Dual-500 king of the Castle
- Thread starter grapplesaw
- Start date
Joe the issue is the main power caps do not discharge over a few minutes. Actually hold charge for hours. Not to safe I’d say.
As a new feature I no longer take power from the main caps to the control board as it has its own power supply ( pictured sorta) tied to the the ac output of the main transformer. The reason is to have 80-0-80 constant supply voltage to the control board.
When you run off the rail for supply to the control board this voltage changes from 80-0-80 to 120-0-120. This change in voltage really only effects the Bias voltage as it gets fed from the rails. Therefore it’s not optimized for best bias voltage in one or the other rail voltage as you set it be best with high rail not low.
I have fly back diodes on both positive and negative rail of each channel. These are not discharging residual stored voltage in power caps. I added one 1n4004 across the positive and negative main cap and this did Not help to discharge them. Of coarse I can manual do it and I can also do it with pair of resistors giving a constant drain, not my desired choice.
what part of the pl700 circuit accomplish this job to discharge the caps over time. I always thought it was leakage in the control board.
I do not recall this problem on any other build only this with the second power supply which , by the way drains very quickly?
As a new feature I no longer take power from the main caps to the control board as it has its own power supply ( pictured sorta) tied to the the ac output of the main transformer. The reason is to have 80-0-80 constant supply voltage to the control board.
When you run off the rail for supply to the control board this voltage changes from 80-0-80 to 120-0-120. This change in voltage really only effects the Bias voltage as it gets fed from the rails. Therefore it’s not optimized for best bias voltage in one or the other rail voltage as you set it be best with high rail not low.
I have fly back diodes on both positive and negative rail of each channel. These are not discharging residual stored voltage in power caps. I added one 1n4004 across the positive and negative main cap and this did Not help to discharge them. Of coarse I can manual do it and I can also do it with pair of resistors giving a constant drain, not my desired choice.
what part of the pl700 circuit accomplish this job to discharge the caps over time. I always thought it was leakage in the control board.
I do not recall this problem on any other build only this with the second power supply which , by the way drains very quickly?
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My change to a separate board power supply has now been sorted out. I changed to high voltage supply windings after confirming with Joe on doing this. Thanks again Joe for being there for us.
I still get a small change in Bias but only .02v swing and this is because of residual heat difference from the rails static voltage change. Now I have .372v on high and .354v on low. I am very pleased with the out come
I have added a 15k wire wound resistor across the main caps for slow discharge when turning off. This may be replaced with a fast dump resistor and relay combo. We’ll see if that’s needed or not
I still get a small change in Bias but only .02v swing and this is because of residual heat difference from the rails static voltage change. Now I have .372v on high and .354v on low. I am very pleased with the out come
I have added a 15k wire wound resistor across the main caps for slow discharge when turning off. This may be replaced with a fast dump resistor and relay combo. We’ll see if that’s needed or not
- Joined
- Jan 14, 2011
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- 74,224
- Location
- Gillette, Wyo.
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- Halfbiass...Electron Herder and Backass Woof
So the King has new life
here are residual noise
A channel is left
B channel Right
1k across inputs and 8 ohm load on outputs.
two reading for each as lower numbers are at low rail and the tad higher numbers are at high rail
As well here are the other details
output each channel into 8 ohms with less that .008 N+THD 525 watts. and low 250 watts. That’s Awesome Boys
dc offset .68 Land .98R
here are residual noise
A channel is left
B channel Right
1k across inputs and 8 ohm load on outputs.
two reading for each as lower numbers are at low rail and the tad higher numbers are at high rail
As well here are the other details
output each channel into 8 ohms with less that .008 N+THD 525 watts. and low 250 watts. That’s Awesome Boys
dc offset .68 Land .98R
Attachments
Well it doesn’t drain without this. When you turn off supply the main power relay releases fine but due to my crazy second supply for the control board the main caps just sit there fully charged for hours without some form of drain. Any ideas other than what I have would be great. I do mot think this may be the best solution long term
I have the resistor mounted in This photo
I have the resistor mounted in This photo
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- Joined
- Jan 14, 2011
- Messages
- 74,224
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
Thanks. RN all due to Joe and his G board and some sound wire work. I did not think I get these numbers due to the transformer not having any shielding ( end Bells)
as to your comment why the concern you may be right and I have over thought it. I always have my discharge setup connected when it’s open. I’ll try it without and see if al good. It’s going to have “You’ll get zapped and Killed if you open this cover” on the top and bottom.
as to your comment why the concern you may be right and I have over thought it. I always have my discharge setup connected when it’s open. I’ll try it without and see if al good. It’s going to have “You’ll get zapped and Killed if you open this cover” on the top and bottom.
- Joined
- Jan 14, 2011
- Messages
- 74,224
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 74,224
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 74,224
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 74,224
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof