# Simulcast  / Duocast - LT1054CP or LT1044SCPA  - which is better?



## lcipher3 (May 5, 2020)

Simulcast  / Duocast - LT1054CP or LT1044SCPA  - which is better?
I have some of both - any reason one is better than the other?


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## reubenreub (May 5, 2020)

lcipher3 said:


> Simulcast  / Duocast - LT1054CP or LT1044SCPA  - which is better?
> I have some of both - any reason one is better than the other?


I'm not 100% sure but I think both are designed with the LT1054 in mind. Generally if you use a 1044S or 7660S you'll need to connect pins 1 and 8 in order to not get an audible whine in the circuit. In the Simulcast, those pins are not connected. You might be able to get by with creating that connection yourself as it's not on the PCB and using the 1044S, depending on how much current is needed.


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## lcipher3 (May 6, 2020)

Sounds like LT1054CP is the way to go


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## Nostradoomus (May 6, 2020)

I used a 1044, I don’t quite recall if the PCB had the little connection on the underside or if I just used a clipped lead to attach it. It was easy either way and I saved 5 bucks not buying a 1054.


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## Robert (May 6, 2020)

reubenreub said:


> In the Simulcast, those pins are not connected. You might be able to get by with creating that connection yourself as it's not on the PCB and using the 1044S, depending on how much current is needed.



The Simulcast and DuoCast both have solder jumpers on the back of the PCB to connect pins 1 and 8 if you want to use a 1044S or 7660S   Just bridge the connection with a little blob of solder.


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## Fuzzonaut (May 7, 2020)

Robert said:


> The Simulcast and DuoCast both have solder jumpers on the back of the PCB to connect pins 1 and 8 if you want to use a 1044S or 7660S   Just bridge the connection with a little blob of solder.



Can I piggyback on this and ask, if and how it would be possible to replace the TY-141P (Frequency Response: + 2dB from 200 to 15,000 Hz) with a TY250P (Frequency Response:  + 1db from 20 to 20,000 Hz), although the TY250P has 8 pins?


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## lcipher3 (May 7, 2020)

The TY-141P is a 10k input/out impedance and the TY250P is a 1k input with various configs for output (center tied it's 1k).
I think the huge difference in impedance wouldn't work very well


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## ch ra (Jul 12, 2020)

@lcipher3 would this one work as a substitute transformer?


			https://www.mouser.com/ProductDetail/Xicon/42TM018-RC?qs=plB1iWz%252BJMzT%2FlIWSnGXLA%3D%3D
		

I don't know s--t about transformers, but it looks like the impedance and turns ratio is the same. The listed frequency range listed is lower however, but would that make a difference? The 141p is hard to get unless you want to pay $$$


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## Nostradoomus (Jul 12, 2020)

Digi-Key has TY-141P, they’re only a buck or two more than those.


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## ch ra (Jul 12, 2020)

That's true, but I've already got a Mouser order ready to go, and I'd have to shell out another 8 bucks in shipping from Digikey to do the separate buy.


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## ch ra (Jul 13, 2020)

Just as an FYI, Mark Davis on the DIYSB FB group told me that this one will do the job: https://www.mouser.com/ProductDetai...xc5f_S12X7_h8Yqv9StL6WWZDhkcNgen9H-qcbpyzZrjM

I don't know much about what the transformer is actually supposed to be doing in the circuit, so I'm not sure yet and will need to try it out and see.


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## caiofilipini (Jul 22, 2020)

@ch ra Did you end up using those transformers from Mouser? Looks like the TY-141P is out of stock at DigiKey right now.


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## ch ra (Aug 8, 2020)

Yes I think I got this one on a recommendation from another internet group: 42TL218-RC

Haven't tried it because I still need to get the germanium transistor. God this circuit is a pain for sourcing parts!


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## caiofilipini (Aug 8, 2020)

ch ra said:


> Yes I think I got this one on a recommendation from another internet group: 42TL218-RC
> 
> Haven't tried it because I still need to get the germanium transistor. God this circuit is a pain for sourcing parts!



Indeed! Thanks for the link.


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