freestompboxes.org

Aight,
i got a unit from a friend atm, its not the vintage one, but i think that doesnt matter to much, board layout seems to be still the same.
So i opened it today and revisited your corrections, which i can agree.

- found some additional differences, i have marked em in green.
- added component names.
- orientation of Q1 for the OD led is okay, dont know if it matters to use 2N5088 instead the one ive noted in txt.
- checked the offboard wiring, and added text. (unsure how the switch is working, never used one from that sort, so i drew it in the jpg, shown from behind. i guess its switching from 4-5 and 4-7)

There is also a 502 (5nf) capacitor on the echo out jack from tip to ground, which i didnt note in the pic.

regards,
jazzmaster

Thanks so much! Whew, mind finally at peace.

Thinking about Kaputepalla's work, I've realized he (to put it this way) knew what he was doing. Which is to say I think he copied an actual unit as it were, only it was a different (slightly older?) revision than the one on the "factory schematics".

But I figure this "revised edition" which you have proofread is the better one.

Now to find some MN3005's...

Yeah, this is a fantastic layout and project. I'm still a big noob at this stuff and don't have a scope, but this along with the Neovibe and the ADA Flanger are some "difficult" level stuff that I definitely have on my to do list.

Cheers!

hmpf, im just thinking about the age of the unit of my friend.
the braids was like wires, really hard and not much flexible, so 3 of fell of during investigation, resoldered them, replaced the bottom plate gnd because it was way to short.
now after complete reassemble fx works, but the OD led doesnt come one anymore..
grmbl i should have replaced all of them instead of thinking uh, just put it carefully back together.
i think theyre timebombs... just some shok or some vibrating and the fx will be dead... well tomorrow is another day im gonna replace all.

for the differences i give you right rocket roll, im thinking too thats just different versions/revisions of the unit, which may be better to have a later one..

jazzmaster wrote:...which may be better to have a later one.

Oh yes, it's definitely improved a bit - from that 2M2 pulldown resistor in R1 (which I suspect is the part of Analogman's "volume drop fix" mod for older units) to... I don't know.

About the Q1 overload LED indicator - you're right, it must be a PNP epitaxial silicon transistor such as KSA1015, since it's ECB oriented. That's been bugging me - schematics call for a 2N5087, but it also shows overload LED connected to a Q1 collector and Q1 basis connected to the R19/C12 connection.

jazzmaster wrote:There is also a 502 (5nf) capacitor on the echo out jack from tip to ground, which i didnt note in the pic.

Thanks for clearing that up! Couldn't find it on the schematics, but I have a picture that shows it:



I've re-marked the Q1 orientation & added (most of) the confirmed corrections on the layout itself:

well, the orientation of q1 was ok, now its flipped....

as i said i replaced all braids, because they felt like wires...

also took a photo of q1 as i had the unit open, time to change it again in the layout

Argh I'll do it.

Speaking of power section, I've wondered - why is that LM7915 without an aluminum cooler? It's cooler-less on all the DMM pictures I've seen so far. Is the cooler totally unnecessary?

...and I'm confused about Q1.

I've got two schematics confirming ECB pinout and one (plus your picture) confirming EBC pinout.

Datasheets for xxA1015GR transistors (http://pdf1.alldatasheet.com/datasheet- ... 015GR.html, http://pdf1.alldatasheet.com/datasheet- ... 015GR.html, http://pdf1.alldatasheet.com/datasheet- ... 015GR.html) show that xxA1015GR transistors have ECB pinout.

someone have this pedal?! what about the FINAL schematic?! thanxs

OK, I've followed the layout as given in "Refined Layout 03" and found that

- Overload LED works as it should, blinking with the strums when "Level" is set high, wtc
- voltages seem to be generally getting to their appropriate pins.

However, mine needs some debugging - signal is faint. Could anyone, please, post the working voltages on an operating unit?

Found the problem - ground wasn't connected to the sleeve terminal of both jacks...

Yeah, it works. Overdrive section of the circuit, at least. It'll be some time before I test it with MN3005 chips installed (they cost an arm and a leg here).

...aaand it's done. A bit sooner than I expected, but nevertheless later than I wished









As for the chips, I've paid them like they were solid gold, but what can you do when your country does not support PayPal? I was lucky to be able to get them anyway.

Calibration was easier than I expected, because I wasn't the one staring in the oscilloscope. My friend, an amp builder who used to make a living cloning old Japanese mixing desks with built-in MN3005 echo lines, calibrated it with only a couple consultations of the calibration manual. Since it works, I presume that better job couldn't be done.

As for the parts, I've used TL072's through and through, NE571 compander, Alpha 24mm pots mounted on peaces of solidcore wire... metalfilm resistors... WIMAs where available, etc.

There were a couple of heart-stopping moments during the final mounting (first I've connected negative pole to ground while wiring in a new DC jack, then I've discovered that you must use isolated DC jack or the EHX 24V adapter gets really hot and generally wants to die), but luckily nothing fried. 24V adapter comes from Banzai, btw: http://www.banzaieffects.com/EH-24V-DC- ... 17532.html

A couple of sound files: http://www.box.net/shared/jag45h8kor

(DiMarzio Heavy Blues II -> E-MU 0404 -> AmpliTube 2 running a VOX AC30 emulation)

that is such a great use of the dark side of the moon cover! perfect for this project.

Thanks I wanted to name it "Delta T" (Δτ, time difference), then I started thinking about the logo that has a τ inside a Δ, and then I remembered a similar design idea...

I've forgot to add a "straight delay" example: http://www.box.net/shared/dkn634nxvu

500ms delay time (250pF silver mica at C43).

congratulations Rocket....

how about some details about build.....which schem is correct....which layout....or even better...........ready to transfer PCB layout?

and again ......very nice,and I am happy you did it......

boris

p.s.

svaka cast.....

Hvala! (Thanks!)

Ok, here's a "final final" layout - essentially same as the (I believe) last one posted, but with an added note about the 5nF cap connected from output jack tip to ground. I've followed this one down to the "t"...

..and here's a PCB with added lettering so as to show it's "looking into the copper" oriented...

...and the schematics corresponding to those files would be this one: https://www.freestompboxes.org/download/file.php?id=1305