Fulltone - OCD  [traced]

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Re: Fulltone - OCD

Postby ansil » 17 Sep 2010, 11:09

I have version 4 of the ocd, no. 40,001 and thought this was the biggest crapfest i have ever witnessed [i traded a broken sm-58 though so considering i had nothing in it it didn't really matter] however after seeing the tl082 i thought wow way to go with the cheapness mike.

I put a socket in this thing can i can attest to this fact the latest version of this pcb have really really thin foil on them and pull up even on low heat settings. I am using a 1000dollar soldering station with de-soldering station built in and it fell apart in my hand.

but alas i put in a socket finally re wired the stupid thing and was going to get rid of it till i put in an burrbrown chip in it and thought this is usable albeit if only slightly. lastly i slapped a tlc2262 in it now and although i cannot use the 18V mod anymore i can finally achieve decent tone out of it.

thinking of stacking opamps in it utilizing a jrc4558 BB opa and tlc2262 and running it at 16v. should be a hoot.

if you put a socket in your let me know what you think of the 2262

ed
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Re: Fulltone - OCD

Postby jg » 17 Sep 2010, 17:33

I kind of like the TL082. With its jfet inputs and bipolar output it sounds good in a lot of circuits. The 2262 being all MOSFETs can sound good on their own being overdriven as they clip nicely, but as a buffer they always sound 'flat' to me. Plus there's the max 16V supply issue.
I've reworked 100s of OCD boards with my $80 soldering iron and have never had a problem with lifted traces. Maybe your technique could use a little work? The PCB looks to be the standard CE approved FR-4 with 1oz copper.

I think you will find that stacking it with a 4558 will make it sound just like a 4558 alone. The lower gain (slew rate) and max voltage swing of 7 volts (9 volt supply) means it will probably dominate the response.
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Re: Fulltone - OCD

Postby ansil » 18 Sep 2010, 06:22

i think we can always improve our technique but as i stated before this is a version 4 not sure if you have seen these yet but if you have i do certainly apologize. but they contain NO copper near the IC. these are very tiny silver [not sure what the hell they are actually] but even under the microscope after scraping away what i thought was where it was pre tinned it contained no copper. currently i am out of acid or i would like to see what it is. i have seen one of each of the first three generations and each one was indeed a nice copper board with no problems. however this isn't one of them.

to give you an idea of how bad the traces on this board i can remove the trace from the board with my fingernail with less pressure than it would take to remove a paint fleck from glass.

my Fulldrive isn't like this nor any other of my fulltone products

[edit] after re examining this board i found by the pots and switch there is pre tinned copper but everything by my socket is what appears to be a silverish foil. almost like it was factory second that got new foil traces?? i am unsure if it didn't mean taking it all apart again i would post some pics and well lets say its sold anyway.

i have emailed mike just to ask him about it although it is working fine now.

i do like your idea about the buffer though i have noticed in designs that they seem to avoid them for buffer stages. so i may just try another trick via halving the opamp.

ciao for now
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Re: Fulltone - OCD

Postby jg » 18 Sep 2010, 18:57

I'm very familiar with version 4 boards. More than you know. Since you sold the pedal and therefore cannot illustrate your point with pictures, I guess the point is moot.
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noob debug question: slightly lower voltages

Postby BennyB » 03 Oct 2010, 03:13

What might cause a slight overall lower voltage reading for the pins of the empty chip socket?

I built one of these, and it sounds mostly good, but with a faint, sizzly, sputtery high end on the decay of a ringing chord.

It kinda sounds like when you starve the voltage of a fuzz. But REALLY slight and faint.

Some voltage measurements: (with the chip out)
Battery: 9.2
Pin 1: 4.15
Pin 2: (with the drive all the way) 4.15
Pin 3: 4.39
Pin 4: 0
Pin 5: 4.15
6-
7-
Pin 8: 9.2
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Re: Fulltone - OCD

Postby ansil » 03 Oct 2010, 07:17

did you check the continuity of the pins to make sure they are reaching all the way through the board?? there are quite a few jumps from top side to bottom side of the board i had a trace fall off that was never heated or even touched anywhere near it.


JG meant to tell ya, you were right i tried it and i never noticed about the 2262 as a buffer before but you blew my mind with that.

but you know i am starting to think that this thing was monkeyed with before i got it. i picked up another one at guitar center to do a different mod to it and this one is so much better. so i am thinking the guy i got it from may have tinkered with. which happens
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Re: Fulltone - OCD

Postby BennyB » 03 Oct 2010, 22:44

ansil wrote:did you check the continuity of the pins to make sure they are reaching all the way through the board?? there are quite a few jumps from top side to bottom side of the board i had a trace fall off that was never heated or even touched anywhere near it.


Well mine's from a pcb.

The thing sounds great, cleans up and no one can really tell that something's wrong. But there's this minute, niggling sizzle sputter on the high end of a sustained barred chord.

Just wondering if those voltages were indeed too low, and what might be a culprit... I realize it's a vague question, but...
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Re: Fulltone - OCD

Postby evaninsky » 20 Oct 2010, 15:52

I'm confused and could use some help....

I built an OCD based on ver. 4. It's AWESOME but I'd like a bit more high end sparkle. it seems that Fulltone changed the volume pot from 100k to 500k (ver.1 to ver. 2) and the cap from .1mf to .047mf (ver. 2 to ver.3)

they report that both these mods result in softer highs and more mids. doesn't lowering the tone cap's value increase the highs or do I have it backwards ?

I'd like to restore a bit of the high end... which (or both) of these changes should I restore ??

please help guys !!
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Re: Fulltone - OCD

Postby BennyB » 10 Nov 2010, 07:24

BennyB wrote:Some voltage measurements: (with the chip out)
Battery: 9.2
Pin 1: 4.15
Pin 2: (with the drive all the way) 4.15
Pin 3: 4.39
Pin 4: 0
Pin 5: 4.15
6-
7-
Pin 8: 9.2



Sorry to pester, but are these okay voltages?
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Re: Fulltone - OCD

Postby Seiche » 18 Nov 2010, 15:59

hey,

i just build an ocd from the vero layout above. The Volume and Tone Pots work, though the volume is not "lots" more when i turn it up all the way.
What concernes me is that the drive knob doesn't do anything at all. I don't get any grit, just a clean boost. What could be the problem? I tried troubleshooting it with the schematic (i tried to exchange drive 1 & 3, as in the schematic it is noch really clear which is which) but no luck.

Has any experienced something similar?
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Re: Fulltone - OCD

Postby Seiche » 18 Nov 2010, 16:53

nevermind, i went over all the solder-spots and cleaned the vero strips as to not accidentally connect one to another and it works now! [smilie=a_goodjob.gif]
I haven't tried the real thing (same with the Tubescreamer i built the other day) but I am really impressed! that thing screams! I like the LP mode better for now.

cheers guys [smilie=18_13_1.gif]
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Re: Fulltone - OCD

Postby Seiche » 27 Nov 2010, 20:41

Okay now after some testing and twiddling, i have one thing that annoys me.
My favorite setting for a nice crunch is the LP mode with gain and tone roughly on 10-11 and the volume on 2 o'clock. But whenever i dim the gain all the way i get this very slight bit of grit creeping in. Now i tried to fiddle a bit with the clipping stage and took out the ge-diode (no dicernible difference) took out one of the jfets and put the ge back in (a little cleaner, still that bit of grit), put an LED inplace of the ge-diode (no dicernible difference), took out both jfets and the diode, still the same sound as before.

what's going on? maybe i made a mistake wiring up the veroboard?
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Re: Fulltone - OCD

Postby hakanenlauri » 31 Jan 2011, 19:07

Hi there everyone.

I recently undertook a couple of new projects one of which is the Stratotrasto version of the OCD (Rev 4). I have now bread boarded it but have some issues with it. First and foremost, when the drive pot is all the way up (-ish), the distortion gets this very stuttery tremolo-like quality. Also, the volume pot doesn't really add that much volume to the sound as opposed the bypass sound. And, pulling one of the transistors (or both) out doesn't have any effect on the distortion sound. Shouldn't it?

Any ideas on this?

Thanks in advance,
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Re: Fulltone - OCD

Postby RomYch » 01 Feb 2011, 09:32

Hi guys!
Here's my OCD:
OCD_lay.jpg

OCD_sch.PNG

http://ifolder.ru/21647572 - LAY in Sprint-Layout 5.0
I slightly modified scheme. Added output buffer and the millennium bypass.
Now this is my favorite device!!! :D
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Re: Fulltone - OCD

Postby siore » 08 Mar 2011, 09:04

Hi y'all.. if you're like me who's following the thread holding markm's layout together with tuemmueh's schematic... I thought this might help. I basically re-drew the layout. Values indicated are the ones on the schematic, I flipped the mosfet orientation, and... the resistors on the HP/LP switch I put in parallel.



Cheers!

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Re: Fulltone - OCD

Postby siore » 15 Mar 2011, 04:48

Made a mistake in the re-draw, noticed it as I was drilling :slap: . Power supply pin on the IC was left hanging. Also cleaned up a little, some traces are too close for comfort. Sorry about this, I'll PM the mods to have the wrong one removed.
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Re: Fulltone - OCD

Postby telecaster » 15 Mar 2011, 18:32

Hi siore, I built mine using Marks old layout to version 3 specs. I notice you have a 100r for R14 and Mark used a diode. I built mine with the diode and it worked fine. I wondered what that diode was for. I also used a jumper to correct the switching. HP was louder than LP, is that how yours is? I liked HP better, other than that I didn't notice any major tonal differences. I would build another without the switch. It did sound very good at 1-2 o'clock gain setting, past 3 o'clock the sound was more compressed, almost like a light fuzz sound. Very usable.. I gave that pedal to a stoner rock friend of mine and he loves it. I may have to make another one with your corrections, thanks.
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Re: Fulltone - OCD

Postby joeboo88 » 15 Mar 2011, 19:20

Hi telecaster, the pcb layout is different layout from the vero i used a few months ago, mine sounds like the you tube videos of the OCD.
(I'm Not bragging, actually i was amazed i got it to work first try)
I think there are a lot of variations to this layout, sorry to add to the confusion.
When i built mine i read the whole tread, because that helped me learn what i can expect with each version and what possible mods there was (at The Time).Also what problems other guys found while building.
I think i read somewher that the LP was supposed to be quieter than the HP. I accepted this and this proved right when you watch the
videos. One the video'rs Andy from proshopguitar video said that the LP was supposed to imitate a fender amp, and the HP was supposed to emulate a Marshall. I dont know if i believe that but what the hay.
You should read the thread and and look at all the schematics and layouts then decide which one to use.
Good luck :D
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Re: Fulltone - OCD

Postby telecaster » 15 Mar 2011, 22:08

Hi Joeboo, I'm well aware of the other versions of this circuit, that's why I built it to V3 specs. I like the sound of that version best.
I have also read this entire thread, and referred to it many times, good advise though.
My post was simply to express my experience and observations with this circuit. I think it sounded great and plan to build another just like it, without the switch next time. :)
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Re: Fulltone - OCD

Postby joeboo88 » 15 Mar 2011, 22:33

Hey telecaster, after i wrote this, i reread your post and realized you probably did all that, sorry.
Anyhoo, good luck with the new one...I like using this pedal a booster, gobs of volume. take care 8)
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