Dual rail +/- 80v power supply.
- pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#1 Dual rail +/- 80v power supply.
On the new 811A amp I need a +/- 80v power supply for the mosfet follower part.
I'm not sure where to start.
If I use PSU designer to design a 160v power supply can I then use the transformer secondary centre tap to create an 0v rail and connect to the other two with capacitors ?
I have a transformer with two 120v secondarys, what sort of current will the circuit take ?
I'm not sure where to start.
If I use PSU designer to design a 160v power supply can I then use the transformer secondary centre tap to create an 0v rail and connect to the other two with capacitors ?
I have a transformer with two 120v secondarys, what sort of current will the circuit take ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#2 Re: Dual rail +/- 80v power supply.
whatever load you put on it until it smokes
the diodes will be specced for the load or use heavy duty bridge depending on load..like this plus as much smoothing as you need
the diodes will be specced for the load or use heavy duty bridge depending on load..like this plus as much smoothing as you need
There's nowhere you can be that isn't where you're meant to be
- pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#3 Re: Dual rail +/- 80v power supply.
Thanks Ed.
I was more thinking of the mosfet follower likely current draw.
I was more thinking of the mosfet follower likely current draw.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#4 Re: Dual rail +/- 80v power supply.
Ohms law gives you that. 20ma I think I remember, 104v across 5k
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#5 Re: Dual rail +/- 80v power supply.
Thanks Nick, although I can't see from the circuit where those numbers came from ?
Regarding the PSU I found these PCBs on Ebay, and as space is a consideration I'll get a couple to try.
https://www.ebay.co.uk/itm/Dual-Polarit ... 0009.m1982
Regarding the PSU I found these PCBs on Ebay, and as space is a consideration I'll get a couple to try.
https://www.ebay.co.uk/itm/Dual-Polarit ... 0009.m1982
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#6 Re: Dual rail +/- 80v power supply.
Not claiming equivilance:
At the question period after a Dirac lecture at the University of Toronto, somebody in the audience remarked: "Professor Dirac, I do not understand how you derived the formula on the top left side of the blackboard."
"This is not a question," snapped Dirac, "it is a statement. Next question, please."
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- Paul Barker
- Social Sevices have been notified
- Posts: 8988
- Joined: Mon May 21, 2007 9:42 pm
#7 Re: Dual rail +/- 80v power supply.
Nick wrote: ↑Fri Nov 17, 2017 1:16 pmLike!pre65 wrote: ↑Fri Nov 17, 2017 12:25 pm
At the question period after a Dirac lecture at the University of Toronto, somebody in the audience remarked: "Professor Dirac, I do not understand how you derived the formula on the top left side of the blackboard."
"This is not a question," snapped Dirac, "it is a statement. Next question, please."
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
#8 Re: Dual rail +/- 80v power supply.
my apologies Philip, I was trying to be funny, then facetious, then I lost it by not referring to the circuit post....
it is a valve, put a voltage across it and bias it through the grid(gate) and current will flow through it...you have supplied most of the figures
There's nowhere you can be that isn't where you're meant to be
#9 Re: Dual rail +/- 80v power supply.
I thought something was familiar...I believe it's George Anderson's power-drive. I used to follow him on diyaudio back in the day when he'd test big valves to find the limit..and then push them over the edge...most amusing...and he also used to play his guitar whilst semi naked..not as much fun to watch...
anyway, I digress, this may be of some use if you're scratching your head:
http://tubelab.com/articles/circuits/po ... /cookbook/
anyway, I digress, this may be of some use if you're scratching your head:
http://tubelab.com/articles/circuits/po ... /cookbook/
There's nowhere you can be that isn't where you're meant to be
- pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#10 Re: Dual rail +/- 80v power supply.
Semi naked in front of an 833a amp no less.
Yes, Powerdrive it is, and I've wanted to try it for a while.
Yes, Powerdrive it is, and I've wanted to try it for a while.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#11 Re: Dual rail +/- 80v power supply.
The split rail PCBs came today.
I've populated them as much as I can from stock parts, the rest are ordered.
The board has provision for four (4) 2200uf caps @ 25v, but as I'm using a higher voltage than intended I can't fit them on the PCB.
Anyway, I've soldered PCB pins in the mounting holes, and the caps will be off board.
I've populated them as much as I can from stock parts, the rest are ordered.
The board has provision for four (4) 2200uf caps @ 25v, but as I'm using a higher voltage than intended I can't fit them on the PCB.
Anyway, I've soldered PCB pins in the mounting holes, and the caps will be off board.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#12 Re: Dual rail +/- 80v power supply.
I remember him! Did he have videos on YouTube? Can't find any now. Or was it not YouTube?
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#13 Re: Dual rail +/- 80v power supply.
More progress.
I'm running these dual supply boards with a 240v - 9v transformer into a 12v - 240v transformer.
Output (unloaded) was 120v, but loading both + and - outputs with 390R resistors has given me +/- 80v, which was the target.
When in situ the mosfet load may drag the voltage down a bit but I can adjust on test.
I was surprised how hot an Arcol 50W 390R resistor gets when passing 102ma, which is 4.1W. I know the 50W rating is halved when not on a heatsink but even so.
The 390R value was selected part by calculation and part by whats in my resistor box.
This supply (one of two) is on a breadboard and far too big to go in the amp case, so will have to go offboard.
I'm running these dual supply boards with a 240v - 9v transformer into a 12v - 240v transformer.
Output (unloaded) was 120v, but loading both + and - outputs with 390R resistors has given me +/- 80v, which was the target.
When in situ the mosfet load may drag the voltage down a bit but I can adjust on test.
I was surprised how hot an Arcol 50W 390R resistor gets when passing 102ma, which is 4.1W. I know the 50W rating is halved when not on a heatsink but even so.
The 390R value was selected part by calculation and part by whats in my resistor box.
This supply (one of two) is on a breadboard and far too big to go in the amp case, so will have to go offboard.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#14 Re: Dual rail +/- 80v power supply.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- Mike H
- Amstrad Tower of Power
- Posts: 20189
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#15 Re: Dual rail +/- 80v power supply.
Ah thanks.
I'm always surprised how hot 1 or 2 Watts is.
-
Oh yes!
I'm always surprised how hot 1 or 2 Watts is.
-
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."