Saturday, 17 June 2017

Tubeworks Real Tube 901

JohnK had made a layout for the 903 awhile ago, so I thought I'd give the 901 a shot. The layout should be small enough to give you plenty of room in a 1590BB. I took his switch wiring to make it true bypass, and removed the additional LED to tell you that it's got power, which I feel is unnecessary. Schematic can be found on Revolutiondeux.

The 901 has higher gain then the 903.





30 comments:

  1. I downloaded the schematic from Revolutiondeux and compared it to the vero layout and there seem to be some differences. Not sure if they are errors in the layout, or if these changes were made for other reasons.

    The schematic shows the 1M pull-down resistor connecting to the 47nf and 1k in row 1, but the vero shows it connecting to the other side of the 1k.

    The schematic shows the 22k (between the 12pf and 2.2uf) in column 12 connecting before the horizontal 1k resistor (on the left), but the vero shows it connecting to the other side (on the right) of that 1k.

    I think this next one was mentioned in another post relating to the Vox tone-stack vero layout, but the schematic shows the 10k (between the 1.5k and 68k) connecting to A-, but the vero shows it connecting to ground.

    If I am off-base, and my ignorance is showing, feel free to put me in my place. :)

    Thanks!

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    1. nope, went back over the schematic and you're spot on. made the corrections and updated the layout.

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    2. Cool, I'll take another look. Hope to build this later this week.

      I built the Dumble 70's version from the other post which was not working. I found a few issues that I have corrected, but still not working. If you recall (I know there are a lot of posts), I noted that when I plug the tube in, the LED goes off and I get nothing.

      Any chance this issue could be related to these three components being out of place.?

      Regardless, Ill get this one working first since its a bit simpler, and then move onto making the changes on the Dumle 70's and see if I can get it working as well.

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    3. And one more thing...when I was reviewing the board this time...I was drinking coffee, so lesson? Drinking Beer and Soldering...bad....Drinking Coffee and verifying a schem vs. vero...good.

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  2. I just printed out the new vero and schematic and ran through them, and they look correct now, so I'll give it a shot later this week and report back.

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  3. Zach,

    Can you explain why the B+ / B- and those diodes are not required on this layout? is that related to the JFET switching...or something else?

    I started my build last night and hope to finish this weekend, but was curious about that.

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    Replies
    1. I'm not sure what you're asking because both are on the layout.

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    2. The RT-901 schematic uses A+ / A- and associated diodes, at the input...but if you look at the output, after the tone stack, there are two more diodes going to B+ / B-, which are not on the vero.

      I just wanted to be educated on why these two diodes and B+ / B- voltages were left off of the vero and the power supply?

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    3. Still not seeing what you're talking about. The output from the circuit is from lug 2 of the volume pot. If you look at the schematic there is nothing after that as that connects to the switch.

      On the schematic right below the tonestack is the built in power supply which has a diode rectifier, and future to the right there's the stock switching with the indicator led.

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    4. Sorry dude. I'm referring directly to the RT-901 Schematic on the revolutiondeux site in the "Dean Markley Overlord to B K Butler Tube Driver" article, which I am assuming is what this was based on. I would post a link here, but I'm pretty sure that's a no-no.

      In that schematic, Volume Lug 2 goes to a 2.2k resistor, then to the JFET (obviously not in use in the vero) and then to (2) diodes, with one connecting to B+ and the other to B-...then through a 1k resistor and finally to the output.

      If everything after the Volume Lug 2 is related to the JFET switching, that's cool, I just did not know and wanted someone "in-the-know" to confirm for me.

      Does that make sense?

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  4. Has anyone verified the Power Circuit for these pedals?

    Can someone post what the + / - voltages coming out of it should be?

    The Layout says "4 cuts, 2 jumpers" but there are 5 cuts..is the latter correct since thats the number of cuts?

    Thx!

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    Replies
    1. 5 cuts it's a typo. should be ~ +12 & ~ -12V

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  5. Thanks. I figured, but wanted to confirm.

    Will this power board properly drive this pedal? I think the LT1054 maxes out at 100ma and the tube pedals I have built in the past (Tube Driver Types) all have pulled 300ma - 550ma...that, and when I got this board...the RT-901somewhat up and running, the 1054 got super hot and eventually failed... went through two of em.

    Thx!

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  6. Really having a helluva time with this little guy. It seems like the issue is the bipolar converter. getting +12.3v to the IC and +12.3v out at A+ and the LED but only getting 1.24v at A-. I got the LT1054's at small bear hopefully I didn't get 2 duds never gotten any bum parts from them yet!! I rechecked for solder bridges or misplacement but there isn't much room for a mistake on the converter...LOL There is some sound coming out of the circuit and the controls seem to do what they are supposed to. I normally try to figure it out on my own but I see everyone is having some issues with getting it working. Also wanted to thank you all again for all the work you put into this site. It is much appreciated.

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    Replies
    1. Swap it for a 7660s.

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    2. I don't have any 7660s but I plan on building a bipolar power supply based on what's on the schematic to rule the PS out.

      Nerdgod... what I found initially is that if my tube was not plugged in, my led on the PS lit but I got no sound. The moment I put the tube in, the LED went away.

      I later found that if I increased the amperage from my bench PS, the tube heaters would glow...and I measured the amps during this process...ended up somewhere around 200 - 350mm for the heaters...too much for the 1054...but I wonder if the 7660 would work? At this point the 1054 IC in the PS got so hot it burned my fingers. I then tested that IC in a known working 9v bi-polar PS...and it was providing erroneous voltages...so...I burned out two of them this way before I figured that out. UGH... $7.00 down the drain. :)

      I just got four of these myself from small bear a few weeks back. Two I fried, the other two I tested and they work...so I'm guessing what you got from small bear was good. You prob just fried em like I did.

      I was comparing this PS to others that use the same IC (or the Max1044) and I'm wondering if the 47uf on this PS is supposed to touch IC pin 5 and not 6 like the diagram shows?

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  7. My tube is nice and warm at 12.3v but there is only half of the appropriate (+12v -12v) current going to the board creating a low output almost low volume fuzz type sound. The converter schematic in the LT1054 specs has a few extra parts than this layout so not sure about it. Since a 7660S won't work in this PS layout This goes on the back burner for now. Will post if I have any success with alternative supply circuits. Thanks for the info Brandon! Have a great day! ....Cheers!

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    1. The power board ws copied from Johns's working build using his bigger layout. Looking at it he used a 7660s, I'm comfident to say I labeled the IC wrong and it should be a 7660s not an lt1054. Swap the chip and it should get the right voltages.

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  8. Thx Zach. I'll get some 7660s at some point and give it a shot. Nerdgod...interested to hear if you get yours up and running.

    Zach, thanks for all you guys do on this site...I've built some great stuff from your posts.

    Later!

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  9. On the power supply...Using a 7660S Should the 47u negative be connected pin 5 (per pinout) + to ground? as with the other bipolar power supply here on the site. ( http://3.bp.blogspot.com/-p41sc9zjSEw/Ute2GBD1dMI/AAAAAAAAF70/owslltSwwKg/s1600/Negative+Voltage+Inverter.png )
    Using the other layout I used a 12v regulator into the 7660s and I am getting +12.1 -11.7 still don't have a working circuit. I am just failing all the way around on this. If someone gets it working let us know. Thanks again guys! Have a great day!! Rawk!

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  10. I don't have an educated answer for you, but yesterday when I was not sure if the PS on this vero was correct...and i had no confidence if my 1054's worked...I built this one to test them with...

    http://www.sabrotone.com/wp-content/uploads/2011/01/Charge-pump.gif

    It worked with my "non-fried" 1054's and gave me +12 / -12 so maybe you give it a shot with the 7660...assuming the pinouts are all the same. ..I assume they are.


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  11. shit, didn't realize that 47uF cap is 1 row up, should be as you described, negative side on pin 5 not pin 6.

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  12. Nice! Too many pints when doing Veroboard layouts? :) That's always my excuse... :)

    Nerdgod, let us know what you find out...I really want to get mine up and running...then I'll be moving onto the RT-903.

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  13. Thanks Zach! I thought I was just bat shit crazy...well I am bat shit crazy but thanks for clarifying :) ....Power supply working main board still not working but that could be 100% me. Will get a chance to play with it the coming weekend. Have a great week guys and thanks again Brandon!

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  14. the power section has been updated to give the correct +12V/-12V.

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    1. Cool. I modified my power board and -it- works properly now. With the 1054 it powers the pedal, but I still can't get sound out of it. I'm pretty sure it's because of the current limitation on the 1054, so once I get my 7660's in, I'll try them out.

      Also important to note...the 1054's don't seem to burn out now, like they were before. ..they can't power the tube properly, but at least they don't fry *which I think was related to the cap being linked to the wrong pin on the 1054 initially).

      I'll post an update when I get mu 7660's.

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  15. Are you using a 12V power supply? The heater is supposed to get 12V directly from the supply, not the charge pump. The charge pump should have enough current for the plates

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  16. Well. I tested with a 7660s and whike I get some sound, its much lower than unit...and even when I pull the tube the sound stays the same, so I must have something wired wrong...prob with the tube I guess, as I thought I verified everything else already...

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