Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jeff on April 04, 2023, 12:47:34 pm
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Had an idea
We have a C.T. Power Transformer. Each leg puts A.C. on each plate of the tube rectifier. It's advised to put a diode(1n4007) between the A.C. and tube rectifier. So now, the s.s. diode puts half wave rectified A.C. on one plate, and out of phase half wave rectified on to the other and the tube gives you the full wave rectified A.C.
Now what if...
We connect the two s.s. diodes?
The s.s. diodes would now present full wave rectified A.C. to each plate of the rectifier tube(now connected parallel).
Would this affect sag/voltage drop now that, instead of using each diode in the rect tube as a half wave rectifier... resulting in full wave rectification, the s.s. diodes are presenting a full wave rectified signal to a paralleled tube rect.?
To take it one step further, add a filter cap. Now, the s.s. diodes are giving full wave rectified A.C., the cap smooths it to D.C.(rippley?) then the tube is in parallel, passing D.C.
An on-off-on switch would work. Connect top two lugs, connect each middle lug to each S.S./Plate connection, connect the bottom two lugs together to a cap.
Down: S.S. diodes feed full wave rectified A.C. to paralleled tube rect.
Mid: Normal, each diode feeds half wave rectified A.C.(out of phase) to each plate of tube rect.
Up: S.S. Diodes +cap feed rectified D.C. to paralled rect tube.
Would this work?
What would be the expected results?
Thanks for listening, can't wait to hear your thoughts
Peace
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> add a filter cap. Now, the s.s. diodes are giving full wave rectified A.C., the cap smooths it to D.C.(rippley?) then the tube is in parallel, passing D.C.
Thanks for listening, can't wait to hear your thoughts
Words don't do it justice. Can't wait to see your sketch of this parallel tube.
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sorry, I have now way right now to upload a pic.
Don't have computer, using Xbox.
I tried to explain the best I could.
Will work on uploading schematics
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C--------------->|----•------\
C. | \
C. | \
C. • • • \___
C. -----| | / = l \------B+
C---C.T.-g | • • • \ = L / |
C. = | / 5Y3 =
C. | | / |
C. g | / g
C-------------->|-----•------/
Best I can do for now
|
=
|
g
Is cap to ground
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C--------------->|----•------\
C. | \
C. | \
C. | \___
C. | / = |-\------B+
C---C.T.-g | \ = L / |
C. | / (5Y3) =
C. | / |
C. | / g
C-------------->|-----•------/
Left(parallel plate, full wave rect AC)
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C--------------->|----•------\
C. | \
C. | \
C. ____•| \___
C. | | / = |-\------B+
C---C.T.-g = | \ = L / |
C. | | / (5Y3) =
C. g | / |
C. | / g
C-------------->|-----•------/
Right(parallel plate DC)
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C--------------->|----•-----\
C. \
C. \
C. \___
C. / = |-\------B+
C---C.T.-g \ = L / |
C. / (5Y3) =
C. / |
C. / g
C-------------->|-----•------/
Center(off/normal)
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I need to figure out how to post pics
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May be you are interested on reading this page
http://www.valvewizard.co.uk/bridge.html (http://www.valvewizard.co.uk/bridge.html)
(http://www.valvewizard.co.uk/fullwave3.jpg)
About the mixed Bridge resistance the Vacuum rectifier will maintain the internal resistance but I think the effect on SAG will be reduced because the diodes don't has such an internal resistance, what can we say ... a Half of the resistance of the rectify using only the vacuum rectifier ?
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I don't understand very much what you want to do, only ... if you use a Full Wave Bridge DON'T use a transformer with CT connected to groud and remember that if you don't connect the PT CT to ground (if it has one) the voltage at the extremities of the windings are 2 times the voltage you measure between one extremity and the CT
I think I've understand something (CT of PT connected to Ground)
If you use two diodes between the PT windings and the Tube rectifier, one for each input of the tube the result is you improve the Vacuum Rectifier voltage performances of the voltage performances of the diodes
as an example a 350v tube with an in series 1000v diode can afford a voltage of 1350v
If you connect the two diodes output together and connect both the input of the tube in parallel the result will be near the same of the previous
What is maintained in this two topologies of connection is the internal resistance of the Vacuum rectifier, so B+ will SAG at the same manner
putting in the middle (between the diodes and the vacuum rectifier) capacitors ... will smoth ripple, think to it as an RC filter formed by the capacitor followed by the internal resistance of the Vacuum Rectifier
Franco
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I need to figure out how to post pics
:icon_biggrin: I think it's easier to do than what you have posted . . .
Honestly, I'm having trouble figuring out your diagrams.
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I don't know what can do an XBOX but if I've understand correctly the problem is the XBOX
with a Smartphone you can simply draw by hand a schematic, make a photo and using the browser on the phone read and post on forums, also attaching files and images
Franco
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Pic
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OK Jeff
Things will be as I told
Franco
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Rect
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S.S. diodes
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Connect S.S. Diodes for full wave rect before tube diodes
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Result,
More efficient?
Full wave rectified A.C. to tube diodes in parallel
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Result
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W cap
More efficient
D.C. to tube diodes in parallel
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Operation
Normal,
Each of the tube's diodes is half wave, one's 'on' when the others 'off'
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Connected
Tube diodes in parallel, each on for the full(rectified) wave cycle.
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W cap
DC to tube diodes, voltage constant on each tube diodes plate.
No swing in and out of non-linear area, more efficient?
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Schematic
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What are the expected results for each position of the switch?
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What is maintained in this two topologies of connection is the internal resistance of the Vacuum rectifier, so B+ will SAG at the same manner
O.K. Thanks