The Nemesis 813 PP Amplifier
- pre65
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#136 Re: The Nemesis 813 PP Amplifier
Ah yes, but it will be the best amp in the world.
Just don't tell DTB or our Andrew I.
Just don't tell DTB or our Andrew I.
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
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- izzy wizzy
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#137 Re: The Nemesis 813 PP Amplifier
A 12V 20A SMPS arrived today. It has adjustable voltazge which is a bonus. I'm betting there will be a load of hash on the output. Any tips on dealing with that at 10A?
Cheers,
Stephen
Cheers,
Stephen
- IslandPink
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#138 Re: The Nemesis 813 PP Amplifier
My experience so far is that there's not a lot of hash and it's more or less at 50 to 60kHz with some higher. I think I remember 40mV as a number from one I used. Just try a 'cough big resistor first and see how it goes.
"Once you find out ... the Circumstances ; then you can go out"
- izzy wizzy
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#139 Re: The Nemesis 813 PP Amplifier
Well I could just turn the voltage down a bit. Why just a big resistor?IslandPink wrote: ↑Fri Nov 23, 2018 1:00 pm My experience so far is that there's not a lot of hash and it's more or less at 50 to 60kHz with some higher. I think I remember 40mV as a number from one I used. Just try a 'cough big resistor first and see how it goes.
But as you say, I'll just be trying it first anyway. I'm hoping the V adjust will get me to 10v without a resistor. Thinner wiring can do it at these currents
Cheers,
Stephen
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#140 Re: The Nemesis 813 PP Amplifier
Ah, "the best amplifier in the world"! Forgot about that.
Be warned, I had to have massive heatsinks for the Coleman regs on my 801A/300B SET amp, and that for only 1.2 Amps. Still too hot to touch. Stupid amounts of heat.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#141 Re: The Nemesis 813 PP Amplifier
Have I mentioned common mode rejection chokes? Or did I just imagine it?izzy wizzy wrote: ↑Fri Nov 23, 2018 12:35 pm A 12V 20A SMPS arrived today. It has adjustable voltazge which is a bonus. I'm betting there will be a load of hash on the output. Any tips on dealing with that at 10A?
Cheers,
Stephen
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- IslandPink
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#142 Re: The Nemesis 813 PP Amplifier
D'Oh sorry, you did say. Rushed out a comment there without engaging brain properly.izzy wizzy wrote: ↑Fri Nov 23, 2018 1:15 pm Well I could just turn the voltage down a bit. Why just a big resistor?
"Once you find out ... the Circumstances ; then you can go out"
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#143 Re: The Nemesis 813 PP Amplifier
Quick google - two sources of common mode chokes for 10 Amps - Mouser and Farnell:
https://www.mouser.co.uk/Passive-Compon ... xiZ1z0wqau
https://uk.farnell.com/c/passive-compon ... urrent=10a
HTH
https://www.mouser.co.uk/Passive-Compon ... xiZ1z0wqau
https://uk.farnell.com/c/passive-compon ... urrent=10a
HTH
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#144 Re: The Nemesis 813 PP Amplifier
In case anyone isn't sure what a common/differential choke filter looks like:
HTH
HTH
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
#145 Re: The Nemesis 813 PP Amplifier
shameless commercial intrusion here...
but if anybody is interested in the heavy duty version of the Coleman regs, complete with sinks then look no further...
as seen here
this chassis I beleive is now in the capable hands of Steve C, the heater regs are nearly the last of the components to be disposed of. Maybe £15 each ono.
but if anybody is interested in the heavy duty version of the Coleman regs, complete with sinks then look no further...
as seen here
this chassis I beleive is now in the capable hands of Steve C, the heater regs are nearly the last of the components to be disposed of. Maybe £15 each ono.
There's nowhere you can be that isn't where you're meant to be
- pre65
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#146 Re: The Nemesis 813 PP Amplifier
Hi Ed, what voltage/current are the regs for ?
I could be interested.
I could be interested.
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
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#147 Re: The Nemesis 813 PP Amplifier
Re the SMPS voltage adjuster, I've not needed to adjust mine but I was of the opinion that the adjustment range was small.
Have you a dummy load to play with ?
Have you a dummy load to play with ?
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)
#148 Re: The Nemesis 813 PP Amplifier
http://www.vitalstates.org/diy/misc/AN_DHT_TX_V4.pdf
these units were running 6.3v heaters at 4 amps but as you can see are very versatile re config change. They were supplied by 2 x 12v 12A smps.
There's nowhere you can be that isn't where you're meant to be
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#149 Re: The Nemesis 813 PP Amplifier
That is a SERIOUS heatsink.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- izzy wizzy
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#150 Re: The Nemesis 813 PP Amplifier
Got the SMPS. Good news is it can be adjusted to 10V. Bad news it won't start up both the fils when cold. It can start one so I think I'll have a delay relay for the 2nd which is a bit irritating. At least the SMPS will be up to power the delay circuit. Unless anyone has some better ideas?
Cheers,
Stephen
Cheers,
Stephen