Pulsar Tremolo LED & Space mods

[rockgardenlove]

Really?  You mean this one?
http://ehx.com/ehx2/Default.asp?q=f&f=%2FCatalog%2F14%5FModulation%2F02%5FThe%5FPulsar

[vanessa]

From what I have read on this site it is not the same. (Puretube claims it is not...) I have not had the opportunity to peek inside. 

[gez]

I guess I'll mess with the 200k resistor and see if that helps a bit. I'll post my findings soon.

It's the 200k connected to the collector of the first trannie in the LFO (bottom left) that you'd need to tweak, not the one connected to the base of the trannie used for the modulation (don't think I made this clear in initial post).  Not sure how much difference it will make, but you never know...

[rockgardenlove]

Hmm, interesting.  Hopefully Puretube will drop by.

[lowstar]

until puretube drops by, i can tell you in the meantime that the newer pulsar must be a different animal, because i tested it already and could not find many similarities. actually it was hard for me to get a useable sound out of it.
i like the original much better.

cheers,
lowstar

[audioguy]

I tried cutting and jumping and that didn't fix the tick, but it made the one of the pots reverse and the speed was so fast that it was unusable. I'll try your PCB later tonight.
Slightly off topic- my Rate is all bunched up at the end is this normal?

[lowstar]

i tried the cutting & jumpering just now as well, the tick is still there (i´d call it a bop  ).

it is in the clean part of the signal, so the more the depth pot is set to fx, the less noticeable it is...the more the orig sig is mixed in, the more bop.

comparing the before & after, to my eye i see no difference cause the wiper and one lug of the pot are connected with a trace anyway, so jumpering or not, the end effect would be the same ?!?

cheers,
lowstar

[vanessa]

I guess I should have mentioned this mod but I did not think it would have mattered...

When I first wired it up I had an initial tick problem. I did a search and found a mod by Mark Hammer where you change C2 from 47uf to 100uf and C5 from 22uf to 47uf. For better use with a dual opamp (the original used a single 741).

It did not solve my issue because I accidentally wired up a SPDT ON-OFF-ON instead of an ON-ON.    After I put the ON-ON switch in my tick was gone completely (maybe also due in part to Mark's mod, and the trace fix). He speaks of a couple other mods that may help. One was raising the value of R5 a bit. I did that but it seemed to lower the depth of the effect. He also suggested running a .001uf cap parallel with R4. They may work for you. Like I said I had a ON-OFF-ON switch in and they did not do anything to cure the tick with the wrong switch in. After I put the right switch in I left the C2 and C5 caps in out of laziness... 

[audioguy]

I'll try the cap changes tonight.

[vanessa]

I just put a 500k and a 250k pot in place of R13 (200k). I liked the 500k the best. It seemed to give some changes in the spacing, but at around 390k and above it had a really bad ticking (oddly enough there was a faint ticking with the pot in the circuit where there was not before). The 250k had the same issue (ticking) but there was not much of a difference in spacing over the stock 200k resistor. I'm thinking that above 200k the spacing gets tighter (sounds like an increase in speed at higher speed rates). What I don't understand is why the ticking started at 390k on the  500k pot and why it started at about 225k on the 250k pot?