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Thread: DIY "Keeley"-TS9 mod questions

  1. #20
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    For future Googlers, as you say , usually looking up the transistor type gives you the datasheet, most often in PDF format, and that shows you a picture of the transistor with the pinout clearly labeled.
    Example:

    About lifting traces or solder pads, make sure you're using a proper wattage soldering iron (a 25W should be used for PCB work), and be very careful when desoldering (don't let the desoldering braid, if you're using that, cool and stick to the solder pad and then force it off, and don't pull on the components that are not ready to come out). If a trace does come off, you can fix it with a jumper wire (most of the time a resistor leg can be used for that), or you can scrape off some of the insulating coating from the track near the old solder pad and solder the component leg to that.

    As for having the option to switch between clipping devices, my (unsolicited ) opinion is that these things are better done on things that are designed to do that and are more experimental in nature, such as a BYOC OD2 kit.

    And finally, about MPSA18 vs. 2SC1815, the swap is not really worth it unless you triple the ammount of distortion your pedal can do, or you're using the pedal with very noisy single coil guitars. Even then, the difference is subtle. I'd be surprised if anyone could hear it in a live situation.

    Hope this helps.

  2. #21
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    Quote Originally Posted by red
    As for having the option to switch between clipping devices, my (unsolicited ) opinion is that these things are better done on things that are designed to do that and are more experimental in nature, such as a BYOC OD2 kit.
    Yeah, in retrospect, I don't much care for the switch, but I already have a hole where the switch goes. I'm in a learning and tinkering phase, so there's no harm in playing around as long as I'm careful not to blow things up. And as for removing components, I got the cheapo Radio Shack desoldering iron, and it's made component removal way, way easier that using a regular desoldering pump and desoldering braid.

    Thanks for the feedback. Much appreciated.

  3. #22
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    IME the 2SC1815 is already a pretty good device. I don't think there is any point in changing them out in these pedals. If they had used 2N3904's from the factory, then maybe, but I'd let the 2SC's be.
    Currently a bad bass player pretending to be a worse guitarist.

  4. #23
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    Quote Originally Posted by Stormrider
    IME the 2SC1815 is already a pretty good device. I don't think there is any point in changing them out in these pedals. If they had used 2N3904's from the factory, then maybe, but I'd let the 2SC's be.
    Again a little further off-topic, if you had a device you were trying to lower the noise floor in, and you changed out the capacitors based on Some Internet Guy's advice, but it made no difference, and it had 2N3906's in it (the PNP version of the 2N3904's, to my knowledge), would you swap them for something else? And what would you swap them for?

    This device is a Boomerang+ phrase sampler.

  5. #24
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    Quote Originally Posted by thegnu
    Again a little further off-topic, if you had a device you were trying to lower the noise floor in, and you changed out the capacitors based on Some Internet Guy's advice, but it made no difference, and it had 2N3906's in it (the PNP version of the 2N3904's, to my knowledge), would you swap them for something else? And what would you swap them for?

    This device is a Boomerang+ phrase sampler.
    This probably won't help you much, but since we're drifting further and further away from the original topic here's my own contribution to that.
    The boutique guys swear by silver mica capacitors and WIMA metal film capacitors. The wiring's also a thing with them (teflon coated wire mostly), and almost everyone seems to prefer 1% metal film resistors. Some people prefer higher fidelity op-amps where applicable.

    Not many people care about transistors though, the only mention I've seen about "better" transistors were recommendations for MPSA18s. I guess you could always find all the compatible transistors with what you have in your gadget now and look up their spec sheets for more details. That would certainly help you make a decision based on more than some Internet guy's advice.

  6. #25
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    Quote Originally Posted by thegnu
    Again a little further off-topic, if you had a device you were trying to lower the noise floor in, and you changed out the capacitors based on Some Internet Guy's advice, but it made no difference, and it had 2N3906's in it (the PNP version of the 2N3904's, to my knowledge), would you swap them for something else? And what would you swap them for?

    This device is a Boomerang+ phrase sampler.
    The transistors won't make too much of a difference in most guitar effects circuits. Shielding all the wires carrying signal within the unit, using carbon film or metal film resistors instead of carbon comp, ensuring good ground connections (all connections really, not just grounds) etc... will make more of a difference than just changing the transistors.

    That said, if i was building a circuit from scratch i would just use the better transistors as there is little cost differance; but i wouldn't bother to mod an existing circuit just because of them.

    Better opamps can help; changing 4558 chips to NJM4580, NE5532, or the OPA's will help. I would, however, shy away from the OPA and burrbrown type opamps as they are almost TOO good for some circuits. They can introduce noise and oscillations unless the circuit layout, grounds, etc... are perfect

    Caps won't make much of a difference as long as they work. Using poly or mica types for power supply bypassing (battery or whatever) will actually make things worse as ceramics are more suitable. Then again, i don't go for the audiophile "this cap sounds better than that cap" nonsense. :

    All IMO.
    Currently a bad bass player pretending to be a worse guitarist.

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