Friday, 15 July 2016

FYA Garagemaster

This day had to come.

Recently i was asked if i could build a vintage sounding treble booster for modern pedal board. Sure. Why not. And quick looking around showed that there were not that many (!?) rangemaster modernizations around. Or yes there are, but most of them do have something wrong with them - missing vital controls, still using PNP transistors and/or positive ground, sounding too thin or trying to be something completely different, not a treble booster, etc. So i took out the classic Rangemaster schematic and had my way with it. Basics are still there, only with an NPN transistor, large power supply filter cap and a series polarity protection. The switchable input cap is probably the oldest trick in the book, but i tried to voice it so that the frequency response stays at treble boosting area, while still being usable all the way. After all, we're trying to make the best possible treble booster for a modern setup. So to go forward, we got our input pulldown to keep switching POPs to minimum, followed by the "EQ switch" that has a standard 4n7 input cap in circuit all the time, upped by another cap at 2n7 for a fuller frequency response. Transistor also gets its forward bias voltage as the original Rangemaster does, from 470K resistor from supply and 56K resistor to ground. This equals in around 0,958 volts if the supply is at dead 9 volts. Gain is applied by setting the output from between the collector and supply via 10K linear pot. At zero, the output is killed by supply voltage, at maximum the boost amount is enough, or at least enough. This is followed by an output cap (to keep the DC away from the output) that has a slightly bigger value than the original and a another pulldown. Now, what's different in my take on the classic is the "bias" pot. The original Rangemaster would have 3K9 resistor from transistor emitter to ground in parallel with a bypass cap of 47µ value. After a short breadboard session, i settled for 2K7 and a 50K pot in series with it. At maximum, the gain is slightly more than it would be in verbatim Rangemaster clone - and staying clean and soft like a true Rangemaster would. But here's the thing, once we put the 50K+2K7 in parallel with the 47µ, we'll get the misbiased germanium tones ála Hornby Skewes Shatterbox, EHX GeOD and/or Germanium4 Big Muff Pi. If you are familiar with either, you'll know what i'm talking about - that mushroom cloud tone that is both super ugly and yet still pretty cool. The one that makes everythign sound truly broken. In my take of the Rangemaster, i've incorporated a control to set that amount of total destruction to the the classic. This should take you further than a Shatterbox, EHX GeOD and anything else. If not by itself, you should try to boost another pedals with it.

Just finished building a three piece set of these. One for the guy who was asking, one for me and one's for sale. And here's the "factory layout". I hope you are happy with it without a schematic - i just told you what the differences between this and the original Dallas Rangemaster are, so you really shouldn't need one.

The transistor model, gain and leak range- that's one thing i'm keeping a secret. You should be happy with anything - maybe even a 2N3904 could work, if you care to tweak the value of the 2K7.

Oh. The name? The tone of this circuit reminds me a lot of the guitar sounds of the 60s garage bands, such as The Iguanas, The Vistas and so on. Use this circuit to make your modern amplifier sound like the 60s. Yeah. That's the magic in the FYA Garagemaster.

And here are two, more compact versions from Alex. Should be easy fit for 1590A, if you use 9mm pots.



 

29 comments:

  1. "I think Alex could make this 1590A friendly in a heartbeat if there was a demand for one..."
    After this layout description I find myself screaming Alex name...
    Willing to throw my nagaviper through the window...

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    1. Hey Miro.
      Great design!
      I've drawn a layout but I didn't know how to show it to you.
      I've added in the Contributions/Unverified Layouts section of the forum at the bottom of the topic: "Visual Sound Jekyll & Hyde (Grey Version)"
      I'll delete it after.
      You can copy it and paste it to your main post if good enough.

      Delete
    2. Will do. Nice and compact!
      +m

      Delete
  2. Built and verified. Sounds great, but I'm not sure I have the transistor choice or gain range right yet - I'm not getting much "broken amp" mis-biased action going on at the moment.
    Seems to like lower gain transistors - am I on the right track Miro?

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    1. What transistor you have in there? The broken quality is at least partially a feature of germanium transistors. I doubt the effect of the "bias" pot will be 1:1 with silicon device.
      +m

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    2. I've tried MP38 and 1047U germanium, with a gain spread from 40 to 105 HFE and a bunch of silicons. By far the best Si choice seems to be BC170A at 72 HFE. They sound good and really crap out when I turn the bias pot down.
      The MP38 (40-65 HFE) and 1047U (60-105 HFE0 both sound equally good, but as I said don't seem to be affected very much by the bias pot.

      I'm not noticing any particular gain value as being spectacularly better than others - sound great at 40, sounds great at 105.

      Maybe I'm testing it with the wrong amp?

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    3. Hmm. Strange - so you're getting the desired pot functiopn with BC170A, but not with any of the germaniums? The effect of that pot should be very noticeable. Is the 47u ok?
      +m

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    4. hi, I've breadboarded also a ringmaster with bias control (the sparkle motion) and also had to adjust some resistors to get the "mis-biased" sounds or take a larger bias-pot

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  3. Super cool. I have made just under 100 pedals now. I am still amazed at how great one transistor circuits sound . My first build was a DAM red rooster . Still probably my favorite build. Its just perfect for my 1970's Marshall half stacks.You guys Rock!

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  4. Why keep the transistor choice secret? That seems to go against everything you say this site is about.

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    1. For two reasons.

      1. Go and match your own favourite - this goes strongly to everything this site stands for.

      2. It's my desing. Buy one, open it up and tell the world. I believe i have the freedom of doing what ever i want with my designs... I could have kept it a secret altogether.

      "That seems to go against everything you say this site is about."
      We have said what? And where?
      +m

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    2. May I ask: what's this site about? Miro has probably spent hours modding a Rangemaster and made his layout (once again) freely available to everyone. People should just be grateful. If he wants to keep a detail for himself it's his right to do so. Nobody has ever said that people should share their designs with everyone. If you check the "Circuit Designs" in the Forum/Contributions section, there are only 25 topics. In this blog people share their layouts and diy knowledge without asking anything in return. A lot of people come here, take what they want and contribute nothing. That's ok, but nobody should complain.

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    3. The DIY FX world wouldn't be the same without you guys, thanks for the layout Miro! I have some philips NPN germaniums lying around that I'd love to try for this

      Delete
    4. Didn't meant to ruffle your feather so much. :-) What I meant was that you are so keen to discover and expose every other designer's secrets that it seems churlish to impose your own. I have no problem at all with trying things - in fact if I build anything here it is rarely as written. It just seems to me that this place is all about sharing secrets, not keeping them.

      Have I hit a nerve??

      Delete
    5. I don't think you get it mate. Mirosol has donated hundreds of layouts, and thousands of hours of work to this site - for free. He's done it to help YOU. He's entirely free to do whatever he wants - post things up, take things down or even post up in his native Finnish and let use all have a great deal of fun trying to get Google Translate to make any sense of it.

      He, or any of the other contributors to this site for that matter, might not be so keen to post up next time if he ends up getting grief for it.

      Just be grateful for what he has done for you over the past years and back off graciously. Better still, get involved in the forum, and help spread your obvious knowledge and experience to others who may need a hand.
      If you don't want to do that, you have no right to complain.

      Delete
    6. Hey Hamish. This blog is about sharing vero layouts and some diy knowledge. There are no discoveries or secrets revealed here. Most reverse-engineering and schematics are done by the good people of freestompboxes.org and similar websites. I don't personally know Miro but I'm grateful to him for the hundreds of layouts that he's shared with people without asking anything in return. How many of your own designs or secrets have you shared with all of us? And even if you did you shouldn't complain about other people choices. Noone is obliged to do anything on this blog. There are no ethics involved.

      Delete
    7. Second again. For both, Beaker and Alex. Only nerve HamishR has hit is the "complainer nerve". Anyone complaining about posts has always gotten the same treatment since 2010 - a hefty load of comments showing the complainer a strong middle finger. All your comments do say is basically just: "I'm not happy with your free service and i want my money back". Think of this for a second before complaining about anything.

      There are number of layouts that do not have the original device type mentioned due to that information not being available. For example, most pedals that have sanded ICs say only "is a dual opamp, try 4558 etc" or something similar. I see this as a standard. And mine is not sanded and it is not a secret. Buy one and share the info. There is one for sale right now in finnish musicians gear forum. And yes. Where can we seee your designs shared?

      Partially, this all may come down to the complainer simply assuming that we are some sort of outlaws hiding behind screen names. This is not, and has never been the case. And what comes to assuming anything, i think Benny Hill put it quite well; https://www.youtube.com/watch?v=R6jaKkE0RsI

      +m

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    8. You know what? You are all right - I don't get it. I may make too many assumptions but you all are too. When did I say you were all outlaws?? I just asked a question - and I am sorry if it seemed outrageous - and got some very defensive retorts. Geeze... Sorry if I don't get it but this is the interwebs - some things don't translate. I am not accusing anyone! I am grateful for the circuits I can build - thank you! But a circuit like this is very much dependent on the transistor, and without knowing what to use it is useless to me!

      Anyway, deep breaths all around. :-)

      Delete
    9. Well. Someone above said that the part i used for mine didn't work for him, so that information might not even be helpful. Part type doesn't quite matter in case of most germaniums. It all comes down to leak and hFE among other things like temperature etc. So assuming a certain germanium type will always work isn't a viable assumption. So yes, it most definitely is dependent on the transistor, but know the part number i used isn't going to help you.

      I didn't even feel agitated or offended yet..

      In your comments there were still two things that will always get the middle finger around here. This has happily been the case with every single complaint for about 6 years now. First is obviously the complaint. Second is the thing i'm sort of still waiting an answer for; "That seems to go against everything you say this site is about."
      We have said what? And where?

      I'm still happy that almost everyone here feels welcome. If you do not, i'd suggest you read your original comment again. And then read your next comment about "hitting a nerve" again. Then you can probably evaluate how over the top the response has been.
      +m

      Delete
  5. Would anybody think this is build worth trying for Bass? I guess not, but it sounds just to interesting :D

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    1. Just up the caps by factor of 100 and you'll have a bass OD :) 470n and 270n for the input and 1u for output...
      +m

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    2. Bass OD is a good thing to have too, isnt it :D

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  6. Looking forward to building this. I hope it's a good learning experience. I love happy accidents! At some point we'll hear a demo of yours, Miro? If yours sound more broken and mis-biased than mine, it's back to the drawing board for me! Hahahahaha
    :D

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    1. A demo, possibly.. But with current life situation, i don't see it happening anytime too soon.
      +m

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  7. Just want to say thanks to all who contribute here, but especially mirosol. Your sharing is key to our education in the world of DIY electronics.

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  8. I am loving this one! The whole fun with this project is trying different transistors in there. I went through a lot of them and almost anything works fine. Both switch positions are useful and you can really cut through the mix with either.

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  9. Just built this and I love it!
    But I did a slight adjustment with the eq switch:
    I used a on/off/on switch with a 4.7nf in center position, 12nf for the down position (=16,7nf) and then 2.2uf in the up position (ala Red Rooster) for a "Fat'N Dirty" mode.

    I used AC187 and it is insanely loud.
    Unity level is below 9 o'clock on the dial, so I'm considering adding a voltage divider at the end, as the Gain pot greatly affects the sound of the circuit, and the fact that the sweet spot is around 2 o'clock (and that is way too loud)

    When pushed by a booster this turns into a monster Fuzz when the 2.2uf is selected on the Eq switch.
    A very versatile circuit indeed!
    Thanks mirosol for a great contribution!

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