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Already getting into my next build - Valvecaster tube OD

Discussion in 'DIY Effects Forum' started by Mr. Lumbergh, Dec 25, 2016.

  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've been side-tracked with other things and haven't gotten anything done on this for a couple of months, and I decided last weekend that this project needed to get done. Injuring my hand Wednesday helped with that in a sick sort of way; with no time behind a guitar while my finger heals, I could spend the time behind the soldering iron instead.
    I got some work in on it several nights in the last week, and tonight got the last solder joint in place...
    The good:
    • The smoke stayed inside.
    • The tubes warmed up.
    • The LED's did their thang.
    • Primary and secondary bypasses all worked; that is, the signal got through from guitar to amp as long as I didn't try to turn the effect on. Which brings me to
    The bad:
    • When activating either channel, the device turned into a mute button.
    • This circuit is noisy.
    Somewhere along the signal path, the sound isn't getting through. The noise has me hopeful that it's a missed ground(s) somewhere, but it's late, I've had a few coldies, and I need to get up somewhat early as I have a footy match in the morning. Not the best troubleshooting circumstances, so I will pick it up again tomorrow.
     
    mshivy likes this.

  2. Robins

    Robins Dr. von Loudster Strat-Talk Supporter

    Dec 22, 2010
    Germany
    Find some time later and relax. A fresh mind and you soon will find the ground issue.
    It always helps doing something different and return later to find and solve the problem.

    All the best,
    Robin
     
    mshivy 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.
    I think it is in fact a grounding issue. There are parts of the ground network that connect to the power supply before the regulator circuit, and after. The input jack is meant to be stereo, so that there is no power-on without having a plug inserted, and it bridges this gap presumably to have a mono plug inserted. I mistakenly purchased and installed a mono jack with power-off separator instead of a stereo. I'll have to get one tomorrow from Radio Shack and see if that's the issue.
     
    Robins likes this.

  4. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    @Robins:
    Success! Well, I'm halfway there anyhow. The lack of signal was in fact a grounding issue at the output jack as I thought. I got home from my business trip today to find my StewMac order waiting for me on the porch, which included a stereo jack for this and some shenanigans I have planned for the Gretsch. I pulled the switching jack out and replaced it with stereo jack, and lo and behold, the left channel works! It sounds a bit like the Zeta Drive I just picked up, kind of a raunchy, greasy OD that I think is well suited to Classic Rock and Blues. I modified the circuit by adding a fat switch, which brings in a negative feedback between the tube terminal 8 and the output jack, and it really gives it a noticeable amount of punch in the bass.
    The bad news is that the right channel is still missing something; it's still functioning as a mute. :rolleyes: It's back on the table cooling off right now while I grab a bit to eat, but I suspect the signal from that side is also not making it to ground for some reason. More to do later...
    So not quite ready to call it done, but progress is always nice, especially when I originally intended for this to be a 2014 project. :eek:
     
    Robins likes this.

  5. Robins

    Robins Dr. von Loudster Strat-Talk Supporter

    Dec 22, 2010
    Germany
    Great news and I am absolutely positive you find it later in no time. That can´t be a big thing as you know already.
    Very cool you made a mod on the fly to enhance the sound.
    Well, you didn´t had a dead line so no worry about the years xD

    All the best,
    Robin
     

  6. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    Success! Thursday, Channel 2 was working, but not Channel 1. I had a few rounds of troubleshooting today, taking the enclosure off, tweaking, reassembly, and test.
    First, I went over the circuit and found what appeared to be a missing ground on the 3rd lug of the volume control, so I added one, and the neither channel worked. Adding it killed Channel 2! o_O It turns out I misrouted it on the first channel, and saw something missing on the second decided to add it without checking the schematic. Turns out, that was the reason why the first didn't work, it was sending the signal to ground. Rookie error. :rolleyes:
    Fixed that, and both channels came to life, but the Channel 1volume control now didn't do a thing. Off came the enclosure again. This I determined to be a missing ground on Ch. 1's 3rd volume pot lug, which was an easy enough fix. I also noticed that the Fat switch wasn't connected properly, and that what I'd been hearing Thursday was actually the tone profile switch; I'd gotten so used to seeing everything from the back that I forgot to consider that everything will flip 180 degrees when assembled and on the floor. I put that together, reassembled, and viola, both channels worked and had functional volume controls. :cool:
    The Fat switches don't work independently of each other as I had thought they would though, so one of them is redundant. Channel 1's will affect the tone of Channel 2, even if it isn't on. It also behaves differently then I expected... The bass does tighten up and get crisper, but the volume decreases and it also scoops mids a bit. Not really what I thought a fat switch would do. Honestly, I'm not sure that was much of a worthwhile mod, but it's there; no point in leaving holes in the enclosure by pulling it.
    There are a couple things I still need to work on, though. It's noisy at high gain; it sounds like 60-cycle hum. I'm going to go back in and shield the wooden sides of the enclosure, but I'm worried I may have a ground loop issue as well. There's a lot of spaghetti in this thing; if I do something like this again, I'm definitely going to use the enclosure as the primary ground and send everything there. I didn't on this build because when I was first planning it out, I wanted to keep power ground and signal ground separate in an attempt to isolate the signal from electrical noise, not realizing of course that by putting in the correct jack on the input side I was bridging the two anyways. Live and learn. ¯\_(ツ)_/¯
    The other issue is that there is some tone suck going on in bypass mode. I'm gonna try adding a 1M resistor between the input and ground lugs of the input jack and see if that doesn't clean things up; I remember having this issue on my Klone build until I remembered to add it back. Gotta make sure the guitar sees the correct resistance. :D Either that, or stack it behind a buffered pedal. The Butler Tube Driver has an op-amp in it, and I think I now understand why.
    When on though, this thing has a real fat, warm tone to it. It sort of reminds me of the Zeta Drive I just picked up, and when both channels together with the gain dimed, it turns into a raunchy fuzz. Except for the fat switch, the channels stay independent of each other, so I can dial in a good single-coil sound on one and bucker sound on the other for quick switching between a Strat or Tele and my Gretsch, or I can dial in different amounts of drive on each for different sings, etc. I'll keep tinkering with it and let you know how things go, but for now I'm off to take care of the next set of changes I just mentioned.
     
    mshivy and Robins like this.

  7. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    The shielding really helped the noise issue a ton. It's not much more noisy now than a typical dirt pedal. There's also a less noticeable change in tone when in standby; the resistor seems to be doing its trick. Very pleased with how things are turning out today. Now I get to rip it all back apart again so I can finish it with graphics! :rolleyes:
    So far, I'm finding it to be very touch-sensitive, and when pairing the channels it's easy to get a warm saturation on Channel 2 by upping the gain, dropping the volume, and hitting it with Channel 1 with higher volume and low gain, or vice-versa when I just want a bit of an edgy volume boost. More playing to do, but that'll have to be tomorrow; I just realized I've been at this for hours and have forgotten to eat; haven't had anything today except for a couple small tacos about 8 hours ago. :eek:
    Plus, it's getting late and don't to upset the neighbors. Looking forward to hitting the tube amp with it tomorrow.
     
    Robins likes this.

  8. Robins

    Robins Dr. von Loudster Strat-Talk Supporter

    Dec 22, 2010
    Germany
    It is alive !
    Great job. Very good news.

    All the best,
    Robin
     

  9. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    Yes, my own personal Frankenstein is alive. Now I need to finish out the graphics, and I think I also want to put in a power switch and fuse. I'm glad this is nearly done, it's taken me a lot longer than it should have.
     
    Robins likes this.

  10. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    @Robins:
    I had a pondering: if I were to hit pin 3 with an oscillator circuit, I could basically turn this circuit into a bias-vary tremolo by modulating the gain. What do you think?
     
    Last edited: Jun 28, 2017

  11. Robins

    Robins Dr. von Loudster Strat-Talk Supporter

    Dec 22, 2010
    Germany
    Or a sustainer/compressor.

    All the best,
    Robin
     

  12. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    A tube-powered compressor? Do tell, I'm not sure how I'd make that work. Run a negative feedback on the transistor controlling the input gain?

    As for the Double Barrel valvecaster build though, I'll be adding a power switch so I don't have to fully unplug it every time I'm done, then finishing with graphics and calling it done. I've been out of town for most of the last week and haven't been able to play with it much, but so far I've found it to be a nice "greasy" sounding OD. I think a lot of the negative feedback this circuit gets comes from:
    1. Using poor-quality power supplies. Adding the regulator circuit seems to have helped with the noise a lot; this isn't any noisier than any of my other pedals
    2. Running it at 9V rather than 12. Lower voltages tend to make this circuit sound brittle, at least from what I've seen in demos online. I'm half inclined to try swapping out the 7012 for a 7018 and running it at 18V to see if it gets better still, but I've already got my mind on next one... :rolleyes::whistling::D
     
    Robins likes this.

  13. mshivy

    mshivy Most Honored Senior Member

    I'm anticipating the finished product here. Go Lumbergh!

    ( no green paint?)
     

  14. Robins

    Robins Dr. von Loudster Strat-Talk Supporter

    Dec 22, 2010
    Germany
    Lol @Mr. Lumbergh there you have it.
    Multiple addictions add up and make us slaves of ourselves xD
    I would say we just enjoy life as we can.
    No mercy, take it while you can.

    All the best,
    Robin
     

  15. suncrush

    suncrush Senior Stratmaster

    Mar 25, 2014
    Pittsburgh
    As I mentioned above, I run mine at 18, and it's a very nice sound. That said, I'm still thinking about making one that runs at 24.
     
    Mr. Lumbergh 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.
    Nope, no green paint. I stained the wooden sides of the box dark oak, and I liked the look of the brushed aluminum from when my dad did the finish work on it, so I'm planning on a bit more finish sanding to take out the scratches I put in when installing everything and shooting it in clear with the decals applied between layers.
    Addiction is the right word for sure... I spent a few hours trolling the net for information on the Magnatone vibrato circuit last night instead of watching TV and I consider it a better use of my time. It was a bit of a thrill for me to see the tubes light up on this, and even though it didn't make any sound the first time, identifying problems and correcting them was a part of the process and taught me what to look out for next time. I'm gonna try building a tube-bias tremolo and Magnatone vibrato next, and I have a couple other ideas as well. Your previous post also has me pondering a tube compressor...
    I dig this, it's where my engineer and artist brains get to hang out together.
     
    Robins likes this.

  17. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    Have you tried it at 12, or did you go 18 from the start? I'm curious about any differences in sound.
     

  18. suncrush

    suncrush Senior Stratmaster

    Mar 25, 2014
    Pittsburgh
    I have a variable regulated supply, so I tried it at 9, 12, 18 and 24. The higher you go, the less difference it makes, but I liked 18 enough more than 12 to go to the trouble.

    I want to do 24 because I want to be able to switch to a higher gain tube. With a 12AU7, the quality improvement from 18 to 24 was minimal.
     

  19. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    Gain isn't the issue for me; I can go from a smooth OD to a raunchy fuzz by lighting up both channels.
    I may go ahead and try 18V then; I'm getting ready to order a bunch of components for some more builds, so a set of 7018 regulators will only add a couple bucks.
    Thanks.
     

  20. Mr. Lumbergh

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

    Jan 10, 2014
    Initech, Inc.
    I got around to placing the order for the 18V power supply, and I want to give a shout-out to my downstairs neighbors Miku and Sheben(?) for the funds... They came by yesterday announcing that they had a baby on the way, and they wanted to explain what will be going down in a couple weeks and "pre-apologize" for the noise with a nice of bottle of sake and a $50 Amazon gift card! Here I am, the guy with amps right on the other side of their ceiling, and they're apologizing to me??? :confused:
    It's good to have neighbors from Japan. :cool:
    Ahywho, the Double Barrel (yes that's what I'm going with for a name) is getting torn down again this afternoon to make way for the finish work. I like the brushed aluminum look, so I'll be sanding out the scratches I put in it while mounting everything up, and shooting a coat of clear on to get it ready for decals and keep the aluminum from taking any further scratches.
    Also included in the order were a new 12AU7 for the tube tremolo and a Belton reverb module... I have some other things to get from Tubes and More tonight, but I have at least 6 builds in mind I want to try to make a reality, so there's going to be some R&D going on here at Initech.
    Enjoy your 4th folks!
     
    Last edited: Jul 4, 2017