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Discussion in 'DIY Amp Forum' started by Mr. Lumbergh, Sep 23, 2017.

  1. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    I'm not sure if this the appropriate place for this, or if DIY effects is better, but I'm getting ready to build an attenuator to place in the loop of my Hot Rod to quiet it down a bit and just make the volume controls more useable in general. It goes from "barely can hear" to "neighbors pissed off" with just the tiniest fraction of a turn, and I want to be able to get a more precise adjustment out of it. From another thread I've learned that a 100K audio is the way to go on the pot. My question is: the jacks I have handy are those that ground the out the input unless a plug is inserted. I know the input jacks do this to protect the OT if the power is on but nothing is plugged in, but does the HRD have the same for the loop jacks, and would it make sense to keep this feature the attenuator?

    Thanks in advance.
     
    Last edited: Sep 23, 2017
    CigBurn likes this.

  2. LeicaBoss

    LeicaBoss Strat-O-Master Strat-Talk Supporter

    770
    Sep 4, 2015
    New Jersey
    Sounds like you are looking for a volume control, if you're looking at the loop.

    You may consider an EQ or volume+EQ. Lower the volume and goose the treble and bass when you go low volume (to account for the Fletcher/Munson effect.).

    If you're getting your crunch mostly from pedals and the preamp this is a fine way to go. If you care deeply about how your power tubes work, then you're thinking about attenuators and the like at the speaker output... And your Transformers might not like that.
     
    ZlurkCorzDog likes this.

  3. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    Most of the time I do get crunch from pedals, so that's not a problem for me. Mostly I'm just looking to add a crude master volume to this thing so that I don't disturb the neighbors, especially since Winston seems to like to get up there lately. I've been unpleasantly surprised; if me bumps the volume control that makes a huge difference in volume that I wouldn't necessarily notice just by looking.
    Do you think the tip grounding is a good idea in case I forget to plug something in or it comes loose, or is that not really a worry in the loop?
     

  4. Tone Guru

    Tone Guru Senior Stratmaster

    Dec 13, 2011
    Music City TN
    The jumpy master volume issue exists on several Fender amp lines, including as far back as my '80s Champ II.
    This has to do with their choice of component values.
    One way to deal with it is to replace the existing master pot with one of a more gradual audio taper, like a guitar pot but of the appropriate value.
    Patching in a loop attenuator accomplishes the same goal and gives you even more control with a second 'master-master' volume.

    The shorting and switching function of the jacks is used for a different purpose in the loop - to route the signal correctly when nothing is plugged into the loop.

    As far as the value, try the 100k audio, it won't damage anything.
    If it sounds thin or dull you might want a higher value like 250k or 1Meg.
    In any case you definitely should use an audio taper pot.

    Which model is yours ? The original HotRod Deluxe?
     
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  5. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    Yes, it's an original edition. From what I've read, the taper on those is worse than the newer generation, which I've not played with yet.
    Thanks for clarifying the function of the grounding tips in the loop, for this I won't worry about it. Something else has come up this afternoon so it looks like a project for tomorrow.
     
    CigBurn and LeicaBoss like this.

  6. johnnymg

    johnnymg Senior Stratmaster

    Sep 5, 2015
    Central Coast Ca
    A lower gain preamp tube(s) might be a better option than a power attenuator.
     
    rolandson likes this.

  7. Tone Guru

    Tone Guru Senior Stratmaster

    Dec 13, 2011
    Music City TN
    Just to confirm, are we talking about a line level signal volume control, not a speaker power "soak", correct ?
     

  8. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    Correct.
     

  9. CigBurn

    CigBurn Most Honored Senior Member Strat-Talk Supporter

    Age:
    60
    Jun 22, 2014
    The Shed
    Mines an early MIM HRD, and the effects loop volume box is so useful with it I can't imagine doing without. I had tried putting in an 12AU7 before and that was ok, but this is by far more flexible.
     

  10. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    Yours is a 100K audio pot in a box, right? I think it was you that double-checked the value for me in another thread, but at the moment I'm running off of memory (which is always suspect...).
     
    CigBurn likes this.

  11. johnnymg

    johnnymg Senior Stratmaster

    Sep 5, 2015
    Central Coast Ca
    If this is for the Send-Return circuit you could try a pedal (equalizer would be best). I'm not sure this is the best overall approach to lowering volume. My WAG is that the S/N ratio will suffer.

    I think lowering the front end gain would be better from a S/N perspective.
     
    rolandson likes this.

  12. rolandson

    rolandson Senior Stratmaster

    Jul 13, 2015
    Cascadia
    I don't know if this is applicable to the Hod Rod line...
    I've 'tamed' both my Super Reverb and Deluxe Reverb by substituting preamp tubes of different values at various points in the signal.

    I reduced the clean headroom in the Deluxe by substituting a 12AX7 for the 12AT7 phase inverter (V6), thus reducing the volume for breakup. In both the Super and Deluxe I use a 12AU7 for the reverb driver (V3) in place of the prescribed 12AT7, which smooths out the reverb effect substantially.

    There are also effective substitutions at the gain stages which can either subtlely or substantially affect headroom, and the affect that the volume pot has.

    And none of these modifications involve a soldering iron... Not that I object to soldering irons, but being a lazy curmudgeon don't ya know...
     
    ZlurkCorzDog likes this.

  13. CigBurn

    CigBurn Most Honored Senior Member Strat-Talk Supporter

    Age:
    60
    Jun 22, 2014
    The Shed
    Correct. I basically just built a unit as that Wampler guy. I hear he makes pedals or something so figured he is probably smarter than me. Vid linked again below for anyone interested.

     

  14. Robins

    Robins Dr. von Loudster Strat-Talk Supporter

    Dec 22, 2010
    Germany
    Long cables can and will make problems if that is the way you go. But that is always a problem when using FX loops.
    It is a very good way to tame the volume and noise floor of an amp though.

    All the best,
    Robin
     
    ZlurkCorzDog likes this.

  15. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    I was just going to use a couple of pedalboard patch cables and leave it on top of the amp. I'm having a quick bite then heading out to the garage to get my drill, then knock this thing out. It'll be good to get to play with the HRD more, it has more versatility than the Two-Tone and I want to play with amp-switching as well.
     
    Last edited: Sep 24, 2017
    Robins likes this.

  16. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    Well, I've already gotten the holes drilled and the jacks and pot mounted, and my soldering iron won't heat up. I tried it on a couple different outlets; it seems to have given up the ghost.
    Time to take another trek out to the garage to get the gun, this job won't need much in the way of finesse.
     
    Bodean likes this.

  17. Strats4me

    Strats4me Senior Stratmaster

    Age:
    50
    Feb 17, 2014
    Florida Panhandle
    This...
     

  18. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.
    Boom:
    Image1506293077.777691.jpg
    It did just what it was supposed to do, though the HRD does seem brighter now. I dunno if that's because I got so used to the sound I was getting out of it at 0.5 on the volume it if the control is making it brighter; I'll have to play around some and see.
     
    Tone Guru, CigBurn and johnnymg like this.

  19. Mr. Lumbergh

    Mr. Lumbergh needs you to go ahead and come in on Sunday, too. Strat-Talk Supporter

    Jan 10, 2014
    Initech, Inc.

  20. CigBurn

    CigBurn Most Honored Senior Member Strat-Talk Supporter

    Age:
    60
    Jun 22, 2014
    The Shed
    Looks great to me! and yeah bestest easiest pedal build ever. :)
     
    Mr. Lumbergh likes this.