Renew vintage Pioneer speakers

[scagnoz]

Hi everybody, Brothers in Sound,
Since I don't like to waste money and speakers, I recently decided to renew my vintage Pioneer X-S450 (140W 8Ohm approx. 1978).

The sound is not bad at all (yes I know is a crappy budget pair, but I can not afford a high end pair of speaker right now), so what I want to do to enjoy them at best, keeping the old MDF box, is:
1 - Reinforce the cabinet with bracing and battens
2 - Rebuild the crossover with updated better performing components
3 - Rewire both the drivers and the speaker connectors

I hope this work will improve my speaker's voice a little bit (do you think it is worthwhile?), with just a little money.
Now since I'm a real noob in electronics I kindly ask you to help me redesign the crossover according to his original specifications.
Here is some pictures of the crossover himself, seems to me to be a pretty simple circuit.
What should I do beside replacing the capacitors, and how to pick the new ones, just same specs, or there are other possibilities, different kinds... Should I keep the rest o it has to be replaced as well?
Thank to everybody wishing to help!

 

[stereofanboy]

All the cool kids switch to poly caps when doing this sort of thing, but that can really cost quite a bit more. Replacing 38 year old caps with new ones of the same type should still yield an improvement without spending too much.

I don't know your budget, but I've picked up pretty nice speakers at thrift stores and yard sales for $30 or less. Maybe take a ride around this weekend to see what's available in your area.

I searched around a little, but found only one mention of your model speaker and that turned out to be this thread on AK. How about a picture of the front and back of the cabs?

 

[Bratwurst7s]

Those are nice air core coils in that crossover. They do not need to be changed or updated. Just replace the caps with like values. If you have a little extra money perhaps foil caps on the tweeter if they aren't too bright sounding now. But if the tweeters are on the bright side to begin with then putting foil caps on the tweeters can tend to exaggerate that. (I don't know your speakers, your ears will have to decide).

Your plan of bracing the cabinets is a good idea, go for it. The wires don't look to small, replacing them may not bring you any hearable results. On the other hand if you just use basic 14 gauge speaker wire it won't really cost very much to find out. But if the speakers have those spring clip connectors on the back typical of many '70s speakers replacing them with some good quality binding posts would be a useful upgrade.

Knowing the general part of the world that you are in will be helpful for people trying to give specific recommendations as to parts brands and sources. I tend to buy Mundorf bi-polar electrolytics and Jantzen foil caps because they are easy for me to source here in Germany. If you are in the USA your available choices will tend to be different.

Enjoy the ride,
James

 

[toxcrusadr]

If you're in the US, Dayton metallized polypropylene caps from Parts Express will be great for these speakers. Post the values - likely there will be some higher value ones for the woofer circuit, and they get expensive and quite large, so nonpolar electrolytics are a good substitute. PE has those too. Post the values and we can help you sort it out. Nothing else there to change out, the inductors look dandy and you can check that resistor if you have a meter. If it's more than 10% out of spec, PE has nice audio grade noninductive resistors for pennies.

There are plenty of threads here on crossover caps, if you want to do some reading.

The bracing is never a bad thing. If there are spring clip connectors, replace with 5-way nickel or gold plated ones. PE sells those for a couple bucks per speaker.

This will not cost you much in total, they will sound better, and it's great experience for when you find more expensive ones in need of TLC - which you will.

 

[Bratwurst7s]

One more thought concerning bracing. Everything that you add to the interior reduces it's volume, which will if have a detrimental effect on bass response if taken to extremes. So some bracing is good but adding too much can be bad. I don't see any stuffing in the photos, fibreglass fill is good and would tend to help with bass.

Cheers,
James

 

[scagnoz]

First of all thank you everybody for your useful tips & tricks.
I'm posting a picture of the front and back of the box.
I'm in Italy so definitely looking at the european capacitors market! Any suggestion on EU brands will be more than appreciated!
The box has a fiberglass filling inside. Do you think I should replace the screw speakers connectors? The actual ones doesn't seems to me too bad.
The high frequencies range is perfect and brilliant for me, since I've just replaced the original (dead) Pioneer tweeters with a brand new pair of Ciare HT259.
Do you think that add some batten too will reduce too much the interior volume??
ROE Gold caps values seems to be 4.7/23V for the woofer, 3.3 and 2.2/23V for mid and 10/23V for the tweeter (I bet). From the pictures I have I can't read the values of the two top caps (between blue and green inductors) but the values should be 3.3 as well.
To good the inductors are nice ones!! Thanks Pionieer! )
So next is redisign the crossover, should I reuse the actual base or should a build a new one using the same inductors and resistor (resistor is a VITROHM WW Power Resistor 5W 10% 1R8 208-8 5W 10% 1R8 : Vitrohm)?

Cheers to everybody!

 

[scagnoz]

Here is the crossover with values...

 

[Bratwurst7s]

Try these people...
http://www.lautsprechershop.de/index_hifi_en.htm

I've bought from Stassacker often and never had a problem, and they ship fast. Their prices are very reasonable, sometimes I find better prices elsewhere but their service is good enough that I usually buy from them anyway. And when I have questions they are good about answering email very quickly.

For electrolytics, I use Mundorf,
For film caps I've been using Jantzen Cross-Cap 400, just the basic type, sometimes when money is tight but I still want a film cap for a tweeter I use Monacor MKT.

There is no need to change your resistors unless you measure them and their values are off, which is unlikely.

Your screw binding posts look serviceable. Unless they have a problem (like stripped threads) I wouldn't change them. But if you do decide to I've used the "Binding Bost PK 28l" from Strassacker several times and like them.

I'd give you direct links to each item but that doesn't seem to be working for me. Just look under "Our Components". If you look up top you can set the language to Italian by clicking on the flag.

Cheers,
James

 

[CoogarXR]

I've never seen that model before. Doesn't look crappy to me!

 

[Njoy-Music]

I'm with coogarXR on this one. Looks like some care and thought went in to this. I know you replaced the tweeter and I'm curious how close the match was to the original in it's measurements. Just because it works doesn't mean it's working as it should. Crossovers are designed with the individual drivers they will be working with. If you still have the old tweeters I'd make try to find something about them and their parameters.

Now I'm no expert here but when I redid the crossovers on my Infinity Qb's I redid the layout as well to simplify the wiring and the layout overall as best I could. I also use a normal hair dryer to loosen up the glue to take old components off as it doesn't overheat the components and makes it easier to remove them.

It looks like a fun project and should yield some great results when you're done. Keep us up to date please!

 

[scagnoz]

I will guys!
Thank you very much Njoy for the hairdryer hint it will be useful when all the pieces will be in my hands.
Believe I've tried hard to find some specs on my old tweeters (still Pioneer, not some strange russian brand...) but nothing serious appears over google... If someone wants to try the research here is some picture of the corpse...

on the soundy side I like how the design the high range, unfortunately I cannot confront them with the old one 'cause I never heard them, and something is still better than nothing.

I basically tried to find the closer one at affordable price... I know I'm terrible -_-
On the crossover side, my brother, informed by me, has already buy these guys here (without inform me -_-):
http://it.farnell.com/webapp/wcs/st...estType=Base&partNumber=1679345&storeId=10165
http://it.farnell.com/webapp/wcs/st...estType=Base&partNumber=2529154&storeId=10165
http://it.farnell.com/webapp/wcs/st...estType=Base&partNumber=2529153&storeId=10165
http://it.farnell.com/webapp/wcs/st...estType=Base&partNumber=2529152&storeId=10165

anyone knows them? they seems pretty expensive.
I'm looking forward to receive them to start the job... I'm thinking to follow you, guys (and my bro suggestion) and keep resistor and connector in place (this good'ole speakers seems not to be that bad! ))

Thank you all again!

 

[toxcrusadr]

I have not used such a cap on a crossover but they appear to my non-Italian speaking mind to be film and foil or metallized film so that's good. They are made for mounting on a circuit board so you may have a fun time mounting them.

What kind of plastic film are they made of?

 

[scagnoz]

This is one of their technical data:

The R60DN51005030J is a metalized polyester Film Capacitor with radial leaded tinned wire leads termination. The general purpose capacitor is encapsulated in a self-extinguishing solvent-resistant plastic case with thermosetting resin material meeting the UL94V-0 requirements. The radial leads are electrically welded to the contact metal layer on the ends of the capacitor winding. The R60 series film capacitor is suitable for bypassing and interference suppression in low voltage applications.

• Self-healing
• Metal layer deposited by evaporation under vacuum plates

Product information

• Products range AEC-Q200 Series R60
• capacity 10uF
• Capacity tolerance ± 5%
• Application Capacitor PET (Polyester)
• Nominal voltage 63V
• Model homes Capacitor -
• Capacitor Terminals Radial Leads
• packaging Piece
• Spacing between conductors 22.5mm
• Operating Temperature Min -55 ° C
• Max Operating Temperature 125 ° C
• Extremely Worrying substances (SVHC) No SVHC (15-Jun-2015)

What you think, toxcrusadr, are they any good?

 

[toxcrusadr]

Those should be fine. I was just talking to another AKer on the weekend who was using similar square Wima caps for audio and was very impressed with them.

EDIT: Mylar is polyester and there are plenty of quality Mylar capacitors in speakers, so I think you're OK with these. The last word will be in how they sound, or as we say in USA, "the proof is in the pudding!"

 

[scagnoz]

So, first part is done, wood by one side for restoration, and components by the other (safely home ... I'm waiting the capacitors for next week, in the meanwhile, do you have any suggestion on how to remove the huge balls of glue that seal the components to the crossover tablet?