2400pf = 5K at 13,270Hz!!!
I'm not sure, if the calculation (2500 par 2500) for PP should be:
2400pf = 1.25K at 53,077Hz?
For your single ended example:
1400pf = 2.5K at 45,496Hz
Is bypass at this frequency significant enough to call a "path"?
These measurements may still be in tilting the windmill territory.
And I expect they are even less for a Torroidal, but I'd like to
see that confirmed or denied with a real measurement.
I'm not sure, if the calculation (2500 par 2500) for PP should be:
2400pf = 1.25K at 53,077Hz?
For your single ended example:
1400pf = 2.5K at 45,496Hz
Is bypass at this frequency significant enough to call a "path"?
These measurements may still be in tilting the windmill territory.
And I expect they are even less for a Torroidal, but I'd like to
see that confirmed or denied with a real measurement.
Antek AN-3T325 115,115,325,325,6.3,12.6
All Pri to All Sec = 680pF
But I get really weird reading All Pri1 to All Pri2 = -4uF.
Yes Negative 4uF! I measured a 4.7uf normal cap to
make sure the meter worked, and the - sign wasn't
supposed to be there. The meter works...
Shorted the leads to each other and retested, its
consistantly measuring Pri1 to Pri2 negative, and I
don't know why. But throws a shadow of doubt
if any true readings have been made today.
All Pri to All Sec = 680pF
But I get really weird reading All Pri1 to All Pri2 = -4uF.
Yes Negative 4uF! I measured a 4.7uf normal cap to
make sure the meter worked, and the - sign wasn't
supposed to be there. The meter works...
Shorted the leads to each other and retested, its
consistantly measuring Pri1 to Pri2 negative, and I
don't know why. But throws a shadow of doubt
if any true readings have been made today.
Probably has a bifilar wound set of primaries. Typical of dual primary toroids, saves winding time. Next to useless for P-P audio unless you can come up with 1/2 a Mac circuit. Crowhurst twin? Hmmm, no, even that doesn't work. Thats why we need to find a 240V to 240V isolation toroid with no 120V connections.
OOPs, Correction!
The Crowhurst Twin Coupled configuration DOES (sorta) work OK for bifilar wound 120V primaries as plate/cathode windings. I was thinking there was a DC magnetization problem, but the two windings on each xfmr are used for opposite tubes, so DC cancels. This is a nice way to overcome the bifilar problem and get twice as much primary winding turns/inductance besides. But the windings are still random wound typically, so don't expect super results. Plenty of distributed capacitance still. Since twice as many turns usually requires 4 times the inductance to go with it, but we are only getting twice the inductance here, it will be a good idea to use even smaller xfmrs to compensate the Henries.
Don
Edit: I just realized that with bifilar windings they want to be cathode and plate type on each xfmr set. This will work as long as the two windings are separate (not center tapped). Of course the insulation had better be good enough to withstand B+ across the wire enamel. (The Crowhurst Twin did not use bifilar windings and so had two cathode windings on one xfmr and two plate windings on the other xfmr. Those combos can be center tapped.)
The Crowhurst Twin Coupled configuration DOES (sorta) work OK for bifilar wound 120V primaries as plate/cathode windings. I was thinking there was a DC magnetization problem, but the two windings on each xfmr are used for opposite tubes, so DC cancels. This is a nice way to overcome the bifilar problem and get twice as much primary winding turns/inductance besides. But the windings are still random wound typically, so don't expect super results. Plenty of distributed capacitance still. Since twice as many turns usually requires 4 times the inductance to go with it, but we are only getting twice the inductance here, it will be a good idea to use even smaller xfmrs to compensate the Henries.
Don
Edit: I just realized that with bifilar windings they want to be cathode and plate type on each xfmr set. This will work as long as the two windings are separate (not center tapped). Of course the insulation had better be good enough to withstand B+ across the wire enamel. (The Crowhurst Twin did not use bifilar windings and so had two cathode windings on one xfmr and two plate windings on the other xfmr. Those combos can be center tapped.)
Not much space left! The 6H30 is biased at Ia=10mA, Ua=110V. Would maybe have used higher current if the DC/DC converter had allowed it.
Next I will meausure frequency response to see if the toroids are worth using. Otherwise I have a pair of amorphous core Lundahls to replace them.
Next I will meausure frequency response to see if the toroids are worth using. Otherwise I have a pair of amorphous core Lundahls to replace them.
An externally hosted image should be here but it was not working when we last tested it.
Now playing!
First session on my office setup. Used a mastercopy from our own recording for the Swedish National Radio of Jimmy McCracklins "I´ll See It Through" , to celebrate the happy moment.
Light, relaxed and "See Through" soundstage
.
http://www.eflatjump.se/IntroIllSeeItThroughmaster.mp3
First session on my office setup. Used a mastercopy from our own recording for the Swedish National Radio of Jimmy McCracklins "I´ll See It Through" , to celebrate the happy moment.
An externally hosted image should be here but it was not working when we last tested it.
Light, relaxed and "See Through" soundstage
.http://www.eflatjump.se/IntroIllSeeItThroughmaster.mp3
And the nameplate in place:
An externally hosted image should be here but it was not working when we last tested it.
Hej Fuling!
Thanks for the compliments! Look out for a pair of wild OBs with ESL-mid/high soon!
After one hour of listening I find the sound a little to relaxed, so maybe topend is rolled off.
Will measure frequency response 10Hz to 50kHz(or -3db) and squarewave at 10kHz to check ringing tonight.
Thanks for the compliments! Look out for a pair of wild OBs with ESL-mid/high soon!
After one hour of listening I find the sound a little to relaxed, so maybe topend is rolled off.
Will measure frequency response 10Hz to 50kHz(or -3db) and squarewave at 10kHz to check ringing tonight.
!
Had to have an accompaning source so I rebuilt an Ipod Nano dock. It is now ready for painting.
The Ipod has actually got a descent DAC, so when playing *.wav-files it is on par with almost any CD-player.
An externally hosted image should be here but it was not working when we last tested it.
The Ipod has actually got a descent DAC, so when playing *.wav-files it is on par with almost any CD-player.
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