Author Topic: Transformer Question  (Read 1610 times)

Giglawyer

Transformer Question
« on: November 28, 2018, 07:20:06 PM »
I am building a Laika Fuzz from Dead End FX this winter.  It calls for a Xicon 42TL019-RC transformer, which appears to be hard (but not impossible) to get.  It would be much easier to get a 42TL021-RC transformer, which many suppliers seem to have in stock.  The key difference in the two is the primary impedence:  10kOhms for the 42TL019 and 4kOhms for the 42TL021.

Will the 42TL021 work, or do I need the 42TL019?   
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tonyharker

Re: Transformer Question
« Reply #1 on: November 29, 2018, 05:16:07 AM »
It helps when asking a question like this to add the schematic.

antonis

Re: Transformer Question
« Reply #2 on: November 29, 2018, 08:08:41 AM »
Especially in case of primary winding considered as Collector load...
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"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

tonyharker

Re: Transformer Question
« Reply #3 on: November 29, 2018, 08:37:26 AM »
It appears that the transformer is used as an inductor not as a transformer. 
So the inductance of the transformer primary is the important parameter not the transfer impedance which assumes a load on the secondary.

rankot

Re: Transformer Question
« Reply #4 on: November 29, 2018, 09:10:58 AM »
It's actually acting as a pickup load, so you can use this pedal wherever you want in signal chain.

Any 10k impedance inductor will probably work. You can try with any 10k transformer, or you can make an inductor yourself.

There is a transformer table on this page https://abra-electronics.com/power-supplies-transformers-adapters/audio-transformers/miniature-audio-transformers-75mw-max-output/42tl019-miniature-audio-transformers-75mw-max-output-42tl019.html showing that those 10k little transformers have primary resistance of 450-900 ohms, so you may try to use an old modem or similar transformer and try it out.
« Last Edit: November 29, 2018, 09:32:20 AM by rankot »
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Giglawyer

Re: Transformer Question
« Reply #5 on: November 29, 2018, 09:59:25 AM »
Thanks for the answers so far. 

Here is the schematic. 
 


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Giglawyer

Re: Transformer Question
« Reply #6 on: November 29, 2018, 10:01:16 AM »
It's actually acting as a pickup load, so you can use this pedal wherever you want in signal chain.

Any 10k impedance inductor will probably work. You can try with any 10k transformer, or you can make an inductor yourself.

There is a transformer table on this page https://abra-electronics.com/power-supplies-transformers-adapters/audio-transformers/miniature-audio-transformers-75mw-max-output/42tl019-miniature-audio-transformers-75mw-max-output-42tl019.html showing that those 10k little transformers have primary resistance of 450-900 ohms, so you may try to use an old modem or similar transformer and try it out.

Thanks for your input. 
Check out my builds - http://www.giglawyer.com

Rob Strand

Re: Transformer Question
« Reply #7 on: November 29, 2018, 05:36:24 PM »
Notice the 42TL021 is 4k impedance and only 148 ohms DC.  Both these suggest the winding has less turns. So inductance is lower and it probably won't work as intended.
The internet:  answers without the need for understanding.

rankot

Re: Transformer Question
« Reply #8 on: November 29, 2018, 05:37:49 PM »
There's more info on this here https://www.diystompboxes.com/smfforum/index.php?topic=119700.0, so I suggest to move the talk about this transformer to that thread.
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