# ppi Pc pro 12



## antman (Apr 28, 2013)

Hi there,

Anyone familiar with the old school ppi pc pro 12?

Are these sq sub ? What is the best box size for these sub

How do you know f these are 4 or 8 ohms?

Score myself a mint condition for 65 bucks, the guy sold me said his installer told him have slight delay in sound and sold him a new sub.:laugh:



Thanks


----------



## vwdave (Jun 12, 2013)

That's a great sq sub. IIRC it's good in a 1cuft box. One thing to be weary of is that it's liquid cooled. It has ferro fluid in it, and that tends to leak out sometimes. Not sure how to check if it's still in there.

You can use a multimeter to measure the ohms, otherwise I'd look for a marking on it indicating if it's 4 or 8 ohms.

I really like those subs. A friend of mine ran one back in the day and it was a great sub until it leaked out everywhere.


----------



## antman (Apr 28, 2013)

Ppi manual given 3 enclosure volume to choose 1, 1.25 & 1.5 cubic. Should i go w smaller or bigger?

Ppi manual say 300 w rms for the woofer, will a600 bridged be ok?:laugh:

What is the purpose of the fluid? You get leaked when it is abuse?


Thanks


----------



## mikelycka (Apr 4, 2008)

I used them when they came out in my 68 beetle
they got a very different sound to them like a noise/pop almost im sure it would not be heard in a trunk but when you 3 ft away you can here it
it from the material used to make the cone I was told 
very nice sub for the money imo


----------



## alm001 (Feb 13, 2010)

Go with the bigger box. I think the popping came from too small of a box. Last box I built for a 10 was 1.5 ported at 34hz and sounded great


----------



## alm001 (Feb 13, 2010)

I have different info than you do for the box sizes... 
http://www.soundbuggy.com/Eric/Car Audio/precision_power/PPI Pro10 Data and specs.pdf


----------



## mikelycka (Apr 4, 2008)

It was not the box the sub make a odd sound anyone that has used them know what I mean its thensound of the vc make noise through the cone. I have never heard another sub do it


----------



## vwdave (Jun 12, 2013)

antman said:


> Ppi manual given 3 enclosure volume to choose 1, 1.25 & 1.5 cubic. Should i go w smaller or bigger?
> 
> Ppi manual say 300 w rms for the woofer, will a600 bridged be ok?:laugh:
> 
> ...


The fluid was to cool the voice coil. Almost all other subs are air cooled.

I never heard any popping sound, maybe the sub was bad?


----------



## antman (Apr 28, 2013)

Strange from the link soundbuggy it requires the sub in 2cu of box,

I want good sq w a good punch , thats why i go from 10 to 12 inch sub, i still will use my idq 10 v1 f i need the space, i will make removable box

Any more input w these sub? Thanks


----------



## hot9dog (Mar 23, 2013)

Im very familiar with these subs. I truely feel that these are the only decent sounding flat cone subs ever made. The fluid cooling was very unique. Slighty over 1.5 volume would be perfect. Dont overpower them and keep them out of direct sunlight for long periods and the sub will good for many years. If your not happy with them... i will be glad to take them off of your hands... lol


----------



## hot9dog (Mar 23, 2013)

The leaking issue came from when people would install these in hatchbacks facing the glass, the exposure to the sun would weaken the bond at the top of the coil that retained the seal for the fluid and it would start to leak or dry up. Even when this happened , the sub was still useable. ... just that is was susceptible to the coil being burnt/coked.


----------



## vwdave (Jun 12, 2013)

The sub that friend had that leaked was in an extended cab for ranger.


----------



## superspec (Jun 3, 2014)

I know the sound you are talking about mikelycka. I had 2 of the 10s in a 1cf sealed box back in early 2002. they sounded like someone or something was constantly tapping on the cone with a fingernail.


----------



## hurrication (Dec 19, 2011)

They are very tight gap motors, and the ferrofluid helped keep the coil off the pole. When the fluid dried up or leaked out, the popping noise you'd hear is just the voice coil former against the pole.


----------



## superspec (Jun 3, 2014)

hurrication said:


> They are very tight gap motors, and the ferrofluid helped keep the coil off the pole. When the fluid dried up or leaked out, the popping noise you'd hear is just the voice coil former against the pole.


I could see that except mine were BNIB when I installed them. They had been stored since I bought them new.


----------



## hurrication (Dec 19, 2011)

Ferrofluid can dry up over time even if they aren't used. How old were they when you took them out of the boxes?


----------



## superspec (Jun 3, 2014)

That install was done in 2002. I bought them new and put them in a closet...I think I bought them in 1998 or so.


----------



## BaasTurbo (Aug 27, 2009)

hot9dog said:


> I truely feel that these are the only decent sounding flat cone subs ever made.


Don't forget about the Phase Linear Aliante 12 and 12Si (LTD). Those sounded pretty darn good too.


----------



## cajunner (Apr 13, 2007)

BaasTurbo said:


> Don't forget about the Phase Linear Aliante 12 and 12Si (LTD). Those sounded pretty darn good too.


or the Alto Mobile Falstaff.

the one PPI PRO I have, showed a fail mode where the cone was glued to the former.

what you had essentially, was a ring of adhesive applied to the cone, and the voice coil former was simply pushed into it, contacting the cone and allowed to dry.

I was actually able to remove the honeycomb panel from the former by tugging, the coil slipped from the ring of dried, hard adhesive intact, which should never happen.

this could be part of why some coils make tapping noises, as a portion of the glue joint no longer adheres to the former while there is a part that does, causing rocking modes that are audible outside the enclosure.


the gap didn't seem all that tight but in comparison to big subwoofer coils of today, it is.

and I wonder how it is that they built these, as the cone doesn't allow for using gapping jigs, I wonder if they just used the tension of the dual spiders as sufficient force for the VC formers to "stick" in the glue?

the glue on the cone looks just like Liquid Nails, lol.

construction adhesive. 

If the front plate had not shifted on my woofer I'd have been able to re-glue the joint with some rubberized CA glues that they may not have had back when these were made, and salvage the sub.

one thing about these subs, is the actual basket is made from high-grade aluminum, it's very strong structurally compared to most sub baskets and on par with the aluminum used in TAD woofers.


----------



## ntimd8n-k5 (Nov 11, 2008)

Any way to repair the ferrofluid? I am guessing no? I got a bunch of these but I am afraid to run them, a pair each of pro 8s, 12s, and 15s.


----------



## MikeT1982 (Jul 6, 2011)

This is such an interesting post! I forgot that the pro pistons were ferrofluid cooled, I remember and know that some horn tweeters are. It would figure with precision power being into the liquid cooling deal back then they would have left it alone and carried it on even with the PowerClass series of amps in '97 that were no longer possible to liquid cool. If I recall correctly the original flat piston drivers were available during the reign of the art series lineup and remained untouched for the first gen gunmetal Powerclass/limited chromes lineup, second gen chrome powerclass and third gen silver sparkle. I could be incorrect. Because Alma Gates use them in her bronco with art amps before switching to PowerClass, correct me if I am wrong, my memory is pretty foggy. I did not own the pro but did own the lower line, a pair of 10's in a shared chamber sealed box with a precision power PC 275 applying 300wrms. They sounded great but I will agree the sound was very unique, if you did not fire them backwards and load them off the back of the car they were very quiet to go to a normal sub, not that you would not do that anyway however in a demo room they sounded very very weak and would just flop around if they did not have something to load off of, half the diameter or greater away from the woofer. I do not know the reason for this and I do not know if other factors were involved, it is just an observation I had witnessed in person and was told by the shop installers not to judge by how they sounded in the demo room. They look amazing though watching the Precision power lightning logo levitate!  I could stand there and watch them all day! Sort of like the JL audio logo back then  when they actually had dust caps dammit!  So lets talk ferrofluid… You can buy it on eBay in a bottle lol! check out YouTube and there are really really wacky experiments with it, it is basically some type of oil with iron particles suspended in it. So the liquid itself somehow is one with the iron particles so the liquid will stick to a magnet and not separate from the iron particles. Once again I believe I am correct but could be wrong. From what I have seen described is extremely messy kind of like motor oil on your fingers. Even though in the demonstrations it looks like some type of alien life form, extremely creepy and psychedelic if you ask me, it is totally harmless I believe no more so then oil and iron, just a freaking mess on your hands. The iron particles I believe are almost microscopic if not microscopic. I am an experimenter and a vintage lighting and also electronics guy/high voltage hobbyist also I kind of like this wacky stuff LoL! I'm not sure how you would get it into the gap,(hypodermic syringe through spider maybe? Lol) I think they made a gamble putting fluid into a motor structure that moves so much. I can see it in a tweeter not being an issue because the excursion is so small in fractions of millimeters but in a woofer with inches of xmax wow… Props to the engineers! I'm not sure if anyone else did this for if it is continued to today but that would be an interesting situation maybe in ProSound application it is truly still used and maybe that's where precision power based it on. However if they did it as a first time thing way to go for their innovation, it's too bad it wasn't practical. But I will tell you some of my most favorite things in my hobbies are the impractical and different ways of doing things!


----------

