Hello 🙂
Last Year I built myself this lovely sounding amp, pics can be seen here
Rixsta
I had it running for about a year, then when i blew one channel up and was too lazy to fix it untill last night. It was the input i thought that caused it to blow as i have no voliume control so if the amp is on and i plug things in it can be sensitive to the buzz or static at the input,which is what seemed to have done it . am i right in saying that if i put in a Volume coltrol and have the amp turned down wheni plug things in i will no longer have this problem of blowing the thing up ? lol
Here is the schematic
http://www.passdiy.com/pdf/zen-v4.pdf
Well anyway to my surprise i open it up and ill tell you which parts have gone
Z1 - Z5 totaly blown and possibly D1 not sure yet
R7 burnt out compleately
R0 slight burn marks
and one of the mosfets was blown i think Q5 the others were ok but i replaced them so far anyway.
So anyway im just about to replace the Zeener stack which i didnt do last night and fire her up again.
When i fire her up i just charge the power supply then connect it to the amp powering from the charge in the capacitors, it's a good way of testing and if all is good you get sound for about 10 seconds untill the capacitors have discharged.
brb 😀
Im no electrician btw lol
Last Year I built myself this lovely sounding amp, pics can be seen here
Rixsta
I had it running for about a year, then when i blew one channel up and was too lazy to fix it untill last night. It was the input i thought that caused it to blow as i have no voliume control so if the amp is on and i plug things in it can be sensitive to the buzz or static at the input,which is what seemed to have done it . am i right in saying that if i put in a Volume coltrol and have the amp turned down wheni plug things in i will no longer have this problem of blowing the thing up ? lol
Here is the schematic
http://www.passdiy.com/pdf/zen-v4.pdf
Well anyway to my surprise i open it up and ill tell you which parts have gone
Z1 - Z5 totaly blown and possibly D1 not sure yet
R7 burnt out compleately
R0 slight burn marks
and one of the mosfets was blown i think Q5 the others were ok but i replaced them so far anyway.
So anyway im just about to replace the Zeener stack which i didnt do last night and fire her up again.
When i fire her up i just charge the power supply then connect it to the amp powering from the charge in the capacitors, it's a good way of testing and if all is good you get sound for about 10 seconds untill the capacitors have discharged.
brb 😀
Im no electrician btw lol
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Ok, replaced the parts, fired her up just from the charge in capacitors, working channel still ok and the channel im fixing, well powers getting thru all the board but as the music fades away on the working channel the music slowly comes in on the broken channel lol of corse it's distorted becuase im running of capacitors for testing purpose.
is it possible a capacitor needs replacing ? i might just replace Q4 now altho it seems ok
If i had the gut's id just wack the power right in but i dont have a variac to slowly bring it up, so dont want to risk it going up in smoke again.
is it possible a capacitor needs replacing ? i might just replace Q4 now altho it seems ok
If i had the gut's id just wack the power right in but i dont have a variac to slowly bring it up, so dont want to risk it going up in smoke again.
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Thankyou, ill have to rig that up, always meant to lol
basicly it's taking ages for power to get thru the circuit ? i hear the music come thru about 10 seconds after power up and i know thats not right !
am very confused now lol
basicly it's taking ages for power to get thru the circuit ? i hear the music come thru about 10 seconds after power up and i know thats not right !
am very confused now lol
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Ok The 4V thats meant to be on Q2 is like 0.5 and ive replaced R7
all transistors but Q4 have been replaced, im realy thinking a capacitor is at fault now
any help apreciated, Time for a break i think lol
all transistors but Q4 have been replaced, im realy thinking a capacitor is at fault now
any help apreciated, Time for a break i think lol
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Might be worth looking at this thread!
http://www.diyaudio.com/forums/pass-labs/96737-fail-safe-power-supply-4.html
http://www.diyaudio.com/forums/pass-labs/96737-fail-safe-power-supply-4.html
Cheers, ive got something setup now
am feeling happy with my troubleshooting stuff 🙂
am now at the point where everything works, however
The only reading thats right is the 46Volt after that point it's pretty much half voltage on the whole circuit hmmm
am feeling happy with my troubleshooting stuff 🙂
am now at the point where everything works, however
The only reading thats right is the 46Volt after that point it's pretty much half voltage on the whole circuit hmmm
Ok am realy actualy stuck now lol
I am about to look one more time to see if i missed anything daft, ive check near enoth every component on the board, it works but is just not as loud as it's meant to be because half of the circuit is running on too low power, but i cant figure out how or why thats happening.
I am about to look one more time to see if i missed anything daft, ive check near enoth every component on the board, it works but is just not as loud as it's meant to be because half of the circuit is running on too low power, but i cant figure out how or why thats happening.
Novice electrician almost sorts it out lol Ok dont laugh
i didnt have it biased right, so i learn something new (bias efects almost whole circuit!) 🙂
now it looks like only problem is theres no .66 Voltage drop over R0
it's about .002
the investigation continues 🙂 think im nearly there, hopefully
i didnt have it biased right, so i learn something new (bias efects almost whole circuit!) 🙂
now it looks like only problem is theres no .66 Voltage drop over R0
it's about .002
the investigation continues 🙂 think im nearly there, hopefully
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Im Judging by the amount of reply's i must have done something dumb!
it's just realy odd i now have 0V over the bias resistors, yet i still hear sound.
how can this be that all voltages check right apart from the 0.66 ?
it's just realy odd i now have 0V over the bias resistors, yet i still hear sound.
how can this be that all voltages check right apart from the 0.66 ?
Check if you have half of PS voltage on the Drain of your output transistor...do you have a AC line fuse installed?
Thankyou Blues.
Q1 (no heat at all from the device, i presume this is the output transistor hehe)
Drain = 22volt it is correct
Gate = 3.4volt it is not quite correct but im sure thats not the problem
U have a fuse before the transformer and 2x 6amp fuses on the secondarys.
Q1 (no heat at all from the device, i presume this is the output transistor hehe)
Drain = 22volt it is correct
Gate = 3.4volt it is not quite correct but im sure thats not the problem
U have a fuse before the transformer and 2x 6amp fuses on the secondarys.
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Q2
Gate to Source = 0.6V instead of the mentioned 4V
Drain = 40v
Q3
emitter to base 0V, should be 0.66v
Kind of odd, dont you think!
I checked for a short circuit there but it's ok, checked resistance is same as the working channel.
Gate to Source = 0.6V instead of the mentioned 4V
Drain = 40v
Q3
emitter to base 0V, should be 0.66v
Kind of odd, dont you think!
I checked for a short circuit there but it's ok, checked resistance is same as the working channel.
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ZTX450 was dead!
I think this thread will be good for anyone else who has this problems 😀
or just plain confusing lol
I think this thread will be good for anyone else who has this problems 😀
or just plain confusing lol
Thankyou Very much for your help, it's apreciated!
Well i have it working now with 0.77v over R0/R1. Ive not had the gut's to turn it on compleatley yet as id like to try and bring that down to 0.66v
Would you happen to know how to do this ? it's not the R4 Potentemetre is it ? thats for the main bias, im learning here and i like it!
When unplugging the music fades slowly, on this channel im working on with 0.77v it fades almost instantly. So im a bit worried with such high ampage ill be Toast! 😀
How would i change this ?
Well i have it working now with 0.77v over R0/R1. Ive not had the gut's to turn it on compleatley yet as id like to try and bring that down to 0.66v
Would you happen to know how to do this ? it's not the R4 Potentemetre is it ? thats for the main bias, im learning here and i like it!
When unplugging the music fades slowly, on this channel im working on with 0.77v it fades almost instantly. So im a bit worried with such high ampage ill be Toast! 😀
How would i change this ?
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Right it was simply just adjusting the Bias resistor, to get the .66v and the 22V called out in the schematic at the same time!
Well i have a Working amp again 😀😀😀😀
Well i have a Working amp again 😀😀😀😀
Check all resistor values around Current Source...if they check out correctly try a diff Q3 or the other option is to install trimmer on R11.
Glad you found the fault, but do you know the root cause? If not the same thing may happen again. Sometimes it is hard trying to puzzle out what when wrong because your thinking is based around the correct circuit diagram, not the actual circuit you have with the fault condition. I found this whilst fixing an Aleph 4 whose fault condition was caused by a short circuit to the underside of the lid of the amp which is of course removed for repair!
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