Saturday, 17 December 2016

Bartolini Tube-It

Came across a schematic for this awhile ago as it seemed interesting. It's supposed to be a fairly rare overdrive pedal fetching up to $500. Here's some information I found about it:

The rare 1980s Bartolini tube-it Distortion Overdrive pedal made in Livermore, California, USA. Makes any amp sound like a Marshall. This may be the only pedal Bartolini ever made. Three position switch for more or less overdrive -- plus treble, bass, sustain and output controls.

It was designed to emulate the distortion characteristics of an early 80s Marshall JCM-800. Probably made in the mid 80's. Three way boost switch unloads tons of gain from mild to overkill. The circuit is set in a giant block of epoxy so there are no clones or schematics available.
 

Does anything from smooth, cleaner OD to straight up blistering, sustaining lead tones. Has the three way boost for different tone styles. Can do TS-9, Marshall, or its own thing all together. Controls include bass, treble, sustain , and output.
 

Whip the bottom off the tube-it and inside there's a little trim pot for adjusting the sound to be bit more, or less present. All models may not have this option. The trim is a small plastic wheel (see photo in the Disqus section) similar to the color to the exterior paint job.
 

Some of the tube-its were said to be mercilessly treble boosted. The pedal can get a sound like a healthy Tube Screamer in the first position. Now up the boost one notch, to add a little more drive, and fullness.
 

Perfect for lower output pickups. Need some grind? Just flip the boost switch to position three. It's at least double the increase in gain, as between positions one and two. The circuit is now presenting significant drive, and a fuller, slightly distorted tone. Let's not forget the absence of tone suckage when it's not kicked in. A very fine, versatile pedal.

The only thing I changed was make the high low switch 2 different switches so you can control each one independently.


27 comments:

  1. Thanks, Zach, great stuff! Keep 'em coming ;)

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  2. Zach, I compared the layout to the FSB schemo and I'm sorry, but there are quite a few mistakes, even large ones that will make this layout completely non-functional :( Here are my findings:

    - First jumper in column D should go down to Q1's base
    - Sustain 3 should go 2 rows down
    - Based on the schematic from FSB the 1.8M resistor from Q2's base should go to Q2's collector and not the VCC
    - There is a major problem at the Hi-Boost switch connections: Hi Boost SW1 does not connect to anything, the 8uF from Q2's emitter connects to a 390pF cap which goes to ground and the 180R resistor that should connect the 8uF cap to ground just "hangs" there connecting to nothing. Also there is a cut missing there, as this way the Lo-Boost SW1 connects to the 8uF cap as well.
    - At Q3 the 120k resistor should connect Q3's collector to the VCC, but it connects Q3's base to VCC
    - Q4's base connects to Q3's base instead of its collector
    - The complete filtering net seems to have problems:
    1) The net starting with the 1.nF, 750pF and 330pF caps should connect to Bass3 instead of Bass2
    2) From the 750pF cap there are two 47k resistors going to ground instead of only one
    - Q5's 1uF output cap connects to the base instead of the emitter

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    1. hey man. i'll have to see if the schematic i have is the same as the one one FSB and make changes as necessary. for now i'll put it on hold.

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    2. Yep, my next question should have been if you have used the FSB schematic :) There are too many deviations... Though if you did use another one, then I'M afraid that in some points that schematic is wrong. E.g.: the last cap going from Q5's base to the Level pot is certainly wrong, the output buffer would then be completely bypassed.

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    3. yea, did a quick check and the schematic i got was way off. i'll fix it tomorrow after my last final. a lot of the changes shouldn't take long and the board should remain relatively small, and not many more cuts and links. glad you point that out. cheers

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    4. Good luck with your last final ;)

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    5. thanks man. so i went back and made the corrections. there were a few others i spotted as well that should now be correct. the board grew 1 more column and added 1 more link, so not terrible.

      the switches should be right, since they work independently now instead of together. the hi-boost SW1 is connected to the + leg of the 8uF, the - is connected to the 180r to ground. hi-boost SW2 is connected to the E of Q2. the lo-boost switch is just SW1 390pf to ground, and SW2 to B of Q5.

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  4. Hallo, ist there a schematic? Can't find anything at FSB...

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  5. Just type in bartolini tube it in the search box on fsb then scroll about half way down the page you will see it.

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  6. just added to the notes that Volume 2 to Output. must have deleted it when moving stuff around and didn't notice.

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  8. something wrong with 1uf around sustain , but most important , we can't have jumper AND resistor together ....( 4.7M )

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    1. correct. that was not supposed to be like that, each spans 1 more row then it should. went back over the layout with the schematic to see about the area around the sustain, but it looks right to me. what to do mean something is wrong with that area? did you build it and use scope it?

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    2. built it but no scope ..... no sound at all ..... 2n3906 instead of 5087 .... retried tomorrow ...

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    3. rebuild from scratch .... still no sound ;(

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    4. ok. what will be a tremendous help is to use an audio probe to figure out where the sounds stops in the circuit this will help be able to figure out where the problem is within the layout. i'm going to go back through the layout and check it against the schematic again and see if there's anything i missed. the one cap is backwards going into sustain 3, but that i don't think that's the problem with the layout. but out of shits and giggles flip that cap and see what if that gets it working.

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  9. Only thing I see is the electrolytic capacitor is turned backwards coming off the sustain and is backwards in the input to. Don't it have to run through the + side first I have never seen a capacitor turned backwards like that. And what about the 7k resistor with a ? Beside it.

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  10. The orientation of the electrolytics at the input and sustain are correct. The + side of the cap simply goes to the side with higher voltage, and of course the transistor has a higher voltage than your guitar.

    I haven't looked at the whole schem, but while looking at that part I see that Q1 has the 2M and link from 9V mixed up.

    The 9V link should go to collector and the 2M from 9V should go to the base. As it is right now, the signal is going to die at the Q1 base

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  11. so ... interchange E jumper with 2M resistor ?? .... i try this , i think you right ! .... thanks all !

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    1. Travis , Zach ... thank you so much ! works perfectly now ! ;)

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    2. great pascal. what did you change so that it's working right so i can make the correction on the layout. also, how does it sound? i've been curious about it based on it's description, but couldn't find any videos with it.

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    3. Q1 base is 2M and Q1 connector is jumper ! .... sounds good but bass and treble react weirdly , thanks again

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  12. That tone stack is the most craziest one I have ever seen. I can't wrap my head around it how it even works. What is all the capacitors and resistors above the bass pot doing?

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    1. I think I'm going to bread board it first to see if I like it. I seen a video of a guy with one sounded good. I guess if the tone stack dont sound that good would it be possible to try different tone stacks with it like the fmv tone stack.

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    2. I guess if I like it I will probably just build it on tag Strips. Nothing against vero I have built a lot of layouts on vero but it seems more fun to me to build it on tag strips

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