# Simulcast IC—is it a charge pump? And which type?



## farwest1 (Mar 9, 2020)

Hi all, I'm assembling my parts list for the Simulcast. This one has been a bit of a hunt.

The last thing I need is IC1 LT1054. I can get one on Amazon for $16 but it takes until April to arrive.

Or I can order one from Mouser for $3. Does it matter if it's LT1054IP or LT1054CP?  Both seem to accept input 15V and output 5V. Is that right?


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## twebb6778 (Mar 9, 2020)

Get the TC1044S from Tayda and bridge the pads on the pcb that say 1044.









						TC1044SCPA TC1044 Voltage Regulator IC
					

MICROCHIP - Get It Fast - Same Day Shipping




					www.taydaelectronics.com


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## farwest1 (Mar 9, 2020)

twebb6778 said:


> Get the TC1044S from Tayda and bridge the pads on the pcb that say 1044.
> 
> 
> 
> ...


Thanks! I assume I just bridge them with a piece of solid wire? They're very small and close together.

What does bridging and then using a 1044 do different than tracking down a 1054?


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## Nostradoomus (Mar 9, 2020)

Pins 1-8 are setup to boost the oscillation frequency above the human range of hearing when they are tied together. The LT1054 doesn’t have that feature.

And yeah just lay a solder blob across them!


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## Robert (Mar 10, 2020)

Another one I was just made aware of is the TC7660HEPA.

It doesn't need the jumper and runs at 125kHz, so is _far _out of the audible range.  (vs 25kHz / 45kHz in the usual suspects)


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## Nostradoomus (Mar 10, 2020)

And it filters the air around it!


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## farwest1 (Mar 10, 2020)

One other question!  C4 calls for a 35v 120uf capacitor. 

I have a 63v 120uf capacitor. Would it matter if I put the one in with the higher voltage?


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## Nostradoomus (Mar 10, 2020)

Nope, that’s fine. If it fits use it!


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## farwest1 (Mar 10, 2020)

Ok, almost done with the board!  

I find myself without a 450R resistor at r12. Is there another value I could swap out? Something fairly common?

Also, for the 100uF at c11, I only have a 16v 100uF Aishi. Will that work?

Thank you!


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## Nostradoomus (Mar 10, 2020)

Anything close to 450r is fine. 470, 510 etc.


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## farwest1 (Mar 10, 2020)

Nostradoomus said:


> Anything close to 450r is fine. 470, 510 etc.


I have a 390R.


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## Nostradoomus (Mar 10, 2020)

That should work too


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## farwest1 (Mar 12, 2020)

welp, I thought I was done, but then noticed that I was about to install a B250K pot instead of a B25K pot. Ooops!

And the B25K pots are surprisingly hard to source. Is there an alternative? B50K? Thank you!


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## Robert (Mar 14, 2020)

25K OHM Linear Taper Potentiometer PCB Mount Round Shaft Dia: 6.35mm
					

ALPHA - Get It Fast - Same Day Shipping




					www.taydaelectronics.com


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## zgrav (Mar 14, 2020)

if you don't already have a spare, order an extra charge pump or two while you're at it.


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## PedalBuilder (May 6, 2020)

Robert said:


> Another one I was just made aware of is the TC1044HEPA.
> 
> It doesn't need the jumper and runs at 125kHz, so is _far _out of the audible range.  (vs 25kHz / 45kHz in the usual suspects)


Do you know of a source for the TC1044HEPA? This page was the only result when I googled it.


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## Robert (May 6, 2020)

PedalBuilder said:


> Do you know of a source for the TC1044HEPA? This page was the only result when I googled it.



My apologies, it was the TC7660HEPA.  (not TC1044)


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