What people are working on at the moment
pre65
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by pre65 » Wed Nov 30, 2016 8:01 pm
Seven months since the last post and nothing has happened since then.
The transformer mods are still going to be done, but I really should get on with the 50W SEMOS first.
Just need a shed load of enthusiasm.
The only thing necessary for the triumph of evil is for good men to do nothing.
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Mike H
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by Mike H » Wed Nov 30, 2016 11:06 pm
When a project becomes a chore?
"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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by IslandPink » Wed Nov 30, 2016 11:19 pm
So this posting is a false alarm
- I thought you'd started something !
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pre65
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by pre65 » Wed Nov 30, 2016 11:29 pm
No, not a "chore" as such. Just that my life has expanded a tad and audio amp construction is not the only thing to attract my attention.
I have "stumbling blocks" at the moment, one being the power supply capacitors. My frugalitanariasism is preventing me from purchasing what I think are the ideal caps, and my Ebay searches are not finding the "bargains" that would entice me to part with dosh from my pensioners purse.
Normal service WILL be resumed.
I must remind myself to ask Arabian Nick for an up to date copy of his capacitor stock, as I can't find the last one he sent me.
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)
cressy
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by cressy » Wed Nov 30, 2016 11:38 pm
You're not the only one phil, i need to give myself a kick up the arse and get the mike h amp built.
Things got in the way, and I got waylaid by more prosaic matters. I keep staring at it thinking must do this, or that.
Then bottle it and walk away and do something else......
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by Mike H » Thu Dec 01, 2016 1:24 pm
pre65 wrote: I have "stumbling blocks" at the moment, one being the power supply capacitors. My frugalitanariasism is preventing me from purchasing what I think are the ideal caps, and my Ebay searches are not finding the "bargains" that would entice me to part with dosh from my pensioners purse.
Normal service WILL be resumed.
I must remind myself to ask Arabian Nick for an up to date copy of his capacitor stock, as I can't find the last one he sent me.
Frugalitarianism! Must try to remember that
Can't you just use "something" for the caps in the interim? Just so it works...
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
pre65
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by pre65 » Thu Dec 01, 2016 1:29 pm
Mike H wrote:
Frugalitarianism! Must try to remember that
Can't you just use "something" for the caps in the interim? Just so it works...
Probably.
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)
Mike H
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by Mike H » Thu Dec 01, 2016 1:34 pm
Well there ya go.
Know what you mean tho when I'm doing valve amps stuff I'm doing valve amps stuff, when I'm not is cos I'm doing something else.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
pre65
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by pre65 » Fri Dec 02, 2016 11:31 pm
I have seen some 900v (working voltage) 116uf MKP capacitors, which would need to be used in pairs, 1800v rating will be enough.
Series R is listed as 4.6m ohm.
Is there any benefit using MKP over electrolytics in amp power supplies ?
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)
pre65
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by pre65 » Sun Dec 04, 2016 12:04 pm
pre65 wrote: I have seen some 900v (working voltage) 116uf MKP capacitors, which would need to be used in pairs, 1800v rating will be enough.
Series R is listed as 4.6m ohm.
Is there any benefit using MKP over electrolytics in amp power supplies ?
Perhaps I should have asked, are their any negative reasons for using MKP capacitors ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
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Mike H
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by Mike H » Sun Dec 04, 2016 10:26 pm
Presumably we're not sure!
Benefit I'm guessing better chance of finding high Voltage MKP than high Voltage elec.
Personally if MKP I'd want them to be audio-grade, having had some unfortunate experiences with motor-run caps etc.
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by Paul Barker » Mon Dec 05, 2016 12:55 am
pre65 wrote: I have seen some 900v (working voltage) 116uf MKP capacitors, which would need to be used in pairs, 1800v rating will be enough.
Series R is listed as 4.6m ohm.
Is there any benefit using MKP over electrolytics in amp power supplies ?
are you sure you need an amp thta requires 1800v headroom in the power supply caps?
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
pre65
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by pre65 » Mon Dec 05, 2016 10:11 am
Paul Barker wrote: pre65 wrote: I have seen some 900v (working voltage) 116uf MKP capacitors, which would need to be used in pairs, 1800v rating will be enough.
Series R is listed as 4.6m ohm.
Is there any benefit using MKP over electrolytics in amp power supplies ?
are you sure you need an amp that it would seem requires 1800v headroom in the power supply caps?
I'm fairly sure that I have NO NEED for such an amp, but as I have most of the parts for the rebuild it would be a shame not to finish them off.
Ht should be about 1300v depending on how it sims up when taking into account the change to cap input, which Nick suggested was a better option.
I need to get all the parameters measured first.
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)
Paul Barker
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by Paul Barker » Mon Dec 05, 2016 7:08 pm
You made a very good 833a amp already. But I appreciate more than many the drive you are experiencing.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
pre65
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by pre65 » Tue Dec 06, 2016 10:04 pm
I found some 1200v (working voltage) 5uf MKP caps on Ebay, so have ordered four (4).
64A max and very low ESR, should be good for the first cap in pairs.
Coming from a supplier in Holland so will be a week or so.
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)