Building the Echo Base PCB

[Taylor]

I just wanted to give Taylor some props for that part of the circuit in particular,

Thanks but Slacker designed the circuit - I had nothing to do with it other than designing the PCB itself. So he deserves all the credit for the way it sounds and works. 

[garcho]

Ooops! Sorry y'all, I meant Slacker. Nice PCB, though! 

[Barcode80]

Depends which side of the board you're looking Mine works like this (middle and right lug connected):



-Jaska-

Figures, I assumed I was talking about the front face view of the board like yours, so I jumpered it the other way. Have to fix that tonight. Thanks for the pic and clarification! Should have my case done being painted tonight. I put my board in this way because I didn't want to have the knobs be "backwards." Doing the dub mod with led indication for the 2nd footswitch, and a clean kill toggle (upper left hand side). After doing so many 1590A pedals lately this thing was great to work with so much room!

What do you mean by "backwards?" The way you have them they will turn and function the same way as the other way people have been doing it. Or do you mean the order of the controls?

[ugly_guitar_guy]

What do you mean by "backwards?" The way you have them they will turn and function the same way as the other way people have been doing it. Or do you mean the order of the controls?

Yeah, I was referring to the location of the controls. Having Speed and Depth on the left side doesn't mesh well with my OCD tendencies. 

[ugly_guitar_guy]

Alright... populated the board, wired everything up (with clean kill and dub mode switches, and no toggle for tails) and it freaks out my PSA-120S adapter. The board LED doesn't come on, and the status light on the PSA just blinks rapidly, which possibly indicates a missing ground, a short, or not enough current for the circuit. This is problematic because I can't get a reading on pin voltages of the IC's because the power is literally blinking on and off rapidly. I just really get frustrated when a simple build like this doesn't fire up right away so I guess I'll wire up a 9V directly and get back with some pinout readings.

I'm wondering if I broke one of the pins in the 7805 when I bent it over to fit in the case, but wouldn't the status led still light up?

Thanks in advance...

[slacker]

Sounds like you might have some sort of short across the power supply. Check that the DC jack is wired correctly and that the reverse polarity protection diode, the one next to the 7805, is the correct way round, also check that all the ICs are the correct way round.
After that, with the power off, try measuring the resistance between the positive and ground on the DC jack, you'll need to hold the probes there a while to charge up the caps, but you should get at least a couple of hundred K Ohms. If you get a low value you have some sort of short somewhere on the power traces.

[ugly_guitar_guy]

Sounds like you might have some sort of short across the power supply. Check that the DC jack is wired correctly and that the reverse polarity protection diode, the one next to the 7805, is the correct way round, also check that all the ICs are the correct way round.
After that, with the power off, try measuring the resistance between the positive and ground on the DC jack, you'll need to hold the probes there a while to charge up the caps, but you should get at least a couple of hundred K Ohms. If you get a low value you have some sort of short somewhere on the power traces.

Apparently I need to stop building pedals quite so late at night. My 4066 was in upside down.  Always something simple... I also had to replace my 7805 as well because I bent it too many times and broke the pins. Now it's good as gold. Very fun to mess with and going on my pedalboard this week.

I think I'm going to add a pot in place of the resistor for the dub mod so that i can dial in how much feedback I want the max feedback switch to be. Other than that it's pretty damn sweet! Thanks!

[wizardsofzen]

so i'm about to wire in the last part, the DC power receptacle, i don't have the matching wall-wart to use yet, should i wait to wire this power connector so i know what the polarity is from the power supply, all power supplies don't follow standard negative pole, positive outer wall method? and thank you all in advance !

[StereoKills]

Actually, most "standard" adapters will be center positive. The ones we use for guitar effects are almost exclusively center negative.

Make sure you know what your power supply is before.

[wizardsofzen]

ah ty! and my last silly question of the day,,, after i built this up, i realize i used a mix bag of "new" panasonic capacitors, from 450 volts to 1.6k volts... thats gonna be an issue or not?

[Taylor]

The voltage rating specifies the max voltage that the part can take without derating, melting, or exploding. So you can always use a part that's rated for a higher voltage than it will ever see - in fact you always should use an over-rated part. The only real downside of using extremely over-rated parts is that they are often more expensive and bigger.

[mthibeau]

Finished my Echo Base with mods. Finish came out more yellow than I wanted (bummer) but looks cool kinda aged.

Mods done:
- Dry cut on a switch
- Waveshape mod
- Runaway Feedback (on a momentary stomp)



Thanks for the great board Taylor!

- MikeT

[greyscale]

I finished building up my Echo Base yesterday, which initially went very well.

The problems arose when I realized I accidentally had the I/O jacks on the wrong sides. I switched the sides (resoldered them), and now I don't have control over the feedback. The level knob seems to control it somewhat, but both controls start oscillating when turned up too high.
Can anybody figure out what could be wrong in my build? I had complete control before I switched the in and out jacks.

Thanks,
Travis

[Taylor]

When you had the jacks the wrong way, you were still connecting your guitar to the input and the amp to the output right? If so then switching the jacks won't have changed anything by itself - some other wire or part must have been messed up while you were swapping wires around.

Do you have any mods in your build, particularly the dub madness mod?

[djaaz]

It might add a small amount of hiss, but not enough to be a show stopper. Possibly you have a problem with your build.

Thanks for the videos links.

Here's a mp3 sample i made from the pedal. The first seconds are the echo base, the last one are a memory toy.
http://djaaz.free.fr/echobase.mp3
They illustrate two things:
1. The hiss is quite obvious
2. The lack of bass

Is there anything that i could/should check?

Thanks in advance!

That sounds like it is either a bad PT2399 or you have a bad connection or wrong components round the PT2399. If you turn the level to zero does the hiss stop? If it does it is definitely coming from the PT2399.
I would check all the components and connections down the left and right sides of the PT2399.

Hi guys,

I'm still having this issue with this hiss. I unboxed the pcb. Changed the PT2399. Removed the dub madness mod. Removed the led.
Still the same hiss even with level pot at zero.

I will try to audio probe as well as i can.

While i'm at it. something i can change to have more bass on the repeats?

Thanks in advance.

[greyscale]

When you had the jacks the wrong way, you were still connecting your guitar to the input and the amp to the output right? If so then switching the jacks won't have changed anything by itself - some other wire or part must have been messed up while you were swapping wires around.

Do you have any mods in your build, particularly the dub madness mod?

I had the input/output right as far as amp and guitar. The pedal worked fine like that.

I didn't do any mods at all, not even tails/boss or lfo.

[slacker]

Still the same hiss even with level pot at zero.

If you remove the PT2399 does the hiss go away? With the PT2399 removed the pedal should sound pretty much the same as plugging your guitar straight into your amp and be the same volume. If it does not then you have some sort of problem round the opamp near the level pot.

While i'm at it. something i can change to have more bass on the repeats?

I would get it working properly first, then see if you still think it needs any mods.

[djaaz]

If you remove the PT2399 does the hiss go away? With the PT2399 removed the pedal should sound pretty much the same as plugging your guitar straight into your amp and be the same volume. If it does not then you have some sort of problem round the opamp near the level pot.

Did not try that. I changed this TL072 already as i probed the hiss on pin 16 of the PT2399. Might sound lame but any chance the dc supply cables could provoke some interference with the opamp?
What about the level pot having a direct relation with the nature of the hiss (but not the volume)?

And indeed you're right, let's fix this first.

[djaaz]

Kind of half solved:
I remember testing this box with a 9V battery could not trigger any modulation.
So i changed the power supply for a bad regulated supplying 10.3V and no hiss anymore.

Could it be that my build require more voltage?

[slacker]

It is a known problem that the modulation stops working with a weak battery, a fresh one putting out 9 volts should work fine though, also if the battery was very weak the voltage regulator wouldn't work properly, which could cause strange things to happen.