Friday, 17 February 2012

Landgraff Dynamic Overdrive

The ultimate souped up and mojo'd TS808?  Comes with free absolution with every pedal, and don't forget the carbon comps, Tropical Fish caps and silver solder!

Stock version using 2SC1815 (BCE) transistors:




Version using more modern and easily obtainable CBE transistors:





Updated 12th August 2014
New more compact layout added using the more modern CBE pinout transistors



31 comments:

  1. Hey mate, does back to back for the LEDs mean POS to POS and NEG to NEG, and then each POS and NEG pair to each SW1 pole? Or POS/NEG pairs to each pole? Thanks

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    1. It should really say top to tail, and so you want them in opposite directions. Anode and cathode one side, cathode and anode the other.

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    2. Thanks mate. I'm building this one embarrassingly with metal film resistors.

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    3. I've got a copy of this (Effects Pedal Boutique SRB808+) and that was made with metal film resistors and it sounds pretty good to me. I'm making mine with carbon comps though so I don't have to say any Hail Mary's :o)

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    4. Sing to Him a new song, play skillfully on the strings, with a loud noise. Psalm 33:3

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  2. I read somewhere that the Paisley Drive was an 808 with J201s instead of the npn silicons, you can't just hot swap them though right?

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    1. No you couldn't just swap them, the accompanying components would need to change to. At the end of the day though they're just unity gain buffers and so something like this from Jack Orman would do the trick even if it's not exactly the same type that has been used with the Paisley Drive:

      http://www.muzique.com/images/buff3.gif

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    2. Thankyou mate, finished this one, sounds great( like $400!!) used 2sc1815's. Is it normal that when switched to the diodes the volume drops quite a bit?

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    3. Yes, the diodes reduce the signal level to their own forward voltage so there will always be a volume drop. Thanks for verifying.

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  3. Hi, Mark. Just tried this build and I'm getting a spluttery output when using either set of clipping diodes. I get no output in the diode lift setting.
    Tone and Level seem to work OK, but the drive pot sounds scratchy and I get a high pitched squeal when Drive is turned all the way down.
    I've subbed the small cap for 47pF and the tone pot is B22K as that's all I had lying around near the quoted value.
    I take it your representation of the trannies above is just generic and the actual orientation for 2n5088s is the other way round?

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    Replies
    1. Yes you're right about the 2N5088's. You've obviously got some issue around the gain stage which is where both the diodes and gain pot connect. Check for an unwanted bridge around there, or maybe a bad solder joint. No idea why you'd get no output in the diode lift position though, all that does is remove all diodes from the feedback loop and shouldn't mute it. Are you sure the switch is ok?

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  4. Hi. Looking to 2SC1815 datasheet it seems the direction is opposite to this layout, I mean the image should be horizontal flipped to have BCE top to bottom, is it? Thank you.

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  5. Ok, done. The thing sounds good but I get loud squeal with gain and volume past half way, the tone pot "tunes up and down" the squeal as an old radio......... Any idea to solve?

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  6. Hi. Where exactly should the sw1a wire be soldered to? I guess the Drive 2&3 and the sw1a are sharing the same spot. Could I solder the sw1a wire to an open spot next to it below the transistor or to a drive pot lug #2? Thank you,

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    1. Yes it needs connecting the Drive 2 and 3 and the point shown on the vero. Easiest way to do it would be to take the vero board wire to Drive 2, take a wire from sw1a to Drive 3 with extra insulation removed so you can also wrap the wire round Drive 2 and create the required link.

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    2. Thank you very much for your reply. Could I connect a wire from the sw1a to an open spot below the letter E on the Q1 transistor instead? I am sorry if that is what you meant in your reply. Thank you once again for your help.

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  7. Hi,
    What's the meaning of LED+ ? Just for the board?

    Karsten

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    1. It's a current limiting resistor for the indication LED. So LED+ goes to the anode, then the cathode goes to the stomp switch as per the offboard wiring layout

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    2. Thanks a lot.
      Just one short question over the gain/switch wiring.
      One cable from vero to pin 2 and 3 of the gain pot. From there with one cable to Sw1a and from Sw1b back to the veroboard. Correct?

      Karsten

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  8. Replies
    1. I update them from time to time if I find something about one that annoys me. I didn't like the link in the same hole as the Volume 1 wire, so I shifted things about a bit so I could put the link further down the rows. Both are absolutely fine though, so you can use either layout if you have the previous one saved.

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  9. Hey guys.... any idea why I would be getting 9v on the input? It just sort of popped up and I was able to figure it out because of the sound of a scratchy pot when the circuit is engaged. Could it be a cap? Transistor maybe?

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  10. Caps block DC, and I can't even see it being a faulty cap because there are none in the vicinity that will have anything like 9V on them. More likely you've got an unwanted bridge caused by solder or a burr with the row below the input which is connected to the supply via a 4K7 resistor,

    That's the area to look at, so I'd suggest knifing the gaps and tidying up any soldering around there.

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  11. Ok, I'll check that out.

    There is something I'm noticing about this circuit, I've played the actual DOD and I feel like there's a bit of some mid's and low's lacking. Also it feels like the Drive pot needs to be dropped down to a 500k. I searched around and I've seen schematics with a 500k in there. It does feel like it's got more gain than the original circuit, any modifications you could recommend to address the mids and lows? I am pretty sure I am going to replace that drive pot since I've got to take it apart to find where the DC is hitting my input. But while I've got it out if I can change around some values on filter caps I'd be much grateful for your advice.
    Appreciate all you do!

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    Replies
    1. i feel ya on this. did you ever try modifying this layout to sound better?

      Has anyone out there built this layout and really liked it a lot? the only people that have said it sounds good in the comments have also mentioned that something wasnt working correctly haha. mine is functioning perfectly, just sounds lame as anything

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  12. Could you help me, please? My build sounds great, but when the switch is in middle position and the Tone knob is turned all the way up I'm getting high pitched oscillation in the background. Is it normal? When I turn down the Tone a little, oscillation disappears. I also used 22n instead of 20n and 47p instead of 51p.

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    Replies
    1. Try 100p in place of 47p/51p. That should cure it.
      +m

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  13. I have similar feelings as jeremy above. It sounds pretty flat and lame. There is too much gain (maybe just the resistance in the gain circuit needs to be shifted), there arent enuogh highs or there is too much high end content. the lows and mids just sound boring. I dont know... im not into this circuit at all and i'm feeling like something isnt quite right about it. i'm 99% sure mine build is correct according to layout. but it just sounds boring, more boring than another boutique tubescreamer ;)
    ill post voltages soon

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  14. If your circuit doesn't work correctly be sure to try turning the 1815's the other way. With mine they were opposite. Don't know why! Don't know what to think of this circuit. I see some don't like it. It doesn't sound that bad to me but I haven't been able to play it much. Cheers...

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