Could somebody recommend a transformer for a valve pre-amp with a 12ax7 and a 12at7 the first valve may need DC heater as I need some gain. So I need heater + HT with HT about 170-200V maybe about 3W HT. Problem is I need something off 230V UK mains. Hammond only do 115V mains.
As I have just made this schoolboy error.
Something new I can order.
Cheers.
As I have just made this schoolboy error.
Something new I can order.
Cheers.
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Hammond's 260 and 300 series have universal primaries.
If you want something geographically closer, something like TRA200 from Ask Jan First might do as well.
The economics of being able to use that which is already on hand may make the Triad N-68X isolation trafo, with its "universal" primary configuration, a good choice. Step "230" VAC down to "115" VAC.
UK VAT and duties, along with regulations, may make this idea a non-starter. In the US, we deal with state and local sales taxes. Canadians get walloped with goods and services tax (GST) plus provincial sales tax (PST). No matter where you live, taxation is a PITA.
UK VAT and duties, along with regulations, may make this idea a non-starter. In the US, we deal with state and local sales taxes. Canadians get walloped with goods and services tax (GST) plus provincial sales tax (PST). No matter where you live, taxation is a PITA.
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A mains toroid may be better for the low level input as it radiates less magnetic.
Tube-Town Store - Toroidal 30VA - Universal Primary. That would give me a bit more HT than I need but that does not matter.
Tube-Town Store - Toroidal 30VA - Universal Primary. That would give me a bit more HT than I need but that does not matter.
FWIW, I approached things purely from the money angle. The Euro is worth a bit more than the USD. Tube-Town's prices for toroids are roughly 2X that of a N-68X.
Perhaps a "wall wart" can be constructed containing the N-68X. It seems that UK wall outlets, like their US counterparts, are safety grounded. Acquire a UK computer power cord made with adequate gauge wire and cut it into 2 parts. That takes care of the wall connection and the IEC power inlet connector on your chassis.
In the US, the Dyna-clone transformer would probably work gret (depending how hot the 12AT7 works).
PA211 Power Transformer Dyna PAS for Dynaco Replacement MADE IN USA
I do not know if there is a source on your side of the postal/shipping jam-up.
PA211 Power Transformer Dyna PAS for Dynaco Replacement MADE IN USA
I do not know if there is a source on your side of the postal/shipping jam-up.
These transformers are very much limited in capacity. 15mA is the limit !
Yes, there is swedish compatibles with PS522, but they are still limited
to 30mA http://n.manet.nu/tubedoc/ENO19023.pdf
The toroids from tubetown.de is a much better alternative, they are also
offered in several sizes.
Maybe PrimaryWindings.com in the UK might have something suitable. They have a range of transformers for valve pre and power amps. Ive used then for a valve headphone amp and found them good quality.
Primary windings have a 200v HT 6.3V part so that will do me just fine. That decided on the HT voltage then of 280V! They are a little less common than I was expecting. Maybe valve pre-amps are not that common.
Thanks for all the help much appreciated.
Thanks for all the help much appreciated.
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Thanks for the tip of "primary windings", new to me.
Especially valuable in europe, and let's hope that we can buy from UK
as easy as we can buy within EU.
