Blues Breaker v1 -- a noisy pedal?

[Cruton]

Hi everyone,

I recently built a clone of the v1 marshall bluesbreaker using the schematic here: http://www.generalguitargadgets.com/pdf/ggg_mbb_sc.pdf

I did add a 10k resistor in series with the drive pot in the first opamp gain stage like in the King of Tone, to give a little more gain. Otherwise, I believe it's identical to the schematic.

The pedal works just fine, other than it's pretty "noisy" at higher gain settings. I made a sloppy little demo of it here: https://www.youtube.com/watch?v=-pYhaKFM9Dg where you can hear what I'm talking about. In the demo, it's powered using a OneSpot, so it's probably the worst case noise scenario, but I've also run it off of my isolated pedalboard power supply and it's more or less the same sound.

For those of you who might have experience with this pedal, is this a normal amount of noise for this circuit? I know some higher gain pedals are just inherently noisy, but as this is a low-to-medium drive pedal I wasn't expecting this level of noise. If not (or maybe regardless), is there anything about my layout or wiring that would make this more noise prone? I thought I had been following decent practices, but now I'm not so sure...

Here is the layout I created:



Note that the output cap and pulldown resistor are mounted on the 3pdt, and so are not shown on the layout.

Here is a picture of the wiring:



I tried laying a cap across the 9v jack to see if that would filter some of it out, and it made no difference. I'm not sure what I've done, but I suspect this is a good learning opportunity.

[stallik]

I had the original blues breaker for many years and never found it noisy even when used in conjunction with other drive pedals. I can't speak about this particular layout.
Also, my 1spot is also extremely quiet.

[Cruton]

Thanks for sharing your experience, stallik. Sounds like I've done something to make it noisy then... just not sure what. I guess I need to play around with some more options in terms of filtering, etc.... hopefully I can figure it out without having to change anything that affects the tone. It's a great sounding pedal, aside from the hiss.

[ElectricDruid]

Try running it off a 9V battery for a test, just to see if the noise is from the circuit or is coming in on the power supply. If it's quiet run like that, then your build is fine. If not, then it's worth looking at the layout and build. Could be as simple as a wrong part somewhere.

[Cruton]

Thanks for the tip, I didn't build it with a battery clip so I'll need to unsolder the jack and swap it for a clip real quick to check that.

On that note, I did just plug it up again to try the ole' wiggle check (probing wires to see if location/overlap is affecting the noise) and it was dead quiet. Realized then that I had it plugged into my J Bass with both pickups on... rolled the volume off either pickup and the noise was back. So it seems like it's just amplifying the heck outta the single coil noise. I don't know if that narrows it down any.

[stallik]

Let me add something to my previous comments. Single coil pickups can be noisy. You know that. Any overdrive or distortion pedal will amplify that. When I stated that my original pedal was not noisy, I was ignoring single coil hum which I consider to be normal. The fact that your pedal is quiet with humbuckers tells me that there's nothing wrong with your build.
What happens when you move the guitar around? One thing I always try to do with any pedal is to use shielded input wire. Not sure it ever helps but it does give me peace of mind

[Cruton]

Thanks for adding to that earlier comment! Yeah, you're right that I know the single coils can be noisy. I assume it's going to change when moving around, but I can do that check ASAP just to confirm that in the "magic position" the whole thing is quiet. I guess it just seems weird to me that it seems to amplify that noise to a greater extent than my *other* ODs I've built. I can AB it with my AC booster build, a recent Zen Drive build, and other non-op amp drives (e.g., electra distortion) and the BB is noticeably noisier. The only OD I've built that's close in terms of the noise is my Box of Rock clone, which has truckloads more gain on tap (at least to my ears). Maybe the difference I'm hearing is in the tone controls-- the BB definitely sounds tinnier overall compared to those other builds. Maybe my other builds would sound just as noisy if they were running into the same tone control?

Maybe I'll go for the shielded input wire. I have a bunch laying around that I salvaged from an old receiver, I just hadn't anticipated needing it for this little crunch box!

[tubegeek]

Thanks for the tip, I didn't build it with a battery clip so I'll need to unsolder the jack and swap it for a clip real quick to check that.

Another tip: wire a battery snap to a male DC power supply plug so you can fool your pedal into thinking you're using a wall wart while actually using a battery.

[Cruton]

Wow, I had to laugh at myself when I realized just how common sense that suggestion was, and how completely incapable I was of coming up with that myself. Thank you very much, tubegeek, for saving me some hassle.

[willienillie]

I didn't hear any noise in the YT clip, but maybe my 'puter speakers aren't turned up loud enough.

If the noise you're hearing goes away when you turn your guitar's volume down, it's not coming from the pedal.

[tubegeek]

Wow, I had to laugh at myself when I realized just how common sense that suggestion was, and how completely incapable I was of coming up with that myself. Thank you very much, tubegeek, for saving me some hassle.

Don't sell yourself short - you'd have gotten there eventually. Glad you got a laugh out of it!

[Cruton]

So having gone back and played the pedal some more, I'm convinced it's just single coil noise. I plugged in the strat again and confirmed that at high gain it's noisy when on the neck and bridge pickups, but found it to be dead quiet on the bridge humbucker. Switching to the out-of-phase neck and middle pickup combination kills most of the noise, too. With the guitar volume rolled all the way down, switching the pedal on and off makes no audible difference in noise.

I guess I'm left with the conclusion that, for whatever reason, this circuit just really amplifies single coil noise more than the other ODs I've built. I wonder how much of that could be due to my specific pickups/setup, but then again it was also quite audible through my J bass single coils.

Thanks for all the troubleshooting help everyone. Your common sense suggestions saved me from tearing this thing apart trying to solve a problem that doesn't exist.