SS vs Tubes

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Postby tony » Tue Jan 10, 2006 6:56 pm

btw, look up david berning in the web, you will find his works fascinating as he is a class all by himself. many of his designs you will not find anywhere else. he's got smps powered tube amps, which could be 20 years old.
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Postby tony » Tue Jan 10, 2006 10:03 pm

hey rascal, look here and see if you can follow the power supply!
http://www.davidberning.com/ea-2101.htm
Last edited by tony on Wed Jan 11, 2006 6:40 am, edited 1 time in total.
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Postby rascal101 » Tue Jan 10, 2006 11:01 pm

joan2 wrote:
For flyback, it is when MOSFET is off that energy is transferred to the secondary unlike forward topology which has same waveform as secondary. My question is, for tubes is it a flyback or forward topology?


you don't ask questions like these, smps operates in the non-linear region, the switching devices, be they tubes, bipolars, mosfets or igbt's are either on(saturated) or off(cut-off), never in between.

amplifiers operate in the linear region, (ask S_B) of their characteristics curves.
it is a no-no for tubes and transistors to saturate nor be in cutoff, distortion rises abruptly in such cases.


Sorry if you got me wrong ... I was referring to the transformer topology. My guess is for tube design the transformer is configured as "forward". Primary voltage is in phase as secondary. I don't think it is flyback, cause problem of flyback transformer is very high fly voltage.

Understand amplifier design is different from SMPS and that it is operated in the linear region not at saturation and cut-off. Not much but I've already designed (and using) an SS buffer on my CD player. Am thinking of upgrading the constant current source using TL431 voltage reference. Do you think this is a good idea?

Anyway, I am now reading the RCA tube manual and taking a good look on how our magnetics people wind transformers and asking them if they have special winding techniques. I only know how to wind toroidal chokes. BTW, do you know of any local sources for transformer cores? And how do measure inductance without an oscilloscope or an inductance meter?

Saw some tubes at Eleshop in Raon, is it a good place to buy tubes? I mean how do I know that they are selling original parts?
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Postby tony » Wed Jan 11, 2006 6:59 am


Sorry if you got me wrong ... I was referring to the transformer topology. My guess is for tube design the transformer is configured as "forward". Primary voltage is in phase as secondary. I don't think it is flyback, cause problem of flyback transformer is very high fly voltage.


by "forward" you mean current flow thru the secondary when there is primary current flow, i can accept that. "flyback" is when current flows thru secondary when primary has no current flow, nothing like that happens with tube amps.

Understand amplifier design is different from SMPS and that it is operated in the linear region not at saturation and cut-off. Not much but I've already designed (and using) an SS buffer on my CD player. Am thinking of upgrading the constant current source using TL431 voltage reference. Do you think this is a good idea?


tl431 will make a stable refference at 2.5volts,still there are many other options available though.

Anyway, I am now reading the RCA tube manual and taking a good look on how our magnetics people wind transformers and asking them if they have special winding techniques. I only know how to wind toroidal chokes. BTW, do you know of any local sources for transformer cores? And how do measure inductance without an oscilloscope or an inductance meter?


look around the raon area for transformer cores, also in dalandanan in valenzuela, there is a scrap dealer selling surplus equipment.

i use a series resistor with the choke and apply ac voltage, 60hz is fine. you are an engineer, you can figure it out!


Saw some tubes at Eleshop in Raon, is it a good place to buy tubes? I mean how do I know that they are selling original parts?


why not, but look around first, there are mmany here selling tubes, check out their prices first.


@rascal,

we could be out of topic now, why don't you start another thread and we can get thechnical on things you as much as you like. :D
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Postby rascal101 » Wed Jan 11, 2006 9:43 am

Started a thread on the technical section about overcoming disadvantages of tubes and SS designs. Am going there now. :)
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