Thanks for the help, even for MJE15033 and MJE15032 you use A1837 and C4793? I already finish my board but in getting unstable dc output and motor booting can be heard on the speaker. Trying to look for a close specf. for the MJE15033 and MJE15032.
yes i replace them with those trannies...
please post pictures...
mr. mile and some of our friends here might help...
regards
ees...
fake transistors
The only thing that will make you fail to have a working B500 are fake transistors, this also happened to me when i assemble the B500 and with limited knowledge on how to build it, but with the help of the diy community I have got a working B500 and fully satisfied with the result. I will give you some advice( to Sir WSDS ), check your driver and pre driver transistors: MJE15032/33 or 2SA1837/2SC4793 for their pin orientation ECB/BCE with the multimeter if the multimeter can not determine if it's NPN/PNP probably it is fake or damge, also the 2n5401/2n5551(EBC/CBE) and mje340/350(ECB/BCE). on the first power up put a 100 ohms 3 to 5 watts resistor in series with positive and negative rails before the fuse, this will save your transistors if there is any fault. check the voltage across the 100 ohms resistor in positive and negative rail normally it is between 3.5 to 6 volts dc in the B500 that I made, whatever you read in the positive side should almost the same in the negative side, check the dc offset in the speaker output it should be less than 10 milivolts DC and 0 volts AC, then use a dc detect circuit/ speaker protect
circuit in between your amp and the speaker this will save your speaker if ever the amp fail while testing, remove the 100 ohms resistor when all the test goes well and try to play some music. A B500 fitted with original transistors well work fine in the first power up, just check for some mistakes, shorts or fake transistors if ur B500 fail in the first power up.
Good Luck to your Build.
regards,
mj777
The only thing that will make you fail to have a working B500 are fake transistors, this also happened to me when i assemble the B500 and with limited knowledge on how to build it, but with the help of the diy community I have got a working B500 and fully satisfied with the result. I will give you some advice( to Sir WSDS ), check your driver and pre driver transistors: MJE15032/33 or 2SA1837/2SC4793 for their pin orientation ECB/BCE with the multimeter if the multimeter can not determine if it's NPN/PNP probably it is fake or damge, also the 2n5401/2n5551(EBC/CBE) and mje340/350(ECB/BCE). on the first power up put a 100 ohms 3 to 5 watts resistor in series with positive and negative rails before the fuse, this will save your transistors if there is any fault. check the voltage across the 100 ohms resistor in positive and negative rail normally it is between 3.5 to 6 volts dc in the B500 that I made, whatever you read in the positive side should almost the same in the negative side, check the dc offset in the speaker output it should be less than 10 milivolts DC and 0 volts AC, then use a dc detect circuit/ speaker protect
circuit in between your amp and the speaker this will save your speaker if ever the amp fail while testing, remove the 100 ohms resistor when all the test goes well and try to play some music. A B500 fitted with original transistors well work fine in the first power up, just check for some mistakes, shorts or fake transistors if ur B500 fail in the first power up.
Good Luck to your Build.
regards,
mj777
Last edited:
bridge mode(point A and B)
please refer to page 64 post 631 by Apex, that is for bridge mode application.
link below:
http://www.diyaudio.com/forums/solid-state/164208-500w-pa-amplifier-limiter-64.html
regards,
mj777
please refer to page 64 post 631 by Apex, that is for bridge mode application.
link below:
http://www.diyaudio.com/forums/solid-state/164208-500w-pa-amplifier-limiter-64.html
regards,
mj777
So if we need single channel mono(not bridge or anything like that),we just use input for our signal and omit a and b right?
I wondered too!
I am currently building this amplifier to use it as a bass guitar amplifier!
What are the specs of the amplifier?(input impedance,input sensitivity etc)
Also with 4pairs of transistors 2sc5200,2sa1943 and powering with +-55volt what is the output power?
Lastly,for the first power up, i can't find 150ohm/20w resistor....
Is it ok if i use 2x330ohm/5w in parallel?
Or should i use 4x680ohm/5w in parallel?
Thank you in advance!🙂
hello mile my b500 with 6 pairs 85vdc work good but the zobel network 4R7/2W is burn out,,any reason why? load 4 r per side ,application mid low.