I've build this amp (M250) and i have some questions about it. Could i possibly add a volume pot in the input stage ? I'll ask more if someone replys. Thanks already !
Easily - just connect it before C1... one end of the track to the source, the other to ground, and the wiper to C1.
Power rating ?
This might be a stupid question , but what is the power rating for 4 ohm speaker with this circuit ? I've been thinking 250w ,but i'm not really sure :O?
Thanks already 🙂
This might be a stupid question , but what is the power rating for 4 ohm speaker with this circuit ? I've been thinking 250w ,but i'm not really sure :O?
Thanks already 🙂
Yes, it is 250w @ 4ohm 🙂
Well, to have that power you need at least 750VA transformer for stereo!
Well, to have that power you need at least 750VA transformer for stereo!
chemelec said:
The current homepage of Marcus M250 - 250 Watt amplifier
is now here:
http://marcusgun.awardspace.com/elektronik.html
A attach an image of the M250 Inside.
Lineup
Attachments
Vivek said:
Andy L. Francis said:
Yes, Vivek.
Whatever you do, Never get yourself a free AUDIO website at
a-w-a-r-d-s-p-a-c-e.c-o-m
Marcus 'M250' Gunnarsson did http://marcusgun.awardspace.com/ 🙁
I also did: http://lineup.awardspace.com/ 🙁
If you surf:
-> Marcus Startpage -> then elektronik -> then M250 page
..... then you will se images.
http://marcusgun.awardspace.com/index.html
http://marcusgun.awardspace.com/elektronik.html
http://marcusgun.awardspace.com/m250.html
Because the REFERER was his - elektronik.html page.
But if you go from here, directly to his M250 ... you see NO Images.
http://www.diyaudio.com/forums/showthread.php?postid=1561549#post1561549
http://marcusgun.awardspace.com/m250.html
That is, you can never use those images outside your site
for example here in diyaudio forum.
They have a script.
When this script see that your REFERER is another site (that is where you came from, where you were. where you are)
then they wont show The Image, but show some crazy Advert for their site.
========================
Now, 50 times better host for your free AUDIO website is www.freehostia.com
See for example this website I have .. At least a Startpage:
http://lineupaudio.freehostia.com/
Free Hostia also have no banners ads on your site. ( Like others have e.g. www.geocities.com )
And you can link to your images
An externally hosted image should be here but it was not working when we last tested it.
Andy. You are right also. If we go via Marcus elektronik.html page his M250 page will work. At least most of the time. If it does not .. you may have to close down your browser .. and try again
🙁 🙁
chemelec said:
This One:
http://www3.telus.net/chemelec/Projects/Misc-PCB/Corrected-OVERLAY-M-250.png
hi quasi
without your permission i modified your nmos200 pcb to suit my needs
i will be using this pcb for nmos350 please comment on this pcb
and also please suggest a matchiing pre amplifier based on opamps
i have already made nmos200
thanks for the lovely amp
with best regards
without your permission i modified your nmos200 pcb to suit my needs
i will be using this pcb for nmos350 please comment on this pcb
and also please suggest a matchiing pre amplifier based on opamps
i have already made nmos200
thanks for the lovely amp
with best regards
chemelec said:
An externally hosted image should be here but it was not working when we last tested it.
thanks, chemelec
very good 😎
How do you design and produce your PCB boards layouts?
You use what software?
please tell me
Lineup
Re: Commentable Thoughts
That is your opinion, Workhorse.
I know you make great N-Channel HEXFET amplifiers in India.
I love your works, man 😎
But you are not the only one to make good useful amplifiers.
We can do good DIY Audio amplifiers in Sweden, too.
Don't you think we can?
If not you think, then just build it and listen .....and you see
Regards
Lineup
Workhorse said:
That is your opinion, Workhorse.
I know you make great N-Channel HEXFET amplifiers in India.
I love your works, man 😎
But you are not the only one to make good useful amplifiers.
We can do good DIY Audio amplifiers in Sweden, too.
Don't you think we can?
If not you think, then just build it and listen .....and you see
Regards
Lineup
Lineup.......... I use an older program called: Quickroute , to create the artwork.
I produce the boards using a photograpic process.
Gary
I produce the boards using a photograpic process.
Gary
possible causes for distortion
hi all... i built this amp about 9 months ago, and it worked great... untill 3 days ago...
The symptoms, amost halved output power, and some audiable distortion at all frequencies. Ive put the amp through some frequency tests with a cro and signal generator and i can only see some cross over distortion on the output. I cant blame all this distortion im hearing on that can I? i mean it only just started happening, which makes me think ive cooked a transistor somewhere.
anyway, the reason im posting this problem here is because i cant see how a little bit of crossover distortion is making that much difference to what I hear, and also i wouldnt know where to start in removing it.
anyway, im new to this forum (well im an avid reader) so be nice 😛.....
hi all... i built this amp about 9 months ago, and it worked great... untill 3 days ago...
The symptoms, amost halved output power, and some audiable distortion at all frequencies. Ive put the amp through some frequency tests with a cro and signal generator and i can only see some cross over distortion on the output. I cant blame all this distortion im hearing on that can I? i mean it only just started happening, which makes me think ive cooked a transistor somewhere.
anyway, the reason im posting this problem here is because i cant see how a little bit of crossover distortion is making that much difference to what I hear, and also i wouldnt know where to start in removing it.
anyway, im new to this forum (well im an avid reader) so be nice 😛.....
As a Simple Test:
With the amp on, But No Input signal, Check the Emitter to Base Voltages on All Transistors. It should be About 0.6 Volts.
If Not, the transistor is probably bad.
This MAY help you find it easily.
HOPEFULLY!
Gary
With the amp on, But No Input signal, Check the Emitter to Base Voltages on All Transistors. It should be About 0.6 Volts.
If Not, the transistor is probably bad.
This MAY help you find it easily.
HOPEFULLY!
Gary
k, measured results.
ok, i measured all the Vbe values of all the transistors. Here are the results:
T1-0.6v, T2-0.6v, T3-0.57v, T4-0.6v, T5-0.6v, T6-1.02v, T7- 0.51v, T8-0.54v, T9-0.56v, T10 to T13-0.26v, T14 to T17-0.54v, T18-0.64v
well for some reason the Vbe of T6 is rather high, unsure as to why as that is the shortcircuit protection. Wonder whether that means i have a short someone on the output tracks, will check that later..
As for the main output transistors T10 to T13, seems a bit low. That might explain crossover distortion. But what does this mean? output transistors faulty? something else causing them to become unbiased?
any ideas? still at a loss...
ok, i measured all the Vbe values of all the transistors. Here are the results:
T1-0.6v, T2-0.6v, T3-0.57v, T4-0.6v, T5-0.6v, T6-1.02v, T7- 0.51v, T8-0.54v, T9-0.56v, T10 to T13-0.26v, T14 to T17-0.54v, T18-0.64v
well for some reason the Vbe of T6 is rather high, unsure as to why as that is the shortcircuit protection. Wonder whether that means i have a short someone on the output tracks, will check that later..
As for the main output transistors T10 to T13, seems a bit low. That might explain crossover distortion. But what does this mean? output transistors faulty? something else causing them to become unbiased?
any ideas? still at a loss...
I would definately Suspect problems with T10 to T13.
Since they are in Parallel, It may be only One of these causing the Problem.
And that 1.02 Volts on T6 also seems STRANGE.
You could Remove T10 to T13 and put in Just One New Transistor.
Than test the Base to Emitter voltage of it and see if the voltage is Corrected.
Without knowing your Electronic capabilities, Its hard for me to advise you on trying to test the origional T10 to T13 transistors.
Since they are in Parallel, It may be only One of these causing the Problem.
And that 1.02 Volts on T6 also seems STRANGE.
You could Remove T10 to T13 and put in Just One New Transistor.
Than test the Base to Emitter voltage of it and see if the voltage is Corrected.
Without knowing your Electronic capabilities, Its hard for me to advise you on trying to test the origional T10 to T13 transistors.
- Status
- Not open for further replies.