Pulsar Tremolo

[bioroids]

Hi there

i've posted a corrected and modified version of the Pulsar Tremolo schematic, until Matt uploads the new corrected version at Tonepad.

If you want it, you can get it from

http://ar.geocities.com/bioroids

Luck

Miguel

[petemoore]

Looks like an OA version [the original was transistor?]
 That hard/soft cap switch at the end...does that vary the amt of attenuation or the shape of the LFO wave [or something else?]
 Does this sound quite similar to the original Pulsar?

[bioroids]

I cant tell if it sounds like the original, i've never heard one. I made this schematic from the one at tonepad. The oscillator is all transistor, i've seen other schematics supposedly of the original and its pretty much the same, just different switching and no buffer. I added the buffer and it sounds so much better, at least with my equipment.

The hard/soft I think controls how much it softens the LFO waveform. But its never a sine wave. In hard mode the sound is muted for mor time that is not, its like a duty cycle control. Anyone?

Luck

Miguel

[ethniccheese]

Can anyone tell me how I can increase the range of speeds for this circuit?  I like the slow speed with the .47uf caps, but the fast speed with .1 or .22uf caps is perfect for my taste...  I'm stumped.  Any suggestions?

[bioroids]

Hi, I find it to be very fast, so fast it almost chops all the sound.

What are the other values you use for the lfo section?

Regards

Miguel

[ethniccheese]

I actually used all of the values suggested in your schematic.  I can double check tonight, but I am pretty sure that is the case.  I was using .1uf caps in place of the two .47uf caps until I got them ordered and that was very fast.

[bioroids]

I dont really know how to modify it, i proced on a trial an error basis.

I though it was pretty fast, lets see if we are talking the same here.

I got 9hz on the fastest setting with .47 caps and 3hz on the slowest setting.
You get the same speed and you want more, or you're not getting that speed?

Luck

Miguel

[ethniccheese]

How are you measuring the speed?

[bioroids]

Well, i do it in a very practical way. I put it in hard mode, then I record some audio on the pc with it, I then select a 2 seconds fragment and count the modulation waves, wich are pretty easy to see. Then I divide by two.

I hope this helps, if someone has a better way, please tell me

Miguel