I'd like to use this transformer as piezo stepup - which leads to use for the "8 ohm" primary?

[Audio>X]

PS.
I found during experimentation that to add significant "AIR" to the sound, a 680uH coil in series with a terminal of
every piezo driver is very effective. The drivers capacitance and the coil create a resonant circuit.
The amount of "air" can be tailored with a resistor 🙂

 

[mattstat]

I am curious to know at what frequency the impedance figures are taken?
Cheers 🙂

I don't know. They are the values from the EV/University Sound spec sheet. Midband with an 8 ohm resisitive load seems like a reasonable guess. If you go to the frequency extremes the transformer limitations start influencing things more, so I would think they'd stay way from there when creating a general specification.

 

[Audio>X]

YES >
Many many moons ago I read or heard that 400Hz was the 'test standard'.
I always thought it strange that 1Khz wasn't used.

 

[freddi]

I thought it odd that PWK's "LB76" which used a K33 required a stepup transfomer on the midrange. LB76 doesn't sim "hot".

https://www.itishifi.com/archives//2010/01/klipsch-lb76-or-little-bastards.html

 

[freddi]

gee @Mister Audio - I missed your post re:680uH per piezo "trick" - that's very interesting - how much DCR would you say is allowable per coil?

 

[Audio>X]

Something like 2 or 3 ohms.

 

[freddi]

are the Goldwood piezo the best these days? - How about those 88 cent 1005 at Partsexpress?Here's ten Goldwood 1005 I measured a few years back:

?

 

[JMFahey]

Something like 2 or 3 ohms.

In fact you need some DCR to tame resonance, or it would be unbearable.

 

[Audio>X]

Because the capacitance of a Piezo element measures as a 'Lossy Capacitor' the actual L/C resonance Q
is not actually "unbearable". Resistance in parallel with the coil is actually better for 'taming' than series DCR.

One of these per piezo terminal (so they're not close together) will add significant 'brightness & sparkle'.
https://www.ebay.com.au/itm/1650141...Cawvgqi8R7DFUBIX2xxXVCsA==|tkp:Bk9SR_LJy6PvYw

 

[Freedom666]

@JMFahey

You wrote you wire your own step up for piezo tweeters.

Would like to learn how this is done?

You have some fotos or description how this is done?

Would be grateful for that.

 

[JMFahey]

Ok, will wind 1 of those step up transformers and show pictures and wire needed.
Just in case remind me in 1 week.

 

[Freedom666]

@JMFahey

you are great!

 

[asuslover]

JMFahey,
I didn't see you in a while. I hope you are ok.

 

[mattstat]

Using the @JMFahey format sends the user a notification, which increases the odds they'll see your post.