There are guitar amps (Ashdown LB30 is one, see attached file) with a line-out provided by a tap on the output transformer . This would seem to be a way of using the tone created by a small SE amp and boosting it to gig levels with a power amp. Does this work as described or are there other factors involved? And how would you best implement it when winding a transformer?
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Excellent idea and way easier/better than adding an external transformer.
Did I mention easier/cheaper?
IF you are winding your own transformer, (I wind mine) calculate turns ratio to have about 1V RMS to be able to dive a generic power amp or 50-100 mV RMS to go into a mixer.
Say you have a 50W amp, your 4 ohm secondary will have around 60 turns, providing 14V RMS to speaker.
Your line out winding will have 60/14 turns=about4 turns (I said it was cheap and easy 😉 ) for about 1V RMS out.
If you want it balanced, center tap and ground it if you want it ground referenced or straight send both ends (in tour schematic yellow-yellow) floating and let far end deal with grounds.
Best way to avoid ground loops is not to create them first.
But ... but ... only FOUR turns? Isn´t that a typo?
Mic/line level transformers have hundreds of turns!!!!
True ... in pinky nail sized cores.
But here you are using the huge core (by mic standards) 50W OT.
Turns end up being what I mentioned.
Did I mention easier/cheaper?
IF you are winding your own transformer, (I wind mine) calculate turns ratio to have about 1V RMS to be able to dive a generic power amp or 50-100 mV RMS to go into a mixer.
Say you have a 50W amp, your 4 ohm secondary will have around 60 turns, providing 14V RMS to speaker.
Your line out winding will have 60/14 turns=about4 turns (I said it was cheap and easy 😉 ) for about 1V RMS out.
If you want it balanced, center tap and ground it if you want it ground referenced or straight send both ends (in tour schematic yellow-yellow) floating and let far end deal with grounds.
Best way to avoid ground loops is not to create them first.
But ... but ... only FOUR turns? Isn´t that a typo?
Mic/line level transformers have hundreds of turns!!!!
True ... in pinky nail sized cores.
But here you are using the huge core (by mic standards) 50W OT.
Turns end up being what I mentioned.
Great!... thanks for that , I'm about to embark on my first pp transformer having had success with an se one. The pp will involve some basic interleaving , is it simply a matter of putting the line-out wind on top of all the others?
You can put it anywhere, it´s floating relative to others.
In practice, wind the "main" transformer first, then add 4 extra turns, center tapped if you wish.
Wire is not critical at all, since it outputs voltage, not power, but hair thin will be fragile, I suggest something around 0.1mm to 0.15mm diameter.
In practice, wind the "main" transformer first, then add 4 extra turns, center tapped if you wish.
Wire is not critical at all, since it outputs voltage, not power, but hair thin will be fragile, I suggest something around 0.1mm to 0.15mm diameter.