Toko / Murata inductors
« on: June 14, 2019, 01:06:40 PM »
I came across some old posts on here talking about using individual Toko inductors for a Pultec EQ.

Toko belongs to Murata now, and near as I can tell the old series numbers are gone. Does anyone have any experience using the Murata 1300R or 2200R series for audio? Or really any general purpose fixed inductors in the 15-47 mH range?


squarewave

Re: Toko / Murata inductors
« Reply #1 on: June 14, 2019, 03:17:47 PM »
Bourns makes radial shielded ones like the those Toko inductors:

  Bourns RL181S-473J-RC

Even though they're sort of for power supplies, I think they would work fine.

But if you're building an EQP1 I would just get the Audio Maintenance multi-tapped inductor (VTA1444 I think it is). They have all the right taps on one pcb mount toroid core and it's not expensive.

Re: Toko / Murata inductors
« Reply #2 on: June 14, 2019, 03:37:19 PM »
Well for me this is two fold. One, for prototyping, and two for designs that use inductor values or steps that aren’t on one of the common cloned parts. If I have an alternative I can buy from mouser, pricing and delivery get a lot simpler. Lead time on a custom inductor is 4-6 weeks at least usually.

rackmonkey

Re: Toko / Murata inductors
« Reply #3 on: June 19, 2019, 10:50:59 AM »
Maybe a reach, but for prototyping I have a small pile of old UTC VIC variable permalloy powder inductors I keep around.  They pop up for under $15 frequently on ebay. Work well. Handy to have around.
Whether you think you can or you think you can't, you're probably right.

pvision

Re: Toko / Murata inductors
« Reply #4 on: June 20, 2019, 06:26:57 PM »
I've been experimenting with some Kemet common mode chokes which have two sections of 190MH each. It's hard accurately to sort parts by particular criteria on some vendors' sites but I think this has a low DC resistance

https://www.digikey.co.uk/product-detail/en/SSR21NH-M031900/399-19541-ND/9741759



Nick Froome

squarewave

Re: Toko / Murata inductors
« Reply #5 on: June 20, 2019, 08:20:42 PM »
That's for power supply filtering and not so much audio. It would work but it's probably huge and may distort more easily depending on the core (air core distorts less easily but Henries is much less). Not sure why you would care so much about DCR.

rackmonkey

Re: Toko / Murata inductors
« Reply #6 on: June 21, 2019, 12:14:48 AM »
Not sure why you would care so much about DCR.

To play it back a different way Squarewave, why wouldn’t you care about the Q of an inductor in an audio filter application?
Whether you think you can or you think you can't, you're probably right.

squarewave

Re: Toko / Murata inductors
« Reply #7 on: June 21, 2019, 10:48:26 AM »
To play it back a different way Squarewave, why wouldn’t you care about the Q of an inductor in an audio filter application?
That will have zero (0) effect on Q in an EQP1 or in just about any other cirucit. In the EQP1 there is series resistance in the transformer, the boost control and the Q control. Even in the most extreme positions the input transformer impedance is going to limit Q. So an inductor that has DCR of 5 vs. 50 isn't going to matter. And you wouldn't want the Q that high anyway - it would sound like you're whistling in the shower and clip downstream.

rackmonkey

Re: Toko / Murata inductors
« Reply #8 on: June 21, 2019, 10:53:47 AM »
Okay, you were commenting in the context of the OP's EQP-1 project. I was focusing on the generic "for prototyping" part. The thread seemed to have devolved in that direction.
Whether you think you can or you think you can't, you're probably right.

squarewave

Re: Toko / Murata inductors
« Reply #9 on: June 21, 2019, 11:09:51 AM »
Even for prototyping you would never want a Q that high. Usually there's a couple hundred ohms in series with the inductor to set the Q to a sane value. At 50 ohms it would be nasal sounding and annoying. At 5 ohms you would have a 30+dB spike at the resonant frequency.


rackmonkey

Re: Toko / Murata inductors
« Reply #10 on: June 21, 2019, 11:29:08 AM »
Point taken, but I didn't see a reference to "how high" in the threads above. I think it was pvision who just mentioned without detail that DCR wasn't that high on the inductors he pointed to.  So I was responding to the notion that DCR wouldn't be of interest generically in audio application prototyping. 
Whether you think you can or you think you can't, you're probably right.

pvision

Re: Toko / Murata inductors
« Reply #11 on: June 21, 2019, 07:17:32 PM »
I was throwing the component in as a data point, not as a suggestion for a Pultec build

The thing I am "designing" is passive and I was looking for something cheap & available to test with. Hopefully someone will find the URL useful

Nick Froome


 

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