10W SET
- Mike H
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#76
Nah unit #1 seems to check out, just increase cathode resistor for unit #2 so it's under 10W, sorted.
A clue is in the fact that on schematic it sez "5 watt" for the "1k ohm", yes 'cause it's dissipating 2.5W.
I suggest the 1k could be increased to something like 3.3k, that would reduce Ia to about 20 - 30mA, the cathode will then be around 75V.
A clue is in the fact that on schematic it sez "5 watt" for the "1k ohm", yes 'cause it's dissipating 2.5W.
I suggest the 1k could be increased to something like 3.3k, that would reduce Ia to about 20 - 30mA, the cathode will then be around 75V.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- Dave the bass
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#77
yes!pre65 wrote:Perhaps I should do something completely different ?
no!pre65 wrote:Like hibernation.
Gwaaarrn, build it as is but knowing it could be a bit manky (tech word that) but put it right using your newly honed fault finding and fettling skills.
That way you'll know how it works and can then adjust values to get safe OP's and the like. Think of the knowledge and skills you'll gain.
Valves are more forgiving than Transistors so a brief over running of anode dissipation wint kill 'em.
I'll sponsor you with even more 6EM7's, gwwwwaaaarrrrn!
DTB
"The fat bourgeois and his doppelganger"
#78
Yes, and then check what a crap op point that will put the valve into.Mike H wrote:Nah unit #1 seems to check out, just increase cathode resistor for unit #2 so it's under 10W, sorted.
A clue is in the fact that on schematic it sez "5 watt" for the "1k ohm", yes 'cause it's dissipating 2.5W.
I suggest the 1k could be increased to something like 3.3k, that would reduce Ia to about 20 - 30mA, the cathode will then be around 75V.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#79
You may as well just use the BK circuit, direct couple and stand the cathode at 150v or so. Still too much anode voltage IMHO.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- pre65
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#80
I don't know if this gives the circuit any credulity, but it was on a Svetlana technical bulletin.
http://www.tube-town.net/info/sed-techn ... eNo46.html
http://www.tube-town.net/info/sed-techn ... eNo46.html
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
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#81
Well spotted bwanaNick wrote:Yes, and then check what a crap op point that will put the valve into.
I'd go with your method
"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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#82
Well, Mike may be able to answer this one.
I was thinking of using an old amp and modding as necessary. Paul was saying a choke loaded cathode follower was ideal.
This is the circuit in question.
I was thinking of using an old amp and modding as necessary. Paul was saying a choke loaded cathode follower was ideal.
This is the circuit in question.
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)
- Dave the bass
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#83
HT was 325V DC if using the BK cct. Worth remembering the heater will need elevating otherwise the heater cathode insulation can be breached.Nick wrote:You may as well just use the BK circuit, direct couple and stand the cathode at 150v or so. Still too much anode voltage IMHO.
DTB
"The fat bourgeois and his doppelganger"
- Mike H
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#84
Always something isn't there?
(That's one reason I like 6SN7's, 200V incl. signal)
Phil you're deviating from going-with-as-is into DIY (design it yerself)
Personally I still prefer my DC-coupled grid, common-cathode idea (IT in anode) which Nick seems to agree with ~ in basic principle at any rate
(That's one reason I like 6SN7's, 200V incl. signal)
Phil you're deviating from going-with-as-is into DIY (design it yerself)
Personally I still prefer my DC-coupled grid, common-cathode idea (IT in anode) which Nick seems to agree with ~ in basic principle at any rate
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
#85
Hey, don't bring me into thisPersonally I still prefer my DC-coupled grid, common-cathode idea (IT in anode) which Nick seems to agree with ~ in basic principle at any rate
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- pre65
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#86
I've been without electric since 11.00 and it came back on about 4.50 PM.
I had a reply to my wanted ad for Eric Barbour's amp article and I'm now studying the 4 pages. It's still 6EM7 driven but cathode follower. 1st impression is favourable.
I had a reply to my wanted ad for Eric Barbour's amp article and I'm now studying the 4 pages. It's still 6EM7 driven but cathode follower. 1st impression is favourable.
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
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#87
It was tough in the middle agespre65 wrote:I've been without electric since 1100
"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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#88
I posted this circuit a while ago, and no one made any comments.pre65 wrote:I found this circuit earlier.
Seems quite simple.
Any thoughts ?
Does the panel think it would work as drawn ?
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)
- andrew Ivimey
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#89
'MQ parafeed output' - what's/how's that?
I've very happily built a 10watt SE class A amplifier. Twas very easy indeed and it sounds very good indeed and it was very cheap indeed and it gets very very hot indeed; it is a Nelson Pass Aleph M - the schematic is freely available on the web and circuit boards are for sale from Hongkers.
Much Respect to NP, indeed!
I've very happily built a 10watt SE class A amplifier. Twas very easy indeed and it sounds very good indeed and it was very cheap indeed and it gets very very hot indeed; it is a Nelson Pass Aleph M - the schematic is freely available on the web and circuit boards are for sale from Hongkers.
Much Respect to NP, indeed!
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.