Choke loading Anodes.
#166
Yes, the second triode is intended to drive field coils so is nice and linear, the first is not aimed at chokes, other than as part of a tuned circuit as a oscillator. Doesn't stop it working well with them though.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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Dave the bass
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#168
... 6DN7 works very well indeed IMO, better than 6EM7 in the same cct. Its got a lovely rich deep natural string sound, very nice, I heard the same sound in AndrewI's interstaged 6dn7 amp when we had bass-fest earlier on in the year. It deffo sounded more alive than my own 6EM7 which I've been enjoying for a good while now.
I'm interested to see where the O.P's are so I'm going to draw out exactly what I've got in this cct and what voltages I've got at all the right places. Then maybe I can work out current flow and O.P's i hope.
DTB
I'm interested to see where the O.P's are so I'm going to draw out exactly what I've got in this cct and what voltages I've got at all the right places. Then maybe I can work out current flow and O.P's i hope.
DTB
"The fat bourgeois and his doppelganger"
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Dave the bass
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#170
The 'bay.Mike H wrote:Interesting, where did you get 'em from?
.
DTB
"The fat bourgeois and his doppelganger"
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Dave the bass
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#172
Here we go...
[img][img]http://i195.photobucket.com/albums/z109 ... NEM7-1.jpg[/img]
^PICTURE EDITED^ due to pencil operative being dense.
Now then, after a bit of calculator work .....
6DN7
1st triode is sitting at 54.8V @ 2.7mA
2nd Triode is sitting at 311V @25mA
6EM7
1st triode is sitting at 131.8V @ 1.6mA
2nd triode is sitting at 170V @ 54mA.
^I think that's right.
...from these conclusions we can see..... ermmmmm ...errrrr...
DTB
[img][img]http://i195.photobucket.com/albums/z109 ... NEM7-1.jpg[/img]
^PICTURE EDITED^ due to pencil operative being dense.
Now then, after a bit of calculator work .....
6DN7
1st triode is sitting at 54.8V @ 2.7mA
2nd Triode is sitting at 311V @25mA
6EM7
1st triode is sitting at 131.8V @ 1.6mA
2nd triode is sitting at 170V @ 54mA.
^I think that's right.
...from these conclusions we can see..... ermmmmm ...errrrr...
DTB
Last edited by Dave the bass on Thu Nov 26, 2009 10:24 pm, edited 2 times in total.
"The fat bourgeois and his doppelganger"
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pre65
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#173
On your diagram the 2nd grid connection comes after the 120K resistor but before the two chokes.
Is that right ?
Mr I. Nose-Buggerall (Major-retired)
No reference to the "real" Mr I intended.
Is that right ?
Mr I. Nose-Buggerall (Major-retired)
No reference to the "real" Mr I intended.
Last edited by pre65 on Thu Nov 26, 2009 10:52 pm, edited 1 time in total.
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)
#174
Yep, I thinks the grid should be going to the first anode.
I think it would work nicely as a DRD amp with a bit of twiddling.
I think it would work nicely as a DRD amp with a bit of twiddling.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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Dave the bass
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#175
Yep, sorry about that, I'll amend and repost tomorrow. Bedtime. Early start tomorrow.....grrrrrr.
DTB
DTB
"The fat bourgeois and his doppelganger"
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Dave the bass
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pre65
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#177
So if you took the feed to the two anode chokes straight from the second cathode that would be DRD ?
This is interesting and (almost) exciting.
Tell us more Dave baby.
This is interesting and (almost) exciting.
Tell us more Dave baby.
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)
#179
Yes, cept you will need to loose another 10v or so. Could be done with a extra resistor in the cathode circuit to generate another 10v or so of bias.
Replace the 1k4 with another 1k3 and 200R in series. 200R end to the cathode. Take feed to top of first anode choke from between the 1k3 and 200R. remove the cap of first choke, and resistor to b+, and it should be something like.
Replace the 1k4 with another 1k3 and 200R in series. 200R end to the cathode. Take feed to top of first anode choke from between the 1k3 and 200R. remove the cap of first choke, and resistor to b+, and it should be something like.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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pre65
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#180
Something like this ?
How does one add a picture like DTB did with his circuit ?
How does one add a picture like DTB did with his circuit ?
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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)