Pioneer Speaker Package subwoofer transformer.

[stitchy]

Re: Pioneer Speaker Package subwoofer transformer.

thanks for the advice momaka.. it's good so far.. perfect for pc use, makes a good foot stool as well.

[momaka]

Re: Pioneer Speaker Package subwoofer transformer.

My solution was to gut out all the electronics. Now I have it working passively.. connected directly to the subwoofer speaker terminals on my receiver.

The receiver doesn't seem to draw any more power doing this.

The sound quality is %100 fine for my setup.. perfect really.
But let me know if my solution is some sort of fire hazard... pleeease

That is an absolutely fine solution. In fact, a good quality receiver may have better sound quality and offer more features (in terms of adjusting the tones and whatnot) than the built-in amps of these subwoofers.

And not, it's not a fire hazard. If I had a good receiver with amplified subwoofer outputs, I'd do the same.

On that note, if you don't have a receiver with subwoofer outputs but do have an amplifier that is bridge-able, you could always tie the subwoofer to the bridged output, turn down the high tone control and max out the low tone control... and you got a subwoofer amp of sorts.

[stitchy]

Re: Pioneer Speaker Package subwoofer transformer.

i can post photos but basically it's as per original photo.. SF - 76E / 232128e Thermal fuse 115) can't see any issues/burns.. continuity on each side.

[stitchy]

Re: Pioneer Speaker Package subwoofer transformer.

btw.. I have the transformer sitting in front of me. could post it within australia, $20 would cover postage/satchel/iceblock for my walk home.

[stitchy]

Re: Pioneer Speaker Package subwoofer transformer.

I have this same active pioneer sub (on vsx-s300 receiver)..
It also died. Transformer tests fine (continuity on both sides anyway).

As Madan guessed back on page 1, it did kinda chew power.
(despite 'power saving' auto-switching on/off when signal was detected)

When switching on/off it was really obvious/abrupt 'crossover'.. and I could hear the relay clicking (or whatever it was.. I'm very new to electronics). I use it at a computer desk.. maybe it's more suitable when sitting back on a lounge chair.

My solution was to gut out all the electronics. Now I have it working passively.. connected directly to the subwoofer speaker terminals on my receiver.

The receiver doesn't seem to draw any more power doing this.

The sound quality is %100 fine for my setup.. perfect really.
But let me know if my solution is some sort of fire hazard... pleeease

[momaka]

Re: Pioneer Speaker Package subwoofer transformer.

^ Forget about Mouser and Digikey when it comes to parts like that - they would be way too expensive. You're better off looking for a junk transformer on eBay with the same voltages.

If nothing is readily available, then you can get two used 20V, 90W laptop adapters and wire them in series (just need to unground one of them). This will give you about 40V instead of 48V. This will limit the speaker's output power slightly, but it's also the easiest and most readily-available option probably (due to no shortage of used laptop adapters online).

[ben7]

Re: Pioneer Speaker Package subwoofer transformer.

Something like this may work. Dual primary (117/234V), 48V @ 4A output, center-tapped (so it's 24V-0-24V).
https://www.mouser.com/productdetail...QoM4NQfOLcs%3D

But, it's almost $100 and weighs 8 pounds. (Shipping would be expensive.)

-Ben

[momaka]

Re: Pioneer Speaker Package subwoofer transformer.

Can anyone suggest a transformer that will power this amp?
I can't seem to find anything on ebay. I might head into jaycar tomorrow and see what they have....

Probably a 24-0-24V transformer (i.e. 48V with center tap), as budm suggested here:
https://www.badcaps.net/forum/showpo...2&postcount=11
Though I will note here that it's also worth looking up the part number of IC21 (the amplifier chip) to make sure you don't go over it's maximum rated voltage.

In terms of current, that will depend on the sub's woofer driver impedance. If it's 8 Ohms, you will need a transformer capable of 24V/8 Ohms = 3 Amps RMS. If the speaker impedance is 4 Ohms, then the current will be 6 Amps RMS. And for 2 Ohms, it will be 12 Amps.

To me, that transformer doesn't look that big, so I doubt it's rated for more than 40-60 VA, if even that much. Thus, a replacement transformer capable of 3 Amps of current and/or 70 VA should be enough, probably.

[cubic25]

Re: Pioneer Speaker Package subwoofer transformer.

There's meant to be a pic in the above post, but it isn't showing for some reason.
Anyway, hopefully this one works.

[cubic25]

Re: Pioneer Speaker Package subwoofer transformer.

Hey all.

Sorry to revive an old thread, but I have this exact sub with a very similar issue.
I took the transformer appart, and attempted to locate the thermal fuse, only to discover that not only had the fuse disintegrated, but all the wires were burnt out too. I thought it was going to be a simple solution, such as the OP's, but it turns out that I will need a new transformer.

Can anyone suggest a transformer that will power this amp?
I can't seem to find anything on ebay. I might head into jaycar tomorrow and see what they have....
While I'm here, does anyone know if I can disconnect the standby feature on this sub? It is really annoying hearing the relay clicking every time it turns on and off.

If I can't find a new transformer, or if it is too expensive, I might just get a new active sub off ebay for the cheap.

Thanks in advance for any help.

Pic of transformer:

[bamix]

Re: Pioneer Speaker Package subwoofer transformer.

Khron,

Thanks for the additional info, you have given me some homework to do.

'To a price' are probably the keywords in this example of a cheap sub. They must have saved money by not printing any info on the transformer....

Take care.

[Khron]

Re: Pioneer Speaker Package subwoofer transformer.

"Good" transformer datasheets specify a voltage regulation rating, in percent.

http://www.electrical4u.com/voltage-...f-transformer/

From my understanding, that percentage is how much higher the no-load voltage is, compared to the fully-rated-load voltage is. For example, a transformer i've selected for a project of mine has a 25% specified regulation.

https://cdn.badcaps-static.com/pdfs/...7102c93d7c.pdf

On each 6.3VAC secondary, i'd expect to see about 7.8VAC at no load.

And besides, since this transformer is from a relatively affordable(?) consumer range subwoofer, you can bet your booty it's built down to a price, same as the component parts, so the loaded voltage on your transformer WILL be considerably lower than the no-load one

Taking a pessimistic(?) 25% regulation into account, the 30-0-30VAC you measured at no load would drop to 24-0-24VAC at whatever load that transformer's rated at.

Some rule-of-thumb figures - http://www.zen22142.zen.co.uk/Design/dcpsu.htm

[bamix]

Re: Pioneer Speaker Package subwoofer transformer.

Thanks guys.

budm, AC feeding the unit is 240v. I see your point with head room in the capacitors. Best to not to squeeze that margin at all.

Khron, understanding there are deviations from ideal, is it safe to assume then that the 'rated' voltage is always a loaded one ?

From the online content I have seen trying to find a replacement the specifications are listed differently from site to site. When I started this thread, the idea I had in mind was that given a transformer with no output and no markings, there may be a choice of 'standard' parts that would fit the bill. I can see now that the choices are quite varied and dependent solely on the properties of the components on the surrounding boards. I have learned quite a bit these past days covering this matter and for that I am very grateful.

Thanks again.

[budm]

Re: Pioneer Speaker Package subwoofer transformer.

That means the DCV on the caps will be around 42VDC, if your line Voltage goes higher then you do not have that much head room since the filter caps are rated at 50VDC.
What is the AC feeding the unit?

[Khron]

Re: Pioneer Speaker Package subwoofer transformer.

Well, the 30VAC you measured was unloaded(?), which will be higher than the "rated" voltage.

https://en.wikipedia.org/wiki/Transf...al_transformer

24-0-24VAC ones may be more common, i'd think (or whatever other values there may be, up to 30-0-30VAC).

[bamix]

Re: Pioneer Speaker Package subwoofer transformer.

OK, just to wrap up. The new Thermal Fuses arrived this morning.

I have carefully soldered one back in place of the original failed piece and reset the layers of insulation all the time checking that I had maintained a circuit through the windings. I reconnected the transformer to the boards and speaker and powered it up.

All good.

For the record I measured the output of the secondary winding unloaded at 60vAC between the two yellow wires. Measuring each back to the centre white wire of the connector I got 30vAC.

From that, I expect it's a 30-0-30 AC Transformer.

I expect the output is then rectified and regulated to around 24vDC to run the other components on the amplifier board.

I have had a quick look around on the Internet and it seems that this 30-0-30 type is not so common. If it fails again, might be time for the sub-woofer to go to the bin.......

Thanks again to everybody.

[Khron]

Re: Pioneer Speaker Package subwoofer transformer.

Well, since the original's leads are so long and thin, i guess you could indeed get away with soldering them.

A while ago i had to replace a chunky thermal fuse (with 0.8-1mm thick legs) which the datasheet recommended crimping.

Yes, something like vise-grips should do fine - just don't totally squash the legs and risk them falling apart

[bamix]

Re: Pioneer Speaker Package subwoofer transformer.

Thank you again everybody for your valuable insights and contributions.

My Thermal Fuses are due to arrive tomorrow so I will replace the failed one and give it a shot. I will post the result. The original is soldered in, is it possible to install the replacement in the same way if I use some sort of shunt to stop the heat from getting to the fuse ? I was thinking of using a pair of Vise-Grips, a G-Clamp or similar on the leg between the fuse and the solder point. Is that the best way to approach it ?

In my trawling of the web for info on this model I found a lot of sites where people were complaining of a similar issue so I hope that the detail and structure of this thread may be helpful for someone else in the future.

Thank you so much, it is really appreciated. In fact, I found it awesome that I can reach out from right down here and have kind people from all corners of the globe lend a helping hand. If only the rest of the world worked that way....

[Khron]

Re: Pioneer Speaker Package subwoofer transformer.

Good, the bulb not lighting up (maybe apart from a flash just when you turn the thing on) is what you want.

Sounds like it was just the darned thermal fuse indeed

Quite odd that the LED lamp in series(!) with the thing somehow worked, though...

[Agent24]

Re: Pioneer Speaker Package subwoofer transformer.

From what you have done it seems the transformer is OK.

If the transformer had shorted windings, the 60 Watt lamp you tried would have lit brightly. If the transformer was open-circuit, the LED lamp wouldn't have lit at all.

For the record though, LED lamps are unsuitable for this test as they will not limit the current in the same way an incandescent one will.