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So I noticed that my Lil Beaver Triangle sounds weak. Then I see the Sustain / drive pot cuts the volume. I was told to check the 1k resistor that Muffs have from the #1 leg to ground. Not this one. I checked the schematics on other muffs, beavers big and Lil, all seem to have the 1k resistor but this one. What's up with that? Keeping true to the original muff? Was the 1k later added to other versions as an upgrade? Should I just add one? What's the story?

The 1k is a limiting resistor. It keeps it from cutting out completely when you turn the sustain knob full turn counter clockwise.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

By the same token, since it's in series with the 100K Sustain pot, its effect once you start dialing up the sustain (or gain or drive, depending upon your preferred term!) quickly becomes negligible.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I'm just a little confused as to why the 1K resistor is not here oh, not in the schematic, and not on this model...? Is this a mistake to not be included? Or is it true 2 unoriginal Big Muff that also drop the volume while dropping the sustained? I can easily add it if I wants to I'm sure.

Sent from my SM-G960U using Tapatalk

As to why the 1K resistor is omitted in this particular variant of the Li'l Beaver, I'll leave answering that question to Keith. However, the bottom line is that its presence or absence has very little real impact on the function of the circuit, as it amounts to 1% of the total resistance in the sustain control portion of the circuit. It's true that if you turn the Sustain pot all the way down on the Triangle Li'l Beaver, the output will be shut off due to the absence of this resistor. However, I can think of no reason to run the pedal that way, as it would really defeat the purpose of the circuit--to produce plenty of smooth fuzzy sustain.

I intentionally set the Sustain pot on my own Triangle Li'l Beaver to provide 1K resistance between the pot wiper and the ground lug, and it does pass some signal at that setting, though at substantially reduced output volume. It's not what I would consider a useful setting at all. But if you're still concerned about this resistor omission, all you would need to do is to replace the wire connecting the topmost lug of the Sustain pot with eyelet 1 on the PCB with a 1K resistor and it will then function like all the other variants.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Hello all and thank you for your time and attention. Duvoodooman has been helping me more than he knows over the past 2 years and it looks like Keith, the man himself has chimed in. If anything, this has all been very educational and it seems I may need to replace my stock of Traingle Lil Beavers with the closest Ram version for my available builds. I have done much research and still have to make mention that it's a huge bummer here. Being told that the 1k was omitted on purpose, that it "had little impact on the function of the circuit", and that when "dialing up the sustain, it quickly becomes negligible". Untrue. and very misleading. I mean, look at us now. Here we are. I started this inquiry and research because its so obviously impacting my pedal and is quite the opposite of negligible... Significant would be the word. When I posted the question on a Facebook DIY pedal group, assuming I messed up but for the life of me couldn't find the error, another member quickly replied that it was the 1k resistor off the #1leg of the sustain pot, to check the value and or is it blown. The problem? It's not there at all. I thought that perhaps this was keeping true with an original circuit design, but no. All versions of these circuits, big muff and Beavers all have a resistor there, usually 1k, some 1.5k and the 1967 triangle muff version features an 820 ohm resistor there, as does your Large Triangle beaver. So if the Large beaver has one, and the lil version is supposed to be the same? Why no resistor? And, your very own description of what are the different versions of Beavers states that they are all the very same exact circuit... Well, here's the quote...
"As far as the circuit goes, nothing. They all have the exact same number of resistors,
capacitors, and transistors, in the exact same configuration."
This, as of right now is not true and misleading when deciding what circuits to include in certain builds.
I'm still a noob and am not usually a pain in the ass like this. but this place has always been one of support, feedback and open ideas. So I'm sure you don't mind such a reply that points out the contrary to the omitted component's insignificance or negligibility.
I don't suppose I can return the 5 Lil triangle pcb's I have on hand in exchange for the Ram's version, in light of this newly discovered variation to the circuit?... Well, I had to ask. Right? Love you guys. Thanks!

Maybe I'm misunderstanding what you're saying - is the problem that you want to be able to play through the pedal with the Sustain knob turned to the absolute minimum value, and have the pedal produce sound, and it doesn't do that?

Not the point, not the issue, we're way past that at this point. It's very noticeable. No, not "absolute minimum value". I expect there to be absolutely no loss of vol like every other version of this circuit.

I don't believe that anyone said that the omission of the 1K resistor was done "on purpose", Robert. Only Keith can say why it isn't there, though I suspect it it was a simple oversight, caught and corrected on the other Li'l Beavers but not rectified on the Triangle.

I take issue--and some offense, frankly--with your statement that my comments on the impact of the omission are "untrue" and "very misleading." I do my best to be clear, accurate and transparent in all my posts here. I have run my Triangle Li'l Beaver side-by-side with the NYC version, and I assure you that with the exception of the first few percent of the pot sweep on the CCW side, the two Sustain controls behave exactly the same way. And they both affect the overall output volume of the pedal very noticeably across the breadth of their sweeps. The only difference that I can discern is that the Triangle without the 1K limiting resistor will completely shut off the output of the pedal with the Sustain pot set fully CCW. And this is exactly what you would expect with that 1K resistor missing.

If your Triangle Li'l Beaver is not behaving as I just described, please provide some further details on exactly how it is behaving and we'll try to get to the bottom of it.

As I stated previously, this resistor omission can be quite readily fixed by using a 1K resistor to connect lug 1 of the Sustain pot to its corresponding eyelet on the PCB. If you contact sales@buildyourownclone.com and reference this thread, I'm certain they would send you as many 1K resistors as you would need for this purpose at no charge. And if this fix is not acceptable to you, I am quite sure that BYOC would gladly exchange your Triangle PCBs for another variant.

I will also make sure that Keith is aware of that inaccurate description in the Li'l Beaver comparison document. My guess is that, until you brought up this resistor discrepancy, he wasn't even aware that the Triangle version was missing that 1K! I know I wasn't!

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

All good. It's out there, we know about it. I know. I learn. I know more. It is however, quite a significant loss of volume. The 1k should fix it and be fine.

Sent from my SM-G960U using Tapatalk

The 1k resistor wasn't exactly omitted on purpose. It was simply forgotten. This resistor has been added to a newest version of the PCB, but those haven't made it into circulation yet. You can add this resistor by removing the wire that connects lug1 of the sustain pot and replacing it with a 1k resistor between lug1 and eyelet 1 on the PCB.

The omission of this resistor should not have any impact on the sound of the pedal or the taper of the sustain pot. The sustain knob is not an active gain control. It is a passive voltage divider, i.e., it's simply a volume knob between the first boost stage and the 2nd and 3rd clipping stages. So the overall volume of the BMP circuit should diminish as you turn down the sustain knob because it is literally reducing the volume of the signal from the first boost stage. The 1k resistor stops this passive volume control from completely shorting out the signal to ground, so that when you turn it full turn counter-clockwise, the sound doesn't cut out completely. But it doesn't add any gain and it's so small that it doesn't have an impact on the taper.

@RobertJay: I'm sure your sustain knob is not working as expected, but it's probably being caused by something else. Does it sound the way you'd expect with the sustain knob all full turn clockwise?

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Here's a Dropbox link to the video. No change after 1k install.
https://www.dropbox.com/s/0qo8zv8m6nrej ... 6.mp4?dl=0

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Hi Keith, Yes, it actually sounds as I want a fuzz to sound when cranked fully cw. I still have the volume cut with the 1k added. I just checked all resistors and caps, values are as should be. This is new to me. For some reason the 1k added did not solve this mystery. I can easily reorder a few Ram beavers for my trasnsitor based fuzz box. I already use a NYC and a Russian for these types of transistor based builds

The 1k resistor isn't the problem here. You have something else going on. I'm not sure what though. So, it's not a problem that is inherent to the Li'l Triangle PCB. It's some other typical problem like a faulty transistor or a cold solder joint. It doesn't sound like the sustain knob is making it less fuzz. It sounds like it's just reducing the volume. Maybe there's short between lugs 2 and 3 of the sustain pot. Maybe there's a component mixed up in Q2 or Q3 that has the gain set so high that even the slightest signal can cause clipping. I really can think of what could be causing a symptom like this. If you don't find anything, please take voltage readings of the E, B, and C of Q1 - 4.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

The 1k resistor isn't the problem here. You have something else going on. I'm not sure what though. So, it's not a problem that is inherent to the Li'l Triangle PCB. It's some other typical problem like a faulty transistor or a cold solder joint. It doesn't sound like the sustain knob is making it less fuzzy. It sounds like it's just reducing the volume. Maybe there's short between lugs 2 and 3 of the sustain pot. Maybe there's a component mixed up in Q2 or Q3 that has the gain set so high that even the slightest signal can cause clipping. I really can think of what could be causing a symptom like this. If you don't find anything, please reflow your solder joints and then take voltage readings of the E, B, and C of Q1 - 4.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Wouldn't hurt to post a photo or two of the top of the PCB, as well.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks you gentlemen. Always an adventure. I used 2n5189 transistors on this build. Based on this recommendation...
2N5088 or 2N5089 Silicon transistors are the closest modern production equivalents to the FS36999/2N5133 transistors used the the early 1970s Big Muffs. 2N5089 have a slightly higher gain than 2N5088. BC549C, BC550, BC239, SE4010, and 2N5210 are some others that also work in the circuit.
I'll check all solder spots, Maybe replace the 5089's with a number of suitable equivalents. I have BC550 and 549 on hand, 5088 of course...
I'm pretty sure I went 5089 for the extra gain, slight, but extra.

Um.........
Yeah.....
I am pretty sure that all 4 transistors are in fact backwards. 5133 is a round top w a tab at the emitter, ya?
I remember not knowing what that tab was and how it translated to the NPN I had in my stock. Though I researched it and wrote it down, I put them in wrong.
So....
Correcting as we speak... type.

See! I told you fellas.....
The #1 leg on the Sustain pot needs that 1k resistor....
And the 4 transistors have to be oriented properly.
Yeah, that took care of it. The 1k definitely helps and I reinstalled it also. Thank you. and Thank you.