I am currently working on a solid state amplifer. I have seperated the powersupplies for the voltage and current stage. I would like to make a chokeloaded and tube rectified power supply for the voltage gainstages. Can anyone help me with a generic design to a +/- 50 V power supply with tube rectification and Choke loading.
ugh why?
50v.. and tons of current, right? how much exactly?
low voltage and tons of current aren't exactly what tubes excel at... it can be done, but it will be a big abortion most likely.
edit: nevermind, noticed you mentioned just for the gain stages. Anyways, how much current, how much regulation.. etc. This really is a SS job, though.
50v.. and tons of current, right? how much exactly?
low voltage and tons of current aren't exactly what tubes excel at... it can be done, but it will be a big abortion most likely.
edit: nevermind, noticed you mentioned just for the gain stages. Anyways, how much current, how much regulation.. etc. This really is a SS job, though.
As mentioned this supply is just for the gainstages so the current needed i very little, less than 200mA. So I cant see that as a problem.
The reason is that I have a DAC with an IV stage that runs on single supply. Here the tube rectification and choke loading is a tremendous improvement adding an ubeliveable black background and expanding the sound stage tremendously. So speakers littraly fill the room.
The reason is that I have a DAC with an IV stage that runs on single supply. Here the tube rectification and choke loading is a tremendous improvement adding an ubeliveable black background and expanding the sound stage tremendously. So speakers littraly fill the room.
The only difference between a tube power supply and a solid state one that can make a difference in your case is the absence of switching noise in the tube supply. My suggestion is therefore to design a solid state supply optimised for low switching noise using soft recovery diodes and snubbers together with additional filtering it will be as good as the tube power supply. I have upgraded the power supply in my DAC with measureable results and I alos believe I can hear an improvement. I also design all solid state supplies for tube amplifiers in a similar way.
Regards Hans
Regards Hans
the switching noise is still present with softrecovery diodes. Hence the desire for tube rectification. I throughly belive that a good way to proceed.
Does it strictly need to be a bipolar supply? It can be done a number of ways, but you'll find more prior art with single supplies. The best advice I can give you is to read up a bit on tubecad.com. He has numerous examples of such supplies, both singular and bipolar. Then download PSUDII on duncanamps.com and play around.
Then your snubber circuits are not good enough, optimise the snubber according to what is written here http://www.hagtech.com/pdf/snubber.pdf and the switching noise is gone.
Regards Hans
200 mA is still quite high for a tube PS, considering that it will be continuous. One thing you might like to consider trying is a pair of thermionic TV damper diodes in a hybrid bridge together with a pair of good SS diodes. This arrangement will suppress any noise from the SS diodes.
Dampers are pretty rugged and a pair of 6D22S would do a good job. You need 6.3 v @ 3.8 A to heat a pair of them and they use magnoval sockets (like a giant B9A) which are usually available from the tube vendor.
How you organize the filter depends on the input and output voltage requirements. A choke input filter, which should be quieter, will give 0.9 x the RMS input voltage; a capacitor input filter will give up to 1.4 x, depending on the load. If you go for a cap input, don't exceed 50uF or the 6D22S may suffer.
Dampers are pretty rugged and a pair of 6D22S would do a good job. You need 6.3 v @ 3.8 A to heat a pair of them and they use magnoval sockets (like a giant B9A) which are usually available from the tube vendor.
How you organize the filter depends on the input and output voltage requirements. A choke input filter, which should be quieter, will give 0.9 x the RMS input voltage; a capacitor input filter will give up to 1.4 x, depending on the load. If you go for a cap input, don't exceed 50uF or the 6D22S may suffer.
In my experience, about 15v driving a Stereo EL34 PP amp with total current consumption of about 250 mA including all stages.
After some more testing have I found that the gainstages consumption is "only" 40 mA per side. Thus the stereo consumption is a little less than 100 mA total. I suscpect that this increases the selection of rectifier tubes quite dramaticaly. Anyone with a generic schematic of this hybrid bridge rectifier.
Thanks
Thanks
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