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  • May 28, 2010 at 1:00 pm #80268
    rsiferd
    Member

    Right, so I have the repro pcb all populated and checked for good joints. I have a DPDT stomp switch wired in standard bypass mode. No light, no tone bypass, just the basics. The pedal works fine in bypass mode but I get only a faint ghost signal when it is switched on. There is something there: the volume switch has a very faint effect, and the sustain gives me static (hahahaha). Now, before I go over the pcb yet again (or while I am doing that), is there some trick to the switch wiring on the Triangle? I get numerous and varied examples online and I have tried most of them. Can I wire a DPDT switch as a SPDT? (Well I’ll try that anyhow).
    Also, I should mention that the schematic and pcb i have is for the PNP version, but the transistors I’ve got are NPN so that’s how I have the power connected. is the diode orientation the same for the PNP version as the NPN? I am under the impression that the only difference between the two is the battery terminal connexion. Also in the two version the .05 cap is reversed in relation to the diodes. Would this cause the problem. So to succinctly recap: I hev a PNP schematic populated pcb using NPN transistors and negative 9v ground. Any assistance is greatfully received.

    May 28, 2010 at 1:06 pm #103433
    The EH Man
    Moderator

    Any electrolytic capacitors should also be reversed. The only diodes are the clipping ones so they should be fine.

    What transistors are you using?

    May 28, 2010 at 1:30 pm #103824
    rsiferd
    Member

    No electrolytics. NOS 2n5133 from Smallbear.

    May 28, 2010 at 2:02 pm #103751
    The EH Man
    Moderator

    Where is the layout/schematic you used?

    Are you sure you have the transistors inserted correctly?

    May 28, 2010 at 6:44 pm #107553
    rsiferd
    Member

    I don’t know how to post a picture here, I can’t get the file small enough. But it’s the Triangle layout as shown in the Kit Rae Big Muff History site. The schematic is the “Triangle (First Edition)” one from the Pisotones site. I believe the diode orientation is wrong in the diagram I have but after trying all combinations of the four I am still unable to get any sound. I guess it’s back to the drawing board. Thanks.

    May 28, 2010 at 6:55 pm #107526
    The EH Man
    Moderator
    Quote:
    No electrolytics. NOS 2n5133 from Smallbear.

    The schematic shows electrolytics on the input and output.

    May 28, 2010 at 7:04 pm #107497
    rsiferd
    Member

    I’ve just used .1uf ceramics as per most pics I’ve seen of this version.

    May 28, 2010 at 7:14 pm #107423
    The EH Man
    Moderator

    If you could post pics of your build, front and back, I might be able to see the problem.

    May 28, 2010 at 8:41 pm #105123
    rsiferd
    Member

    Is there somewhere else I can send them? I can’t seem to get the image size down to 75kb for this site (I am digitally retarded).

    May 28, 2010 at 10:19 pm #105105
    The EH Man
    Moderator

    send them to me at theehman_AT_gmail.com

    May 29, 2010 at 2:04 am #104780
    rsiferd
    Member

    I will get back to you with this. I went over the layout diagram that came with the pcb and after tracing the circuit against the Pisotones and other schematics I found some seriously variant component values. After replacing the more glaring ones IT WORKS. It doers not work well – yet. There is more to correct. I should have been more dilligent in my comparisons. The pcb is fine; It’s the parts values on the layout that are skewed. And apparently there is a huge difference between 100k and 100r from emitter to ground. Who knew (well … I did, but …). So there it is. How many times do I have to tell myself: “Measure sixteen times, then once more, then cut”. Thank you very much for your patience. I will keep you posted.
    Ralph

    May 29, 2010 at 11:51 pm #103219
    Ned Flanders
    Moderator

    if you wana know some other stuff about collector and emitter resistors in the muff read my article here: http://sovtek.webs.com/bmpgainfactor.htm

    May 31, 2010 at 7:39 pm #103037
    rsiferd
    Member

    Very nice site and some clear explanations. Thanks you.

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