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Technical reason taptation won't work on the Zero Points?

Started by midwayfair, January 24, 2013, 10:29:27 PM

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midwayfair

Brian or anyone else -- what's the reason the taptation won't work with these? My understanding is that the taptation chip controls a digipot, which gets treated like a 100K pot. There's still only one variable resistor here.

Or am I misremembering and it's compatible, but nigh-impossible to fit in a 1590BB? :)

Edit: I suspect it has something to do with the modulation ...

djaaz

Don't get it but experienced it with the echo base. I added some tap temp chip and it killed the modulation.
The tap tempo works though.

jkokura

I haven't examined the schem yet. I'll let you know soon Jon.

Jacob
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Parra

i think the modulation could work with the taptation, the only thing modulation it does is varying the voltage that goes into the time pot, if you substitute the pot with the taptation pot it should act the same way, just have to connect the oscilator (modulation exit) to the new pot.
i never tried it, but it makes sense in my head, probably i'm wrong...=)
but in the case of the zero point sdx, what i don't know, because of the dual pt2399 and the double bc550 is how you can connect the taptation to pin 6 of the chips and if it's possible.

....humm...just read the taptation datasheet and the way i sugested isn't going to work i think, cause when you tap the tempo (clock imput) the time pot is ignored (tempo voltage imput) and only comes active again when it changes for more than 5%, what it looks that would be a problem if there is voltage oscilation in there (modulation). the good thing is that the taptation chip has a modulation output(pin6 tempo PWM output) feature included...

jkokura

Ok. I took a preliminary look at the ZP schems. Here's what I think:

1. ZP Mini I think it will work fine - but you will loose the mod and rate functions in board the ZP board. Not a problem, just use the Modulating Taptation board. Not the same modulation, but it gets the job done.

2. ZPDD and ZPSD may work. Unlike the multiplex which has the PT2399 in parallel, the ZP chips are in series, and there's a single delay point. Really, it's just a digital pot instead of a true analog pot, so there's no reason for it not to work. However, like with the mini, you may loose the onboard modulation.

I have a ZPSD on the way. I wasn't planning Taptation implementation on mine, but I could test it if desired.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
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midwayfair

Quote from: jkokura on January 25, 2013, 12:39:22 AM
I have a ZPSD on the way. I wasn't planning Taptation implementation on mine, but I could test it if desired.


I'm ordering some tt boards soon, but you'll probably be able to get to it before I do. :)

jkokura

Quote from: midwayfair on January 25, 2013, 12:49:15 AM
Quote from: jkokura on January 25, 2013, 12:39:22 AM
I have a ZPSD on the way. I wasn't planning Taptation implementation on mine, but I could test it if desired.


I'm ordering some tt boards soon, but you'll probably be able to get to it before I do. :)

Depends on if you already have the taptation chips already. I have several sets, mostly for my production stuff, so it'll be easier for me to do. However, it may take me some time to even get my zero point built. And I'm also a little hesitant, because I like my builds to be perfect, so I don't want to ruin the zero point board I ordered and have to order another one...

But that's selfish, so I'm willing to try it.

Jacob
JMK Pedals - Custom Pedal Creations
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madbean

I've got plenty of ZP builds and my own TT little setup so I can work it out here in a few days, too. My guess is the current mirror on the ZPSDX or ZPDD could be altered enough to be made to work with TT. It's just something I never got around to exploring.

midwayfair

Quote from: jkokura on January 25, 2013, 04:33:08 AMI like my builds to be perfect

... I have no such qualms, so I don't mind doing the experimentation. :)

djaaz

Quote from: madbean on January 25, 2013, 12:35:53 PM
I've got plenty of ZP builds and my own TT little setup so I can work it out here in a few days, too. My guess is the current mirror on the ZPSDX or ZPDD could be altered enough to be made to work with TT. It's just something I never got around to exploring.

I'm sorry it's a little off topic, but i remember you installed a tap tempo chip on your echobase. Did you loose the modulation as well?


neiloler

#10
So after taking a look at the Zero Point Deluxe schematic a bit and the Taptation docs, I think the general idea would indeed be to replace the delay pot with the digital pot on the taptation setup.

We'd need to make sure that PA0 goes to pot pad 1, PW0 to pad 2, and PB0 to pad three. We'd also do whatever it is in the taptation that removes the taptation handling the modulation.

Anyone else want to confirm this?
OLERAudio - Sole proprietor, engineer, and goofball

neiloler

OLERAudio - Sole proprietor, engineer, and goofball

jkokura

Yep.

It won't work as you're suggesting. What you're suggesting is putting the output of the digital pot in as the expected 'analog' pot. The taptation doesn't work like that - it needs a clock input, which is supposed to be connected to the clock output (Pin 6) of the PT2399(s). Because lug 3 of the delay pot, in this instance, is the clock output, what you're suggesting is to connect the output of the digital pot to the output of the PT2399 clock. Out > Out doesn't work. You need Out > In.

So, with that in mind, completely removing the modulation of the Zero Point is a feasible solution. Essentially, what I'm imagining needs to be done is to remove everything to the right of the 'MOD' switch on the ZPSDX. Go from the Delay Pot Lug 3 pad to the Pin6 input on the taptation, and you should be good to go. Want modulation still? Build your taptation with the modulation circuit - yes you lose the rate control, but it's still something more that you'd usually get.

Truthfully though, I wouldn't go this route at all. Much more reasonable would be to design a new PCB that follows the key structure of the Zero Point Delay but utilizes the Taptation features.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
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madbean

And that's possible, but I was staying away from it since you are offering a slew of TT type projects. I think the best candidate of the current crop is the ZPDD...the double delay, since it has no modulation to start with. But, really, if tap tempo is the most important feature a person is looking for then the Zero Points may not be the ideal project. The ZPs are about including other features that have not been in PT2399 projects before, like multiple filters, double delay in a 1590B, etc.

I will, however, be working on a tap tempo analog delay. Or, at least integration to the Aquaboy, etc.

jkokura

Quote from: madbean on January 28, 2013, 11:47:57 PM
I will, however, be working on a tap tempo analog delay. Or, at least integration to the Aquaboy, etc.

And that is much more interesting to me.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals