
if the transformer has an output of 2*55V AC this will be 2*75V dc,and you can't use this much voltage..
i would sugest a 2*60V dc max
is this your first amp??? if it is i would sugest you read a little more about amplifiers...
after you build it before testing it relace the fuses with a 50-120 ohm 3-5W resistor ,because if you did something wron smoke will come out of these resistors and not out of the output transistors 😀
it works fine...
the amp run's on dual power suply...
a simple power can NOT be used...
if the transformer has an output of 2*55V AC this will be 2*75V dc,and you can't use this much voltage..
i would sugest a 2*60V dc max
is this your first amp??? if it is i would sugest you read a little more about amplifiers...
after you build it before testing it relace the fuses with a 50-120 ohm 3-5W resistor ,because if you did something wron smoke will come out of these resistors and not out of the output transistors 😀
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