NEW PRODUCT: Taptation Tap Tempo controller

[The Tone God]

Sorry for being slow folks.

gitaar0: I'll look over your layout in the next day or so.

For those asking about a dual pot setup. I don't have a problem offering a dual setup if there is enough demand. I would probably make it so it ran off two of the 8pin single pots instead of one of the dual 14pin IC. Easier to stock the parts for both versions then and make for easier board layouts. Some features would have to be sacrificed though to make room for the needed I/O. It would  be alittle while as there is something else in the pipeline for DIYers.

Andrew

[Marcvv]

Sorry for being slow folks.

gitaar0: I'll look over your layout in the next day or so.

For those asking about a dual pot setup. I don't have a problem offering a dual setup if there is enough demand. I would probably make it so it ran off two of the 8pin single pots instead of one of the dual 14pin IC. Easier to stock the parts for both versions then and make for easier board layouts. Some features would have to be sacrificed though to make room for the needed I/O. It would  be alittle while as there is something else in the pipeline for DIYers.

Andrew

Hi Andrew,

No problem. I am glad you can get a look at it to see what might have gone wrong.

Thanks, Marc

[Galego]

One controller can connect to two digipots and command different resistance values, using the communication protocol (different command words for each pot). This might allow for a single controller to run a dual delay setup with different tempos/subdivisions for each delay. However this would require a code change. Also, I'm not sure if there is enough input capability to select different tempo subdivisions for two delays.

If this was possible, I'd want to ship my chip back to TTG and have him reprogram it for dual. Unless a controller with more I/O options is required for dual. Otherwise, we're back to the two controllers, two digipots.

The easiest way to have two different values on both digital pots, would be to use a MCP42100. You'd still only connect to one digipot (dual), the only difference would be in the programming.

[tigert10]

I was stoked to see a new Tap Tempo controller being developed.  I had a project designed on paper for a PTAP2 but then I guess they are not available any more. 

What I would like to do is in essence build two PT-80 delays in one housing.  The delays will be independent from one another so that I could say have dotted eighth delay on one and quarter notes on the other.  A simple footswitch then selects which side of the delay is being heard (only one side at a time) BUT I would like the tap tempo to control the delay tempo for each side without having to re-tap the tempo when I switch from one side to the other. 

The PTAP2 had this capability (to control two separate PT2399's).  What about the Taptation in this setup?  Is there any hope for my dual delay project?  Please give me some hope 

[jkokura]

The PT80 I have I couldn't make work with the PTAP by the way...

I think you can do that with the Taptation, take a look at the datasheets provided. If you can understand those, you can figure out how to make it work. I myself and working out how to make a dual PT2399 circuit, only instead of two seperate delays like you, I want them in series for longer delay times. I want to use the Taptation to control the tap tempo for the longer delay.

Jacob

[tigert10]

Thanks for your reply, in my Dual Delay setup, after reading the data sheets on the TapTation, it looks like the only way for me to get two independent delays running off of a single tap tempo switch is to use two TapTations and two digital pots running off of one tempo clock switch?  Someone please correct me if I am wrong.
Thanks for helping us average (in over our heads) Do-it-your-selfers out!!!!

[The Tone God]

The easiest way to have two different values on both digital pots, would be to use a MCP42100. You'd still only connect to one digipot (dual), the only difference would be in the programming.

Yes I could do this but as I mentioned earlier I would probably stick with the single version. That way both versions would use the same parts (easier to stock) and the layout would be easier as the two individual pots can be placed close to the PT2399s which is important to keep accuracy.

I was stoked to see a new Tap Tempo controller being developed.  I had a project designed on paper for a PTAP2 but then I guess they are not available any more. 

What I would like to do is in essence build two PT-80 delays in one housing.  The delays will be independent from one another so that I could say have dotted eighth delay on one and quarter notes on the other.  A simple footswitch then selects which side of the delay is being heard (only one side at a time) BUT I would like the tap tempo to control the delay tempo for each side without having to re-tap the tempo when I switch from one side to the other. 

The PTAP2 had this capability (to control two separate PT2399's).  What about the Taptation in this setup?  Is there any hope for my dual delay project?  Please give me some hope 

I have no problem stepping in and take over this particular DIY need that being a dual PT2399 controller.

My thinking right now is to keep the design in a 14pin IC is I would have to drop a few features. I think the modulation and double time functions would be dropped. I can then add a second time control pot so each delay can have it's own independent time control. I would also add a separate time scale switch for the second pot so if you want you can to do multi-tap style delays setting one for quarter and the other to eighth for example when used with the tap tempo function. If I drop one of the tempo LEDs, say the tempo LED, I can add a switch input to select serial or parallel modes so the two PT2399 can be cascaded for longer times or run in parallel for multi-tap.

Just a few thoughts.

Andrew

[tigert10]

Andrew, you just made my day!  Thanks for entertaining the idea of the "Taptation Duo" (dual pt2399 controller).  I completely agree that in this dual setup the first thing to go would be the modulation control and the double time control (these can be added by a builder if they want later).  It would be genius to add the functionality to use it in serial or parallel based on the needs of the design.  Be assured that I am eagerly awaiting news on this great idea!  Maybe an early Christmas present?  One can only hope 

[Skruffyhound]

This is starting to sound very interesting

[Marcvv]

I have a setup now with two taptations in parallel.
This way I like to drive two pt2399's in parallel to simulate a multihead delay.

What would be the best way to set the tap tempo of both taptations with one switch?

1) I am controlling  the tap tempo now from both taptations with a dual momentary switch.
Setting a tempo works fine. As soon as I use the tempo scale or double tempo the base tempo of the two goes out of sync. So this is not reliable.

2) Can I use the tempo clock output of the first taptation (pin 3) to drive the tempo clock of second taptation (pin 2) ? If so can I just connect them form the 1K resitor at pin 3 (taptation 1) to where the tap tempo switch is on taptation 2??

Thanks, Marc

[Galego]

One thing that might be useful. I've tried to connect the 3 wires that go from the controller to the digital pot, also to another digital pot, and it works just fine.

[The Tone God]

I have been asked this a few time in private but I'll mention it now. The TapTation can drive multiple digital pots in parallel without the need for extra logic. Just wire up the other pot digital connections in parallel with with the other pot. You can use the output of one TapTation to set another TapTation but you have to come up with a pulse feed switching arrangement to do that.

Remember there is also the issue of the internal clocks in the PT2399 floating around. They have accuracy issues too that the TapTation cannot compensate for.

Just an idea for a quick hack-ish multi-tap setup. Wiring the digital pots in parallel and put mechanical pot in series with one of the digital pots to ground, like the modulation MOSFET does, then adjust that pot to put that delay slightly out of sync with the other delay. Not the greatest but easy to do.

Andrew

[ppatchmods]

what other mosfet can i use besides the bs170? i know the 2n7000 is a popular choice but i have neither. any other choices? jfet? fet? i have some random trannys from boss pedals...

[The Tone God]

what other mosfet can i use besides the bs170? i know the 2n7000 is a popular choice but i have neither. any other choices? jfet? fet? i have some random trannys from boss pedals...

The 2N7000 should work as well. Basically any transistor that has a low on resistance and can be driven by the 5v logic should work. I recommended the BS170 because its popular and if people didn't have any they could order some with the TapTation from Aron.

Andrew

[ppatchmods]

any other choices? i don't have either of those... does it have to be a mosfet?

[Valoosj]

Is it me, or is this no longer available in Aron's store?

[Marcvv]

You can use the output of one TapTation to set another TapTation but you have to come up with a pulse feed switching arrangement to do that.

So this is out of my scope of knowledge. Anyone willing to school me on this and help me set something like that up?

Thanks, Marc

[MoltenVoltage]

I've taken a look at your TapTation PT2399 application note and see that you say the circuit design has an average accuracy of 5ms using a MCP41100 digipot.

This seems impossible given that the 100K ohm MCP41100 digipot has a typical resistance tolerance of +/- 30%.

I understand how you arrived at the 5ms value - dividing the 257 step resolution by the device's target resistance, but unfortunately digipots are extremely variable in their actual resistance and can be expected to have a nearly 30% error.

With the PT2399, a 30% error can amount to an enormous error in accuracy.

For example, at 27,600 ohms, the PT2399 datasheet calls for a 342ms delay time.

70% of that value is 19,320 ohms.

Even, very conservatively, at the next value down on the datasheet (21300 ohms), the stated delay time is 273 ms, with a resulting error of 69ms.

Of course this error is even more dramatic when you get up around 100K ohms (> 1 second of delay time) where you can expect an error of over 150ms!


Have you come up with any way to calibrate the output resistance or otherwise account for this typically huge tolerance error?

[ppatchmods]

I've taken a look at your TapTation PT2399 application note and see that you say the circuit design has an average accuracy of 5ms using a MCP41100 digipot.

This seems impossible given that the 100K ohm MCP41100 digipot has a typical resistance tolerance of +/- 30%.

I understand how you arrived at the 5ms value - dividing the 257 step resolution by the device's target resistance, but unfortunately digipots are extremely variable in their actual resistance and can be expected to have a nearly 30% error.

With the PT2399, a 30% error can amount to an enormous error in accuracy.

For example, at 27,600 ohms, the PT2399 datasheet calls for a 342ms delay time.

70% of that value is 19,320 ohms.

Even, very conservatively, at the next value down on the datasheet (21300 ohms), the stated delay time is 273 ms, with a resulting error of 69ms.

Of course this error is even more dramatic when you get up around 100K ohms (> 1 second of delay time) where you can expect an error of over 150ms!


Have you come up with any way to calibrate the output resistance or otherwise account for this typically huge tolerance error?

sounds like a good pm...

[Kindly Killer]

I bought a couple Taptation chips and I just started hacking away at a Fab Echo. I hotwired the pedal to be always on b/c my pedalboards have loopers. Once I removed the actuator, lever, and onboard switch, there is lots of room in the enclosure so I am going to try to jam everything in there.  Sooooo.....

What would be a good choice for a SMALL 0.1uF cap? There are many on this board and if I use the giant poly film caps I have it won't fit.

I have a bag of momentary DPDT switches I got to build controllers for digital amps and effects, but they might not be the best thing for this. I am replacing the actuator from the original pedal - the shaft that goes thru the spring under the black foot pad - with the tap tempo switch. What would be a good choice here? I want something SMALL and QUIET. I don't want a loud click and I don't want to take up a lot of space. The kind that comes to mind is what they have at Radio Shack, but a lot of components I get from there give me problems.

BTW I get 99% of my stuff from either Small Bear or Mouser if you have part numbers or links.