i have a problem where across r0 and r1 theres 1.6V
iv'e checked for inverted connections on q3 and checked my wireing.
if i leave the amp on too long the risistor will go up in smoke..
so it's hard to get a good reading on any of the other voltages
iv'e checked for inverted connections on q3 and checked my wireing.
if i leave the amp on too long the risistor will go up in smoke..
so it's hard to get a good reading on any of the other voltages
An externally hosted image should be here but it was not working when we last tested it.
by oscillate you mean weird sounds
no it dosent
plain dc theres about .40v or so of ac between r0
you are right there is nothing to lol about my amps nearly compleate apppart from this small problem
the other channel of the amp works fine and is running at about 1.5 amp which keeps those mosfets not so hot...
i disconected r16 voltage across r0 is now 3.20v dc more or less
i will post pictures very soon then youll have something to lol about
by the way nothing can be wrong blown i mean because the amp sounds fine it plays music ok without any strange sounds
just r0 has too many volts and will burn in flames if i leave it on for more than 10 seconds thats all
no it dosent
plain dc theres about .40v or so of ac between r0
you are right there is nothing to lol about my amps nearly compleate apppart from this small problem
the other channel of the amp works fine and is running at about 1.5 amp which keeps those mosfets not so hot...
i disconected r16 voltage across r0 is now 3.20v dc more or less
i will post pictures very soon then youll have something to lol about
by the way nothing can be wrong blown i mean because the amp sounds fine it plays music ok without any strange sounds
just r0 has too many volts and will burn in flames if i leave it on for more than 10 seconds thats all
by oscillate you mean weird sounds
no i mean if the bias is stable plain DC or is there an higher frequency AC component. You will not hear but you should measure.
If you a) connected thinks right what you have to check as we can´t
b) Q3 is ok
c) there is no oscillations
ther should be about 0,7V between is base and emitter what is same as across R0.
you will have to replace it, and check if you made a mistake around it. And make sure to use it not reversed. There is the chance to see oscillation also with a) a DMM with frequency counter b) measuring at a place were you expect pure DC in AC mode of the DMM if it is RMS voltmeter and takes higher frequency also and not only 50Hz or so.
cheers
i replace q3 and i now have 0.7v across r0 it's a 0.5 ohm resistor which i think makes about 1.4 amp's
now i have another problem i dont think it's so bad
when i turn of the power the music stays on for 20 odd seconds (im only using 5000uf capacitors on the power supply)
q1 and q2 seem to be getting warm like they should q5 isnt but it would probably take a while for q5..
as well when i put my multimetre on where it says 42V in the schematic at the source of q5 the voltage takes 5 minuites to drain after iv'e turned the amp off.
or is this normal ?
i replace q3 and i now have 0.7v across r0 it's a 0.5 ohm resistor which i think makes about 1.4 amp's
now i have another problem i dont think it's so bad
when i turn of the power the music stays on for 20 odd seconds (im only using 5000uf capacitors on the power supply)
q1 and q2 seem to be getting warm like they should q5 isnt but it would probably take a while for q5..
as well when i put my multimetre on where it says 42V in the schematic at the source of q5 the voltage takes 5 minuites to drain after iv'e turned the amp off.
or is this normal ?
Rixsta said:when i turn of the power the music stays on for 20 odd seconds (im only using 5000uf capacitors on the power supply)
q1 and q2 seem to be getting warm like they should q5 isnt but it would probably take a while for q5..
as well when i put my multimetre on where it says 42V in the schematic at the source of q5 the voltage takes 5 minuites to drain after iv'e turned the amp off.
or is this normal ?
It's normal. Q5 operates much cooler than 1 or 2. When you
turn the amp off, it will play for a little bit, then when the supply
gets down to about 22 volts, Q1 stops conducting, and the
voltage bleeds off slowly.
thats ok, you could simply stop the CD or turn off preamp to avoid it. Did you check both channels for same voltages at the gives measurement points?when i turn it off i hear the sound for about 3 mins and it only plays the beats of the music like crackly beats....
Rixsta said:Thanks nelson btw this amp sounds amazing im a musician and realy dig it.. lol
when i turn it off i hear the sound for about 3 mins and it only plays the beats of the music like crackly beats....
I think you still have problem with the voltage regulator. Normally the voltage will pull down to the regulation value and stay there. Once the reg shuts off the amp should stop playing.
If the amp plays for 3 minutes the string of zeners is not setting the reg level. The distortion you hear is from the bias level set for the output. As the vol.tage drops it pulls it and is giving asymetrical clipping.
George
Panelhead said:
I think you still have problem with the voltage regulator. Normally the voltage will pull down to the regulation value and stay there. Once the reg shuts off the amp should stop playing.
If the amp plays for 3 minutes the string of zeners is not setting the reg level. The distortion you hear is from the bias level set for the output. As the vol.tage drops it pulls it and is giving asymetrical clipping.
George
George i have no zeners connected id better replace them with good ones and reconect them right ?
how do i find the exact voltage of a given zener ?
btw exelent discription of whats happening and you make it so i can understand it being only a begginer in electronics
till thanks tommorow i will compare channels
r16 is ok
now theres one last problem i can't figure out why one channel of this amp is 5 times loader than the other..
Could it be linked to the feedback circuit..?
both channels biased at about 1.5 amp
thats ok, you could simply stop the CD or turn off preamp to avoid it. Did you check both channels for same voltages at the gives measurement points?
yeah ill turn off my graphic eq first then the amp
im sorry to keep asking for help this will all stop soon.. soon i will be able to enjoy my amp and help other people out
ha ha yeah right.
(im not that clever, but i can make fairly decent music)
yes, if you left out a resistor, took the wrong value, or made a bad connectionCould it be linked to the feedback circuit..?
how do i find the exact voltage of a given zener ?
measure, put in series with a resistor, hook on your power supply, measure voltage across zehner.
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