Hi, could someone explain to me what would be the pros and cons of simply using a resistor (instead of the usual transformer) to adjust the impedance of a ribbon to the desired impedance? The only one I could think of is loss of efficiency.
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A true ribbon is lighter than the air load it drives and will be heavily damped by the air. Increasing source resistance should have a minimal impact on damping.
That said, a series resistor will be incredibly lossy.
That said, a series resistor will be incredibly lossy.
So your take is that loosing damping factor on a ribbon might be detrimental as damping factor is crucial for ribbons?
I used a series resistor for my ribbons: DIY ribbon tweer, reductio ad minimum Sure there are losses but were talking high frequency so it's not a space heater. The two main advantages are:
- No issues with induction reducing high end response
- No issues with variations in contact resistance as the current is determined solely by the series resistor (essentially current drive).
Induction reduction has to do with low end response, not high end response.
A pure ribbon is a pure resistive load; no issues of voltage vs current drive.
Putting massive power into a resistive divider works, but a good quality step down transformer will sound better IMO.
A pure ribbon is a pure resistive load; no issues of voltage vs current drive.
Putting massive power into a resistive divider works, but a good quality step down transformer will sound better IMO.
I think, that's what Gerrit meant, the leakage induction of transformer can causes reduction at high end response. "The current drive" is essential at variable contact resistance. Naturally, the best is the near zero contact resistance (soldering for example). You have right: the ribbon is damped by load resistance. And my personal favourite solution is transformer (multifilar, air cored version).
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Thank you Gerrit, yes the current drive aspect was what I was looking into, many thanks for your confirmation.
Actualy it probably wouldn't be hard to build a single ended source follower like the mofo
to drive a ribon directly without a transformer or resistor.
to drive a ribon directly without a transformer or resistor.