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    I'd be nervous about a QnD resistor/zener thing...

    I'd be nervous about a QnD resistor/zener thing for the truck. In vehicle electrical systems there's this thing called a 'load dump' which happens every time you shut the engine off. IIRC, it makes...
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    Digikey has 18 and 20V transformers - should be...

    Digikey has 18 and 20V transformers - should be close enough this is their parametric search : http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=309799&Site=US&Cat=35849111

    You can...
  3. Just as long as each power amp always has a load...

    Just as long as each power amp always has a load connected - and running two power amps into one load is a BIG no-no - you're good.
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    If you're more interested in getting the thing...

    If you're more interested in getting the thing functional than in preserving its vintage integrity, replacing the 'correct' PT with a useable tube-oriented unit and adding a 24-0-24 tranny and some...
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    I think your plan is solid and your expectations...

    I think your plan is solid and your expectations are clear.

    Having those two going in are a powerful advantage.

    If you decide to add a switch to A/B between component choices while you're...
  6. Thread: Introduction

    by Don Symes
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    To echo Arthur B, these circuits are sort of...

    To echo Arthur B, these circuits are sort of modular.

    Pick a power level - if he's going to be playing in a band, 50 to 100W will let him get a good, loud clean tone - and clone the power amp...
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    I dunno - 1.4 x 2.125" (roughly) for 35uF - and...

    I dunno - 1.4 x 2.125" (roughly) for 35uF - and there's only one case size, so even the 4u7s are that big - is pretty inconvenient.

    Unless you're doing big, high-voltage switch-mode power supplies...
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    So am I - what's the JMP-1 way? / never mind -...

    So am I - what's the JMP-1 way?

    / never mind - found a JMP1 schemo at schematic heaven -- hybrid: silicooties + tubes.
  9. Thread: ADA amp

    by Don Symes
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    Thanks, but I just like trying to help. I...

    Thanks, but I just like trying to help.

    I think that's why most of us are here.
  10. Thread: ADA amp

    by Don Symes
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    So no negative voltages anywhere in that chain in...

    So no negative voltages anywhere in that chain in either mode?

    Do you have a -15V supply (U13 pin 11)?

    In GREEN mode, what are the voltages at U13 pins 2 (input), 3 (reference) and 1 (output)?...
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    You have, of course, tried the delay into the...

    You have, of course, tried the delay into the input of the amp to be sure it's not the pedal.

    You've also made sure the cables are good by plugging each one directly from send to return and...
  12. Those digital pots are neat, but they tend to...

    Those digital pots are neat, but they tend to catch fire if you feed them a signal that swings outside their power rails (+/-5 or 5/GND).
  13. Thread: ADA amp

    by Don Symes
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    Got the schemo - thanks! No power amp pages, but...

    Got the schemo - thanks!
    No power amp pages, but we may not need them.

    As far as I can tell, the clean channel is called GREEN and dirty is RED.

    First, does the problem move from RED to GREEN...
  14. Thread: ADA amp

    by Don Symes
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    Please send the schemo to das_float at yahoo dot...

    Please send the schemo to das_float at yahoo dot com.
    The ZIPs at ADAdepot won't unzip for me (Stuffit 10.0/OS-X).

    I'm going to make a blind guess and suggest you look at the channel switching...
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    Oops. So is it a nine-pin socket that's about...

    Oops. So is it a nine-pin socket that's about the size of an octal?

    7-pin 6C4, 9-pin 6EU6, all this thing needs is a 12-pin 6C10.
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    Rather than just resoldering, does it look like...

    Rather than just resoldering, does it look like you can run a piece of wire from the big boxy things' legs to the nearest other component on each of those 4 traces?
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    This is going to be a long, long answer and some...

    This is going to be a long, long answer and some of it may sound condescending - I don't mean it to, but tube circuits can very easily kill you dead, and you're stating that you're an absolute n00b. ...
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    A failed solder joint on one of them would make...

    A failed solder joint on one of them would make sense (be most likely).
    Next would be a cap that failed OPEN. Do you have a DVM with a cap tester function?
    A PI coupling cap that fails short would...
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    Direct boxes can be a good choice, but they...

    Direct boxes can be a good choice, but they expect to be driving a low-level preamp input. Try connecting a stereo line out (Tape RECORD/TO output?) to your power amp input to see if you have enough...
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    Trainwrecks, Matchlesses and some Oranges use...

    Trainwrecks, Matchlesses and some Oranges use rotaries to play with coupling cap values as a means of tone control.

    Your thinking is sound, but with no pots, you're going to be doing a painful...
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    You'd better not be using the DR's SPEAKER output...

    You'd better not be using the DR's SPEAKER output to drive this thing!
    Please describe how you're connecting the two.

    With no SPEAKER connected, you can cook the DR's output section.
    You would...
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    You may want to use a BIG resistor across those...

    You may want to use a BIG resistor across those switch terminals - at least 470k, up to 1M.
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    I've only found them in the usual values - and I...

    I've only found them in the usual values - and I want a mess of hard-mounted switches to A/B some mod ideas - so I will have to re-wafer a few. Sources are Weber, Mouser, StewMac, and AES (tubes...
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    Layout for comment

    The last few times around this design, what I heard was that those layouts were too tight. This pass is intended as a 'tubes-up' rackmount (1U chassis, 4U front panel). Add a Weber MASS attenuator,...
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    Mesa did a rubber mount thing on some of the...

    Mesa did a rubber mount thing on some of the Boogies (the entire chassis ... I think the called it SUS4), but they're the only ones I know of.

    Unless you're building a gain monster or using a...
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    Well, I'd probably start by revisiting the solder...

    Well, I'd probably start by revisiting the solder joints on both ends of each of the connections you mention.

    Then I might try isolating the tube sockets from the chassis with grommets or...
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    You don't want a spark when you drain your caps -...

    You don't want a spark when you drain your caps - they don't like having to source all that current all at once. Installing a bleeder resistor of 390k-500k (2 watss or so) across your main filter...
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    I haven't even seen one in person. What I do...

    I haven't even seen one in person. What I do know is that Ted makes a really high-quality kit, and that something small like this is a great introduction.

    Since you actually build it, and know...
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