Bypass MAX1044

[guidoilieff]

Hi, I was wondering if I could just NOT use the MAX1044 ic in this schematic:

• http://www.generalguitargadgets.com/pdf/ggg_catrem_sc_orig.pdf

Its a Craig Anderton tremolo. I tried connecting a +12/-12 transformer but I don't know how to rectify it because there are billion ways to do in in google so im not sure if I did it right.
Here is a layout where I highlighted the +/-/ground rails based on the max1044 outputs:


The biggest problem: I checked for conductivity in the voltage input and I have some in the positive and ground rails:

I think this is why the TL072 fried, but I cant see where. The original ready-to-transfer design has a short between ground and positive under C6. I think thats a mistake so I corrected it before etching my pcb.


So, any info you can give me will be appreciated.
Thanks


Complete project: http://www.generalguitargadgets.com/effects-projects/tremolo/ca-tremolo-project/

[italianguy63]

The MAX1044 is being used for a voltage "inverter" there.  They also have a reputation for being "fragile"-- if you had a short on the back side, you may have damaged the 1044 first, and then it took out the TL072.

Toss the MAX1044 and replace it with a TC1044SCPA or TC1044SEPA.   It is a direct replacement in this case.  Swap out the TL072-- and you may be good.

MC

[armdnrdy]

Hi, I was wondering if I could just NOT use the MAX1044 ic in this schematic:

I tried connecting a +12/-12 transformer but I don't know how to rectify it because there are billion ways to do in in google so im not sure if I did it right.

It sounds like you never tried using the MAX1044 correct?

There may be a billion different ways to rectify a center tapped transformer on the internet but..there is one good way!
See figure 8.
http://www.bristolwatch.com/ele/power_supplies.htm

[MrStab]

in some cases, you can just swap all the connections to the negative supply with connections to ground, and all connections to ground to 1/2 supply voltage. it's not quite as straightforward as that, though, and you may need to scale any gain for the new voltage. i have to make a shout out here to the guys who taught me almost the exact same thing a coupla years ago!

i wholeheartedly agree with Mark - you should ditch the MAX1044 and use an ICL7660S or some other charge pump with a "boost" feature between pins 1 & 8. MAX1044 has a max rating of 10V, and whilst most people get lucky, it'll be a real pain when you use an unregulated adapter or when you win the battery lottery and find a fresh 9-volter that reads 10V+. if you don't have access to other chips, you should at least limit the supply voltage. you're basically running on "i hope" instead of "i know".

[PRR]

> just NOT use the MAX1044 ic in this schematic:

I do not see a MAX1044 in that schematic?

> +12/-12 transformer

Don't do that!

The CD4049 is rated for 18 Volts MAX. And unlike some other families, the original CMOS chips could be awful close to the edge of disaster at their max spec. Your proposed +/-12V DC plan would apply 24V to the poor little chips. I'd expect quick-death of your 2-bits worth of chip.

If you use the GGG board there is a super-simple way to adapt it for one 6 Volt *AC* supply. The rectifiers are in there (though intended for backward-battery protection). The caps are there but only to bypass battery hiss, you need much large cans to filter AC-supply buzz.



Do NOT go over 6VAC! This already gives +/-8V, 16V total, which is near-enough to the CD4049's MAX rating. 6.3V gives +/-8.3V or 16.6V total, and 6.8V puts you past the chip MAX rating.

[guidoilieff]

It sounds like you never tried using the MAX1044 correct?

There may be a billion different ways to rectify a center tapped transformer on the internet but..there is one good way!
See figure 8.
http://www.bristolwatch.com/ele/power_supplies.htm

Yeah. I forgot to say I'm from Argentina and I cant find any damn replacement for that one, so I have no choice but to use a bipolar power supply.

[guidoilieff]

> just NOT use the MAX1044 ic in this schematic:

I do not see a MAX1044 in that schematic?

> +12/-12 transformer

Don't do that!

The CD4049 is rated for 18 Volts MAX. And unlike some other families, the original CMOS chips could be awful close to the edge of disaster at their max spec. Your proposed +/-12V DC plan would apply 24V to the poor little chips. I'd expect quick-death of your 2-bits worth of chip.

If you use the GGG board there is a super-simple way to adapt it for one 6 Volt *AC* supply. The rectifiers are in there (though intended for backward-battery protection). The caps are there but only to bypass battery hiss, you need much large cans to filter AC-supply buzz.



Do NOT go over 6VAC! This already gives +/-8V, 16V total, which is near-enough to the CD4049's MAX rating. 6.3V gives +/-8.3V or 16.6V total, and 6.8V puts you past the chip MAX rating.

Thanks, I love you.

[PRR]

If you must use a 12+12v 300mA transformer, use a Full Wave Bridge and two 470uFd caps to make +/-17V DC, use a positive and a negative 9V regulator to get it down to what the chips can handle.

[guidoilieff]

So.... I made this circuit for the +-12v transformer, but with 470uF caps an 9v regulators:


I've measured the V output: 17v between negative and positive, 8.87v between negative and ground, 9.10 between positive and ground.
Between pins 4 and 8 of the tl072 it reads 17v, but the damn IC keeps getting hot.
Without the tl072 the led works fine.

Should I cleanse it with fire in the incinerator and forget about this?

[duck_arse]

470uF won't make too much never-mind. when you say '9V regulators', you do mean a positive and a negative 9V regulator, don't you?

with the blak dmm lead to ground, and red to negative, what is your reading? if the IC is getting hot, it is probably being asked to shift too much current into its load. what is connected at pins 1 and 7?

[italianguy63]

All this to avoid a $1.00 IC.  Can't you find an eBay seller with international (global) mailing?!  MC

[PRR]

> IC keeps getting hot.

Which IC?

The regulator(s)? Or the TL0?

Since you are not putting any over-voltage on the TL0, about the only way it would run hot is if you have reversed its two supply pins. (Why would I think of that? HOW many times have I connected chips backward?)

> I've measured

Keep meter black-lead on "ground" and measure *these* voltages:



Which ones are you not getting?

[guidoilieff]

> IC keeps getting hot.

Which IC?

The regulator(s)? Or the TL0?

Since you are not putting any over-voltage on the TL0, about the only way it would run hot is if you have reversed its two supply pins. (Why would I think of that? HOW many times have I connected chips backward?)

> I've measured

Keep meter black-lead on "ground" and measure *these* voltages:



Which ones are you not getting?

The TL072 is the one that keeps getting hot in the right orientation. I tried to reverse it, but gets hot anyway and the LED shuts down.

I remind you that I used a -9 and +9 power regulators. I have 16dcv after the rectifier, +9 and -9v after the regulators. They don't get hot.

TL072:
pin 1:0.05
pin 2:0.05
pin 3:Ground
pin 4:-9
pin 5:Ground
pin 6:0.05
pin 7:0.05
pin 8:+9




Whats the S terminal (light blue cable) and transistor are for? http://www.generalguitargadgets.com/pdf/ggg_catrem_lo.pdf
Should I remove them?

[guidoilieff]

470uF won't make too much never-mind. when you say '9V regulators', you do mean a positive and a negative 9V regulator, don't you?

with the blak dmm lead to ground, and red to negative, what is your reading? if the IC is getting hot, it is probably being asked to shift too much current into its load. what is connected at pins 1 and 7?

Between Ground and negative is -9vcd

Between pins 1 and 7 of the tl072 the dmm reads 0dcv.

[guidoilieff]

All this to avoid a $1.00 IC.  Can't you find an eBay seller with international (global) mailing?!  MC

You come to Argentina and try. The ones I can get are going to be waay more expensive than all the components and transformer in the stompbox when they arrive.

I thought it was going to be easier. Do you really think I'm doing all this because I love the smell of burnt ics in the morning?

[italianguy63]

LOL.. No, and I'm not trying to be a dick (it comes naturally).

Your struggles make me want to just mail you some!

MC

[lars-musik]

Hi Guido,
I just saw that indeed the sellers from overseas I sometimes palce orders at do not ship to Argentina. Must be a pain in the neck. I have some ICL7660S (drop-ion replacements for the 1044) here and a regular letter with a max height of 1 cm costs 1,50 Euro from Germany to Argentina.

If you think there's a good chance that such a letter would arrive eventually, then just PM me your full address details and I'll send you three or four of these chips. The website of our postal service says that it'll take 10.9 days on the average (such a statement sounds very much like Teutonic thoroughness).

Cheers, Lars

[guidoilieff]

With all your help we made some corrections in GGG web. (I emailed jd from ggg)

2015-07-20 - Fixed transistor value from 2N3904 to 2N3906 in the layout file and added Q1 to the Bill of Materials. Changed some wording in the Instructions file.
2015-08-04 - fixed the PCB file where there was an inadvertent trace crossing.


Thanks to everyone, I learned a lot. Going to try the abandoned tremolo again and sell it because I hate it by now.