This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Wednesday, January 13, 2016

Run Off Groove Tube Reamer

Here's a simplified Tube Screamer circuit from Run Off Groove, the Tube Reamer. Basically, it's a buffer-less TS without the tone control. The IC can be just about any dual op-amp. JRC4558 or TL072 are good places to start. Should be a great candidate for a 1590a build. For more info, schematic, and demo see the ROG site.


7 comments:

  1. I have this on my breadboard. For some reason the Drive pot is not getting anything :(
    Any ideas as to what I did wrong?

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    1. Well first make sure it's connected ;)

      Are you getting output signal, just without drive control? Or no signal at all? If you're getting signal, it may just be a bad drive pot. If you're not getting any signal... Could be a lot of things. haha

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    2. Hi there :),

      I do get output signal. Volume pot works fine. I thought maybe the diodes were the problem so I changed those a few times; nothing happened, haha.
      I'll try redoing the circuit. (:

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  2. Tag it!! Sounds really really great with my favorite TS diode combination. Only trouble I had was self inflicted ground points I forgot to connect (vol and gain pots) VERIFIED

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    1. Follow up notes because it was just before midnight when I finished and tested so I had to keep the volume low. This morning I had the chance to turn it up and test it more. Here's the notes, including build notes. Tested using my 2008 Les Paul Standard with non-wax potted Burstbucker I & II pickups playing through my USA Crate V30 amp.

      Build notes: Used 47K resistors as I had no 51K. I know on a TS808 pedal I build and sell lowering one resistor gives less gain at low settings and one other resistor gives higher gain at higher settings. I used a 30K for less gain low and 2.4-2.7K for higher gain at high. This circuit has way more gain than I expected on the low and high ends so I imagine tweaking those same resistors may help. ??? I'll need to compare with my other circuit and find which 51K on this circuit controls that function. I may tinker with different types of gain pots. Might even try a C500K or A1M. Volume is VERY loud. Unity gain setting is well below 10 o'clock. I used a JRC4558D op amp chip. Will try TL072 and 5532 et al. Also pulled some JRC2068 op amps out of a Tascam DAT tape machine that blew the caps. In one quick test on another pedal(Centaur Clone) it sounded pretty good if not similar to the TL072. Haven't compared specs yet. TBD

      The overall tone doesn't sound too thin but I may play with the cap values and bump the low end a tiny bit. Needs a touch more punch. Just preference and I like to experiment. The overdriven sounds is very fuzzy compared at normal volumes and up compared to my low volume test last night. I will try other diodes and as stated earlier other resistors and see how that changes that aspect. If not I'll see if I can figure out a small smoothing cap to apply near the diodes or gain pot. Current diodes are 1n4001 and 1S1588 (silicon with royal blue stripe as used in the early TS808s. I have the 1S2076 which I read were the original diodes used. For now my diodes are socketed so I'll be trying silicon, ge and schottky. Just got in some Russian D9Js which I hear are supposed to be magical in pairs.

      Single notes sound really good on all pickup settings but chords are not as articulate. Low gain settings with my 47K and 2.7K resistors sound very nice and bluesy. Full chords are a bit muddy. May try some other op amps too and see how it changes the contour of the overall tone.

      I'm hoping to get this sounding a little more transparent so I can build these in the 1590A box to save room on my pedalboards. I keep multiple overdrive pedals (don't we all? ) and the more the merrier I always say.

      Will report back after more tests. In spite of the fizzy nature of the overdrive many will find it appealing and I could find limited use for that tone myself. However, I like a more transparent and smoother distortion. So the circuit is very good as is and I'll even try it with 2 matching Si diodes as most have and see how a "stock" type setup sounds.

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    2. Best build report I've ever gotten! Thanks and keep up the good work!

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