Why would a pedal have a delay upon hitting the footswitch and activation of effect?

[soma89]

This has happened to me in the past with various effects but now struggling with my EBS Metaldrive with this. I kick on the effect - and there is silence for a good 4-5 seconds before effect is activated. It is usually the first time I kick the footswith on upon connecting my guitar/amp...after that it works fine, i could kick it on and off and no more problems.

What should be looked at? I've replaced the footswitch and it did not fix issue. Pedal is SMD but has some through hole caps.

Schematic drawn out by BaZZZZZ from Freestompboxes

[Mark Hammer]

It can happen that a design's attempt to provide a smooth and stable supply results in requiring several seconds to reach the intended voltage and stabilize. This is one of the reasons why few, if any, pedals that use batteries disable the battery when placed in bypass mode and then reconnect it when switching to effect mode.

[The Dude]

I often find this type of symptom related to an e-cap that's starting to go bad. It doesn't work "cold", but after initial charging does. The first thing I'd do is a quick in circuit ESR test on all of the electrolytics.

[Steve L]

The schematic you attached does not look like an EBS factory schematic. Maybe it is a reversed engineered one.
It also gets blurry when enlarged, so I can't tell what is really there in the power supply input circuit.

However, I have repaired many of that series of EBS pedals and almost all of them have had the exact same problem.
EBS usually puts a voltage dropping/current limiting resistor in series with the DC power input.
That resistor either opens or goes high in value, and more times than not, burns itself and the surrounding PCB area. I suspect people sometimes use a higher voltage power supply than 9VDC.

It could be another issue with yours since the board looks clean. However, if the resistor value has gone very high, it could easily cause the symptoms you are describing.
As it is quite common, I would look at that first. Super easy too. If that is not the issue, then I second the thought of looking at the electrolytic caps.

Steve

[g1]

The schematic you attached does not look like an EBS factory schematic. Maybe it is a reversed engineered one.
It also gets blurry when enlarged, so I can't tell what is really there in the power supply input circuit.

You can see it better here: https://www.freestompboxes.org/viewt...83b50677a9c4a2

It's reverse engineered and the author said it is un-checked. I don't see a valid dry signal path so I don't think the drawing has much to offer as far as the switching circuit goes.

[soma89]

thanks for all the help thus far. As an update, I've replaced all the electrolytics and...STILL HAS THE DELAY. The rest is smd so it might be a goner. Too bad, pedal sounds great but its just not up to par, sadly.

[x-pro]

Replace C25 with (47-100)uf and check the switching time.

[J M Fahey]

Sadly the reverse engineered schematic dos not make sense.
The FET + Op Amp input looks functional, the rest not so much, signal path is unclear.

As of:

It is usually the first time I kick the footswith on upon connecting my guitar/amp...after that it works fine, i could kick it on and off and no more problems.

I do not call that a problem.

many circuits take some seconds until all voltages inside stabilize.

[Mick Bailey]

I don't see where the reference voltage V/2 comes from. DC is connected to C13 and there's other stuff that doesn't make sense.

4-5 seconds seconds is a long time. As all the electrolytics have been replaced I'd want to monitor the voltage rise on the PSU caps. If that's slow, then perhaps there's a high series resistance slowing down the charge time, which comes back to Steve L's comment.

Do you happen to know if this is a new problem with the pedal, and what's normal for this model?

[x-pro]

There's a lot of stuff there that doesn't make sense.

[x-pro]

... where the reference voltage V/2 comes from.

Take a look at this.
U1C has a different pin numbering. This is output 16 and inputs 14 and 15.

[Mick Bailey]

That's intersting - that's a new one for me - never seen that before. Reminds me of those transistors with integral emitter resistors.