I am planning to change the power supply for an old tube amp (4xEL34), becuse it is way too heavy. The core of the transformere is for about 650W, so I would like to change it for something smaller.
I was thnking about step-up converter, but am not sure if it is the right way, becuase then there would be 500V non-isolated from Ground.
Is there any simple SMPS design without a transformer, which I would just build and leave, without any testing or setting?
And just by the way, will the SMPS bring much more noise to the circuit than the transformer?
I was thnking about step-up converter, but am not sure if it is the right way, becuase then there would be 500V non-isolated from Ground.
Is there any simple SMPS design without a transformer, which I would just build and leave, without any testing or setting?
And just by the way, will the SMPS bring much more noise to the circuit than the transformer?
You would still need to use a transformer for isolation....but it would be relativley tiny compared to what you were using...
SMPS for audio is easy and very do-able...
There are plenty of folks against SMPS for audio applications mostly due to ignorance...they still think in terms of 1970's -1980's switching technologies...This is because most of the books out there on SMPS, were written back then...as with the Unitrode stuff....
The big argument is mostlly over EMI issue... This can be simply avoided by using a quasi-resonant converter...
For your application your best bet is a Push-Pull converter in current mode...Quasi-Resonant... Switching no less than 500kHz..with a cross over frequency around 80kHz to 100kHz...
Chris
SMPS for audio is easy and very do-able...
There are plenty of folks against SMPS for audio applications mostly due to ignorance...they still think in terms of 1970's -1980's switching technologies...This is because most of the books out there on SMPS, were written back then...as with the Unitrode stuff....
The big argument is mostlly over EMI issue... This can be simply avoided by using a quasi-resonant converter...
For your application your best bet is a Push-Pull converter in current mode...Quasi-Resonant... Switching no less than 500kHz..with a cross over frequency around 80kHz to 100kHz...
Chris
EMI = Electo Magnetic Interference and is the plague of SMPS + hi-Z input devices, tubes or FET's.
I did a small (55W) one for auto use. The final schema and thread of R&D is here:
http://geek.scorpiorising.ca/GeeK_ZonE/index.php?topic=1092.msg14416#msg14416
Shielding and feedthrough caps for the power leads are a must.
I didn't try a transformerless boost convertor yet. Plan to in the future when I want to be brave and try SS again
I did a small (55W) one for auto use. The final schema and thread of R&D is here:
http://geek.scorpiorising.ca/GeeK_ZonE/index.php?topic=1092.msg14416#msg14416
Shielding and feedthrough caps for the power leads are a must.
I didn't try a transformerless boost convertor yet. Plan to in the future when I want to be brave and try SS again
kubeek....
I am trying to help you out here...
Traditional SMPS are noisy and lots of EMI....Look up a Quasi-Resonant SMPS topology...They are smoother and don't put out all that noise...since the switching waveform is much like a sine wave..... You will want a Push-Pull design in CURRENT MODE....
The transformer won't be much bigger than using an inductor...Since in thie case, think of it as an inductor with two windings intead of one winding...
You will be using small Ferrite cores...not big EI laminations....
You want to switch around 500kHz and set your cross-over around 80KHz to 100kHz....
WHat is the input voltage range and what output voltage would you like to have and at what power levels????
Chris
I am trying to help you out here...
Traditional SMPS are noisy and lots of EMI....Look up a Quasi-Resonant SMPS topology...They are smoother and don't put out all that noise...since the switching waveform is much like a sine wave..... You will want a Push-Pull design in CURRENT MODE....
The transformer won't be much bigger than using an inductor...Since in thie case, think of it as an inductor with two windings intead of one winding...
You will be using small Ferrite cores...not big EI laminations....
You want to switch around 500kHz and set your cross-over around 80KHz to 100kHz....
WHat is the input voltage range and what output voltage would you like to have and at what power levels????
Chris
cerrem, first thanks for your help
I don´t care if it is small ferrite core or EI. It is allways a transformer with primary and secondary, separated by insulation, on a plastic frame.
I don´t feel like trying to do a good transformer with low capacitances and so on. I just wanted to make a cheap and easy (maybe adjustable) HV source to let me play with tubes, which makes the boost-converter best for me.
The voltage transformation is 12 to cca 500v, maybe 50-100W.
I don´t care if it is small ferrite core or EI. It is allways a transformer with primary and secondary, separated by insulation, on a plastic frame.
I don´t feel like trying to do a good transformer with low capacitances and so on. I just wanted to make a cheap and easy (maybe adjustable) HV source to let me play with tubes, which makes the boost-converter best for me.
The voltage transformation is 12 to cca 500v, maybe 50-100W.
Here's a member of the NEONIXIE-L Yahoo!!!!! group who has built a 100W 170V SMPS, the principles of which hold for higher outputs:
Dieter's CD47 & SMPS project
HTH
Dieter's CD47 & SMPS project
HTH
kubeek said:
Well...
You don't need to wind a low capacitance transformer for a quasi-resonant switcher....instead, the winding capacitance works in your favor sice you are using it as part of the tank circuit for resonance..
One question.... WHy step up ?? From 12v?? What is the source of this 12v???
Chris
Hello, you successfully copied the BaM235 SMPS? How did you find the schematics, and do you have them available?
And how is your experience and success with your amplifier? (Problems?)
Thanks.
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