Here is the first (of apparently many) working solution for tap tempo control of a PT2399 based delay.
The basic schematic is thus:
(http://img58.imageshack.us/img58/7401/tapboardsch.th.png) (http://img58.imageshack.us/img58/7401/tapboardsch.png)
R1 is the existing delay pot (usually 25k or 50k) which now goes in to an AVR microcontroller. Terminal T2 is a momentary footswitch for the tappin'. The MCU handles all the timing and sets the digital pot (50k) which is now wired to the VCO pin of the PT2399 via T3.
The pot has 256 taps to choose from. Depending on the area of the delay curve you're in it ranges from about 3-5ms per setting. (On a typical 300-degree travel pot this is a little over 1 degree per tap.) It is by no means a super-accurate timing device, but given that the average delay only has about 3-5 repeats it is certainly accurate enough for rock'n'roll.
- On power-up it is in manual pass through mode.
- First tap activates tempo mode.
- In tap mode the delay pot selects the beat (eighth/dotted eighth/sixteenth/etc.).
- Taps are timed and scaled to the beat.
- Digital pot is set accordingly.
- Can be booted in to a rough calibration mode by holding down the tap switch on power-up.
- Less than 5mA
Demonstration (of the chip and my lack of rhythm): http://www.youtube.com/watch?v=oE0piMXWmZQ
Now my question to all who are interested: how would you like this project to be available? My thoughts are:
A. Pre-programmed MCU and digital pot.
B. Kit with PCB
C. Fully assembled
For "A" I figured may as well include the pot at the same time as the MCU as it's something a DIYer typically won't have. For "B" the layout is pretty simple but if there's enough interest in a PCB for adding to existing delays I wouldn't mind ordering a small run. I doubt this crowd would have much use for "C". :)
Cool! Thanks for sharing. Seems like 256 steps is "accurate enough" for delay.
Looks good, i was busy making the same thing with an arduino board and a double digital pot.
My thoughts where that if you use 2 digital pots you get 2x256bit and you can make them act as 25K pots.
So thogehter thats 50K.
I had the same features on my arduino tap tempo version. Subdivisions (1/4,1/8*,1/8,1/16 etc.) and i wanted to make an audio tap on it.
But maybe it's an idea to use a double digital pot.
And as far as the project, sell the avr's pre burned with the digital pots. :icon_biggrin:
Good job
Looks like a great solution. I'd definitely be interested in getting one, I'd prefer option A but whatever you decide is good with me, cost permitting.
Quote from: RonaldB on April 15, 2009, 01:35:33 PM
Looks good, i was busy making the same thing with an arduino board and a double digital pot.
My thoughts where that if you use 2 digital pots you get 2x256bit and you can make them act as 25K pots.
So thogehter thats 50K.
I'm not sure I have the arrangement right, but my thoughts:
- 2 8-bit 25k in series = 1 X-bit 50k. I don't see any 25k's on Mouser. (There's a 24k but it's a quad.)
- 2 8-bit 50k in parallel = 1 X-bit 25k. While the PT2399 starts getting lo-fi after the 25k/300ms point I prefer having the extra range just in case.
I say X bits since there is redundancy in there so it wouldn't be a full 16-bit range. (But still more than 8.)
Would the audio tap sync to a metronome signal? That's a pretty good idea!
Well i made a couple of PT2399 delays now and i had good results with 50K delay time pots.
My general idea was to do a double pt2399 configuration with 50k digital pots on them. This would be better for the sound of the delay
But with 1 pt2399 i would use a double 50K digital pot (get them at futurlec.com(microchip)) and do a 22K or 27K resistor across the outher legs.
Then couple them in series.
I have made the Arduino listen to Midi Clock notes. Witch is also a plus. That way you can sync the delay to your sequencer, drum machine or recording software 8).
My point with the audio tap is the same as the Nova delay. So pressing the tap button and stike the rythem with the guitar.
I have to get back on the software + hardware for this. I'm busy now making my custom build Midi controller witch will have Midi Sync tap tempo 8).
best regards
Ronald
how is the calibration done
i mean, is it hardcoded in the uC, using linear formula, conversion table, whatever?
is there enough consistency from pt2399 chip to chip?
I'm assuming that this could replace any time based control, assuming you know the relationship between resistance and time? It'd be a simple matter of changing the look up table values?
Knowing how digital pots work, it would be a simple matter of changing the output clocking frequencies look up table relating to the measured frequency of taps.
I'm thinking replacing rate pots in LFO's and the delay pots in analog delays.
In the examples I'm thinking of the relationships are linear, so it should be pretty straightforward.
I'm busy digesting AVR + PIC programming books, although there seems to be a base knowledge assumption that I'm missing. I'm having a hard time conceptualising how it all fits together. I'm sure I'll get there.
I know this is probably cheeky, but it is a DIY forum.
Any chance of the code?
So ultimately you will just wire this circuit in place of the delay time pot in the circuit?
I would prefer PCB/Kit.
Quote from: cpm on April 16, 2009, 07:59:44 AM
how is the calibration done
i mean, is it hardcoded in the uC, using linear formula, conversion table, whatever?
is there enough consistency from pt2399 chip to chip?
There is a lookup table that is used to convert time to delay settings. The math isn't that complicated, but there's no reason to force a poor little micro-controller to do floating point on the fly when you only have 256 answers to choose from. (The timing of the taps themselves is more accurate than this which helps to lock on to the closest possible setting. It also means the chip can be re-used to drive a true clock line for analog delays. I'm not promoting it as such quite yet though since I haven't verified it, but it is an obvious extension to its current abilities.)
The calibration consists of three parts:
- First is the internal RC oscillator of the MCU. It comes from the factory at +-10% but there's an app. note from Atmel on how to calibrate it to be +-1%.
- Second is adjusting the look-up table for the digital pot. While the samples I've tested have been right-on for the specified 50k the datasheets do allow for a wider variation as is the case with your standard pot.
- Third is adjusting for variations in the host circuit, such as the PT2399 itself or the (typically) 1k resistor in series. While this could be done more accurately at programming time it makes more sense to have it a user-controlled function since the device is intended to be added to an existing pedal. Hence the "calibration mode".
Quote from: nelson on April 16, 2009, 11:18:21 AM
I'm assuming that this could replace any time based control, assuming you know the relationship between resistance and time? It'd be a simple matter of changing the look up table values?
Yes and no. The idea is correct, however the values available for digital pots are limited, especially in the higher values since as I understand it integrated resistors cost a lot of die space. We're lucky that 50k works with the PT2399. As was mentioned earlier there isn't even an easy way to get 25k. I looked in to finding a 1M dpot since that's what is already in analog delays but there aren't any. Hence driving the clock line directly in those situations.
Quote
Any chance of the code?
Not very likely. I view the MCU+code as a single finished product the way one would a design using an FPGA/PLD/etc. I am however perfectly happy to discuss the theory of what's happening inside the chip. I think that's an acceptable middle ground. :)
Quote from: Nitefly182 on April 16, 2009, 02:09:04 PM
So ultimately you will just wire this circuit in place of the delay time pot in the circuit?
I would prefer PCB/Kit.
Correct. I put more detailed instructions up here (http://thoughtprocessinc.com/ptap_instructions). And since there isn't an issue of "minimum quantity" for just the chips the way there is for PCBs I put up a little PayPal store (http://thoughtprocessinc.com/ptap) if anyone is interested. Your vote for the full kit has been counted though.
I am interested in ordering a couple. But, I like running the pt2399 with delay-time pots of 100k and up. Could your taptempo handle a 100k time-pot and also tap into the 100k time-range?
(oh, please add a shipping option to the Netherlands ;) )
Quote from: Auke Haarsma on April 16, 2009, 04:37:57 PM
I am interested in ordering a couple. But, I like running the pt2399 with delay-time pots of 100k and up. Could your taptempo handle a 100k time-pot and also tap into the 100k time-range?
(oh, please add a shipping option to the Netherlands ;) )
The value of the control input pot doesn't matter as long as it's a linear taper (it's just a voltage divider now.) And you're in luck: there's a 100k version of the digital pot so that should be no problem. I'm surprised that it works though. At 50k the repeats are pretty lo-fi already! I wonder what do they sound like at that point?
I'll try to figure out the international shipping option too. (That site is normally used to sell/host proprietary software so I'm new to the whole shipping thing.)
A couple of questions if you don't mind :)
Once it's in tap mode can you get it back out again? Would you have to "reboot it" to get the delay pot to work again?
Does the delay time pot still work smoothly or can you hear the steps as you turn it?
Quote from: decc on April 16, 2009, 04:52:05 PM
And you're in luck: there's a 100k version of the digital pot so that should be no problem. I'm surprised that it works though. At 50k the repeats are pretty lo-fi already! I wonder what do they sound like at that point?
You cannot just drop in a 100K digital pot for the 50K and expect the taps times to match the pot settings.
Andrew
Quote from: The Tone God on April 16, 2009, 05:33:46 PM
Quote from: decc on April 16, 2009, 04:52:05 PM
And you're in luck: there's a 100k version of the digital pot so that should be no problem. I'm surprised that it works though. At 50k the repeats are pretty lo-fi already! I wonder what do they sound like at that point?
You cannot just drop in a 100K digital pot for the 50K and expect the taps times to match the pot settings.
Andrew
Agreed.
Also, I don't mean to be a wet blanket, but it seems a bit premature to be selling it when you have yet to actually test it with an accurate clock:
"My testing has been limited to a cheap metronome, my own sense of timing, and a half-dozen PT2399 chips. (So while there is a sinking feeling that I missed something here and will let everyone down, as far as my experience goes it actually works!)"
As I'm sure you know, binary math and microcontroller outputs don't always mesh with real-world applications.
Quote from: The Tone God on April 16, 2009, 05:33:46 PM
Quote from: decc on April 16, 2009, 04:52:05 PM
And you're in luck: there's a 100k version of the digital pot so that should be no problem. I'm surprised that it works though. At 50k the repeats are pretty lo-fi already! I wonder what do they sound like at that point?
You cannot just drop in a 100K digital pot for the 50K and expect the taps times to match the pot settings.
Andrew
Sorry if I implied that. The tables would have to be recalculated and verified. But there's no reason to think it won't work any worse than a regular 100k pot.
Quote from: MoltenVoltage on April 16, 2009, 05:54:19 PM
Quote from: The Tone God on April 16, 2009, 05:33:46 PM
Also, I don't mean to be a wet blanket, but it seems a bit premature to be selling it when you have yet to actually test it with an accurate clock:
"My testing has been limited to a cheap metronome, my own sense of timing, and a half-dozen PT2399 chips. (So while there is a sinking feeling that I missed something here and will let everyone down, as far as my experience goes it actually works!)"
As I'm sure you know, binary math and microcontroller outputs don't always mesh with real-world applications.
Indeed, but for this application the refrain is "close enough for rock'n'roll." Since then I have checked the timing on a scope and it passes within 4%, depending on the PT2399 chip in use. Hence the calibration mode.
Quote from: slacker on April 16, 2009, 05:03:24 PM
A couple of questions if you don't mind :)
Once it's in tap mode can you get it back out again? Would you have to "reboot it" to get the delay pot to work again?
Does the delay time pot still work smoothly or can you hear the steps as you turn it?
Hold down the footswitch for 2 seconds to get it back to manual mode. I'll add that note to the description.
As for how smooth the turn of the pot is: let's look at a typical 3/4" knob with 300 degrees of travel. That's 1.2 degrees per tap, or moving the pointer on the knob about .007 inches. There's also some code to make sure it doesn't land right on the edge and wobble back and forth to give you an impromptu vibrato. :)
Thanks for the answers decc.
-Would this work with the recent modulation-delays (EchoBase, Magnus Modulus), -> LFO's on the delay-time?
Quote from: Auke Haarsma on April 17, 2009, 02:37:34 AM
Thanks for the answers decc.
-Would this work with the recent modulation-delays (EchoBase, Magnus Modulus), -> LFO's on the delay-time?
Electrically it should be fine since to the rest of the circuit the digital pot still looks like a regular old variable resistor. Having the desired affect might be another story.
With the Magnus I'd say it's very likely as it has the standard 50k pot + 1k resistor arrangement, with the modulation via a capacitvely coupled voltage.
With the Echo Base I hesitate a bit as the modulation is done with a transistor + 39k resistor that are always in the circuit. The
assumption I'm making is that those two don't change the delay curve aside from the intended modulation, but we all know where assumptions get us.
On the Echo Base when the modulation level is set to minimum the PNP transistor + 39k combo looks like a very small fixed resistor, I don't know the value but its probably less than 100 Ohms. Providing the PTAP doesn't need the 1k series resistor for timing accuracy or current limiting purposes it will work fine like this. If it needs the 1k for any reason you would need to add this, this would then raise the minimum delay time so the chorus type sounds with the delay time pot on or very near minimum will probably be affected.
Even if you don't need the 1k resistor, according to the datasheet for the MCP41050 (page 14) the minimum resistance when used as a variable resistor is around 125 Ohms, so the chorus type sounds might be affected anyway.
Once you start to add some modulation the PNP transistor + 39k combo looks like a variable resistor in series with the delay time pot. One of the flaws in the Echo Base is that the modulation also adds a series resistance to the delay time pot, this resistance increases with the amount of modulation. Basically if you set the delay time you want and then add some modulation the delay time you set gets slightly longer rather the modulation being centred around the delay time you set originally.
I would guess that for small amounts of modulation, given the variations you're going to get anyway with everything else in the circuit this won't matter, and the results will still be close enough for rock n' roll :)
If you want to use the PTAP with more extreme amounts of modulation you're unlikely to be worrying about accuracy.
I'm going to buy a PTAP and see if it works with the Echo Base because I guess it's something a lot of people will be interested in adding to theirs.
Quote from: decc on April 16, 2009, 08:08:36 PM
Hold down the footswitch for 2 seconds to get it back to manual mode. I'll add that note to the description.
Thanks.
Quote
As for how smooth the turn of the pot is: let's look at a typical 3/4" knob with 300 degrees of travel. That's 1.2 degrees per tap, or moving the pointer on the knob about .007 inches.
Does it sound smooth though, because on some digital delays you can hear that the delay time is changing in distinct steps. What I'm talking about here is grabbing the pot and sweeping it back and forth as an effect not just setting the delay time with it, I should have made that clearer when I first asked the question.
Just thinking aloud here, I wonder if you could replace the voltage divider feeding the MCU with a CV in and modulate the delay time using the digital pot. That would be fantastic ;D
Thanks for the EchoBase explanation Ian. I'll be looking forward to your review of the taptempo+echobase :D
Quote from: slacker on April 17, 2009, 06:33:04 AM
On the Echo Base when the modulation level is set to minimum the PNP transistor + 39k combo looks like a very small fixed resistor, I don't know the value but its probably less than 100 Ohms. Providing the PTAP doesn't need the 1k series resistor for timing accuracy or current limiting purposes it will work fine like this. If it needs the 1k for any reason you would need to add this, this would then raise the minimum delay time so the chorus type sounds with the delay time pot on or very near minimum will probably be affected.
Even if you don't need the 1k resistor, according to the datasheet for the MCP41050 (page 14) the minimum resistance when used as a variable resistor is around 125 Ohms, so the chorus type sounds might be affected anyway.
The 1k resistor is taken in to account with the lookup tables for timing and current limiting. I think the delay may not be able to get low enough for chorus. (2.5V / 1mA = 2.5k min total R for a min delay time of about 56ms. Good enough for 16th notes at 250bpm though!)
Quote from: slacker on April 17, 2009, 06:33:04 AM
Does it sound smooth though, because on some digital delays you can hear that the delay time is changing in distinct steps. What I'm talking about here is grabbing the pot and sweeping it back and forth as an effect not just setting the delay time with it, I should have made that clearer when I first asked the question.
Looking at the datasheet and the traces of changing from setting 0x7F to 0x80 I'd say it looks like they didn't bother using a grey-code in there. The resistance bounces around for a couple hundred nano-seconds before settling down. So in theory, no. However trying this out I'd say at human scales it seems to work. It's not really intended for that though.
Quote from: slacker on April 17, 2009, 06:33:04 AM
Just thinking aloud here, I wonder if you could replace the voltage divider feeding the MCU with a CV in and modulate the delay time using the digital pot. That would be fantastic ;D
Good idea, not sure it would work though. The code is averaging out the input specifically to avoid the situation where the ADC varies around a bit transition leading to unintended modulation. Then there's the problem of the digital pot transitions as well. So at this point I would say that it is not well suited to modulation circuits. However I also was trying to make the modifications of the host delay circuit to use this controller minimal. Maybe some good old analog cleverness thrown in can help out and make the PTAP "Echo-Base Compatible".
A couple questions then for you: What is the min/max voltage swing and frequency of the modulation, and min/max delay times?
Hi,
did anyone try to put the MV-52 into a pt-80, rebote or echobase? Looks really interesting:
http://www.smallbearelec.com/Detail.bok?no=795 (http://www.smallbearelec.com/Detail.bok?no=795)
http://www.moltenvoltage.com/mvcart/index.php?main_page=product_info&cPath=66&products_id=215&zenid=f4ad791fc6889fb91e077b6075735c0a (http://www.moltenvoltage.com/mvcart/index.php?main_page=product_info&cPath=66&products_id=215&zenid=f4ad791fc6889fb91e077b6075735c0a)
The MV-52 can't be used as a tap tempo to control the delay time, well it probably could with a lot of extra circuitry, but the PTAP is a much better solution for that. Have a look at this thread http://www.diystompboxes.com/smfforum/index.php?topic=75600.0 (http://www.diystompboxes.com/smfforum/index.php?topic=75600.0) for more info.
You could use the MV-52 to make a tap tempo LFO for the modulation in the Echo Base, and use the PTAP to do the delay, that would be pretty cool.
Anybody get anywhere with this yet?
On the echo base in particular :)
No one that has one has given me any feedback yet, unfortunately. (I hope this just means everything's working great, right? :) )
And even though I posted this in the Echo Base thread I guess here would be the more appropriate place for the layout:
(http://img29.imageshack.us/img29/6743/ptap.gif)
(http://img37.imageshack.us/img37/8873/ptappnp.gif)
There's the PTAP2 (http://thoughtprocessinc.com/ptap2) for dual PT2399 delays now too, BTW.
Just orderd a PTAP from your site ;D
I'm looking forward to this.
People have been asking about PCBs as well so I had a few made up for both versions (PTAP (http://thoughtprocessinc.com/ptap-pcb), PTAP2 (http://thoughtprocessinc.com/ptap2-pcb)).
Again thanks for all the help from everybody!
looks sweet!
I purchased this kit and am a little confused ??? as to how to hook it up. I have built several pedals but my knowledge of this stuff is limited. >:( Can someone post a picture or simple diagram of this kit hooked up to a PT2399 delay (mine is rebote 2.5). My end game is to have two rebotes in one box, one always on for ambience, the second hooked up to the ptap for rhythmic stuff. Any help would be greatly appreciated. :icon_wink:
Pardon me for asking, but have your read the manual (http://thoughtprocessinc.com/files/PTAP%20Controller%20Manual.pdf)? There is also a schematic (http://thoughtprocessinc.com/files/ptap-pcb-sch.png) for the PCB that goes with the PTAP.
Basically the delay pot is disconnected from the rebote and is re-connected to R1, and the 3-points labelled J1 go to the rebote board where the delay pot was before. S1 is where the momentary tap switch is connected. And of course don't forget +9V/GND.
Here's a rebote before modification. As you can see all that was done was disconnect the delay pot on the left:
(http://img196.imageshack.us/img196/439/delaydisconnect.jpg)
Next is with the PTAP board installed. The delay pot is connected to the points labelled R1 at the top, and the points labelled J1 go back to the rebote board.
(http://img198.imageshack.us/img198/7579/tapadded.jpg)
Hope that helps
Well yes I did read the manual and yes I saw the schematic. As I said my knowledge is limited. I can follow cook book recipes and wiring diagrams (aka general guitar gadgets project files, etc.) and such. The pictures should help. Thanks.
Quote from: decc on July 30, 2009, 07:04:01 PM
Pardon me for asking, but have your read the manual (http://thoughtprocessinc.com/files/PTAP%20Controller%20Manual.pdf)? There is also a schematic (http://thoughtprocessinc.com/files/ptap-pcb-sch.png) for the PCB that goes with the PTAP.
Basically the delay pot is disconnected from the rebote and is re-connected to R1, and the 3-points labelled J1 go to the rebote board where the delay pot was before. S1 is where the momentary tap switch is connected. And of course don't forget +9V/GND.
Here's a rebote before modification. As you can see all that was done was disconnect the delay pot on the left:
(http://img196.imageshack.us/img196/439/delaydisconnect.jpg)
Next is with the PTAP board installed. The delay pot is connected to the points labelled R1 at the top, and the points labelled J1 go back to the rebote board.
(http://img198.imageshack.us/img198/7579/tapadded.jpg)
Hope that helps
can you post the video in youtube . thanks
I'm sorry, but what IC's do I use? I'm at my work computer and can't enlarge any photos. Will it work woth ANY 2399-builds??? This is genius!!!
hey just bought the ptap and pcb for my rebote. is there a way to have a rate led atached to the board? thanks
mini-bump: What IC do I use? I can't enlarge the schem...
Not sure what IC you mean... the IC's for the PTAP are in the instructions, and it's for PT2399 builds.
It won't work quite right with any PT2399 that don't have the 1k resistor coming out from pin 6, like the echo base.
Quote from: kristoffereide on August 24, 2009, 08:27:28 PM
mini-bump: What IC do I use? I can't enlarge the schem...
If I understand your question, you are looking to build this with off-the-shelf ICs? Like, stuff you can get at Mouser? You can't, because you need the preprogrammed MCU from user "decc".
Oh, thanks! That was the answer I was looking for... Well it's not expensive, so I'll guess I'll just have to try it out :D
What's the best option: the rate led attached to the delay circuit or the ptap? Anyone done this?
You can divide the 2399's clock by some ridiculous number like 625,018 to drive a LED in-time with the tempo, but it requires a couple/few ICs and a lot of diodes. If there's a tempo output from the PTAP, that would be way better... dunno if there is though.
I finally had the opportunity to get this wired up. It works like a champ. My end goal is to have two rebotes in one box. One left on all of the time for ambience and the other wired with the PTAP to be used for rhythmic stuff.
Quote from: decc on May 28, 2009, 10:07:55 PM
(http://img29.imageshack.us/img29/6743/ptap.gif)
I'm a little embarrassed to ask this, because I'm sure the answer is obvious to someone a little more experienced, but I'm putting together a parts list for the PTAP and I'm a little confused.
The diagram above seems really straight forward, I get it. However when I look at the schematics (http://thoughtprocessinc.com/files/PTAP%20Schematic%20A2.png (http://thoughtprocessinc.com/files/PTAP%20Schematic%20A2.png)), I see a capacitor (C3 = 0.1uF) that doesn't appear in the layout above. Ugh, anyone care to help out the not as experienced?
Here's my parts list:
R1 = Existing Delay Pot
R2 = 10K
D1 = 1N4752A
U1 = ATtiny45 (from decc)
U2 = 78L05
U3 = MCP41050 (from decc)
C1 = 0.1uF
C2 = 0.33uF
C3 = ?? (schematic lists 0.1uF)
In the layout posted you have C1 doing the work of C1 and C3 in the schematic. I don't think you need to add C3 to the layout. It is fine as it is.
Quote from: ppatchmods on August 25, 2009, 10:21:38 AM
What's the best option: the rate led attached to the delay circuit or the ptap? Anyone done this?
I'm actually kind of interested in this--is there any reasonable way to do this?
Quote from: liveloveshare on September 22, 2009, 02:05:11 AM
Quote from: ppatchmods on August 25, 2009, 10:21:38 AM
What's the best option: the rate led attached to the delay circuit or the ptap? Anyone done this?
I'm actually kind of interested in this--is there any reasonable way to do this?
http://www.aronnelson.com/gallery/main.php/v/cathexis/Veroboard+Layouts/Magnus+Modulus/PT2399+Tempo+Indicator.jpg.html
http://www.diystompboxes.com/smfforum/index.php?topic=50185.0
i bought the ptap2 for my rebote and used it for the rate led. you have to do some simple modification but it works nicely. i couldn't get it to work with water clear led's though, just standard red, green, yellow.
Finally finished this project. Two rebote delays in one box. I leave one on all the time with the level at about 10 oclock. I have the second one hooked up with the PTAP and level at 100%. Works great! Thanks for the PTAP DECC!
killer bang up job! I'm gonna have to go bang one out now...
Quote from: aziltz on September 24, 2009, 08:26:55 PM
killer bang up job! I'm gonna have to go bang one out now...
Actually I have a couple questions. After reading through the PTAP manual, I'm curious if,
it is possible to separate the functions of the Delay Pot, as in, have a Pot for Manual Delay Time and a Pot for the Subdivisions Selection? I think it would double the functionality of PTAP/2399 Delay if you don't have to change any settings when switching back and forth.
Quote from: aziltz on September 24, 2009, 08:37:02 PM
Actually I have a couple questions. After reading through the PTAP manual, I'm curious if, it is possible to separate the functions of the Delay Pot, as in, have a Pot for Manual Delay Time and a Pot for the Subdivisions Selection? I think it would double the functionality of PTAP/2399 Delay if you don't have to change any settings when switching back and forth.
You can use a standard SPDT toggle to select between two different delay pots, though you will have to manually flip the switch since there aren't any available pins to do this with the microcontroller.
Maybe you might be able to jury rig something with a FET switch and the tempo LED output of the PTAP2? A low level (LED on) on that pin selects the "tap" pot, more than a couple seconds of a continuous high level (LED off) switches back to the "manual" pot?
And I'm glad to hear about the success people are having with their PTAPs!
Thanks for the quick reply decc,
I'm definitely gonna add this to the to-do list.
has anyone built this up yet? I'd love to hear a build report and/or demo!
Has there been any success with the magnus modulus? I see that it has a 1k and a 4.7k after the time pot.
Quote from: ppatchmods on September 22, 2009, 10:55:04 AM
i bought the ptap2 for my rebote and used it for the rate led. you have to do some simple modification but it works nicely. i couldn't get it to work with water clear led's though, just standard red, green, yellow.
What kind of modification? I really want to do this to my Magnus and I really want a tempo LED.
i used the ptap2 and the ptap2 pcb. you have to add all the parts as listed but leave off the extra led+resistor, 2nd switch, & 2nd pot. i used the pad led2 on the board. works great
Thanks! I thought it was going to be more than that!
I did the PTAP2 on the Magnus. It works ok but I'm not getting a manual mode. The tap mode works fine. There is not any delay effect when I put it in manual though which is kind of cool as it works as a delay bypass. Just wondering what I did wrong in case I want to fix it.
I left off the series/parallel switch, the series/parallel led, and the second Time pot.
Actually in manual mode there is a little effect. You can really only hear it when I turn the Time pot and the Feedback pot all the way up.
I wonder if I just have a bad pot but it seems to work fine in Tap mode. I'll just change it out anyway. Do you think I need to jumper the series/parallel connection at all? Maybe I'll try that after I change the pot out.
You don't need to jumper the serial/parallel switch connection since there is an internal pull-up resistor in the MCU.
This is pretty strange behavior though. I recommend putting a pull-up on the unused pot #2 connection since the internal pull-up is disabled on this pin and floating inputs are to be avoided, though if this fixes things I would be surprised. First step I would take in tracking down the problem would be to disconnect the digital pot from the PT2399 and hook up a multimeter to measure resistance. Turn the delay pot and see that the digital pot tracks it.
Should I put the pull-up to 5v or 9v? Does it matter? Also, how would I calculate the value of the pull-up? What formula?
I'll disconnect the PT2399 and see if the digital pot tracks it.
To 5V. Everything in the PTAP operates at 5V (including the LEDs).
The value doesn't really matter. 10k is fine, though whatever you have around between 1k and 100k would be OK. The current drawn is negligible so you don't have to worry about a voltage drop (and since this is configured as an analog input it doesn't even have to be a valid logic level.) You don't want to jumper directly to a voltage rail since the input can be configured by software to be a push-pull output, and while the chances of a glitch doing this is miniscule, better safe than sorry.
Ok. So I opened it back up. I was going to do one thing at a time just so I know what it was that was wrong. First I put the pull-up resistor in and tested it. It worked!!! But wait! I put the bottom back on the pedal and it stopped working. That made me think there was a loose wire or something. Opened it back up and started poking at the wires (focusing on the 3 for the pot. Sure enough, I heard the chip calibrating. Reheated all the solder joints and presto! It works perfectly. I don't know if the pull-up resistor has any effect on it or not but it's there and doesn't have any negative affect at all.
So I can confirm that the PTAP2 does work with the Magnus. When I went to go get the schematic for the PTAP2 the other day, I noticed there was a PTAPH now. I ordered one :icon_biggrin:
Thank you for your help
Hi decc,
Ordered one of your PTAPH units and looking forward to receiving it soon! I had a question about the schematic because I'd like to create my own layout for the circuit. On the ATtiny44, you have Pin12 going to "mode_led" which looks like it is the same as "T4". What is this LED for? Is it to indicate that the pedal is in tap mode and it is a separate LED from the tempo LED? If that is the case, how do I wire up this LED? Do I connect T4 to the anode of an LED and then connect the cathode to GND? Is there a resistor involved?
Hey everyone,
I created a PCB layout for the PTAPH. I noticed that someone has already posted a layout for the original PTAP so I wanted to contribute by posting this for people that want to utilize the PTAP with the added tempo LED indicator. I have not received my PTAPH unit in the mail yet so I have not had the chance to verify this layout. Let me know if there are any errors and I will make the changes and re-post the image. I can also post an editable PDF of the transfer image that will make it the right size for printing if it is requested.
*MODERATORS* : I apologize if I am overstepping my bounds by posting this image. Let me know if it needs to be removed and I will do so.
(http://www.grassrootsaudio.com/pics/PTAPHPCB.bmp)
DECC -
Question for you. Would it be easy to program into the chip a way to use a rotary switch to change the timing increments? I've been looking into another thread for building a tap tempo'd tremolo and the chip that is used for that has the ability to use a rotary to switch between 1/4 note, 1/8th note, triplets, etc... I was just wondering if there were options to be able to do this with your chip as well? Could be something really cool that would make it even more versatile.
Jeff
Since the PTAP's pot input is, I think, a voltage divider between the positive and negative rails, it would work exactly the same as the rotary switch for the tap tempo trem. But then you'd be limited to a set number of delay times, so I'm not sure I see why you'd want to do that.
Hey, I'm back from the dead, questions answered:
Quote from: studiostud on April 30, 2010, 02:59:53 PM
Hi decc,
Ordered one of your PTAPH units and looking forward to receiving it soon! I had a question about the schematic because I'd like to create my own layout for the circuit. On the ATtiny44, you have Pin12 going to "mode_led" which looks like it is the same as "T4". What is this LED for? Is it to indicate that the pedal is in tap mode and it is a separate LED from the tempo LED? If that is the case, how do I wire up this LED? Do I connect T4 to the anode of an LED and then connect the cathode to GND? Is there a resistor involved?
The "mode_led" pin is for the serial/parallel more indicator for the PTAP2 configuration. It doesn't do anything in the PTAPH but I copied over the schematic from the PTAP2 and the label stuck. Leave it disconnected.
Quote from: Taylor on May 08, 2010, 09:49:20 PM
Since the PTAP's pot input is, I think, a voltage divider between the positive and negative rails, it would work exactly the same as the rotary switch for the tap tempo trem. But then you'd be limited to a set number of delay times, so I'm not sure I see why you'd want to do that.
That's correct, it's just a voltage divider. Though I do imagine the usefulness of the option of having the manual delay knob and the tempo beat knob being separated. It's a good idea for a future feature anyway.
Hey Decc, are you still around? Your website has been off-line for a while. Does this mean you are no longer supporting / selling PTAP / PTAP2?
Travis
Yeah, I've been wanting some for a little while now and the site has been down. Wish I knew how to do this myself.
If for any reason Decc isn't supporting it or selling it any more, I wonder if he'd be interested in turning the code over as open source so that the community could start burning our own.
If I knew how to do it, I would do it for us. I just don't have a clue.
There's always the new taptation:
http://www.diystompboxes.com/smfforum/index.php?topic=86294.0
Uhhh...
There isn't really. The store has sold out, and tonegod hasn't answered yet as to whether more will be available...
Jacob
Oh. I haven't really been following it... oops. :icon_redface:
Has anyone emailed decc? He may not be checking here too much. I have his email if you guys want me to mail him and see what's up.
Please do. Thanks.
Tonegod replied on the other thread. Looks like a new batch of taptations are on their way to the Aron already. I'll order one for sure.
I wish I could get some PTAP's though. I already have boards etched. It looks like I might have to try to figure out how to do it myself even though I think it's way beyond me. Off to an AVR forum ???
I emailed decc, but no response. :-\
Well great! Thanks though. If someone can point me in the right direction, I'll see what I can do to make these. I'll see what I can find out. I've already started reading some stuff and it seems pretty nuts. Maybe we could get together on here and do a collaboration to get the PTAP going again. If I had code and the knowhow to program the chip, I'd certainly take the time to make them available. I just don't want to step on Decc's toes if he plans on doing this anymore.
have a feeling Decc is just without interweb briefly. I could totally be wrong, cause it's just a guess though...
Jacob
got an email from decc a week or 2 ago, and he has disabled the online store and will no longer be offering the ptap :'( he had some issues arise as far as priority shifting and was very apologetic. just passing the info along.
Thank you for letting us know. Looks like I'll have to figure it out myself or give the Taptation a try when they are available.
Ok. I'm thinking about trying out the Taptation but in my search for alternatives, I found this that uses a PIC:
http://www.electricdruid.net/images/lfo/TapClock.gif (http://www.electricdruid.net/images/lfo/TapClock.gif)
Source:
http://www.electricdruid.net/index.php?page=projects.taplfo (http://www.electricdruid.net/index.php?page=projects.taplfo)
Does anyone see any problems with going this route? Are there going to be any issues applying this to the PT2399 as used in the Magnus Modulus?
I want to dip my toes into the water of programming and since they make the code available for this, it seemed like a good place to start. Kind of learning backwards but sometimes that works better for me.
That Tap Tempo circuit was used on the Tap Tempo Tremolo Taylor has generously got going around here. I seem to remember that it could be applied to a PT2399 circuit, but that we thought it was better applied to something with an LFO like a Trem or something like that.
Jacob
Thanks Jacob. So someone already tried to apply it to a PT2399 circuit? I'll look into that more. I just want to kind of verify that it could work before I spend the $ on a programmer and stuff plus I don't want to waste time if it isn't going to work at all.
You can use the TAPLFO with a PT2399 as an LFO to do modulation, but you can't use it as a tap tempo to set the delay time.
You could probably use the code as a starting point to do something similar to the PTAP.
Thanks Slacker. That sucks. Now I'm back to square one. So I pretty much HAVE to do some sort of digital pot and MCU?
Quote from: bside2234 on October 04, 2010, 04:05:56 PM
Ok. I'm thinking about trying out the Taptation but in my search for alternatives, I found this that uses a PIC:
http://www.electricdruid.net/images/lfo/TapClock.gif (http://www.electricdruid.net/images/lfo/TapClock.gif)
Source:
http://www.electricdruid.net/index.php?page=projects.taplfo (http://www.electricdruid.net/index.php?page=projects.taplfo)
Does anyone see any problems with going this route? Are there going to be any issues applying this to the PT2399 as used in the Magnus Modulus?
I want to dip my toes into the water of programming and since they make the code available for this, it seemed like a good place to start. Kind of learning backwards but sometimes that works better for me.
http://www.diystompboxes.com/smfforum/index.php?topic=76436.0
Quote from: Lurco on October 05, 2010, 01:38:39 AM
http://www.diystompboxes.com/smfforum/index.php?topic=76436.0
How does this help me? I've read through that twice now.
It answers your question I think though. You pretty much answered it yourself I think. Perhaps he was trying to suggest that if you hadn't read that, it would tell you that it only controls the LFO and not the PT2399 delay signal.
I think you do need to go with a programmed PIC. Fortunately for you, the taptation is available at the store, so you won't have to learn how to program. It's too bad that Decc isn't supplying the PTAP anymore.
Jacob
Oh, I see. I thought I might be missing something.
I think I may go with the Tapation for now but I don't want to be in the same boat in the future and not have the Taptation available.
I'm looking into programming my own stuff. It's going to be a long road though. The good thing is, I have all the time in the world really. Right now I'm just trying to figure out the best and right language, controller, programs, and programmer to use. It's like learning a foreign language, only harder because of all hardware and software.
Yeah, I've ordered the taptation and will give it a try. I'm a little disappointed, as I finally figured out my design for a stereo echobase setup, and I wanted to use a single tap control to drive different divisions in each channel. To do that now, I'd have to have two separate taptation MCPs, which is pricey at 20 bucks a pop. Instead I'll try a buffered splitter to drive two digipots with a single taptation controller, keeping both channels at the same division.
I don't want to experiment too much for fear of burning up the chip. If there was open source code for tap delay, I'd probably invest the money in a PIC interface instead. I took a look at the taplfo code, and it seems non-trivial to modify this to work with a digipot SPI interface.
See I'm trying the Taptation to drive a Dual PT2399 circuit to give me longer delay times. It's going to be a challenge, but my hope is to breadboard and create my own circuit design!
Jacob
Hi. Where I can buy U1 and U3 for ptap2?
He's no longer programming them anymore so you can't but the pre-programmed chip.
I've been wanting some of these too. I'm trying to learn to program my own chips. I'm starting at level 0 so it's going to be a long road.
Would somebody be kind as to tell me how can I purchase this kit? Thank you!
Welcome to the forum. :)
If you check the post right above yours you'll find the answer - you can't. But check this out:
http://www.diystompboxes.com/smfforum/index.php?topic=86294.0
oh, sorry. ;D
Anybody have the most recent schematic and build/setup instructions for the PTAP? I bought the chips and a board some time ago and never got around to installing them in my PT80. Just went looking and the web site is gone....
Thanks,
Deric
I have no chip, but I have the documents:
http://www.sendspace.com/file/500hgp
...and see this topic on pages 2 and 3! There's some pix and images.
Thank you!!!!!!!!!!!!! ;)
Does anyone have the PTAP2 and PTAPH documents?
Jacob
There is a new alternative project:
http://blog.dimehead.de/2010/09/pt2399-tap-tempo-modul-step-your-time/
or
http://uk-electronic.de/onlineshop/product_info.php/products_id/1797
http://uk-electronic.de/onlineshop/product_info.php/products_id/1789
Sweet. Sure wish I could read german! :P
http://translate.google.de/translate?u=http%3A%2F%2Fblog.dimehead.de%2F2010%2F09%2Fpt2399-tap-tempo-modul-step-your-time%2F&sl=de&tl=en&hl=&ie=UTF-8
not the best translation, but understandable :icon_mrgreen:
Hello,
I'm french so sorry for my bad english :icon_biggrin:
I built the tonepad rebote 2.5 delay and I want to add a tap tempo and I've seen this one
http://uk-electronic.de/onlineshop/product_info.php/cPath/105_195/products_id/1797?osCsid=ae89c6ac1c796e6e23034a9539488cce
Someone has tried it ? And especially does it work with the rebote ? ???
Thank you for your help.
Yes it works very well in the rebote 2.5 and mostly all other circuits with one PT2399 chip :)
Great, thanks a lot for your answer.
I will order today. ;D
Bye
Sorry to bump and old thread, but I couldn't find an answer to my question. Okay, so here's the deal: I'd like to add a tap tempo switch to the "Rebote Delay 2.5". These guys sell the kits:
http://uk-electronic.de/onlineshop/product_info.php/cPath/105_195/products_id/1797?osCsid=ae89c6ac1c796e6e23034a9539488cce
If you click on the manual, there's the brown wire labeled "point delay3". Where is this one suppose to be connected at? On top of that, do I just connect the green/yellow/GND wires directly to the time pot on my Rebote?
on this link it says brown to pin 6....
http://www.uk-electronic.de/Download/Beschreibung%20Tap%20TempoSMD.pdf
Cheers, thank you! :) Anyway, I suppose I have to leave out the -1K resistor to pin6- part. There's one already in the PCB, going to pin 6.