Line 6 Echo Park - Modification possible?

[mr_sooty]

Hey chaps.

I just got a Line 6 Echo Park Delay. Anyone had any experience with these? I'd heard about an issue with a sometimes audible LED. The pedal has a green LED indicating tap tempo when it's on, and when you turn it off the LED turns red, but continues to flash the tempo. This way you can set the time even before you switch it on. Cool, but the annoying thing is that you can actually hear a ......wump.....wump.....wump... in time with the light. This is only when it's off (red), and only when it's in a chain of other FX (doesn't seem so noticeable when it's on it's own.

It's a real bummer, because this is the only problem I have with this pedal. I'm replacing a Guayatone MD3, which is a great pedal tonally, but not as versatile and has no foot-tap delay, which I've started to find I really need.

Does anybody know if it'd be possible to somehow bypass the red LED an disable the 'light flashes red when off' feature? The green (on) and red (off) are both on the same light (ie, single light changes colour). If I could do that the pedal would be sweet as. (which is New Zealand-ish for 'fine').

[sumgai]

mr. sooty,

The problem isn't the LED itself, it's the circuit driving the LED. Merely disconnecting the LED won't disable the circuit, and you'll still hear the objectionable noises.

I don't have a clue as to what components are used for that circuit, but I'd bet pretty big dollars that if you were to knock that thing out for the "Officially Off" side of the switch, you'd not only disable the LED, but you'd also kill the "pre-tap" feature described above. If that's a near-must have for you, then you're stuck. If not, then find a good technician, and fire away!

Caution: I'll stick my neck out on the chopping block here, and predict that the oscillator is part of a much larger ASIC processing chip, and that you won't be able to get into the guts at all. But what do I know, don't let that stop you! ;D

HTH


sumgai

[mr_sooty]

Hmmm, thanks for that. I'm gonna maybe just get another power adaptor and give the delay it's own power. I've noticed it's fine if I take it off my board and plug it in on it's own. I don't know how much of that is down to the shared power supply and how much of it is down to the chain of FX. Wouldn't be the end of the world to have to plug in two power supply's instead of one.

[sumgai]

mr. sooty,

Good plan. Being flexible is considered the hallmark of a good musician, and one's equipment is no exception. Let us know if this does indeed solve your problem.


sumgai

[mr_sooty]

Got a seperate adaptor. Means I can run my tuner off my pedal board instead, so I don't need any batteries now. Also means I have an extra wire coming off my board, but small sacrifice I guess. The Delay doesn't make the noise with this set up, so that's the main thing. Pretty cool pedal. One dumb thing is though, you can set the tap delay to quarter notes, triplets, or dotted eighth notes....huh? Why on earth would you want dotted eighth notes? I really wish they put normal eighth notes in there, you know, two delays per tap, that would have been a whole lot more useful!

[sumgai]

mr. sooty,

Double the speed of the quarter notes, now you have eighth notes, sans the dot.

Sometimes an echo that's delayed out of the standard 4/4 beat helps to make the delay more effective. But to my mind, it does seem like a giant step backwards to label the delay at all, such as you've found.

<Caution! Rant directly ahead......>
Whatever happened to the good ol' days, where analog echo devices (tape loops) had infinite (and infinitesimal) control over the length of time between the delays? Many models had a sliding head you manually positioned along the tape itself. Others let you choose from among several heads spaced along the tape, thus you could get some strange timings, if you wanted that. In this day of super-duper electronics control, why are we stuck with factory preset timings, and all we can control is the speed (and number of repeats)?
</rant>

HTH


sumgai

[mr_sooty]

sumgai said:

mr. sooty,

Double the speed of the quarter notes, now you have eighth notes, sans the dot.

You kinda miss the point I think. At the quarter note setting you get one delay per tap. Sure I can just tap faster, but my foot can only move so fast! When I was using the PodXT (horrible days indeed), I had the delay set to eighth notes, which meant I could get a 2 note per tap delay that was nicely in rhythm with the music, but faster than I could have otherwise tapped with my foot. This pedal doesn't have that option, but does have the dotted eighth note, which realy seems far less useable to me.

[sumgai]

mr. sooty,

Double the speed of the quarter notes, now you have eighth notes, sans the dot.

You kinda miss the point I think. At the quarter note setting you get one delay per tap. Sure I can just tap faster, but my foot can only move so fast! When I was using the PodXT (horrible days indeed), I had the delay set to eighth notes, which meant I could get a 2 note per tap delay that was nicely in rhythm with the music, but faster than I could have otherwise tapped with my foot. This pedal doesn't have that option, but does have the dotted eighth note, which realy seems far less useable to me.

Indeed, perhaps I have missed the point. I was just operating on a purely mathematical model, tha's all.

However, allow me to suggest that if your foot can't keep up at this speed, then slide the pedal under your drummer's Hi-Hat foot, and let him/her do the job for you. ;D

Me, I'd tap the delays on the quarter notes, then double the speed with the rate control. Quarter notes, as are all other notes, are in your head, not in the stomp box - it doesn't know squat about what you're doing, or how you're counting things out. So if you take a 120-beat 4/4 time and tap the delays, then double the speed to 240, you have a 120-beat eighth note rhythm, don't you........

Or aren't you allowed to set the speed after the tapping operation? Not being able to do so, that would put my idea in the toilet, I admit.

HTH


sumgai

[mr_sooty]

sumgai said:

Or aren't you allowed to set the speed after the tapping operation? Not being able to do so, that would put my idea in the toilet, I admit.

HTH


sumgai

You can set the speed with the time control after tapping, or before, either way, the time control over-rides the foot tap anyway, and you basically have to listen until it sounds like you have roughly the right time. Fine in a recording situation, but a bit finnicky live, which is the whole point in getting a tap delay. Just being able to tap it our with you foot is far more practical live.

[ChrisK]

Let me jump in here on the LED issue.

Since this is the same LED (or two separate LEDs visually feeding into a plastic light pipe [which actually IS what a bi-color LED is, in the same plastic package], the red and green colors will be driven either separately (a three-lead package with a red LED's cathode and a green LED's cathode connected common at one end and the anodes separate at the other) or driven with different polarities (a two-lead anti-parallel [one's anode to the other's cathode and the other's anode to the one's cathode]).

To drive the first, usually from a current sourcing/limited drive for EACH anode, two separate means are used. Now, these can be two DSP output lines with a resistor in series in each to the respective LED, or they can come from two completely different circuits since both LED's are connected to signal common in the effect.

To drive the second, an "H" bridge structure (similar to a bridged power amp) must be used. These typically come from a common circuit since the polarity must be reversed at both ends of the LED structure.


That being said, the "wumpletons" are likely coming from the current modulation from the LED flashing causing a voltage modulation effect on the common power bus affecting the other effects that most likely have inferior power supply rejection ratios (PSRR). When an effect is usually used with a power source that remains fairly constant (not unlike the power supply in a true Class A amplifier), and the designers did not/had no reason to design for a good PSRR (the 9 volt battery being the metric), this will happen since most effects in this business have a Mean Labor and Burden (MLB - parts/labor/overhead) in the range of 25% of the street price at most. Cheap is. PSR bypass isn't.

For instance, the Digital Signal Processor (DSP) in the Line6 effects is in the neighborhood of $3 in OEM quantities. GC sells this DSP effect for aboot $109.95 in the US. They pay Line6 aboot $65 to $70 in large volumes. Line6 makes it for aboot $20 MLB.

Unfortunately, the reason that most music gear resells for so little is that there is most excessive markup in getting it to the user, and most gear is really "worth" only about half of the going street price.


A. Now, one can buttress the common effects (as in plural) power bus by connecting a large polarized electrolytic cap across said bus (please, mind the polarity, please - holy pow Batman, the cap ruptured two months later), not unlike the application of """"""Digital (NOT) Capacitors"""""" in a "you're out of your dumb-a$$ mind loud" car stereo.


B. Or, one can indeed use a separate AC/DC adapter for the effect. I vote for this option. Done is.

C. OR, if it's a three-lead LED just unsolder the appropriate (you gets to figure this out, it's an end lead, choice of two) LED connection. If you're of a mind to, you could install a toggle switch in series with the resistor to LED connection. IF it's a three-lead bipolar LED.

For the two-lead, it's more complicated. You get to figure out which way a signal diode (1N914/1N4148 or such) has to be inserted in series with one lead of the LED to allow current to only flow in the "green" direction. And, since the DSP likely operates on 3.3VDC, you may not have ANY headroom for the additional diode drop (0.65VDC) since LEDs typically have a drop of 1.6 to 2.0VDC.

(Yeah, 3.3VDC. Most Intel Duo Core or AMD Turion processors work on 0.8 to 1.2VDC or so at 15 to 35 AMPS. There are no junctions, only regions and FETs.)

You could use a germanium diode (0.35VDC drop) if you can find one (I DO have a drawer full of them - coincidently I sell them for $109.95 each when used with digital effects).


Again, I choose "B" since it's cheaper in total as opposed to finding, wiring, testing (required), minding the polarity, and installing the big cap (as in 1,000 to 4,700 uF 25VDC). Or, in the effort required to modify the effect without destroying it (forget the warranty) completely.


Now, if you actually want to try open effect surgery.................

[mr_sooty]

Well, due to the fact that I'm pretty green at this stuff, I'll stick with option B. I have modified a Boss CS3 Compressor/Sustainer with a great result, but this was just a case of replacing to capasitors and 2 resistors and follwing some pretty simple instructions.

Option B works fine apart from the extra wire running from my pedals, no big deal. Thanks for your expertise though Chris!