Search found 15747 matches

by Nick
Thu Mar 18, 2010 9:30 am
Forum: Everyones Projects
Topic: My first 3 stager.
Replies: 101
Views: 25794

Then use a 68k - standard value, init. = 118V at anode. ( + / - resistor tolerance :wink: ) Though I think you will find the valve tolerance far exceeds and normal resistor variation, so don't get too hung up on exact voltages. If a circuit needs that accuracy then you will need to include some mea...
by Nick
Wed Mar 17, 2010 10:33 pm
Forum: Beginners
Topic: 7.5V @ 4A filament supply.
Replies: 18
Views: 6754

Do I need to be careful when connecting the two 9v secs in parallel ?
Make sure they are in phase or you will get no voltage.
by Nick
Wed Mar 17, 2010 10:31 pm
Forum: Everyones Projects
Topic: My first 3 stager.
Replies: 101
Views: 25794

Connect the 20uf cap at the 128v point, no need to have the extra resistor swinging as well.
by Nick
Wed Mar 17, 2010 2:07 pm
Forum: Beginners
Topic: 7.5V @ 4A filament supply.
Replies: 18
Views: 6754

Well, you have got 1.66 ohms in the circuit, so at 4A thats 6.64v burnt. By the way, you can't just do 9v * 4A to work out the rating, as I mentioned before, adding the bridge and cap changes how current is drawn and alters the requirement. In this case its 4A = 4 * 1.61 amp from the transformer = 6...
by Nick
Wed Mar 17, 2010 12:20 pm
Forum: Beginners
Topic: 7.5V @ 4A filament supply.
Replies: 18
Views: 6754

Sounds like something in there has a higher resistance than you expect. What are the voltages at the various pints in the supply?

I would have expected a 6-7v TX to give 7.5v
by Nick
Tue Mar 16, 2010 11:32 am
Forum: Assorted Stuff
Topic: SimonFest
Replies: 80
Views: 22973

I believe Greg is now working in the youth social work area, so yes I expect he will be sensitive.

Andrew: you seem to be intent on prolonging this, I don't see what anyone has to gain from that?

Phil: sorry, thats still not helping.
by Nick
Tue Mar 16, 2010 8:03 am
Forum: Valves
Topic: Are you sitting comfortably?....
Replies: 28
Views: 12251

We do seem to have drifted from the original pantomime intention...

(oh no we haven't)
by Nick
Tue Mar 16, 2010 8:01 am
Forum: Assorted Stuff
Topic: SimonFest
Replies: 80
Views: 22973

Mornin all! I utterly really completely and without any reservation whatsoever do not have the tiniest shadow or the merest suggestion of an inkling of what Greg is talking about. Andrew, I suspect its the result of the combination of "5 year old" and "Guilty" in the same post, ...
by Nick
Mon Mar 15, 2010 10:44 pm
Forum: Assorted Stuff
Topic: SimonFest
Replies: 80
Views: 22973

Lets calm down a bit, If Greg feels he has been offended, then its understandable he is upset, I dont think Andrew meant any such thing, but rather than dragging this out and attracting bystanders, why not, Andrew tell Greg simple that is was not meant as a disparaging remark, and why not Greg, give...
by Nick
Mon Mar 15, 2010 5:59 pm
Forum: Assorted Stuff
Topic: SimonFest
Replies: 80
Views: 22973

I merely mentioned that you bare a passing resemblance to a cross between a hells angel and a well-known christmas benefactor......
Works for me, back to the evil Santa motif :-)
by Nick
Mon Mar 15, 2010 4:15 pm
Forum: Assorted Stuff
Topic: SimonFest
Replies: 80
Views: 22973

Fascinating weekend all in all and got to meet more of the guys, must be said both Steve S and Nick are real characters that don't quite fully come across on the forum (although DTB had warned me about Nick beforehand Very Happy ) Must have a word with that Mr Dave... Not sure you saw Steve S thoug...
by Nick
Mon Mar 15, 2010 2:06 pm
Forum: Everyones Projects
Topic: more on gm70 even more
Replies: 31
Views: 15863

so far we have a paralleled 1n4007 for the psu, a hammond 378 cx power tx a hammon 159T choke and a sotwer 8423 interstage I guess you mean series IN4007? Yes, 400 - 0 - 400 will be fine, I would use a full wave with that instead of a doubler though. That will give you something like 1100v. Still n...
by Nick
Mon Mar 15, 2010 12:21 pm
Forum: New Users
Topic: Nothing in partuicular
Replies: 2
Views: 3503

Well, maybe if you give us a clue as to the topic we can help on that?
by Nick
Sun Mar 14, 2010 5:32 pm
Forum: Everyones Projects
Topic: Low Power SE project ( 6EM7 possibly )
Replies: 121
Views: 41357

One question - I have about 200v across the CCS in total with at mo only 1.4ma going thru , so by my calcs the MJE is having to dissipate about 0.28 watts
Should be ok, I would expect it to run about 24C above ambient (from the first data sheet I found).
by Nick
Sat Mar 13, 2010 11:13 pm
Forum: Everyones Projects
Topic: more on gm70 even more
Replies: 31
Views: 15863

In fact Ian, I am with Phil, I don't see how this is any different to the other thread. No real design I can see, just a list of unconnected thoughts with no sign of them coalescing into a actual design. I am (as it happens) building what is effectively a gm70 push pull for Ali, and I have built sev...