Marshall Tonestack w/LPB1 (Trim or Pot)

[Chris60601]

Here's another tonestack with the addition of Mirosol's LPB1. Again, I have not built this so its not verified.
Would appreciate help in ensuring this is correct. While I won't be using this one in a project anytime soon,
I figured I would continue adding these from the DTSC.  
Again, thanks to Mirosol for creating the original BMP w/LPB1  And, Volume pot to replace trim.

 

[motterpaul]

This is cool Chris, I congratulate you for doing this. I would try to verify it if I had a soldering iron, but Amazon did not deliver today.

I have been really interested in this exact project, because like you I liked the BMP with LPB1 circuit a lot. This is a great way to learn how to do the tone stacks.

I saw Rocket was talking about having a boost in front of this as well. I tried the LPB1 (BMP) after a lot of boosts and it does work really well, so if you add some kind of a gain circuit in front of this you could have your own gain circuit, with a Marshall tone stack, and a recovery phase. That's the whole deal right there.

Keep up the good work, and when this gets verified I suggest they put it in the editorial area, because that section is getting pretty quiet. It's too bad, too, because there are a lot of new pedals out there that it would be just great to be able to try out. If I was experienced enough to do the layouts I would, but I get frustrated just dealing with the DIY layout software.

Maybe you could give us a tutorial on how you got this to look so good. Which version did you use?

[rocket88]

I was not talking about having a boost in front of a tonestack at all. I said you'd have a circuit you want in front of the tonestack, then have the LPB booster after the tonestack like a gain recovery stage, as seen in the BMP.

Example: fuzzface -> tonestack -> LPB set as gain recovery

[motterpaul]

Right - sorry, that was what I meant - some kind of a circuit (not just a boost) but something that can create some sound (presumably, with some gain included) to feed the tone stack, right?

[rocket88]

Correct. take a look at the BMP schematic analysis to see how this works.

[motterpaul]

I do understand how it works. I said "so if you add some kind of a gain circuit in front of this you could have your own gain circuit, with a Marshall tone stack, and a recovery phase"

I said "boost" but I think it is just that my personal lexicon is not always accurate for pedal builders because I have been using the same words when talking about other topics like pro audio for so long.

So, sometimes,  when I say "gain" or "boost" all I am thinking in my mind is the process of adding dBm to a circuit. I forget I am speaking to people who are expecting pure pedal building terminology.

Not trying to make excuses - just clarifying why the things I say don't always make sense in the context of this particular forum. I started in pro audio 40 years ago, but just started building pedals last year. It's hard to break old habits.

[rocket88]

Never said you don't understand, just pointing you to an example the depicts what I'm saying. Don't have such a complex that you're being spoken down too. You asked a question I answered and pointed you in a direction to help you. I could have easily ignored your question, but I wanted to help you and be supportive. All you have to say is "thanks" or "thank you for the help, I appreciate it." I help whoever I can, but I won't go out of my way if it's not wanted or appreciated. If you don't want help from me don't ask, and I will make sure I won't answer your questions then.

Btw, it really doesn't matter what your background is when doing this stuff, but it's important to get the terminology down. This allows all of us to communicate effectively and understand what each other is saying. So you may mean one thing, but in the language of electronics it means something completely different. Then people get angry, and annoyed because no on understands what they mean.

For instance, I am involved in science, and as a scientist there's specific terms and phrases I need to know to communicate effectively and clearly, otherwise shit gets fucked up. Example, the Mars rover that basically buried itself because the hight was measured in feet, but programmed in meters. So when it was measured as like 150ft, the rover went down 150m. So that was a few billion dollars lost, but here it's just so we can understand each other. Just something to keep in mind.

[motterpaul]

There used to be a radio show here in the U.S. called "Mr. Science" - It started out "Meet Mister Science, he has a master's degree, in Science!"

EDIT: I guess it was "Ask Dr. Science" - here it is: http://drscience.com/wordpress/

<nabble_embed>http://www.drscience.com/recordings/Infinite%20Profits.mp3</nabble_embed>

[zosotone]

Nice project Chris!

[Kinski]

This layout verified yet?

I just built it with a one-knob-fuzz running into it. Im just getting a lot of white noise. No signal. however all pots seem to work as i can hear them EQing the white noise.

Ive looked over the fuzz and tone stack over and over. Pretty sure its all correct.

[motterpaul]

As far as I know you are the first to build it and report back here.

[Frank_NH]

Check the output from the 100K trimmer pot.  For some reason, the layout has the output from the LPB1 going to the wiper.  It will work only if the pot is 100% CCW.  I would just remove the trimmer and send the signal from the 100 nF cap to lug 3 of an external pot (lug 2 = output, lug 1 = ground).

[motterpaul]

Good catch Frank. I agree about going to an external pot, too. Too many little changes required on the board to make the trimmer work.

ALSO: (I always end up editing my posts) - that trimmer is only there to "normalize" the output as sort of a "set & forget" thing. You might be able to just find a single resistor that gives you a good working volume.

[Chris60601]

Thanks Frank, muchly appreciated.

I hope this version works as I had some time to work on this.
Please let me know as I have not verified this.

Cheers
Chris

[Kinski]

Thanks guys. I'll report back tomorrow with some news hopefully.

[motterpaul]

Sorry to repeat myself, but to test this all you should really need to do is turn the trimpot fully CCW, or bypass the trimpot (I think you can just go straight out row #2 from the top). It is not a vital piece for the circuit, it is just there for convenience so you can reduce the output if it is too loud.

[Kinski]

okay, tonestack works great.

its the fuzz thats not working. its such a simple fuzz and ive built so many of these and they always sound great. Must be a faulty part somewhere. Ill track it down. thanks guys!

[motterpaul]

Sorry Chris, i did not see that you changed your layout before I posted yesterday.

Kinski - it's all good, just keep trying and let us know what happens. I appreciate the updates.

[Frank_NH]

Kinski - which fuzz are you building?  I'm wondering if the fuzz circuit's output impedance it too high for the tone stack.

If you wanted to design a distortion stage in front of this, an op amp would probably be desirable as you could get a low output impedance, at least enough so to drive the tone stack.  Would be worth bread boarding to find out...

(Edit:  Try putting an op amp buffer between the fuzz the tone stack.  I have built one from the layouts here: http://tagboardeffects.blogspot.com/2014/08/buffers.html)

[Kinski]

Hey, I've had no time to work on this, but I'm certain its the fuzz that is faulty. I separated the tone stack and the fuzz. Tone stack, works. Fuzz does not. I even ran many other fuzzes into the tone stack and they all works beautifully. I'll get around to rebuilding the fuzz section then I'll box it up. Thanks!