stuartmp - I wanted to leave the math as an exercise to the reader, but I figured that no-one else would do it.
Here are some typical sensitivities for a bias current of 100mA:
Double Is: 170mA
Double Hfe: 104mA
10% increase in Tjc: 103mA
Ed
Here are some typical sensitivities for a bias current of 100mA:
Double Is: 170mA
Double Hfe: 104mA
10% increase in Tjc: 103mA
Ed
OmeEd - Yes, Is is about 1.5e-13 amps for the 2SC5200. See my post #3,718.
In the amplifier, the bias current is not exactly proportional to Is because the emitter resistors provide degeneration.
Ed
In the amplifier, the bias current is not exactly proportional to Is because the emitter resistors provide degeneration.
Ed
Thanks team. I am well aware that checks would need to be remade, and adjustments made. I was more curious as to the why. Thanks for the knowledge
Extrapolating your historical performance I predict that to be sometime next year. But, will there be free beer?
I gave up on beating ZM long time ago, no chance. Once i reach 10k, i will stop bugging people here on this forum. To be honest, i am very happy with sound of my systems. Just building stuff is fun. Giving most away to friends anyway. It gives me pleasure building stuff, measuring it, listening to it, comparing it to other stuff...having fun with it. Music can be such ecstasy.
Reference my post #3,689 ......
I've been looking at @voxxonline's 'problem' with his Wolverine - reference his posts just before mine. He sent his amp to me to fault-find and in case this may assist anyone else on the forum this is what I've been able to conclude:
He felt that 'something happened' as he was connecting his speaker wires, because inadvertently the amp was still turned on at the time. Only one channel was believed to be affected. He was aware that the speaker binding posts were not good and needed to be replaced, and this indeed was the source of the problem I believe - any very slight movement caused the posts to short out onto the chassis rear plate.
Symptoms:
I used a 'bulb lamp tester' and, when power switched on the lamp was brightly lit and 'pulsing' rapidly. Immediately switched power off and measured the boards - one channel direct short between speaker + to both V+ and V-, other channel looked OK.
Resolution:
Process of elimination, found output transistors Q110 and Q113 both short circuit, remaining transistors suspect. As a precaution, all output transistors replaced with new. Switched on again to test, and 'pulsing' still evident. Further process of elimination revealed Q104 (VBE) also 'blown'. Replaced Q104 with new - all now working as expected.
Testing/setup:
Ran through the set up from scratch for both channels (5v, bias, DC offset) - all good. Played some music to test and all now seems to be fine!
Conclusion:
Suspect speaker binding post(s) shorted to chassis, which caused surge/spike and blowing of output and VBE transistors.
All's well that ends well.
Moral of this story - make sure your amp's turned off before playing around with wiring and connections!!
I've been looking at @voxxonline's 'problem' with his Wolverine - reference his posts just before mine. He sent his amp to me to fault-find and in case this may assist anyone else on the forum this is what I've been able to conclude:
He felt that 'something happened' as he was connecting his speaker wires, because inadvertently the amp was still turned on at the time. Only one channel was believed to be affected. He was aware that the speaker binding posts were not good and needed to be replaced, and this indeed was the source of the problem I believe - any very slight movement caused the posts to short out onto the chassis rear plate.
Symptoms:
I used a 'bulb lamp tester' and, when power switched on the lamp was brightly lit and 'pulsing' rapidly. Immediately switched power off and measured the boards - one channel direct short between speaker + to both V+ and V-, other channel looked OK.
Resolution:
Process of elimination, found output transistors Q110 and Q113 both short circuit, remaining transistors suspect. As a precaution, all output transistors replaced with new. Switched on again to test, and 'pulsing' still evident. Further process of elimination revealed Q104 (VBE) also 'blown'. Replaced Q104 with new - all now working as expected.
Testing/setup:
Ran through the set up from scratch for both channels (5v, bias, DC offset) - all good. Played some music to test and all now seems to be fine!
Conclusion:
Suspect speaker binding post(s) shorted to chassis, which caused surge/spike and blowing of output and VBE transistors.
All's well that ends well.
Moral of this story - make sure your amp's turned off before playing around with wiring and connections!!
To say that Richard is a superstar is to say nothing. Thank you very much for your help!
You're welcome Ivan, glad I could help ... that's what this community is all about.
Please inform me what is the best supplying voltage to obtain the best performance outcome specifications
Please see 1st attachment on the 1st post of this thread. There is no ‘best’. There is ‘most optimum’ for your existing speakers, listening position and overall SPL needs/desires. Once you know the overall speaker impedance and sensitivity we can help you make a determination assuming a 2ch setup.
Best,
Anand.
I know
But I want to have the objective specification outcome, not related to environmental and subjective environmental factors
But I want to have the objective specification outcome, not related to environmental and subjective environmental factors
Not quite sure what you're asking, but no difference in relative performance between supply rail voltages. A 71VDC supplied wolverine vs a 54VDC supplied wolverine built with identical parts* powering the same load 1W or 100W will have identical objective distortion performance. Lowering the voltage lowers the cost, (slightly), improves longevity (slightly), and lowers output power, and maybe (speculation, not proven) reduced PS noise.
But there's no sweet spot. Like others said, the "sweet spot" is how much headroom you need for your speakers.
Roll speakers lots? Use 71VDC rails 😎
*Use the same board, only swapping the voltage dependant parts - CCS, DCO & Cap Multiplier resistors
You don't need 71 volt rails. My amp.is 80w with 36v rails ( 40v unloaded).
It gets used between 10 and 1000 mW. Mostly below 0.1 watt.
Stability is most important.
It gets used between 10 and 1000 mW. Mostly below 0.1 watt.
Stability is most important.