Echo Base - a new PT2399 delay

[slacker]

The taptation works fine with the Echo Base if you wire it up like this.



Ground goes to ground on the Echo Base. Pins 5 and 6 of the digipot go to pin 6 of the PT2399, pin 7 of the digipot goes to where lugs 1/2 of the time pot went. The only problem with this is that the tapped time won't be accurate, the resistance of the transistor used to do the Echo Base modulation throws out the timing. If you want the timing to be accurate then add a switch like shown above, this bypasses the transistor so the taptation will work accurately. Basically you can't have accurate timing and modulation.
You might not need to add the 1k resistor but the taptation datasheet recommends it, to prevent damage to the digipot.

[Chris oej]

Thanks Slacker,

I've hooked it up like this now but am getting a kind of short delay / ring modulator sound. The tap control and speed control do nothing. The voltage regulator on the taptaion board is only giving me 2v still. Do you recon i have a faulty part?

[slacker]

Yes, if you're only getting 2 Volts out of the regulator it sounds like something is damaged on the taptation board, do you have a link to the board you're using? That might help working out what is wrong.

I assume the Echo Base works if you pot the delay time pot back in and use it without the taptation.

[Chris oej]

Here's the board, I've bent up the leg of pin 7 of the digi pot to connect it to the Echobase. The Echobase was working perfectly before i added the taptation. I'm wondering if its the digi pot that's buggered. Here's the board I've got from Jacob, a man that seems to know his tatptations well:

http://www.jmkpcbs.com/JMK_PCBs/Store_files/%20Mini%20Taptation.pdf

I've ordered a new 78L05, I'll check it on a bread board first to make sure it's working okay.

Thanks for all the help, i really appreciate it.

PS. The Echo Base has to be the best sounding delay ever!

[kurtlives]

Does anyone have a drilling guide for the musicpcb PCB? 

[bluescage]

This kind of thing. Much simplified, I've left all components out except the switching. the bold line shows where the dry/bypass signal goes (with 2 op amps) the rest the switching

Thanks Kesh,

That's what I was looking for!

Regards
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[drummer4gc]

Hey everyone,

I had a working echo base a few months ago that didn't quite fit into the box I drilled  so I removed the circuit and it sat on my bench untouched.

I just rewired all the off-board components and am getting ready to rehouse it. it works - that is, the controls all do what they are supposed to, and there are delays. but the delays are massively distorted, and it goes into wild uncontrollable oscillation with only a slight turn of the feedback knob.

i've looked at the mods to reduce distortion - taking out diodes, reducing resistors - but I don't believe this to be the problem. There was nowhere near this much distortion when I had it working a few months ago. I'm also using the neck pickup of my tele here, there is no reason anything should be clipping. I feel like it has got to be related to the feedback problem. I have a trimpot in place of the 20k resistor off the feedback control, and even with it turned all the way to 100k, the thing oscillates like crazy.

Any thoughts? Voltage looks good at the pt2399....I'm guessing a must have a short somewhere but I don't see it. Any ideas would be much appreciated.

Thanks!

[drummer4gc]

update: an audio probe shows clean signal through the input buffer (obvious since my dry signal sounds fine) and then a dirty signal coming out of the 4066...i'm not sure I'm tracing it right though. into pin 1 sounds fine, out of pin 2 sounds distorted. bad chip?

[slacker]

If you've used a socket you can do a quick check to see if it's the 4066. Remove the 4066 and jumper pin 1 to pin 2 and pin 10 to pin 11 on the socket, this puts the effect in the on position. If you then get no distortion the problem is around the 4066, voltages on all the pins in both bypass modes and effect on would be useful.

[slacker]

This is info for Mr Gambit07, tried to reply to your PM but it says your inbox is full. Thought I'd put his here in case you check out the forum.

As far as I know no one has made a DIY PCB layout for the latest version, the only PCB is the musicpcb one which you have to buy http://musicpcb.com/pcbs/echo-base-delay/.
There is a vero layout with all the mods http://www.sabrotone.com/wp-content/uploads/2011/05/EchoBase.gif

There is a PCB layout for the first version here http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=44171.

If you have the skills you could probably modify this into the latest version, it is mostly changes around the top right hand TL072.

[dave-the-hat]

Here's  an idea you  could possibly use a 555 timer and a relay to switch to full by pass once the delay signal had totally faded.
just a passing  thought.

[Sanguinicus]

Hi there.

I'm having a hard time visualising the off board wiring for the echo base. is it possible to have both dc input with 9v battery? and does the pedal 'turn on' when the guitar is plugged in, with a stereo trs socket (like a conventional true bypass pedal)?

How would I go about achieving these two things?

EDIT: another question. How does it turn on and off? It looks like the bypass switch just controls the 4066, and power is always connected.

[slacker]

If you want a battery then use a stereo input jack connecting the battery and DC jack exactly the same as you would for a true bypass pedal. This will turn off the battery when you remove the input jack, same as a true bypass pedal.

Yes, the bypass just cuts off the delayed sound, the dry sound still passes through the pedal, that's the only way to get delay tails.  True bypass pedals don't remove power when bypassed either, they just remove the circuit from the signal path.

[Sanguinicus]

Thanks slacker, you're a gentleman.

[Moustache_Bash]

Sorry if we've been over this, but has this layout been verified?  Also, does anyone know what size the sides should be scaled to?

Thanks for any help!

[slacker]

Sorry I don't know if that one is verified, this one is http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=44171

[Chris oej]

Hi all,

I still can't get the taptation to work with the Echo Base. I've replaces the voltage regulator and the MCP41100 but still no cigar. I checked the new 78L05 on a breadboard before installing - got 5.1v from the output. However, when i measure the output voltage when its installed i only get 1.72v - this is obviously why it's not working correctly. I can only assume that there's too much resistance coming from somewhere - i've triple checked all the resistor and capacitor values and all seems right. It work fine as a normal Echo Base when i just have a normal pot on instead of the tap circuit. I'm completely baffled. I would be eternally grateful if anyone has any suggestions as to what the problem is - here're some photos.

http://i1294.photobucket.com/albums/b605/cdouch/photo3_zps4e32ea5e.jpg

http://i1294.photobucket.com/albums/b605/cdouch/photo1_zpsbf52fb93.jpg

Thanks

[slacker]

Does the taptation work on its own?

[Chris oej]

I don't think so, when i take it off of the taptation circuit form the Echo Base board i only get 0.78v at the output of the voltage regulator. Although i'm using a 78L05 as stipulated, when tested on the breadboard, mine seems to have the input and output round the other way to how its depicted on the taptation board. I've tried it both ways round. One way i get nothing, the other i get the aforementioned values. Would it be worth trying a L7805 instead?

[slacker]

I would remove both the chips from the taptation board and see if you then get 5 Volts from the regulator, if you do put the chips back in one at a time and see which one causes the voltage to drop, that chip is possibly damaged.
I can't tell from the photo or the documentation which way round the 78l05 is supposed to go, using the continuity tester on your meter or by following the traces you should be to tell which pad is connected to the +9 pad, which one is it? If it's the top one then, unless you have some strange 78l05, the marking on the board is correct the rounded side faces the edge of the board.