# Modding a Diaz Tremodillo



## hollowbody (Jan 15, 2008)

I've got an original Diaz Tremodillo that I haven't been using, even though I love the effect. The reason is that I would prefer something with a power adapter (the orig Diaz's don't have them) and even more, I would really like an LED light, especially one that pulses in time to the trem effect. 

EXCEPT...

I've heard that a lot of pedals with pulsing LED's have an audible pulse that comes through.

I'm not really looking at doing this myself, since the inside of Diaz pedals are a goop-covered nightmare, and I suck with soldering irons. Any idea who I can go to for this, what the cost would be, and most importantly, is there a surefire way of installing a pulsing LED without any accompanying noise?


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## Ti-Ron (Mar 21, 2007)

My fist guess would go to Greg at Solidgold soundlabs! Send him a line, I'm pretty sure he can do something for you!!!!


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## mhammer (Nov 30, 2007)

Audible LFO-based ticking is a problem in a lot of modulated effects. If you are of a certain age, you may remember the effect of your mom using the sewing machine, yuor dad using a power drill in the garage, or simply the compressor on the fridge or deep-freeze, on the "purity" of your stereo or even table radio. All those appliances were using the same power source - wall current - with minimal or no isolation from each other. Consequently, whenever a motor would turn on anywhere in the house, that impacted on the current instantaneously available to devices elsewhere in the house.

In a pedal, it's the same thing, except on a micro-scale. Think of the battery as being like the AC line running to your house, and all the little subcircuits in the pedal as being like separate appliances running off that central power. Unless steps are taken to effectively isolate the power needs of appliance A from those of appliance B, you will observe some impact of line noise.

The decoupling can take place in several complementary ways. One is to use medium-sized capacitors at the supply point of the different subcircuits (typically the V+ pin of a chip, where the 9V connects to it), so that the capacitor acts like a teeny battery to get the chip/subcircuit safely through that millisecond-wide drain on current available to it as a different part of the circuit suddenly demands current (think of it like an ultra-small-scale UPS).

A second is to use as low-current a circuit/device as you can so that it doesn't suck current away from other parts of the circuit, and isn't as affected by current needs in other parts of the circuit. If you look at the schematics for a wide range of modulation effects - phasers, flangers, choruses, tremolos, vibrato, etc - you will frequently find that they use a low-power chip like a TL022 or LM358 for the LFO or sweep-generator section. Such circuits typically generate a square-wave first, then transform it into a triangular waveform for the modulation. It is that initial square-wave that creates the sudden urgent draw of current form the rest of the circuit and produces the tick one hears.

Okay, now to the matter at hand. LEDs draw current too. And the more current they draw, the greater the risk that they too will produce an audible tick should they suddenly want to steal some current from the rest of the circuit. Many folks who have decided that they desperately wanted to convert a pedal to "true bypass" with an indicator LED have found, much to their chagrin, that the conversion resulted in a tick when the LED came on.

Happily, there are what are referred to as "superbright" LEDs. The advantage these have is that they can produce substantial illumination at "normal" current, but can produce useful illumination when supplied with much less current, thus conserving battery power by not needing as much of it.

If you look at a wide range of schematics that involve a status indicator LED, there will always be a resistor in series with it to govern how much current it draws. The higher the resistor value, the less current can pass. Typical values range between 1k and 4.7k. However those are for lighting up an LED rated at 300-600 millicandles (mcd). It is a trivial matter to walk into just about any decent electronic outlet and buy LEDs rated at three to six *thousand* mcd. These are capable of providing equivalent illumination at just a fraction of the power requirement. I regularly use these as indicators and can get away with sticking a 15k-18k resistor in front of them.

As well, it is not just the current drain/draw, per se, but the suddenness as well. If I were to take that resistance leading up to the LED, and divide it into, say a 10k resistor in series with a 4.7k resistor, I would still have a total of nearly 15k of resistance limiting the current going to the LED. If I ran a 10uf capacitor from their junction to ground, that would form a lowpass (i.e., treble-cutting) filter that rolled off any sudden changes occurring faster than 1.6hz (if the order was 10k-> 4k7) or 2.3hz (if the order is 4k7 -> 10k). In a sense the sudden current draw of the LED would be stretched out a bit over time. Less sudden, less audible.

S, it IS feasible. In the absence of a schem for the device, though, I can't tell you where to tap that signal to drive the LED. All I can tell you is that it does not HAVE to result in an annoying tick.


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## hollowbody (Jan 15, 2008)

mhammer said:


> Audible LFO-based ticking is a problem in a lot of modulated effects. If you are of a certain age, you may remember the effect of your mom using the sewing machine, yuor dad using a power drill in the garage, or simply the compressor on the fridge or deep-freeze, on the "purity" of your stereo or even table radio. All those appliances were using the same power source - wall current - with minimal or no isolation from each other. Consequently, whenever a motor would turn on anywhere in the house, that impacted on the current instantaneously available to devices elsewhere in the house.
> 
> In a pedal, it's the same thing, except on a micro-scale. Think of the battery as being like the AC line running to your house, and all the little subcircuits in the pedal as being like separate appliances running off that central power. Unless steps are taken to effectively isolate the power needs of appliance A from those of appliance B, you will observe some impact of line noise.
> 
> ...


Brilliant! Thanks Mark! Now I just need to find someone to do it for me in the Toronto area.

There's the Pedal Doctor, who has an article about the process, but when I contacted him about it a while ago, he never got back to me


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## mhammer (Nov 30, 2007)

I just posted a request for info on the DIY Stompbox forum, Conceivably someone will reply with the sort of concrete info that would let me tell you "Buy one of these, one of those, and connect it to THIS point on the board".


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## devnulljp (Mar 18, 2008)

Second would be go buy mario's one in the emporium right now - its a newer one with all you mentioned. 
Keep (or sell) the original as a vintage-ish piece?


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## hollowbody (Jan 15, 2008)

devnulljp said:


> Second would be go buy mario's one in the emporium right now - its a newer one with all you mentioned.
> Keep (or sell) the original as a vintage-ish piece?


I've tried a newer tremodillo's and didn't like it as much. Probably cuz Cesar himself didn't make it :smile:

Honestly, though, the enclosure wasn't as beefy and it didn't have the same "boutique" feel of mine. I might have just come across a dud though.


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## devnulljp (Mar 18, 2008)

hollowbody said:


> I've tried a newer tremodillo's and didn't like it as much. Probably cuz Cesar himself didn't make it :smile:
> 
> Honestly, though, the enclosure wasn't as beefy and it didn't have the same "boutique" feel of mine. I might have just come across a dud though.


I've heard that...there's also the Swamp Thang, which is pretty much the same circuit right? 
I keep looking at trem pedals, but the trem on my old Traynor is real nice so I never end up buying any of them. The Empress is impressive, but I like old school like yours...


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## hollowbody (Jan 15, 2008)

devnulljp said:


> I've heard that...there's also the Swamp Thang, which is pretty much the same circuit right?
> I keep looking at trem pedals, but the trem on my old Traynor is real nice so I never end up buying any of them. The Empress is impressive, but I like old school like yours...


Yes, from what I hear, the Swamp Thang is the same circuit, but I've never had the chance to try one out. 

I dig the tremolo on my Traynor as well, but it's not noticeable enough. There might be something wrong with my trem circuit, but even with the intensity cranked to 9.5, it's just not very "present," so I'm looking at reinstating the Tremodillo. Also, I like the half-speed feature.

One trem pedal I wanted to try out was the EHX Wiggler, but I never got around to it, but it seems to be a pretty decent pedal, offering Vibrato and Tremolo and pulling off some neat sounding stuff in the videos I watched.


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## Greenbacker (Mar 29, 2007)

The Dr. Sci trem is very nice and all analog, unlike the Empress...


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## mhammer (Nov 30, 2007)

The Empress is "digital" only with respect to modulation. The audio path is analog.

Once you get into unusual modulation patterns, the circuitry starts to get unreasonably complex for what it does. If you have the chops, it is simply much easier to program the modulation patterns into a PIC. Your ears won't know the difference.


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## Greenbacker (Mar 29, 2007)

mhammer said:


> The Empress is "digital" only with respect to modulation. The audio path is analog.
> 
> Once you get into unusual modulation patterns, the circuitry starts to get unreasonably complex for what it does. If you have the chops, it is simply much easier to program the modulation patterns into a PIC. Your ears won't know the difference.


There was bleed through the bypass. No matter what I did, there was flutter in my signal. An all-analog device would defeat when it is turned off, but this one sure didn't...


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## devnulljp (Mar 18, 2008)

Why don't you punt it for a profit as an all-original vintage pedal and buy a Swamp Thang? Same circuit, LED, power adapter. Problem solved. In fact, PM me if you decide to sell it...

EDIT: I'm a dumbass, and already said all this earlier in the thread. I'm having a groundhog day...


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## hollowbody (Jan 15, 2008)

devnulljp said:


> Why don't you punt it for a profit as an all-original vintage pedal and buy a Swamp Thang? Same circuit, LED, power adapter. Problem solved. In fact, PM me if you decide to sell it...
> 
> EDIT: I'm a dumbass, and already said all this earlier in the thread. I'm having a groundhog day...


Haha...well my solution is to send it to Greg at SolidGoldFX, but right now I'm just trying to scrounge up enough cash to do that.

A couple of reasons I don't want a swamp thang are that it's case is so much larger than the tremodillo, and the tremodillo is just so damned cute :banana:


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## hollowbody (Jan 15, 2008)

On second thought, maybe it's not that much bigger. I'll have to ponder this.


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## Ringwraith (Nov 17, 2007)

The Guyatone Flip VT-X is a nice swampy tube tremolo you may want to consider.
It also has a switch that makes the wave more square/choppy which the tremodillo doesn't have.

Cheers
Sean


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## Ringwraith (Nov 17, 2007)

Oh meant to give this link, maybe you've already seen it?
Degouping & fixing a tremodillo.

http://www.pedaldoctor.com/Diaz.html

Sean


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## hollowbody (Jan 15, 2008)

Ringwraith said:


> Oh meant to give this link, maybe you've already seen it?
> Degouping & fixing a tremodillo.
> 
> http://www.pedaldoctor.com/Diaz.html
> ...


Yeah, I've seen that one. That's what got me started thinking about it. I emailed the Pedal Doctor, but he never got back to me. I don't mind soldering, but degooping sounds like it requires lotsa patience, which I'm not good with. I imagine I would try to yank some goop and snap the PCB in half.


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