BYOC British Blues OD Build: Volume Issue

[Commodore 64]

I've embarked on my first build, with a little guidance from DVM. I hooked it up last night, and while it works, there's an issue with the volume. Even with everything dimed, the output volume is way lower than the pedal in bypass.

DVM thinks that I may have switched a resistor somewhere and asked for pics. I decided to make a thread in order to document our process, in case others may find it useful.

As you can all see, my artistic talents rival DVM. OK, so his pedals look a little better...but not much. :master

And here are the innards....

 

[duhvoodooman]

For comparison, here's a BBOD that's on my workbench right now:

 

[duhvoodooman]

Your resistors look OK. The only one I can't see is the one in the shadow of that yellow cap pair. Should be a 1K (brown-black-black-brown-brown), and probably is! The diodes, opamp and electrolytics look fine, too.

I assume the yellow cap at the top of your photo is another 47n? Can you tell me what the labeling on the three blue film caps is? Verbatim, please--exactly as it's written on the cap body.

BTW, have you tried running it off a 9V AC adapter, to eliminate the possibility of a bad battery?

 

[Commodore 64]

The 2 on the drive side of the pedal are 10nk100 1u6

The 1 on the volume side is u1k63 1x7

I have run it off the 9v battery as well as a 9V power supply.

Should be a 1K (brown-black-black-brown-brown), and probably is!.

I assume the yellow cap at the top of your photo is another 47n?

Yes to both.

 

[duhvoodooman]

The 2 on the drive side of the pedal are 10nk100 1u6

The 1 on the volume side is u1k63 1x7

Good. So that doesn't appear to be a problem.

(For those reading this thread, film cap labeling is notoriously random, with several different conventions used! Here, the ones labeled "10nk100 1u6" are 10 nanofarad, 100V rated. The one labeled "u1k63 1x7" is a 0.1 microfarad, 63V cap. 0.1 microfarad = 0.1 uf = 100n.)

How's chances for a good close-up photo of the bottom (solder) side of the PCB next?

 

[Commodore 64]

Good. So that doesn't appear to be a problem.

(For those reading this thread, film cap labeling is notoriously random, with several different conventions used! Here, the ones labeled "10nk100 1u6" are 10 nanofarad, 100V rated. The one labeled "u1k63 1x7" is a 0.1 microfarad, 63V cap. 0.1 microfarad = 0.1 uf = 100n.)

How's chances for a good close-up photo of the bottom (solder) side of the PCB next?

I think I figured it out. My pots are backwards. The B100k is in the volume and the A100k is in the drive. Time to bust out the desoldering pump. :thwap

Would that cause the issue?

For the sake of completeness..this is the best pic I can manage of the backside. I can't seem to zoom in closer and get a clear pic,

 

[duhvoodooman]

No, switching the drive & volume pots does NOT explain low maximum output. The different tapers only affect how quickly the pot goes from 0 - 100% of it's range, but the "100%" is the same either way. So if you have a major volume loss vs. bypass when the drive & volume are both dimed, switching pots wouldn't account for that. Now if you had the 25K tone pot where the 100K volume should be, that would explain things.

Your soldering looks quite good. Couple of ideas:

Probably an "optical illusion", but that's not a solder bridge between the solder joints for the second pair of pins from the left side on the 2x4 header socket, is it?

I can't tell from the straight-on shot, but if you have any component leads sticking up from the board, trim them down as close to the top of the solder joint as possible.

I'd suggest covering the back of the tone pot with electrical tape. Sometimes you can get contact between solder joints on the back of the board and the pot body, bleeding signal to ground.

 

[Commodore 64]

OK for whatever reason, switching the pots fixed the issue. Perhaps it was the soldering/unsoldering/remounting that took care of some issue. I'm gonna mess arund and play it for a little bit, then come back and give my impressions!

Thanks for the help DVM!

 

[duhvoodooman]

OK for whatever reason, switching the pots fixed the issue. Perhaps it was the soldering/unsoldering/remounting that took care of some issue.

Yeah, very possible there was a cold solder joint or something on a pot leg and switching them & resoldering fixed it. In any case, glad to hear it's working now. :AOK :rockon:

 

[Commodore 64]

OK so after playing for a bit I have some observations. I happen to have a Boss Blues Driver BD-2 so I hooked them up side by side and played around a bit. Now if anyone has looked closely at DVMs build and mine, you may have noticed some different caps on mine.

I made some modifications to the build:

1. I used a higher resistor in one spot to add more gain (Thanks for the resistor, DVM)
2. I used a 47n capacitor in lieu of a 10n to get rid of the midrange hump and to darken the pedal a little.
3. I used a 47n capcitor in lieu of a 10n in the low pass filter, to cut out even more highs.

As a result, the pedal is dark, and warm (to my ears). It definitely does not do ice-pick trebles...like the BD2. I don't think you'll get leads that really CUT through the mess with this, but it does have warm tone now. I really, REALLY need to figure out how to record clips so I can post them...because I really, really would like to get folks' opinions on the sound of this pedal.

 

[duhvoodooman]

If you decide it's a little too dark, I'd remove the 47n cap at C7 (the one outlined in fuchsia on page 23 of the instructions) and go back to the stock 10n there. The larger cap there doesn't add bottom end--it just removes treble. So if you find that there's a bit to much high end missing, that's the logical one to change.

 

[mainestratman]

Yup.. I'm ressurecting another ancient post.

DVM.. do you have any audio samples of your Brit Blues pedal? I love the description of something transparent that just adds some dirt, which is exactly what I'm looking for...

Thanks!

 

[duhvoodooman]

Here's a good one for you by Gearmanndude on Youtube. Well recorded and the guy's a professional player. This clip has three BYOC dirt boxes demoed--the Large Beaver (EH Big Muff clone), Shredder (Marshall Shredmaster), and the British Bluues (Marshall Bluesbreaker). The Brit Blues part starts at about 6:30:

​

I modify my British Blues builds to have a bit more available gain (so you don't have to dial up above 12 o'clock on the gain control before you get any decent grit) and a little more bottom end, because the stock pedal sounds a little thin. But that nice transparency remains.

 

[ZMAN]

Yup.. I'm ressurecting another ancient post.

DVM.. do you have any audio samples of your Brit Blues pedal? I love the description of something transparent that just adds some dirt, which is exactly what I'm looking for...

Thanks!

Mainestream: I don't know if you want to build a pedal, but if you are looking for something you can buy, I would take a look at the Radial Tonebone, Hot British. It has a 12AX7 tube in it and you can get some really nice dirt, or just a nice clean OD. I picked mine up used for 125. I use mine all the time for exactly what you are describing. Leave my Marshall on green (clean) and push it with the tonebone. Very tweakable as well. I think there are some youtube vids on it.

 

[Commodore 64]

I ordered an assortment of resistors and film caps from partsexpress yesterday. I will probably swap out the 47n at C7 sometime soon. My pedal is really, really dark with that 47 in there.

I dunno WTF I'm doing but I ordered these, I hope I can use some of them:

1 002-510K 510K Ohm 1/2W Flameproof Resistor 10 Pcs. $0.55 $0.55
1 003-510K 510K Ohm 1W Flameproof Resistor 10 Pcs. $0.69 $0.69
5 020-1800 0.0010uF 100V Polyester Film Capacitor $0.08 $0.40
5 020-1814 0.005uF 100V Polyester Film Capacitor $0.08 $0.40
5 020-1832 0.068uF 100V Polyester Film Capacitor $0.15 $0.75
5 020-1846 0.50uF 100V Polyester Film Capacitor $0.35 $1.75
5 020-1862 0.047uF 200V Polyester Film Capacitor $0.21 $1.05
5 020-1878 0.0047uF 400V Polyester Film Capacitor $0.10 $0.50
5 020-1880 0.010uF 400V Polyester Film Capacitor $0.12 $0.60

I need to get soem more resistors, obviously, but I didn't know the difference between 1w and 1/2w for the purposes of pedal building.

 

[mainestratman]

DVM.. thanks for the video.. I decided I really don't need that pedal (as in the video) because I get all those tones (but better) already.

ZMAN... I'm not horribly interested in building my own... my time is at a premium as it is... I'll check around for Hot Brit pedal vids on youtube.

I think I'm really just having pedal envy.. LOL

 

[Commodore 64]

So, I think that I ordered the wrong capacitors...they are 100v through 400v. Some of the caps I used on my pedal are rated 100v others at 63v...what does that effect from a pedal standpoint?

 

[duhvoodooman]

So, I think that I ordered the wrong capacitors...they are 100v through 400v. Some of the caps I used on my pedal are rated 100v others at 63v...what does that effect from a pedal standpoint?

Higher voltage ratings are fine, as far as function goes. The problem is that the caps will be larger (possibly much larger at 400V!) and might not fit. You'll just have to see when they arrive....

 

[Commodore 64]

Higher voltage ratings are fine, as far as function goes. The problem is that the caps will be larger (possibly much larger at 400V!) and might not fit. You'll just have to see when they arrive....

Yeah the 400v are HUGE.

 

[ZMAN]

DVM.. thanks for the video.. I decided I really don't need that pedal (as in the video) because I get all those tones (but better) already.

ZMAN... I'm not horribly interested in building my own... my time is at a premium as it is... I'll check around for Hot Brit pedal vids on youtube.

I think I'm really just having pedal envy.. LOL

I tried a lot of pedals and this one is very versatile. There are some good vids on Youtube. It sounds really good through both Marshall and Fender amps on clean. Crazy on high gain amps.
I did a pedal tone quest for many years and I have settled on The Hot British and a bunch of Fulltone pedals, and a Boss DD20 giga delay.
These are a great cure for pedal gas.