Author Topic: Building the tap tempo tremolo  (Read 319156 times)

Taylor

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Re: Building the tap tempo tremolo
« Reply #80 on: June 26, 2010, 05:04:24 PM »
Some of the waveforms are definitely on the subtle side, especially the "lumps" aka inverted hypertriangle. Set the wave distort in the center for all testing, then try to locate the square wave. It should be at about 11 oclock or 1 oclock on the waveform knob depending on how you have the pot wired. With that on, you'll need to adjust the trimpot next to the TAPlfo and the one above the opamp as discussed in the instruction PDF.

It sounds to me like it's working, so now you just need to tweak it into proper functioning.

good air

Re: Building the tap tempo tremolo
« Reply #81 on: June 26, 2010, 06:18:29 PM »
Success.
« Last Edit: June 26, 2010, 06:37:18 PM by good air »

Taylor

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Re: Building the tap tempo tremolo
« Reply #82 on: June 26, 2010, 06:20:48 PM »
 :) :icon_exclaim:

.Mike

Re: Building the tap tempo tremolo
« Reply #83 on: June 28, 2010, 09:43:04 PM »
Hey Taylor--

Which NSL-32 are you providing with this?

I'm working on putting together a parts order, and I'd like to order the parts for the tap tempo tremolo.

It looks like Silonex has 14 varieties of the NSL-32.  ???

Both Smallbear and Newark have 3 different choices.

Thanks,

Mike

Taylor

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Re: Building the tap tempo tremolo
« Reply #84 on: June 28, 2010, 09:57:20 PM »
I've only used the plain old NSL-32 with no suffixes. The other ones that Small Bear has require more current to turn on, which could potentially mean more ticking. The 32B and 32H XXX might be something to try since they use less current but I don't know where you can get them. I could also be misunderstanding the current thing since I'm still no guru.

.Mike

Re: Building the tap tempo tremolo
« Reply #85 on: June 28, 2010, 11:49:02 PM »
Thanks Taylor.

In looking at the datasheets, it seems like the SR3 is the fastest of the group with the widest resistance range, but it might be too fast. It also has a lower On resistance at 5mA than the regular NSL-32 does at 20mA. The SR2 apparently has a lower On resistance at 1mA than the regular NSL-32 has at 20mA. That might be a good choice to keep the current as low as possible.

I think I'll order one of each, socket, and compare.

Thanks!

Mike

good air

Re: Building the tap tempo tremolo
« Reply #86 on: July 15, 2010, 07:59:20 PM »
Definitely forgot to take a picture so here it is. 


Uploaded with ImageShack.us

Taylor

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Re: Building the tap tempo tremolo
« Reply #87 on: July 15, 2010, 08:04:28 PM »
Cool.  :)

good air

Re: Building the tap tempo tremolo
« Reply #88 on: July 15, 2010, 08:10:33 PM »
Thanks.  2 questions for adjustments. 

I need more volume when the trem is engaged, getting a drop when I turn it on, gain pot  is already maxed - is it possible?

and what are the chances of putting a sequencer in there in the future?   :icon_biggrin:

.Mike

Re: Building the tap tempo tremolo
« Reply #89 on: July 15, 2010, 08:31:35 PM »
I need more volume when the trem is engaged, getting a drop when I turn it on, gain pot  is already maxed - is it possible?
Yes. R15 and the LDR portion of the optocoupler work with the opamp as an inverting amplifier. Increasing the value of R15 will increase the gain.

Quote
and what are the chances of putting a sequencer in there in the future?   :icon_biggrin:

I'm sure it can be done with a PIC, but it probably wouldn't be a drop-in replacement.

:)

Mike
« Last Edit: July 15, 2010, 08:37:46 PM by .Mike »

Taylor

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Re: Building the tap tempo tremolo
« Reply #90 on: July 15, 2010, 09:20:11 PM »
By "gain pot is already maxed" it sounds like he already has increase R15 (in my PCB it's a trim) as far as it can go. You could add a series resistance, but in my experience there should be tons of gain on tap with that knob. What you need to do is change the setting of the trim right next to the TAPLFO - this sets the current limiting resistance of the optocoupler, and you must have it trimmed way down so the opto is just barely turning on.

By sequencer do you mean something like a ZVex Seek Trem? We could ask Tom but I don't think the PIC 16f684 used in this project can be configured with enough pot inputs for that.  So you'd need to go up to a bigger microcontroller I think.

If you just want a tap tempo Seek Trem kind of thing, I think it would be possible to do that by combining the tap trem with a Vanishing Point (see tech.thetonegod.com), and using the clock output of the TAPLFO to clock the decade counter.
« Last Edit: July 15, 2010, 09:23:47 PM by Taylor »

JKowalski

Re: Building the tap tempo tremolo
« Reply #91 on: July 15, 2010, 10:08:56 PM »
By "gain pot is already maxed" it sounds like he already has increase R15 (in my PCB it's a trim) as far as it can go. You could add a series resistance, but in my experience there should be tons of gain on tap with that knob. What you need to do is change the setting of the trim right next to the TAPLFO - this sets the current limiting resistance of the optocoupler, and you must have it trimmed way down so the opto is just barely turning on.

By sequencer do you mean something like a ZVex Seek Trem? We could ask Tom but I don't think the PIC 16f684 used in this project can be configured with enough pot inputs for that.  So you'd need to go up to a bigger microcontroller I think.

If you just want a tap tempo Seek Trem kind of thing, I think it would be possible to do that by combining the tap trem with a Vanishing Point (see tech.thetonegod.com), and using the clock output of the TAPLFO to clock the decade counter.


You could actually do a drop in replacement chip for a seqencer on your board. You could use a momentary switch on that "extra" pin to toggle between the pots for the setup (I.E. set a pot value, then hit the switch to go to the next one). Maybe use one of the LED's already set up (the tap LED or the clock) to indicate when you are back at the beginning of the "pot row". Hell, you could make it into as many "pots" as you want... Want a 50 potentiometer sequencer?  :icon_lol:

All the control pots/switches/leds on that chip are basically "blank slate" inputs. You can rewrite the code to do whatever you want with them.

Lesse, the tap chip has these controls/ports

Tap switch input
Extra function switch input

Depth
Multiplier
Speed
Waveform
Wave distort

Clock LED
Tap LED

So maybe change them to:

Tap switch input -> Same
Extra function switch input -> Next sequencer potentiometer

Depth -> Same
Multiplier -> Same
Speed -> Same, or maybe instead (since with the tap tempo you can replicate it) something like "order of sequencer" (forward, backwards, forwards+backwards, random)
Waveform -> Sequencer Potentiometer
Wave distort -> Smoothing? That'd be complicated in code, though. # of sequencer pots?

Clock LED -> Same
Tap LED -> same, but also flashes twice or something when you end up back at the start of the sequencer pots

All it would take is changing the chip out on the board and you can flip between wave trem or sequencer trem.

Taylor

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Re: Building the tap tempo tremolo
« Reply #92 on: July 15, 2010, 10:19:14 PM »
That sounds pretty cool. I just meant that it wouldn't have the 8 pots minimum simultaneously to emulate something like the Seek Trem. It would be a little less immediate just stepping through pots, and also difficult to remember how you had set all the pots with no visual feedback, but that's ok with me.

Would it be possible to piggyback the chips and enable one or the other via toggling the power pins?

And when will your code be ready?   :icon_wink:

.Mike

Re: Building the tap tempo tremolo
« Reply #93 on: July 15, 2010, 10:28:56 PM »
By "gain pot is already maxed" it sounds like he already has increase R15 (in my PCB it's a trim) as far as it can go. You could add a series resistance, but in my experience there should be tons of gain on tap with that knob. What you need to do is change the setting of the trim right next to the TAPLFO - this sets the current limiting resistance of the optocoupler, and you must have it trimmed way down so the opto is just barely turning on.

By sequencer do you mean something like a ZVex Seek Trem? We could ask Tom but I don't think the PIC 16f684 used in this project can be configured with enough pot inputs for that.  So you'd need to go up to a bigger microcontroller I think.

If you just want a tap tempo Seek Trem kind of thing, I think it would be possible to do that by combining the tap trem with a Vanishing Point (see tech.thetonegod.com), and using the clock output of the TAPLFO to clock the decade counter.

I meant he could use a larger value resistor/trim/pot. :)

I think we're both kind of right. The maximum gain of the second opamp stage is directly related to the minimum resistance of the LDR. So, if you want to increase the gain of that stage, you can either lower the minimum resistance of the LDR, or increase the resistance of the feedback resistor. If lowering the resistance of the LDR by increasing the current to the LED side of the photocell induces ticking, it may end up being an equally acceptable option to increase the size/add series resistance the value of the resistor/trim/pot. I think.  :icon_neutral:

Couldn't you also increase the value of R12 to give some gain to the first inverting stage, instead of it just functioning as a buffer?

You could actually do a drop in replacement chip for a seqencer on your board.

Cool! I'm surprised that that base chip hasn't been implemented into more designs yet. I think it's only a matter of time. :)

Mike

Taylor

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Re: Building the tap tempo tremolo
« Reply #94 on: July 15, 2010, 10:43:08 PM »
I meant he could use a larger value resistor/trim/pot. :)

I think we're both kind of right. The maximum gain of the second opamp stage is directly related to the minimum resistance of the LDR. So, if you want to increase the gain of that stage, you can either lower the minimum resistance of the LDR, or increase the resistance of the feedback resistor. If lowering the resistance of the LDR by increasing the current to the LED side of the photocell induces ticking, it may end up being an equally acceptable option to increase the size/add series resistance the value of the resistor/trim/pot. I think.  :icon_neutral:

Couldn't you also increase the value of R12 to give some gain to the first inverting stage, instead of it just functioning as a buffer?

Yep, you're right. Maybe I'll play around with that some. The only thing is that you lose max depth when you trim the opto way down like that. If the opto isn't completely muting the signal when the LED turns off (which it probably isn't) and then you cut down the max level (bright LED) and amplify both the max and min levels, you end up with less contrast between loud and quiet. But it could still work and may help if you have ticking issues.



Quote
Cool! I'm surprised that that base chip hasn't been implemented into more designs yet. I think it's only a matter of time. :)

Mike

Just imagine if somebody was putting together a DIY project for a 12-stage tap tempo phaser, using cheap, easily available parts that don't require matching?  :icon_wink:

good air

Re: Building the tap tempo tremolo
« Reply #95 on: July 15, 2010, 11:21:20 PM »
Yeah the trim pot is maxed.  I adjusted the led and opto trimpots for maximum depth.  There was absolutely no ticking at all when I was adjusting the trims, so that led to resistor diagram worked like a charm.  

@.Mike - I was thinking the same thing with the gain trim, maybe raising it to 50k.  I didn't do the external gain knob so I wanted to triple check before I desoldered the trim.  Seems simple and effective but bringing this trem to a show this weekend and don't wanna mess it up.   :D

Quote
If you just want a tap tempo Seek Trem kind of thing, I think it would be possible to do that by combining the tap trem with a Vanishing Point (see tech.thetonegod.com), and using the clock output of the TAPLFO to clock the decade counter.

Thats EXACTLY what I was thinking about the sequencer.  I was aiming for more of a goatkeeper sequencer, could be 4 steps, could be 8, just think your trem has a lot of potential for rhythmic beats combined with the waveshaping and tap tempo.  I downloaded both Vanishing Point pdf's and thought it seemed very do-able.  Then I went to the Electric Druid site and noticed the clock output and the empty pin..  So makes me think its possible if you just send the signal out of the chip ---> sequencer (vanishing point) ---)> back into the chip..  but its way out of my league to figure it out right now.  Jkowalski's idea about the code has me very intrigued now.  Hopefully you guys can make this happen cause as you see in the pic I used a pretty big enclosure and theres def some room for more fun in there.   :icon_biggrin:
« Last Edit: July 15, 2010, 11:23:57 PM by good air »

good air

Re: Building the tap tempo tremolo
« Reply #96 on: July 15, 2010, 11:36:55 PM »
Just imagine if somebody was putting together a DIY project for a 12-stage tap tempo phaser, using cheap, easily available parts that don't require matching?  :icon_wink:

If it makes any difference, my next build was going to be the Phaseur Fleur.. food for thought.  ;)

JKowalski

Re: Building the tap tempo tremolo
« Reply #97 on: July 16, 2010, 03:44:31 AM »
That sounds pretty cool. I just meant that it wouldn't have the 8 pots minimum simultaneously to emulate something like the Seek Trem. It would be a little less immediate just stepping through pots, and also difficult to remember how you had set all the pots with no visual feedback, but that's ok with me.

Would it be possible to piggyback the chips and enable one or the other via toggling the power pins?

And when will your code be ready?   :icon_wink:


Yeah, well that's what happens when you design around things  :icon_biggrin:

Piggyback the chips? Hmm... I don't really know how the chip settles when it's unpowered, so I can't give you an answer on that. It might work fine.

Haha, hmm. I suppose I could try something... I'll let you know if I decide to work something out for it.

Just imagine if somebody was putting together a DIY project for a 12-stage tap tempo phaser, using cheap, easily available parts that don't require matching?  :icon_wink:

If it makes any difference, my next build was going to be the Phaseur Fleur.. food for thought.  ;)

I have an 10 stage version on a breadboard right now that I am finishing up. It uses FETs. I was considering OTA's and did try them but I couldn't do more then 4-6 stages since the 14-pin chips seriously start to fill up the board. I still am trying to figure out how to perfect the phaser controls and where to place the filter peaks. It is a phaser/vibrato combo.

The chip can basically be integrated into any design very easily. It just replaces the LFO, and then you got to work out the biasing. Filtering is easily done with three lo-pass filters in series - the PWM frequency can be massively attenuated without harming the sharp angles in the waveforms... but I have found it is best to push the filter a little lower to eliminate any thumping in the LFO's sawtooth, square, and random waves.

What I mean is that you don't really need to draw up new projects for the chip, just integrate into already made projects. I guess someone could flip through the most popular projects and draw up schematics with the chip integrated already... Hrmm. I'm hesistant to take on too many projects though, since I am finishing up a bunch I have had lying around forever right now and it's a real pain. Life is much simpler when you don't multi-task in your hobby.  :icon_lol:

I'll have to post a sound clip of the random waveform at high speed with deep phasing tomorrow. I think I have a vid of my brother fooling around with it I can pull it from. It is so funny. It makes it sound like you are playing your guitar underwater.




Taylor

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Re: Building the tap tempo tremolo
« Reply #98 on: July 16, 2010, 04:31:19 AM »
My phaser plan was to use the PWM to switch 4066 switches with resistors both in series and parallel. These resistors would replace the FETs in a Phase 90-type phaser. This is cheap, uses available parts, and doesn't require any matching. I may need to clock the TAPLFO faster, need to check if that's possible.

JKowalski

Re: Building the tap tempo tremolo
« Reply #99 on: July 16, 2010, 01:56:25 PM »
My phaser plan was to use the PWM to switch 4066 switches with resistors both in series and parallel. These resistors would replace the FETs in a Phase 90-type phaser. This is cheap, uses available parts, and doesn't require any matching. I may need to clock the TAPLFO faster, need to check if that's possible.

You can't clock the PWM any faster without losing resolution in the waveform. It's a trade off between PWM speed and bit depth. You can't clock the whole chip any faster to enable both higher PWM frequency and good bit depth because 20Mhz is the maximum speed.

It's an interesting plan. You'd have to stick a pretty steep filter stage at the end, though, to remove the hash generated without edging into the audio band at all. I might take a look into PWM'd resistors sometime, I've never actually tried them out.

I think an 8-stage is the best choice for this, since it only takes two quad op amps and two 4066... Though you could use a univibe style transistor follower+phase splitter layout.


By the way, here's that funny phaser sound. Don't mind the aimless noodling, I don't think my brother expected to be recorded  :icon_rolleyes:

The Joe Walsh was inspired by

« Last Edit: July 16, 2010, 02:30:48 PM by JKowalski »