TM018 vs TM019 audio transformer as pickup sim

[m_charles]

Hello!
Had a quick question that I'm 90% sure I already know the answer to, but wanted to get confirmation if someone has a sec. Using Jack's pickup sim to put in front of a FF seeing a buffered signal at the input. http://www.muzique.com/lab/pickups.htm

Any reason subbing a TM018 for a TM019 wouldn't be ok?

I realize the easy route would be to just post this and wait for a yes or no answer, but I do want to learn about this so you'll see the long form of this below, haha.

I know they are similar:

TM019 (Prime-2nd respectively) 10K:600 (Imp) and 600:100 (resistance)
TM018 (Prime-2nd respectively) 10K:10K (Imp) and 550:500 (resistance)

Since its applicaation in this setting is pretty crude, and the primary coils are the only ones used, it would seem there shouldn't be any problem subbing, but in the article Jack says:

"The secondary of the transformer is not used and its windings are left unconnected. Since the dc resistance of the transformer coil is only about 600 ohms, resistance is added in series with the coil."

This had me confused since the 600 Ohm is in reference to the secondary coil when I thought the 2nd coil was of no concern here (still learning about transformers).

Am I missing something? OK to sub?
Thanks in advance for your help!

Charles

[PRR]

He should have said: "Since the dc resistance of the transformer primary coil is only about 600 ohms, resistance is added in series with the coil."

The "10k" is a phantom impedance, not built in, and you can't measure 10k anywhere on the primary. This is the *suggested* working audio impedance. You can work it like 5k or 20k but the response curve will be different. And all moot since you are not using it as a transformer.

When measured with a DC Ohmmeter the IDEAL transformer would have ZERO internal DC resistance. But we don't have superconductors, only Copper. There's always some resistance. Reasonable commercial designs aim for 5%-10% of the nominal audio impedance, so the effect on the audio is small. (600r is 7% of 10k.)

While a transformer should have low DC resistance, here we want to approximate a Pickup. Typical pickups tend to have higher winding resistance. They can be conceptualized as a "50k" audio impedance, and typically loaded with 500k or more, so 5k even 20k of DC resistance would not hurt signal. Ideally we would wind this "fake pickup" on a smaller core with finer wire, build-in extra resistance, and save a few pennies. In real life, a small transformer and a 12 cent resistor is much faster and perfectly affordable, even cheaper than a custom winding.

[amz-fx]

Thanks, I'll correct that immediately.

Best regards, Jack

[m_charles]

Thx!

So the short answer is yes, the TM018 would be a suitable sub?

Main reason is because I ordered it on accident and have a couple now. Want to make it this weekend, haha 

He should have said: "Since the dc resistance of the transformer primary coil is only about 600 ohms, resistance is added in series with the coil."

The "10k" is a phantom impedance, not built in, and you can't measure 10k anywhere on the primary. This is the *suggested* working audio impedance. You can work it like 5k or 20k but the response curve will be different. And all moot since you are not using it as a transformer.

When measured with a DC Ohmmeter the IDEAL transformer would have ZERO internal DC resistance. But we don't have superconductors, only Copper. There's always some resistance. Reasonable commercial designs aim for 5%-10% of the nominal audio impedance, so the effect on the audio is small. (600r is 7% of 10k.)

While a transformer should have low DC resistance, here we want to approximate a Pickup. Typical pickups tend to have higher winding resistance. They can be conceptualized as a "50k" audio impedance, and typically loaded with 500k or more, so 5k even 20k of DC resistance would not hurt signal. Ideally we would wind this "fake pickup" on a smaller core with finer wire, build-in extra resistance, and save a few pennies. In real life, a small transformer and a 12 cent resistor is much faster and perfectly affordable, even cheaper than a custom winding.

[blackieNYC]

Yes. Just use the "10k" winding.

[m_charles]

Thank you sir

[m_charles]

Hey paul. Quick question for ya. I see online that many of the generic auidio transformers are 600:600. much more common than 10k:**.
Any idea why that is?

He should have said: "Since the dc resistance of the transformer primary coil is only about 600 ohms, resistance is added in series with the coil."

The "10k" is a phantom impedance, not built in, and you can't measure 10k anywhere on the primary. This is the *suggested* working audio impedance. You can work it like 5k or 20k but the response curve will be different. And all moot since you are not using it as a transformer.

When measured with a DC Ohmmeter the IDEAL transformer would have ZERO internal DC resistance. But we don't have superconductors, only Copper. There's always some resistance. Reasonable commercial designs aim for 5%-10% of the nominal audio impedance, so the effect on the audio is small. (600r is 7% of 10k.)

While a transformer should have low DC resistance, here we want to approximate a Pickup. Typical pickups tend to have higher winding resistance. They can be conceptualized as a "50k" audio impedance, and typically loaded with 500k or more, so 5k even 20k of DC resistance would not hurt signal. Ideally we would wind this "fake pickup" on a smaller core with finer wire, build-in extra resistance, and save a few pennies. In real life, a small transformer and a 12 cent resistor is much faster and perfectly affordable, even cheaper than a custom winding.

[garcho]

here's a good read for that question:

https://www.soundonsound.com/techniques/understanding-impedance