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For those who crave even more than Crack - Speedball

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Doc B.:
Yup, same kind of manual as Crack.

Mucker:
I just completed the Speedball upgrade ............. phenomenal! The improvements advertised are spot on. The Crack with Speedball is brilliant, it is getting more airplay right now than my WA2 ...... I just love the Bottlehead amp......thanks for providing such a low cost high quality solution......awesome!

[email protected]:
Speedball question.

With the emphasis on CCCC power supplies on the circuit board, might the effect of a Speedball unit be analogous to a mains conditioning power supply?

Thank you in anticipation of your reply,

Andrew

Paul Birkeland:

--- Quote from: [email protected] on March 20, 2021, 02:02:00 PM ---With the emphasis on CCCC power supplies on the circuit board,

--- End quote ---
What does this mean? The Speedball is not a power supply.


--- Quote from: [email protected] on March 20, 2021, 02:02:00 PM ---might the effect of a Speedball unit be analogous to a mains conditioning power supply?

--- End quote ---
I would struggle to draw a parallel.

Deke609:
This may be more info than you're looking for, but I find the following link does a good job of explaining how a CCS (constant current source) makes a close to ideal plate load: http://wtfamps.com/ccss-and-loadlines/

Even if you don't want to get into the whole business of load lines, the graphs help you appreciate the "linearity" (low distortion) of a tube when ccs-loaded versus resistor-loaded. The curved lines represent different input signal voltages to the tube (don't worry about the tube current y-axis for now -- since a CCS produces a constant current it kinda/mostly takes current out of the equation). The bottom axis values are your signal voltage outputs - the music signal that the tube produces. Ideally, you want a linear relationship between input voltage and output voltage - for example, Vout = 50 x Vin (I've chosen the 50:1 ratio arbitrarily just to illustrate the point). That would mean that for every increase or decrease of 1V signal at the input of the tube (the grid), the output voltage of the tube (at the plate) increases or decreases by 50V.  On a plate curve graph, that kind of perfect linear relationship would show itself as an even spacing (distance) between the curved lines along the intersecting operating line (here the dashed green line).  If the spacing is big at one end of the line but small at the other (as it is with resistor loading in the linked graphs), then you have a non-linear relationship and more distortion.

All that said, this kind of distortion can sound pretty good to some ears sometimes. Some people (but it seems only a small minority) prefer the sound of a resistor loaded Crack over a speedball loaded one.

cheers, Derek

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