Topics

1

Open Discussion / Full-frequency boost circuit for bass guitar

« on: November 06, 2020, 03:04:50 PM »

I'm building a bass preamp pedal and looking for a full-frequency boost circuit to put in series before the effect input. A simple, one-knob deal would be best. Is there a better option than an LPB-1?

2

Open Discussion / 9mm Knurled Plastic Shaft C10k Pots (Tayda)

« on: October 29, 2020, 02:49:10 PM »

9mm Knurled Plastic Shaft C10k Pots are (finally) back in stock at Tayda. A bunch of VFE projects use these, so I thought I'd give a heads up.

3

General Questions / MOSFET reverse polarity protection

« on: October 09, 2020, 07:54:08 AM »

I'm working on a Laika V2 from DeadEnd FX. This circuit uses a MOSFET for reverse polarity protection. I wanted to get a quick sanity check because it seems like the MOSFET is oriented backward. Shouldn't the V+ input go to the drain of a p-channel MOSFET with source going to the circuit? Also, could this be improved with a gate-to-source protection (9.1V) zener?

4

General Questions / The Imp: C8 tantalum rating

« on: September 13, 2020, 02:59:56 PM »

Does this cap need to be 25v (per the build doc)? It’s off of the Vb rail (4.5v) and doesn’t seem to be exposed to a larger potential.

5

Open Discussion / Mouser Xicon Resistors — New MOQ of 200

« on: September 13, 2020, 02:51:26 PM »

I noticed today that most Xicon resistors—including the metal film 1/4W (271) and 1/8W (270) and the carbon 1/4W (291) and 1/8W (299)—have a new MOQ of 200 units at Mouser.

6

General Questions / Tonebender Mk I Transistor Specifications

« on: August 20, 2020, 08:11:54 AM »

The Tonebender Mk II and III transistor specifications (i.e., hFE and leakage) are pretty well-documented, but I can't find ranges for the Mk I. Is there a list of nominal values for this circuit anywhere? Or, what values have people found to work with this circuit?

7

General Questions / Total Recall Drill Template

« on: August 17, 2020, 10:35:44 PM »

The total recall drill template is for a ‘125BB’ — height of a 125B but the length/width of a 1590BB. The drill template is for an enclosure that is much higher (1590C?). Which is correct here? It seems like the 1.40” height should be alright, but the height difference has me wondering.

8

Build Reports / Man O' War DX

« on: April 09, 2020, 03:14:21 PM »

Here's a stock build of the Man O' War DX (based on the Maxon AD-900). I've got an MN3005 version of the AD-900, and the modifications added here really add a lot to an already great pedal.

This was my first BBD delay project. I've built a few BBD modulation effects, but the delay proved to be quite a departure. The layout is nicely designed and population was smooth. I ran into problems when I got to biasing, though. Thanks to all who helped me via the Tech Help page. Those problems turned out to be me not seeing things through properly. After populating a new board and many redundant components later, I dug into the schematic and the actual engineering of the circuit. I think that with BBD-based effects (especially in the absence of an oscilloscope) understanding the interaction of the biasing controls is really key. I plan on revisiting this when I have access to a scope, but I'm very happy where it's at now.

Again, thanks to everyone that gave insight and helped me better understand this circuit, I really appreciate it.

The enclosure is finished with acrylic faceplates. They are white with a black substrate and laser etched.

9

General Questions / Collosalus 15V regulator

« on: March 27, 2020, 11:17:03 PM »

Is the on semi MC7815BTG a suitable replacement for the LM7815? The LM7815 is out of stock at mouser. That seems to me fine, but I wanted to double check.

10

Open Discussion / Temporary Sockets

« on: March 06, 2020, 01:00:53 PM »

I think I remember discussion about temporary PCB sockets that had a spring pin and didn't require soldering. Are these a real thing? If so, can anyone point me in the right direction to them? They'd be really convenient during testing and circuit prototyping.

11

General Questions / Naughty Fish – Vactrols and 125B Drilling

« on: February 13, 2020, 09:09:12 AM »

I have two questions about the Naughty Fish project:

Vactrol: There were problems in the past with the Macron VTL5C3, and the Xvive reissues are currently recommended. I got a pair of coolaudio VTL5C3 vactrols. Have others had good luck with those, or do they suffer from issues like the (newer) Macron devices?

125B top jacks: I prefer 125B enclosures with top jacks over 1590B enclosures with side jacks. Would anyone who has oriented I/O jacks this way be able to share their template? I'm mostly concerned about clearance over the vactrols. To be on the safe side, it seems that there is more than enough room to shift the board down completely to ensure there's no interference. But I'm interested in what others have found to work.

12

Tech Help - Projects Page / Man O' War DX - Calibration

« on: December 31, 2019, 10:56:18 AM »

(1) Project: Man O' War DX powered by OneSpot 12V supply (actual reading: 11.73V)

(2) Issue: Unable to successfully calibrate. I'm stuck on biasing the first MN3005. I get a signal at pin 7 of IC3, however the signal at pins 3 and 4 of IC3 have a high-pitched whine mixed in and rather than getting a delay, the signal repeats and ramps up to a high-pitched oscillation.

I'm getting a very high-pitched, amplified signal mixed with the dry signal at pin 7 of IC2a.

Voltage at pin 1 of IC2 is around 1.2V (build doc has 0.88V) all other voltages before the first BBD are in spec.

(3) Steps to resolve issue: I probed the signal path from the input and confirmed part values. The dry signal gets to IC2 without anything remarkable. Reflowed joints. Removed Q2 and Q3 (NPN Si) and put in sockets. Originally had 2n5088 devices in each spot, same issue and voltages when replaced with 2n3904 devices.

(4) Substitutions: Feedback pot is 25kB instead of 20kB. MN3005 sourced from CabinTech; V571 from SBE.

Pictures attached. IC5 has been removed for calibration purposes.

13

Open Discussion / Source for 1590B2 enclosures

« on: December 29, 2019, 08:50:20 PM »

Anyone know of a source for Hammond 1590B2 enclosures or workalikes (NS, etc.)?

14

General Questions / Clari(not) Modifications

« on: December 03, 2019, 08:34:29 PM »

Hiya all. I'm not sure if there's still interest in this circuit, but I'd appreciate some advice here. I've been working on modifying the Clari(not) circuit. I've added an envelope/LFO modulation switch and a feedback path. I'm currently stuck on a gain switch.

Instead of the usual mod of cutting the connection between pins 1 and 8 of the LM386 (since there can be a loss in the wild modulation with this method), I'm trying to split the input into two buffered paths: one path (always on) goes to the LM386 while the other bypasses the LM386 and connects to the junction of the 10k and 22k resistors leading to pt2399 pins 15 and 16. In clean mode, the input goes to the LM386 to drive the LED for the LDR, but the audio signal goes to the 10k/22k resistor junction. In fuzz mode, the circuit input is buffered, but otherwise the same as stock.

All of the modifications work as expected—except for the input in fuzz mode. I'm getting an extremely gated, sputtery fuzz that completely cuts out with high amplitude input (i.e., hard strums with humbuckers). I've used an audio probe and can confirm that the sputtering is present at pin 5 of the LM386. I'm attaching the schematic for the input of the circuit and the power section. Any insight here would be greatly appreciated. Also, I can post the entire schematic if there's interest.

Cheers

15

Open Discussion / Power Supply Units (PSU) and Pedalboards

« on: November 22, 2019, 10:10:19 AM »

I've used wall warts and daisy chains forever. I'm thinking about upgrading to a PSU, though, and put together a proper pedal board instead of chaining everything together whenever I set up. My chain is almost exclusively analog 9v center negative effects (i.e., no high-current digital pedals). There are a few with 12v and 18v inputs (and a DMM at 24v). I'm wondering what's worked and what hasn't.

I'm also interested to hear thoughts on pedalboards (brands, styles, velcro or not, etc.).