Dear Apex,
Thank you so much for the reply,
Ok i will replace those resistor and revert back to you.
meanwhile i tried to voltage check the zeners and I'm getting 14.9Volts on the left and 15Volts on the right, and when i remove the heatsink and hold with my finger the metal case of MJE340 and MJE15033 together DC offset disappear, while holding together the metal case of both tranies i'm getting mV offset up/down (2mV to 25mV), and there is oudio out signal but not clear.
I will update you once i have replaced the resistors.
Thank you once again and more Power to you.
Best Regards,
Wiljj78
Thank you so much for the reply,
Ok i will replace those resistor and revert back to you.
meanwhile i tried to voltage check the zeners and I'm getting 14.9Volts on the left and 15Volts on the right, and when i remove the heatsink and hold with my finger the metal case of MJE340 and MJE15033 together DC offset disappear, while holding together the metal case of both tranies i'm getting mV offset up/down (2mV to 25mV), and there is oudio out signal but not clear.
I will update you once i have replaced the resistors.
Thank you once again and more Power to you.
Best Regards,
Wiljj78
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how is your b500?
most of the trouble appear in pcb cold ,solder or open tracks,another common mistake is forgetting the input ground,another was transistor screws are grounded with collector output/driver and please don't forget to use series lightbulb of your first time powering of the amp......please take time..... always do double check ,make it tripple check much better, sometimes overlooking occured a reverse placement of parts.always remember if power up the amp and series lightbulb continue glow.there is something wrong
Dear Apex,
I replaced the R24,R25 with 2K2/2W resistors and measure the voltage of Z1&Z2 both zeners i'm getting +/-15.5VDC but Output DC offset still persist on 67VDC, i tried to place 33K resistor on MJE15033 collector and MJE340 colletor DC offset disappear but not sure if that is correct.
Please advise....
Regards,
Wiljj78
Hi Engel,
Still no luck with my B500 i replaced those 2K2/2W resistor as per apex but DC offset remain the same.
I'm wondering when i hold those tranies metal metal case DC offset disappear, Have you experience the same?
I installed 150R/10W on my primary and 10R/10W instead of fuse for testing purpose and many many thanks for the info you shared hope i catch the faults soon.
Regards,
Wiljj78
Still no luck with my B500 i replaced those 2K2/2W resistor as per apex but DC offset remain the same.
I'm wondering when i hold those tranies metal metal case DC offset disappear, Have you experience the same?
I installed 150R/10W on my primary and 10R/10W instead of fuse for testing purpose and many many thanks for the info you shared hope i catch the faults soon.
Regards,
Wiljj78
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Last night i pulled out those mje's for check's and they where all fine, i double checked the traces and even adding jumper for doubted traces.
Maybe i need to etch new pcb and try again...
I like the amp design i would be greatfull if i done it successfully.But placing 15-33K as per attached pic below 67VDC offset gone, i'm getting 1.2mV or lower. I treid to give input signal the amp works but not that powerful and distorted sound.
Any comments or suggestions are welcome.
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Measure voltages on 1k5 and 100R resistors around MJE340/350... check tracks on pcb and resistors value...
Hello nazirdigi i'am interest with B500 8 pairs.your design..can you share the layout pcb...to me
thanks
Mr. Miles,
Thank you so much for your advise.
I spend my whole night checking all components on board, with all the hard works i finally found where the fault lies, i found Q3,Q5 MJE340 has 1.Emmiter,2.Collector,3.Base have reverse pin orientation on my MJE340G 1.Base,2.Collector,3.Emmiter, my fault is i focus and depending more on the component guide orientation than having the actual test of the reanies before soldering the parts on board, when i corrected those tranies Damn... DC offset is gone and i'm just getting 1.5mVDC offset.
I hope my piece of experince can help other DIYer's whos interested to build this Amp.
I installed back the 4K7/2W when the DC offset gone though its hot but i feel more comfortable than 2K2/2W that giving smell.
I tested the Amp last nigh and the sound quality of this B500 is perfect, very quiet no hum,hiss etc.. the blending of Low,mid and high are very clear for my hearing, such a nice Amp.
I salute you Mr. Mile for sharing us this wonderful project and i really appreciate your generosity.
Once again Thank you sooooooooo much for your support and keep up the good work.
Best Regards,
Wiljj78
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How is your H900 downgrade to B500?? have you succesfully upgrade to H900??? i saw your post having difficulties of sourcing out those IC's IR2117.
Let me know if your still interested to upgrade your B500 to H900, maybe i can assist you where to find those IC in Philippines.
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Oh yeah...i saw it! Nice work buddy and thanks for sharing!!
I never been through all the way on h900 thread but i will, i'm late on this.
Anyway what's the different between this two amps? (power and quality wise) is there any huge different??
I start having interest of building h900, can you share??
Thanks.