No audio for Deluxe Bass Big Muff π

[pudge]

The LEDs and switches appear to work, but I get no output, not even noise.

If I use the “direct out” as input, then I get output. But nothing through the input, at all.

EHX says they will repair it for $35 (probably not including shipping), so not sure if it is worth it.

Any ideas for how I might try to repair it myself?

UPDATE: more pics of the full PCB, for posterity

 

[Feral Feline]

Yeah, I stuck the reddit info in my post too, it's a 10Ω resistor that should've been spec'd for 1/2w as the 1/4w can't handle the truth...

And the truth is, people are spending money at EHX to get their units fixed, which is probably why it was spec'd with a 1/4w in the first place.

Kinda like how I see 2-3-year-old trucks (whatever the brand) running around with rust already starting on the rear quarters ... buy a new Muff people, ehr, truck, every few years.


Anyway, 10Ω is brown black black gold brown, The 10Ω 1/2w will be physically bigger, which may require some leg bending to get it to fit.

 

[pudge]

Yeah, I stuck the reddit info in my post too, it's a 10Ω resistor that should've been spec'd for 1/2w as the 1/4w can't handle the truth...

And the truth is, people are spending money at EHX to get their units fixed, which is probably why it was spec'd with a 1/4w in the first place.

Kinda like how I see 2-3-year-old trucks (whatever the brand) running around with rust already starting on the rear quarters ... buy a new Muff people, ehr, truck, every few years.


Anyway, 10Ω is brown black black gold brown, The 10Ω 1/2w will be physically bigger, which may require some leg bending to get it to fit.

Thanks!

I ordered the caps and resistors and they’ll be here Monday! Also got the first cap and the resistor removed. So I’ll drop the new ones in and test immediately … then swap out the other cap if it’s a success.

 

[Nic]

Thanks!

I ordered the caps and resistors and they’ll be here Monday! Also got the first cap and the resistor removed. So I’ll drop the new ones in and test immediately … then swap out the other cap if it’s a success.

I would also replace the one @Feral Feline noted. It looks like the top is about to pop, since it's out of the enclosure... You can test it for fun after, but it's suspicious also.

 

[pudge]

I would also replace the one @Feral Feline noted. It looks like the top is about to pop, since it's out of the enclosure... You can test it for fun after, but it's suspicious also.

Yeah, I want to test everything before replacing C28, but I plan to. The bulge is very very slight, but it looks like there is one.

 

[YourGuitarist]

Does anyone have a trace of this pedal? I had one burn out on a voltage spike from power. I tried to replace the thru hole series resistor in the supply stage but it just burnt out again. My suspicion is that a cap is shorted now or the protection diode is busted but I can't tell very easily without schematic.

 

[pudge]

Does anyone have a trace of this pedal? I had one burn out on a voltage spike from power. I tried to replace the thru hole series resistor in the supply stage but it just burnt out again. My suspicion is that a cap is shorted now or the protection diode is busted but I can't tell very easily without schematic.

I do not. I offered to send it to @Robert and he might take me up on it, but he is busy right now.

 

[PJS]

I have just replaced both the footswitches on one of these too. I have heard a lot of moaning about EHX footswitch quality - not just on these units.

I haven't traced mine, but I reckon you could work out something similar - possibly even better/more to your taste. Not sure about where the noise gate fits in the equation, but the fuzz side is fed from the crossover footswitch. The clean side of the blend knob is also fed from the crossover footswitch. The switch will either feed the clean input to both the fuzz and the clean side of the blend, or it feeds the HPF from the crossover to the fuzz input, and the LPF to the clean side of the blend. That allows you to distort only the upper frequencies and then blend in clean lower frequencies. Pick your favorite bass fuzz, get filter designs with variable frequencies and wire up a crossover footswitch like I described and you are cooking.

 

[pudge]

I have just replaced both the footswitches on one of these too. I have heard a lot of moaning about EHX footswitch quality - not just on these units.

I haven't traced mine, but I reckon you could work out something similar - possibly even better/more to your taste. Not sure about where the noise gate fits in the equation, but the fuzz side is fed from the crossover footswitch. The clean side of the blend knob is also fed from the crossover footswitch. The switch will either feed the clean input to both the fuzz and the clean side of the blend, or it feeds the HPF from the crossover to the fuzz input, and the LPF to the clean side of the blend. That allows you to distort only the upper frequencies and then blend in clean lower frequencies. Pick your favorite bass fuzz, get filter designs with variable frequencies and wire up a crossover footswitch like I described and you are cooking.

Interesting idea. I have had no problems with the switches, or how they function. But I love the idea of tailoring it to your tastes!

 

[pudge]

Ugh. I put in the new resistor and capacitor and immediately the new resistor started burning, too. It was the “upgraded” values. 1/2 W, 10 ohms. The PCB is a bit fried.

 

[pudge]

Not sure what to do at this point.

 

[Feral Feline]

Tell EHX to send you a new PCB, as in a re-design. There's obviously a fault in the design since so many people are coming up against the same problem.

Tongue firmly in cheek here. EHX isn't going to do a damn thing about it.

 

[PJS]

I would be suspicious of a short. First thing I would do is check the resistance between the power supply rails (Gnd, Vrf and 9V. If one is shorted or close to then either visually inspect for a short or start removing components that run between the 2 shorted rails until the short goes. I have seen people use thermal cameras to hunt down shorts as well. You would need to be quick though because you already know that resistor is going to burn more and more the longer the power is on.