Help! - Specs for Pioneer HPM-150 ST Transformer

acalunas1

Active Member
Does anyone know the specs for the transformer (Pioneer part # STV-016) used with the super tweeter in the HPM-150?

Thanks in advance.
 
Looks like a laminated core inductor(possibly tapped) to me, not a transformer.

If you have one that's defective, it'll probably be easier to match up a substitute than ever find a correct replacement other than from another cannibalized 150.

I doubt the specs were ever published, but possibly a service manual would state them.

I'd probably just isolate a known good one, measure it for inductance and resistance, and replace that component in both speakers to keep them symmetrical. If it is indeed a tapped inductor, and the tapped portion is also used, it gets a bit more challenging.
 
Manual shows a 1:12 ratio. Assuming the primary is 8 Ohms the secondary would be 96 Ohms. I've seen several complete HPM-150 crossovers on ebay for the past few months, might watch there.
 
Manual shows a 1:12 ratio. Assuming the primary is 8 Ohms the secondary would be 96 Ohms. I've seen several complete HPM-150 crossovers on ebay for the past few months, might watch there.

Impedance or turns ratio? It does make a difference.

If it's impedance ratio, then yes, 8:96 would be right. (BTW: 1:12 impedance ratio would correspond to about 1:3.5 turns ratio.)

OTOH- if it's TURNS ratio, the 1:12 turns ratio would be SQUARED for impedance... 1:12 turns corresponds to 1:144 impedance. That would make it an 8:1152 transformer.

Also BTW: Turns ratio corresponds to the voltage step-up. A 1:12 impedance ratio- turns ratio of 1:3.5- would step up the voltage 3.5 times the original. OTOH, 1:12 turns ratio would step up the voltage 1:12. Either could, plausibly, be used with the HPM units- they need a high voltage, but almost no current, due to their piezoelectric nature.

Just wanted to make sure everything was clear here...

Regards,
Gordon.
 
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Impedance or turns ratio? It does make a difference.

If it's impedance ratio, then yes, 8:96 would be right. (BTW: 1:12 impedance ratio would correspond to about 1:3.5 turns ratio.)

OTOH- if it's TURNS ratio, the 1:12 turns ratio would be SQUARED for impedance... 1:12 turns corresponds to 1:144 impedance. That would make it an 8:1152 transformer.

Also BTW: Turns ratio corresponds to the voltage step-up. A 1:12 impedance ratio- turns ratio of 1:3.5- would step up the voltage 3.5 times the original. OTOH, 1:12 turns ratio would step up the voltage 1:12. Either could, plausibly, be used with the HPM units- they need a high voltage, but almost no current, due to their piezoelectric nature.

Just wanted to make sure everything was clear here...

Regards,
Gordon.


See attached picture from schematic.

Not sure exactly what ratio they are specifying. I have a couple of HPM-100 super-tweeter transformers with 1:8 ratio, and the DC resistance of the primary is about .4 Ohms, the secondary is about 44 Ohms.
 

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BTW: Just doing some calculations...

If you needed 1:12 IMPEDANCE ratio... a 25v speaker line transformer with a 7.5 watt tap would get pretty close (6.5 watts to 25 volts is pretty much exact- if you can find one with that... a 6 watt tap would be very close- 1:13 impedance ratio- if you can find one with such a tap).

If you needed 1:12 TURNS ratio... a 70v speaker line transformer with a 5 watt tap would get pretty close (4.25 watts is the exact figure... a 4 watt tap would be pretty much dead on- 1:12.35 turns ratio- if you can find that).

In both cases, use the specified speaker tap as the INPUT, and the 25v or 70v side of the transformer as the output to the HPM...

Regards,
Gordon.
 
See attached picture from schematic.

Not sure exactly what ratio they are specifying. I have a couple of HPM-100 super-tweeter transformers with 1:8 ratio, and the DC resistance of the primary is about .4 Ohms, the secondary is about 44 Ohms. So it's probably a turns ratio.

Yep... if the wire gauge is similar on primary and secondary, 0.4:44 ohms equals about a 1:110 impedance ratio. That would imply about a 1:10:48 turns ratio, roughly. Extrapolating from that, it looks like it would be 1:8 turns ratio... or 1:64 impedance...

If that's the case, then 1:12 turns would be closely approximated by the 70v line transformer using a 4 or 5 watt tap, I mentioned just above...

Here's one that might work- it has a 5 watt tap (1:11.17 turns ratio):

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-039

If you replaced BOTH of them in a pair of speakers (so the sides would exactly match in "tone" and such), I doubt anyone could hear a difference from stock. It would be within .6dB of stock output level, pretty much. At only about $6 each, it would at least be a cheap experiment... :D

Regards,
Gordon.
 
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Measured from the original HPM-150 crossover and the DC resistance of the primary is about 0.5 Ohms, the secondary is about 105 Ohms.
What is the closely replacement for it?
 
Hi Gordon - REALLY Old Thread pulled up here - Tried PM but 420 character limit was not efficient

I am working on restoring a Cherished set of HPM-150 speakers. There is a 1:12 Transformer that is spec'd across the Pioneer "SuperTweeter"

If you needed 1:12 TURNS ratio... a 70v speaker line transformer with a 5 watt tap would get pretty close (4.25 watts is the exact figure... a 4 watt tap would be pretty much dead on- 1:12.35 turns ratio- if you can find that)[/I].

this transformer:
70volts - a 4 watt tap - BUT Description mentions: "full-range frequency response (+1dB from 60Hz-12kHz)"

QUESTION: Since this is used on a Supertweeter do I need to keep looking for something that goes up to 20kHz frequency response or am I getting mixed up in my Hz?
(I think I am mixing Signal Hz with transformer output Hz???)
 
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