Hi, I'm interested in building a guitar tube preamp using sub-mini tubes. Some are max plate 60V and some are 165V. Any thoughts on the best approach for compact low cost power supplies for these two different voltages (two different projects, so a 60V PS for one, and a 165V PS for the other). The power supplies need to be compact as they need to fit into guitar pedals, and they need to be low cost otherwise I might as well use a lower voltage tube to start with. Thanks in advance for any thoughts.
Due to the limited space, you might try something like this: heesch.net - Schaltnetzteil für Röhren It's a small form-factor and very simple SMPS using a microcontroller to generate the switching frequency and to drive the switching mosfet. You can easily adapt the design to your needs by adjusting the transformation ratio (you'll probably wind the transformer yourself anyway).
Hi Mastodon,
That looks interesting. I don't speak German, but I used Google Translate to read the website, it's not perfect, but I get the idea, with the schematic as well.
Not sure about the transformer pot core though, I haven't wound my own before.
Have you built this circuit yourself? Can you specify a suitable pot core? Maybe a supplier as well if you know one
Thanks for your time. John
That looks interesting. I don't speak German, but I used Google Translate to read the website, it's not perfect, but I get the idea, with the schematic as well.
Not sure about the transformer pot core though, I haven't wound my own before.
Have you built this circuit yourself? Can you specify a suitable pot core? Maybe a supplier as well if you know one
Thanks for your time. John
Hi Boofers
Slight problem there, I live in the UK & the mains voltage is 240VAC!
I see... Move to Canada? LOL. I guess that a step down transformer will take up too much space for you?
If you put 120VAC straight to a bridge rectifier and filter cap you end up with around 170VDC. You could then use series resistor and second filter cap to drop the voltage down to 65VDC. Just make sure you fuse the 120VAC lol.
No no no no no no no no no no no no no no no no no no bad bad bad. Transformer isolation or nothing. I don't think whoever finds you will be loling while he/she breaks your ribs in a (futile) attempt to get your heart started again.
No no no no no no no no no no no no no no no no no no bad bad bad. Transformer isolation or nothing. I don't think whoever finds you will be loling while he/she breaks your ribs in a (futile) attempt to get your heart started again.
If you have a 1:1 isolation transformer you'll still have the risk of 120VAC on the secondary.
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