#valvecaster

[flymychildren]

[rdmv]

Some comparisons between my transistor version of a Valvecaster, and an actual Valvecaster. The transistor seems to be slightly more aggressive. Both clean up at lower input levels, but these graphs just show some more extreme distortion that they are both capable of, and shows the similarities in their asymmetrical clipping characteristics. 

[rdmv]

This is my attempt at emulating the valvecaster using transistors, I haven't got round to building a valvecaster yet, so this is mainly based on the results from somebody else valvecaster build. it's basically the last two stages from a big muff. The first of the two stages is a clipping stage, but unlike the big muff, this gain stage has got variable gain, the 470KB pot adjusts the gain and bias of the transistor, the 22k in series with it, sets the minimum possible gain, and to make sure there can't be 0 ohms here.

The diodes in the first stage are different from a big muff. instead of a single pair of silicon diodes. I have used 2 silicon diodes in series with each other to hardclip one side of the waveform, and used 2 mosfet transistors acting as diodes to soft clip the other half of the wave form. the reason why i used 2 in series with each other was to increase the threshold point before clipping. this increases the dynamics, and allows for softer playing to be less distorted.

the last stage is just a clean boost, but as both stages invert the signal this ensures that the output maintains the same polarity as the input. 6x silicon didoes were used at the output to clip the signal roughly around 3 volts, and to produce symmetrical hard-clipping. this has been built but not fully tested yet.

[praisetheloud]

Guitar boost pedal built by my 12 year old son.

[madeoftone]

No 19 - Tube overdrive

A LPB-1 Booster and a Valvecaster.

I settled for the LPB after having tried a Java boost. The noise level was high for the latter, a problem I couldn't solve. Apparently I'm not the only one: http://www.diystompboxes.com/smfforum/index.php?topic=33180.0.

With the stock 2N5088 transistor the gain was a bit too high making the boost difficult to control. I finally included a switch to select between 2N5088 and 2N2222A (lower gain).

The valvecaster was made without modifications.

The box was designed by an artist friend, who knows what I like.