Friday, 16 March 2012

Demeter Tremulator

Requested by a few people.  This uses a vactrol but it might work with a roll your own LDR if you want to give it a try.  The spec of the VTL5C1 is 600 ohm on resistance and 50M ohm off resistance.

If you would prefer a tempo rate LED instead of a standard always on LED then take a feed from IC1 pin 7, and you will need to include a limiting resistor in series.  I didn't add this to the board because it would add an additional column which I didn't want to do if the feature wasn't required by most people.

Info from Demeter:

A hybrid of vintage sound and state-of-the-art quality, the Demeter Tremulator is designed for years of trouble-free operation.

Designed to emulate the classic Fender tremolo effect (or vibrato as it is often referred to), the Tremulator features "lopsided" amplitude modulation with a rounded off traingular modulant waveform. Suffice it to say, the Tremulator sounds like the classic effect found on many vintage amps, but with less noise and hum and a greater range of speeds and depths.

Operation is fairly straightforward. There are two inputs on the front side of the unit: a 1/4" input jack on the right and a 1/4" output jack on the left with a battery-ground switch on the input jack.

There are two controls on the unit: Depth and Speed, plus a footswitch to bypass the effect, and an LED to indicate effect operation. On the side there is a trim pot to set the bias for the optical unit.

Depth affects the amount of amplitude modulation on the signal or the amount of effect. The tremulator design incorporates a small amount of gain (approx. 1dB) to allow for proper "tremulation." Also, by turning the Depth all the way off, the TRM-1 will function as a low noise volume boost. It's low-impedance output allows it to act as a line-drive, eliminating signal loss on long cable runs.

Speed increases and decreases the frequency of the low-frequency oscillator, enabling you to time the effect as desired.

Trim pot sets the bias of the optical tremolo unit. It effects the signal on and of time ratio. Turned up to height it will squeeze the signal, low it will loosen it. The unit comes preset to Ry Cooder's preferred setting.


Youtube demo showing good examples of the range of sounds from the pedal:






121 comments:

  1. Well spotted :o)

    The original used 4 opamp channels (two singles and a double), this one also uses 4 opamp channels (two doubles). I omitted the TL061 and LF351, and instead used a single LF353 (which is a two channel version of the LF351 anyway).

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  2. Verified.

    I think i have a hearthrob and a schaller clones for sale.... :)

    I didn't have 1N5229s - which are 4,3V zeners, so i used 1N4733s, these are rated 5,1V. I was a bit afraid that it wouldn't work or somehow worked wrong. It didn't. I took the led resistor from IC1 pin 7 (right pin 7 this time:)), and i got very nice blinking led. It just seems to be pulsating in the opposite manner than i expected - light goes away when sound comes up..

    Great tremolo. If it's not perfect, it's damn close.
    +m

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  3. http://mirosol.kapsi.fi/varasto/boxes/tremul.jpg

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  4. Does anybody know if a Silonex NSL-32 can substitute the VTL5C1?

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    Replies
    1. Datasheet is not very informative about on/off resistances - it is telling them in W and kW?!?
      http://www.silonex.com/datasheets/specs/images/pdf/103708.pdf

      I have wondered the same thing, as Musikding offers only silonex nowadays.

      But. You can get VTL5C1s from Elfa distrelect. They are not cheap, but not that expensive...
      +m

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  5. Thanks!
    I found a VTL5C1 here in denmark - almost 10€ :o(
    Still cheap compared to buying a boutique pedal..

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    Replies
    1. Use sockets!! I can't stand soldering expensive components! :o)

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  6. What is a good alternative to the 1N5229?
    Is a Zener 4,7 fine?

    Chears!

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    Replies
    1. It would probably be ok, but if you could find any other 4.3V zener that would be ideal.

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    2. I used 5,1V without any issues, so i would guess 4,7V will be fine.
      +m

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    3. Thanks guys! Fantastic with so fast response :)

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  7. Made one of these last night. I got the Vactrol from Banzai in Germany.

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    Replies
    1. What type of cap did you guys use for the 47n and 1u components?

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    2. Plastic boxes and/or metallized polyester caps would be my choice. Or maybe even mylar for 47n. Can't remember what i've used on either of my clones as those got ripped from my hands when they were finished :)
      +m

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    3. I used a plastic box for the 47n and a multilayer ceramic for the 1u. Pedal sounds fine but I'd like some voltages to check against.

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  8. Built one of these the other night. Dry signal gets through but no trem effect. If I put an LED in place of the Vactrol, its not pulsing, just a steady illumination. If the circuit isn't pulsing, is there something I should check first?

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    Replies
    1. What voltages are you getting at the IC pins and are they all static or are some variable? IC1 pin 7 should have some movement in it.

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    2. They are all steady, none have any movement.

      IC1:
      1 3.51
      2 3.50
      3 1.06
      4 0
      5 3.51
      6 3.52
      7 3.61 (steady)
      8 6.95

      IC2:
      1 3.54
      2 3.57
      3 0
      4 0
      5 3.54
      6 3.38
      7 3.54
      8 7.02

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    3. There's definitely something physically wrong somewhere. The supply pins are connected and yet you're getting two different readings. Yes they are close but they should be exactly the same. IC2 pin 3 and pin 6 are also directly connected because there's no track cut between them, and yet you're getting 0V on pin 3 and 3.38V on pin 6. Have you put a cut in there which should be there? The voltage on those two pins should be exactly half the supply voltage.

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    4. Ok, I checked again and no there's no extra trace cut between IC2 3 & 6 and I must have screwed up the measurement. I'm getting 3.38 at both now. I'm getting 6.95v at both supply pins now as well. Sorry for the misinformation. Other than that do they voltages look right?

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    5. Also, I have a lead coming off of IC1 pin 7 with a limiting resistor to an LED. Immediately at power up, it flashes twice and then holds steady. Since that is a rate indicator, that makes me thing its working but locks up. Not sure if that is possible or makes any sense.

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    6. All i can say is that i built this again on wednesday, and it works perfectly. SO it has to be either a fault in your build (bridge, bad joint) or bad component..
      +m

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  9. I have just finished the Tremulator. It works, but not very well - I hope you guys can help to locate the error.

    The pedal works but the effect is very weak. I have adjusted the bias to max effect, but I can only hear it when Depth is turned all the way down. There are a few components witch are different from the layout, the trimpot is 10K not 5K and the diodes are 4,7V not 4,1V - could that be the problem?
    Also I'm not sure about my 1uF, it says 1K63 - is that correct?

    Any help is highly appreciated! :-)

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    Replies
    1. 4,7V Zener will work fine. I've built this with 5,1V.

      Interwebs suggest that your cap may be 1nF and not 1µF.. So that may be worth checking.
      +m

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    2. The schematic I used definitely shows it as uF (it uses the µ symbol)

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  10. I'm checking the 1uF with Musikding at the moment...
    How about the trimpot, can it be the problem? It is very difficult to adjust..

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    Replies
    1. It shouldn't be as it is wired as a rheostat. You'll just have less of the swipe to get it right.

      +m

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    2. I'm quiet sure that the 1uF is right..

      About the Vactrol, can you confirm that I connected it right?

      http://turntable.dk/diy/tremulator_01.jpg

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    3. Can't see anything wrong in there. You seem to have everything in order.. How about the other side of the board?
      +m

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    4. I have been playing around with a scalpel to clean between the copper stripes - maybe its a little better now..

      Here is the other side: http://turntable.dk/diy/tremulator_02.jpg

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    5. There's a few spots that could be of suspect. Knife all the gaps again, especially between rows 8 and 9. If that doesn't help, then grab the voltages from both ICs. Those could give us some sort of clue..

      I'll need to build this again soon. By the way.. Musikding has VTL5C1s on stock again.
      +m

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    6. The solder side photo is from when I just finished mounting the components - I have been over it with the knife now. It's better but not super.

      I need to borrow a multimeter to make the test - do I measure between ground and the legs on the IC's?

      I got a mail from Musikding when they got them back in stock, and I ordered it just after that. Sorry I didn't give the info to the communitie..

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    7. Don't worry. And your soldering is neat and shiny, so no worries there either. I just received a bunch from musikding.

      Yup. You can get the voltages by measuring DC voltage between the IC pins and ground. Note that the pinout is like this: http://circuits.datasheetdir.com/37/STMICROELECTRONICS-TL072-pinout.jpg
      I got that wrong for the first six months :)

      I'm beginning to think you might have some dead component in there. Could be anything, but trying other ICs, if you have some, wouldn't hurt. Because of the sockets..

      I've built two of these with success, so i don't believe the fault is in the layout.

      You could check your local hardware store for a cheap multimeter. I paid less than 4 euros for my main meter over ten years ago (it was 20 markkaa, FIM, if i remember correctly). Dx.com sells the same meter for ~7€ postpaid... The model is DT-830B. I've bought a few more expensive ones since then, but somehow i still seem to use that one. It has one flaw though. It doesn't understand resistors over 1M, but otherwise it really good. And it really has paid itself off :)

      +m

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    8. Thanks Mirosol, I think I will order a meter like that.

      Anyway, the pedal seems to work now, only a bit of static noise. Think there have been a tiny bridge somewhere, those copper strips are damed close to each other :-/

      Well, then I have to decide witch pedal to build next ;o)
      Maybe it's time for a ts808 with some mods, doesn't everybody need to have one??

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    9. Glad to hear you got it sorted! Did you use 1mm solder? In my experience all my tiny bridges were gone once i switched over to 0,7 and 0,5 solders wires. Plus the "knifing the gaps" is something i did for all my boards for a long time. Thankfully my soldering has got a bit better, so those are rare for me nowadays..

      Yes they do :) But check also Clark Gaisnter. I found it to be simpler to build and just awesome overdrive.
      +m

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    10. One more thing about the meters.. Even though i use that ye oldee meter the most, my favourite new one is UNI-T UT33A, which can be found from ebay for ~10-15€ a piece. That seems to be solid meter. I'm just used to meter that doesn't have any automatic ranging and other hifi features :) So that could be viable alternative too.
      +m

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    11. This comment has been removed by the author.

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    12. Well I have some old soldering wire, at least 1 mm..

      I have already build a Gainster ;o)

      I tried a friends BYOC TS-808 and I really like it as the first in the line of OD/distortion pedals, great breakup sound.I will then build it with the Keeley mods..

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    13. I've the same problem than Christian Tersløv.

      I can hear the effect but only when depht control is close to max. The effect is weak and there is a volume drop respect the bypass signal. I've checked twice the cooper stripes with a scalp looking for accidental bridges but I can't see anything strange...

      Any ideas?

      Thanks a lot

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  11. Awesome term. For some reason I am getting a click in time with the swells. The rate is also faster ccw than cw. Is that the source of my problems? Did I wire the pot backwards?

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    Replies
    1. How did you wire the pots? This shows the way I interpret pot connections in these layouts. If the rate is reversed then yes you need to reverse what should be connected to Speed 1 to the opposite lug. I haven't built this but I'm sure Miro would have pointed it out if any of the pot lugs were reversed.

      Did you socket the ICs? If so try swapping them to see if it affects the noise. Assuming the ICs are ok it sounds like you're getting some bleedthrough from the oscillator. Check all ground soldering and reflow anything that looks suspect.

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    2. Will do. I cannot say how much I love this site and all that you and contributors like miro do to advance my addiction (ehm, hobby).

      I am sure I swapped lug 1 for 3 as I have built several from the sight with no problems. I am also having an bear of a time with the deep blue delay. I am starting to think I got a bad batch of pt2399s...

      Thanks again!

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    3. Actually.. as i built this again this week, the rate was in reverse. Didn't make anything of, as i thought i'd just accidentally wired it wrong. Don't recall having that issue on the first build - but then again, i've built over 100 layouts so it' pretty hard to remember something i did six months ago.

      Anyway. I get some ticking too, but only when there's no input connected. Once i plug the guitar in, it it goes away. So to fix this, i would recommend using 4PDT stompswitch. That way you could ground the output too when effect is off...

      Saddly the second one got ripped off from my hands straight away too, so i can't debug it further. I think i should build yet another for myself...
      +m

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    4. Thanks for the reply miro. The effect is great if it were not ticking. Checked all grounds and it looks good??? Mine is ticking even when the guitar is playing...

      So, I built another and this one is ridiculously loud and unusable. Fuzzy but sounds like it is pulsing and depth works. Arrrrrgh...

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    5. I'm still guessing a microscopic solder bridge.. I don't recall the first one ticking at all, and the second manifested it when the input wasn't connected.. I'll build this soonish again, and we'll see. Then we'll know if the pots are correct too. I do have my hands pretty full at the moment and i'm not quite sure when i get around to it..

      If you're looking to build perfectly working tremolo, then check out Schaller and Hearthrob:
      http://tagboardeffects.blogspot.fi/2012/03/schaller-tremolo.html
      http://tagboardeffects.blogspot.fi/2012/03/heartthrob-tremolo.html

      I like both of those a lot, even while they are not as soft as tremulator. Both layouts are verified, and as far i can tell, they have had a lot less issues than this one. Actually, Schaller is one of those that got me started. I had the original unit back in ~99 or so. I had to sell it, and i just had to have one...

      There is also Kay T1, if you happen to have transistors with BCE pinout. That is very good too. Softer than Schaller.
      +m

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    6. I had an id10t error. Wrong resistor in the second build. Now I have two builds that both click. Since I am new to trem pedals I will assume it is me. How sensitive is the circuit to cap materials? The only change I made was the 1uf electro I used a grey box film... Nice tremolo but unusable the with the clicking.

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    7. Thanks for the help miro! I would love to get rid of that click. If I do this will be board worthy indeed! I may try the heart throb. I built the vox and love it, just wish it didn't boost the gain so much.

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    8. Cap material shouldn't matter at all. But. If you're using electrolytic as 1µ, you should probably check the polarity. That's the first thing that comes to mind.

      About the Percussion Repeater.. Take 4x3 piece of vero, solder 100K trimmer to it and take the output to trimmer lug 3. Lug 1 to gorund and lug 2 is your new output. That way you can tune it to unity easily. I have the same "problem" with that one. Just haven't got around to add the trimmer yet.
      +m

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    9. Officially giving up on the tremulator, for now, and moving on to build a bunch of vox repeats with a soft touch spst for double time and the volume mod. I cannot thank you enough miro! If someday we meet I owe you a drink...

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    10. Before you give up, just try one other thing. You're obviously getting noise off the LFO, and I just noticed the filter caps at the two half supply networks are lower value than I would normally expect to see. Try increasing the left hand middle and top 4u7 caps to something like 47u and see if that help with the noise.

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    11. Thanks mark, I also did some research and it appears the discussion here recommends that the LFO should have its own express route to ground at -ve... http://www.diystompboxes.com/smfforum/index.php?action=printpage;topic=62637.0

      Do you think it might help if 1&3 on the vactrol go directly to -ve?

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    12. The LFO does have its own voltage divider, you'll see there are 2 sets of 100K resistors from supply and ground to the two points of 1/2 supply. I made this layout from a modified version of the schematic that I did based on those discussions, but it seems that despite that the clock oscillator noise is still coming through. So upping those filter caps may help with the noise. Definitely worth a try.

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    13. All I had was 22u and they did not work. I am going to try 47u next.

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    14. Socket them if you can. The thing with filter caps is that they can do nothing up to a point and then it does the trick. Try 100u or 220u if you have to just to see if it reduces the noise to an acceptable level.

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    15. Ok, I have gone all the way to 220uf. Still clicking. Cutting the trace and sending vactrol 1&3 to the AC directly will not help? Sorry if this is a stupid question I am still trying to figure out what is happening here. It woul e a shame to have to undo all that work.

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  12. Miro, you rock! Just cleaned up the traces on both of the clicking tremulators and they are still clicking away. I am curious to here what you end up with next time you build this...

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  13. I built another one and it suffers from the same clicking problems rendering the effect useless. I checked everything against my working one and it looks identical. I have run a scalpel over the track spaces to be sure but can't get rid of this annoying tick!!

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    Replies
    1. I had the same issue with both of my builds. Very frustrating since it sounds like such a nice trem behind all the clicking.

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    2. What ICs have you both used? The clicking is obviously noise from the LFO which some ICs are more susceptible to.

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    3. LF442. Shoul I try a tl072?

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    4. Ok tried ne5532 in both q1 and q2. Sooooooo frustrating cuz I know this thing sounds awesome. Still clicking away. Could this be a bad vactrol? That would stink because those are expensive and both of my builds have the same issue.... Any other suggestions? I might try and do it over...

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    5. Try a low power opamp like the TL062. I've seen those recommended a few times when people have had LFO clicking with others.

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    6. I will try that out tomorrow. Thanks mark.

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    7. No good. Pulled ic1 and the pedal ticked in double time. So I replaced ic2 with the tl062... Fail.

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  14. can i sub a tlo72 for the lf442?

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    Replies
    1. Should be ok, but we do know from past experience that sometimes alternative ICs don't give quite the desired results like with the Vox Repeat Percussion. Best bet is to socket it and give it a go.

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    2. I would try on NE5532. Those are usually less noisy..
      +m

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  15. I used the tl072 and it works and sounds great but the depth knob is not responding. I doubt this has anything to do with the ic choice so now I've got to look over the board and see where my mistake is. Also, for what it's worth, I do believe the speed knob is wired backwards. I had to flip the speed 1 to the speed 3.

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  16. My speed is backwards too.

    This circuit sounds sooo amazing though. I boxed it up yesterday and it's really addictive.. It's easily the best trem I've used

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    Replies
    1. Heh. I really do think it's backwards too :) It's been discussed on these comments before, but from my personal experience - i know that fixing that can be forgotten between all the other things. I recall someone mentioning that some of my layouts has some pot in reverse, but i can't remember which it was. Plus checking all the posts looking for that one comment... argh.

      But now i'm pretty confident that the speed is in reverse. Mark! Commit a fix! :)
      +m

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    2. That must have been beer night :o)

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  17. The new layout is missing the 5k vactrol trimmer in the top right corner of the board

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    Replies
    1. Ha. I changed the names of some of the components in their configuration files a while ago so they were in groups and the order that I want, but changing the name means the software doesn't know what you're talking about when you open an old file you created before the changes. Now updated.

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  18. I'd also encourage anyone building one of these to just build your own vactrol. I got a VTL5C1 and one I built with a 5mm red LED and a LDR and I notice no difference between the two in the time it takes for me to change them out.

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    Replies
    1. Yes definitely, the Vactrol's a really expensive for what they actually are. A few years ago the EU banned the use of cadmium in electronic components and these LDRs (and Vactrol's) contain cadmium sulphide. We can still source them at the moment but you never know when that may change, so anyone who likes using these may want to get a few in to make sure you've got some to hand.

      The good old EU, protecting us from the blight of cadmium and straight bananas.

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    2. what type of LED did you use? - Defused, Water-clear. And what LDR type?

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  19. Having an issue with the build and could use some help. When I have the vactrol LED + in the 1 spot and the LED - in the 2 spot it doesn't light up and when the circuit is engaged I only get dry signal and no response from the controls. When I switch the + and - of the vactrol LED the LED lights up but doesn't pulse and when the circuit is engaged the dwell knob acts as a master volume but there is no tremolo. Can't find any solder bridges and double checked the layout so I think it's a bad part. What do ya think

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  20. how could i add a switch for depth and speed halving like the supatrem?

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  21. Hi!
    First of all, thank you all for sharing the information on this site.

    I have also built this pedal and have the same issue as Gc66: it works, sounds nice but there is a ticking along with the effect.
    Is there a fix for this?
    Thanks a lot

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  22. Fantastic tremolo, thanks for the layout as always. I had some trouble with the vactrol positioning at first but looked at the datasheet and fixed it right up.

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  23. I've had click problems like others. I tried a TL072 and NE5532 in the IC2 slot, but the difference was negligible. What I have noticed is that the click gets louder as I put the board into the enclosure. If I pull the board out of the enclosure it's noticeably quieter and if I slide the base of the enclosure between the board and the offboard components it gets even quieter. Could this just be my messy wiring causing interference? Any ideas?

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  24. To clarify: Have people built this successfully without any clock ticking?

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  25. Hello,

    I seem to be having some problems with this circuit, I put it together last night and I seem to have created a monster.... Basically, it is boosting my signal and I just get mush out the other end, clearly I've done something wrong. I've attached some photos below, apologies for the terrible soldering, my tip broke halfway through. I've been over the board with a knife a few times and checked it out with the continuity checker on my multimeter, so there don't seem to be any bridges.

    I've taken some measurements around the ICs so hopefully this will help the diagnosis. The only subs I've made are the diodes (5.1v zener) and IC2 is a Tl072, both of which have been used above. IC readings are taken from top left, counter clockwise:

    IC 1:
    1: oscillates between 4-7v
    2: 4.52
    3: 4.12
    4: 0
    5: 6.55
    6: 9.05
    7: 1.47
    8: 9.05

    IC2:
    1: 1.36
    2: 2.64
    3: 4.05
    4: 0
    5: 5.72
    6: 4.05
    7: 8.25
    8: 9.05

    https://dl.dropboxusercontent.com/u/7620516/Trem%201.jpg
    https://dl.dropboxusercontent.com/u/7620516/Trem%202.jpg

    Thanks in advance,
    Sam

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  26. I made a bonehead move and didn't order the 33k resistor. If I place 3 10k resistors in series I should be just fine correct? Basically a 10k where the 33 is supposed to be and then 2 more directly to the right of the of the 2.2k but on the same strips as the first 10k replacing the 33k.

    ReplyDelete
    Replies
    1. That would put the resistors in parallel which will give you 3K3. You will need to put the 10K's in series if you want to end up with 30K, or alternatively put a 100K where the 33K is shown and a 47K in parallel with it where you describe. That will give you 32K.

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    2. This comment has been removed by the author.

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    3. This comment has been removed by the author.

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  27. Ok I finished building the pedal last night and the effect sounds incredible. I used to have the original tremulator and it sounds pretty much identical to what I remember. I do have that clicking sound going on though which does kind of render it unusable unfortunately. Did anyone figure out the fix for this? Mine clicks in sync with the rate so the faster the speed goes the faster the click. It's also there faintly when the effect is turned off which is odd to me because I wired it for true bypass and when I pull power from the pedal the signal still makes it through which I believe means it's in fact wired correctly. Anybody?

    This is my very first pedal build so I am pretty psyched and surprised how smoothly it all went. I think that says a lot about this site and how great it is!

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  28. I just finished this and it sounds fantastic! I can verify that this build can be done without clicking too. I didn't run a ground wire to my output jack and kept my ground leads short. Thanks lVlARK!!

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    Replies
    1. Nice to see it is possible! Thanks :o)

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  29. Built this and it works great. I haven't boxed it up so I can't say anything about the LFO noise - I haven't experienced any as of yet. I used a TL072CP for IC2. 1N4732A diodes.

    Thanks for the layout!

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  30. The video doesn't work on my computer; it says "This video is private." Is it just me?

    ReplyDelete
    Replies
    1. Yes it worked at first but he must have made it private after I'd made the post. I've changed the vid to one made by someone with less hair :o)

      Delete
  31. Built it recently and of course the LFO ticking noise is too annoying. I gave it a try and built Tremulator on the etched board from layout found on the internet - now it's quiet and sounds great. I think that the thing going on with this stripboard trem is non-isolated LFO part from the rest of the circuit. What's more I connected the LFO ground at DC - pin. Maybye this would be the answer for LFO noise...

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    Replies
    1. I don't like this layout anyway, it's pig ugly so I think I'll redo it. Which PCB did you build and is there a schematic with it? Just so I can compare to the scheme I did this from.

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  32. Has anyone built this without LFO ticking only to have it randomly appear some time later? I built this earlier this month and its been great but just tonight I started to get LFO tick!!!

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  33. Hello! Very good blog!
    I built this circuit and I have a problem: The DEPTH potentiometer and the TRIMPOT work fine, but the SPEED potentiometer does not! When it's down the speed is medium like. When I turn the speed pot up the speed effects turn slow, very very slow.
    Where could be the problem? I think the wire is OK.

    Thank you very much and greetings from Spain.

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    Replies
    1. My Ic's Voltages:
      IC1
      1 - 4.5
      2 - 4.5
      3 - 1.13
      4 - 0
      5 - 6.95
      6 - 5.11
      7 - 6.93
      8 - 9

      IC2
      1 - 6.9
      2 - 0.24
      3 - 5
      4 - 0
      5 - 6.77
      6 - 5.12
      7 - 7.85
      8 - 9

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  34. Hi, concerning to the Vactrol numbers (1,2,3,4) Which of them are the led+ and led -?

    Thanks a lot.
    Luis

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  35. If I would increase the gain, which is the resistor I have to increase?

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  36. Hello, I wanted to share my experience with this ticking problem. My build does it too, I noticed it when I was checking it with just the guitar and amp. However the click goes away when I put in in my pedalboard. I am now quite sure that this is due to the Orman buffer that I have as the first stompbox. At least the click appears and disappears as turn the buffer on and off. Is this possible? With the buffer sounds perfect so I am thinking in boxing this together with a buffer. One thing, I have not connected the led to the circuit as in the layout but I have it connected to the 3pdt directly as in Ivklark's guide, I don't know if this may be important. It didn't make any difference when I did it as by the layout so I decided to do it this way.

    What I don't get very well is the trimmer. It seems that it affects the range of the depth pot, I can't really decide from the pedal's description if this is how it is supposed to be. Anyway, will this new layout that has been mentioned in previous messages be available? I wonder if that would kill the click without the need for the buffer since I really like this effect and want to box it permanently.

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  37. My boss PN-2 does exactly the same thing - a tick without a buffer in front, and none with.

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  38. I've the same problem than Christian Tersløv.

    I can hear the effect but only when depht control is close to max. The effect is weak and there is a volume drop respect the bypass signal. I've checked twice the cooper stripes with a scalp looking for accidental bridges but I can't see anything strange...

    Any ideas?

    Thanks a lot

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  39. Hi all, I'm slooooowly getting round to putting this and a couple of other circuits together - many, many thanks to everyone involved in this site :) - so just a quick question, is it possible to add in a momentary switch to the circuit for some Oz Noy inspired goodness?
    Thanks again chaps..

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  40. Hi chaps, sorry about the last question, bit of a dumb one :) Have figured it out (not too tricky!) Another quick question though, could I use a 1uF tantalum cap instead of a mylar or whatever - in which case, which way round for polarity should I fit it? Tried to follow the circuit through but couldn't quite work it out, and didn't want to risk blowing it up..
    Cheers for now
    J

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  41. Hello, DIY supporters!

    I have constructed the pedal, LFO works, Vactrol also, 1db of gain also,quite but the pot of depth behaves like of pot volume, independently that the vactrol continues working.
    The veroboard is the schematic of 'monkeyxx' ,but with IC less (A double LF353 instead of singles TL061&LF351), all Ok.
    I understand that in this schematic the Depth Pot is wired up as a Master Volume of any pedal.
    Then if the mistake this one there,How it wired up one of this Pot Depth?

    Thanks!!

    Here Monekyxx Schematic:

    http://1.bp.blogspot.com/-rxDiLcyJ1pM/TykgQyQjOmI/AAAAAAAAAzg/RUnLn9re8xc/s1600/DEMETER+TREMULATOR+schematic.gif

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  42. My error is another...,I could have verified with multisim monkeyxx schematic and the wiring of the depth pot is correct.

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  43. Resolved problem.
    The vactrol is defective doesnt reach the correct values, I have replaced for a combo led/ldr and now yes, demeter tremolo working!!

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  44. Mine is working now, but with the click noise. Any ideas? I've tried switching to a TL072 but... nothing... the click is still there.

    Has anybody builded this layout without the noise???

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    Replies
    1. I've built two of these. Second one had slight clock bleed, which cleared once the circuit was boxed. You could try JRC4558 to see if that helps.
      +m

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  45. Built this today with the vactrols available from musikding . great sounding pedal no clicking. one thing to note: The vactrol needs to be placed so the - ve of the LED is going to ground. this meant in my case the vactrol was placed with the markings NOT on the front but face down.

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  46. after checking this out I realise that the depth control isn't as strong as in the demeter video. I have a 1 db volume boost if the depth is fully off but as I increase the depth I'm getting a volume loss and at full depth it's not as deep as it should be. Any ideas?

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  47. Maybe the issue I had with this build will help someone here...
    I couldn't get the tremulator working (the led pulsating) until:
    1) I linked (jumper between) trimpot lugs 1&2
    2) I wired speed 2 to lug 3 and vice versa (speed 3 to lug 2)

    (By the way, thank you Mark for your great work. Since I met your site I became addicted with soldering and electronics! Cheers!)


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  48. I found a 4.7nf from speed 2 to ground stopped the click

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  49. Built this today and found that adding a 100r resistor from 9v DC jack to the PCBs 9v input, and a 10uf cap from IC2 pin 7 to the PCBs 9v input stopped the clicking!

    I love the pedal but was wondering if there was any way to make the LFO waveform a little smoother? Would changing the trimmer value help?
    Thanks!!

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