| A Sanchez |
Hi,
I brought my preamp from the USA to the UK and I have been using it with a step up transformer, which is horribly noisy, and I would like to eliminate it.
I have opened the preamp and found that it has a pcb mounted transformer with four primary and four secondary points.
On the primary side 1-2 and 3-4 are connected and then on the secondary side 1 and 4 go to preamp and 2 and 3 are not in use.
Can I assume that this is a dual primary 115-0 115-0 trafo where the current USA configuration is:
1-2 115-115
3-4 0-0
and if the above is the case change bridging as shown below to make it UK ready:
1 115
2-3 0-115
4 0
I would like to post a drawing of the current physical connections and the proposed change but I do not know how to. I could e-mail it to anyone if that could be of any help.
Many thanks
Antonio |
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| AndrewT |
hi,
remove mains connection from 2 & 3.
link 2 & 3.
fit a mains light bulb in series with the primary.
stand back and switch on.
If the bulb lights, then 2 & 3 were wrong.
If it stays off, then check your transformer secondary voltage.
If OK, then remove the light bulb and you have a 230Vac powered pre-amp. |
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| A Sanchez |
Andrew,
Thanks again.
I will do as you are suggesting.
I forgot to mention that there is a small capacitor before the transformer in between the mains leads. Will I have to change this capacitor due to the new Vac ?
Regards
Antonio |
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| AndrewT |
Hi,
a cap across the mains leads must be X rated @ 275Vac. |
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| A Sanchez |
Andrew,
It all worked fine. I made the changes and tested with light bulb.
Now I have a 230Vac power noiseless preamp!
Thanks again!
Antonio |
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