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Old 16th October 2006, 08:38 PM   #1
diyAudio Member
Join Date: Oct 2006
Default F1 at 15VAC instead of 18VAC?

Hi everyone,

I'm building an F1 for my K1000s. The biggest 18/18 toroidal transformer I can find on Digikey is 240VA; from what I've read here that's probably insufficient.

Would it be possible to use a 15VAC/15VAC transformer instead? If I recall correctly the nominal speaker output voltage on this amp is in the 13-14V range. Would this drop to 11-12V if I used a 15VAC transformer? 11-12V would still deliver up to a watt into the K1000's 120 ohms, which is what AKG recommends.

I don't plan to use this amp for anything else, and it would also greatly decrease its heat dissipation.

Would the transistors still bias correctly? Is there anything else I'd have to look out for?

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Old 16th October 2006, 10:55 PM   #2
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Join Date: Oct 2003
Location: San Jose
What about an Avel Lindberg? They are very reasonably priced and work very well. You could take the model below and connect 115VAC to the 220VAC trafo primaries to get 17+17vac secondaries.

35 + 35 VAC Secondaries
Model #Y236803


Just a thought,

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Old 16th October 2006, 11:06 PM   #3
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Join Date: Oct 2003
Location: San Jose
Here's another option from Antek on Ebay. I have bought a couple of diffferent transformers from this company and they are simply great to do business with. I'm using one of their large toroid's for my Aleph30. It did buzz and hum for the first 200 hours of use, but now it is dead silent.

Antek has an 18+18VAC at 400va for only $38USD, $43CDN. The primaries can be wired for either 220vac or 115vac. They are also located in Canada.


Good luck,

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