Pulsar tremolo: want to reduce its noise? here's how

[bioroids]

The EA Trem sounds great, of course it lacks the choppy mode of the Pulsar, but I really liked it when I build it.

Luck

Miguel

[sta63bmx]

Thanks so much for your help guys.  I tried switching the board's power to kill the LFO in bypass mode, and it definitely killed that, but then I was back to getting a bad pop when I switched the pedal on.  I didn't put a cap in there or anything for a "soft-start", just soldered it for curiosity's sake.  It made some hilarious noises, though, because the pop was getting fed through the LFO somehow or something and it would kind of make this weird bap-bap-bap noise when it powered up.  It was kind of entertaining.  But I'll try those mods.

[audioguy]

Can someone point out on the layout how to execute this fix? I love the Pulsar and would really like to have it quieter.

Thanks!

[sta63bmx]

Here is what I am trying.  I *think* this will work.



NOTICE: This is the Tonepad layout, all rights remain the property of Francisco Pena, since he drew this and did all the work, not me.  Since I'm working from the tonepad layout, I went ahead and showed where I am cutting and hacking on that layout.  It is NOT MINE.

I think the goal was to isolate the LFO ground and LFO power from the power and ground for the rest of the circuit.  I think these cuts will do it.  On the tonepad schematic, R17, R18, R19 and R20 are the only places where 9V power comes into the LFO, I think.  The right sides of those four resistors are hooked to 9VDC.  The only places the LFO is grounded are the emitters of Q2 and Q3, and the right side of R16.  So here's what I did.

Red = cut
Green = jumper
Blue = LFO ground
Purple = LFO 9V

I cut the 9V trace on either side of that gang of LFO resistors and jumpered around it with wire.  I just drilled two holes and put wire there.  Then I cut the ground trace on either side of that black jumper on the layout, since it connects the emitters of Q2 and Q3 to ground.  I jumpered around that as well with a piece of wire.  I am going to lift the right side of R16.  Now the circuit ground and power should be separate from the LFO ground and power.  At this point, I am going to run a couple wires offboard to the resistor/cap combo described in the few previous posts.  I may just wire these parts in a bundle instead of perfing them.  I will run a separate 9V wire straight from the DC jack to that 1k resistor (not labeled, sorry) and a separate ground wire from the bottom of those two caps to the star ground.  I will also probably run a wire from the right side of R16 to the nearest LFO ground point I can find, either on the board or right to the bottom of the caps.  I think at that point the LFO will have its own supply with filtering.

I'm also going to put a 1uF cap from VCC to ground on the TL072.  Can someone comment on whether this os the correct implementation of the circuit snippets described on the first page of this thread?  I really appreciate your help.  If I make this again, I might make some changes to the layout before I etch. 

Last Note: This layout does NOT show the rate pot fix, which I *did* implement in my build.

[bioroids]

Sounds good. Consider how you are gonna route the extra wires so they not end up near the audio part of the circuit.

Also, I'd make that 1nf resistor more like 100nf (and ceramic).

Please have in mind that besides the power supply, there are other sources of noise in this circuit

Luck!

Miguel

[Psych0F0x]

I was wondering, did this fix work? I'd like to know that before I mess up my perfboard pulsar(neatly copied from the tonepad layout)

[lowstar]

with mine (pcb), it did not.

cheers,
lowstar

[audioguy]

with mine (pcb), it did not.

cheers,
lowstar

Well thats a drag!

[sta63bmx]

Before I chucked my Pulsar in the recycle bin, I did get it to be very quiet.  I worked awesome and didn't click and didn't feed loads of noise to the rest of the circuit...

UNLESS!

...it was hooked up with a bunch of other pedals.  Alone or at the end of a chain with maybe one other pedal, he was a champ.  But once a bunch of pedals got in there, if you turned the depth past maybe halfway, there was an awful click-click-click in time with the LFO.  ANd this wasn't a subtle thing that only got picked up with high gain.  It was as loud as the guitar volume even when going into a clean amp, with no other pedals turned on.  The kicker is that my whole pedal chain was true bypass.

I never figured out why it did this.  It's too bad, cause it had a wider range of weird sounds than the EA Trem, which I built for someone else (and did not really care for).

My Pulsar build was pretty quiet to begin with, and with those mods, it was a little quieter.  I want to say that clicking ONLY bled through when the Pulsar was switched on.

[markm]

Unless I have some kind of luck, mine doesn't have an real noticable noise that I can tell. 
It dosn't click if that's what everyone's concern is.

[Psych0F0x]

My problem was that I got ticking that bled through when it was off, but yesterday I was fooling around a bit with the order of pedals and did notice no ticking when I had the pulsar as last pedal( Guitar > Boss SD-1 > Line DL-4 > Pulsar > Amp). Makes sense, all the other pedals weren't really true bypass. So I guess I could live with it.

Still would be nice if someone can really get rid of the problem, I have no idea how this LFO thingy works, let alone the rest of the circuit.

[audioguy]

how does it sound in an FX loop?

[sta63bmx]

Yeah, if anybody can explain the Pulsar-last-only-please thing, I would really appreciate it.  That's what I never understood.  THEY ARE ALL TRUE BYPASS!  At least mine were.  So there's a little bit of resistance and some capacitance.  That's it.

[lowstar]

mine also clicks only if switched on.
in clean, it´s practically unnoticeable, but in front of distortion, it becomes annoying. i always thought it has to be dead quiet either way ??
never tried an original one, though. has anybody else ?

cheers,
lowstar

[audioguy]

I just tried it and the noise is reduced, but not gone... however I only had a 330UF on hand, not a 470. BUT it is much less noisy. I use it in an FX loop, so its really not bad at all.

Thanks for the help!

[Psych0F0x]

Yeah, if anybody can explain the Pulsar-last-only-please thing, I would really appreciate it.  That's what I never understood.  THEY ARE ALL TRUE BYPASS!  At least mine were.  So there's a little bit of resistance and some capacitance.  That's it.

Are you sure they're all true-bypass? I thought the "last only thing" was because it goes through buffers of other pedals thus enhancing the very faint ticking of the LFO.
Maybe it's possible to use this?

thus grounding the circuit when it's off? Got this from another site where they were talking about getting rid of LFO ticking.

[sta63bmx]

My switch was set up to ground the input when the effect was bypassed, and I still got very faint clock noise if it was in front of high gain stuff.  BUT that nasty last-only-clicking went away, I'm 99% sure.

[g.e.o]

hey guys. i just read all the complains and i as markm have no clue why this is happening to u. i built the tonepads layout and have no problem apart from a little click-click sound only when in chop mode and turned on without playing the guitar. nothing annoying though and imagine its not even in a box yet. the only fix i made is a fix i found at tonepads builting reports from some other guy called pekka and its here http://www.kotipolttoinen.com/sisalto/kitara/pulsar/kuvat/pulsar_pcb_fix.gif

its about the "last 5 degrees" problem on the rate pot, when u cant really set the speed easily where u want to coz its not linear at all. this fix works really good. try it anyway.

never had the chance to thank this guy btw so, thanx Pekka if u ever read this!

Good luck solving this wizard people!

George

[bioroids]

Oops I just noticed there is a link to my site at the top of this thread, and the related schematic is long gone from the site 
I think I lost it somehow, so it would be cool if someone has downloaded it to send me a PM

I will add that I could never get fully rid of the ticking on this effect, it seems the design has lot of sensible places where noise can creep in.

Luck

Miguel

[Canucker]

Has anyone done up PCB layout for this yet? I was just about to use the tone pad version but this seems like an improovement for sure! I'd love to get it right the first time.

John

This about sums it up for me. I actually built two though already. A lot of whats been said here is over my head. One post talks about
Red = cut
Green = jumper
Blue = LFO ground
Purple = LFO 9V

and I'm not sure if there is suppose to be an image with that post but I don't see it and on my tone pad layout I see no green or purple.
I find when I play the pedal clean its fine (like others have said). When I use the amps built in distortion CLICK CLICK CLICK....can't really put the trem pedal after that. Bummer!