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JPW AP2s - worth repairing or not?

Currently in the process of re-foaming a pair myself.

I bought these which are perfect: http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=250830194110

They also do an alternative "kit" which includes glue, applicators & detailed instructions... If you haven't done it before it can seem daunting & fiddly but as long as you follow the instructions you should find the process quite forgiving of errors.

If your really not confident enough to go ahead it could be worth sourcing some new units locally ? The part number is: VIFA M21 WG 09-08.
 
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thanks for the feedback, especially the link, which I can use as a reference point. There is a supplier in my city, but their website didn't state whether their measurements were in inches or metric, so I was all at sea about what to order. Someone finally confirmed my suspicions: ie that the Woofer is the BIG roundy thing at the bottom, and the tweeter is the LITTLE circle at the top. It's been a long road, but armed with the info you sent, I cunningly deduced that my speakers must be "8 inch speakers"- apparently a standard size. I was planning to slowly, haltingly, painfully order the correct repair kit by phone, but now I will try to email them the link, explaining that this is the thing I want, and do they have one please.... yay:)
 
I have just got hold of a pair of these which need refoaming - if you learnt any handy tips let me know ta - also foam or rubber which is best ,Anybody have an opinion ?
 
Gerald, definitely foam. Don't fit rubber surrounds under any circumstances which are too stiff and you'll have no bass. The correct foam allows the driver to work correctly with the sealed box.

Guy Sargeant now of Puresound had some connection with JPW and still carries some spares.
Have a word with him about a suitable foam kit. Very nice 'speakers so worth the effort.
 
The ones linked to above look fine although the profile of the roll is slightly different to that used by Vifa (Scanspeak now actually).

How much that matters is open to conjecture. I do get contacted by a few people who aren't happy with the sound of their re-foamed speakers but whether that's because of the new surrounds or because they haven't fitted them well or aligned the cones/voice coil properly I don't know. I'm sure there must be many others who are happy enough with the results.

I don't sell the surrounds, just new production units. Scanspeak now makes them in Vifa's old factory using the original tooling, jigs & many of the staff.
 
I've refoamed 3 pairs of AP2/AP3 now with differing results. I used replacement foams from goodhifi... They do have some that match the original roll surround but don't advertise them for some reason... I had to email & ask. Apparently AudioNote UK can also supply them.

The first pair I did had the incorrect roll surrounds & the bass suffered badly, the latter two pairs with the correct surrounds sounded perfect.

Of course if the cabinets are in good condition & you can afford it I would go for new replacement drivers from Puresound every time but if their scruffy or whatever refoaming is a good second choice.
 
istari_knight said:
I've refoamed 3 pairs of AP2/AP3 now with differing results. I used replacement foams from goodhifi... They do have some that match the original roll surround but don't advertise them for some reason... I had to email & ask. Apparently AudioNote UK can also supply them.

The first pair I did had the incorrect roll surrounds & the bass suffered badly, the latter two pairs with the correct surrounds sounded perfect.

Of course if the cabinets are in good condition & you can afford it I would go for new replacement drivers from Puresound every time but if their scruffy or whatever refoaming is a good second choice.
Click to expand...

Cabinets look perfect - not arrived yet ,for what I paid , that's why I bought them , they match my PT and hifi table . I was thinking if I don't like them I could fit in money no object drivers ,but that's for later .

ta for the advise
 
pure sound said:
I worked for JPW for a few years. The cabinets for some models were indeed made at HMP Channings Wood & sometimes Dartmoor. There are some funny stories about that arrangement. Occasionally one of the prisoners in the woodwork shop would get close to release, become 'gate happy' and qc could deteriorate rapidly! They'd have to keep an eye on that. On other occasions messages would be written inside the cabinets or notes left on bits of paper. We used to have to take a lorry in & qc check finished cabinets in their workshop. I remember being warned to avoid a particular red faced prisoner who was working in there who'd tied people to chairs & done unspeakable things to them. Was never sure whether that was true! Most of the guys in there were quite enthusiastic about what they were doing. On leaving, the lorry we were in would be thoroughly searched inside & underneath for unauthorised stowaways. JPW had problems selling speakers to Australia at one time because of some sensitivity about where the cabinets came from.

JPW eventually bought another cabinet making facility & set up a large new factory outside Plymouth which did oem work for other brands, Denon, Monitor Audio, Toshiba and TDL & Gale (while both brands were owned by Richer Sounds) as well as making JPW & Heybrook speakers. The timing was wrong. Most of these brands moved their production to lower cost asian suppliers and the overheads of the factory were too great to be met by JPW & Heybrook sales. It folded & those brands were acquired by the Indian driver manufacturer Peerless, now a separate entity to the Danish company.
I believe they still make JPW & Heybrook branded speakers for certain markets but not the UK.
Click to expand...

So JPW means 'Jobs for Prison Workers' then ?
 
Okay these have arrived.

cabinets very well built , the light wood venner is top quality and matches my PT .

Ordered the foam surrounds and I am to do my usual modifications - remove damping , line inside of cabinets with steel plate , add internal bracing and modify the crossover .

So issues to debate are , all opinions welcome

1. There is an inductor on the bass unit positive lead - remove this and hard wire speaker cable direct to the driver or leave it in circuit on the + or - terminal . Either way I will be removing the speaker terminals and hard wiring the cables to the drivers .

2. What 4.75uf cap to use instead of the cheap bi-polar , they range from pennies , to hundreds of pounds , when does the law of diminishing returns kick in £10, £20 £100?
 
I'd just re-foam them first and then listen for a couple of weeks.

Removing the bass inductor will put a large and broad bump of several dB in the midband, and looking at how that driver behaves without any crossover it will honk and shout since it exhibits a rising response which is corrected by the inductor. It isn't built to run 'open'.
You will also make the HF response drop by several dB relative to the mid from the bass driver. In addition the bass inductor will have some resistance which aids the ability of the bass driver to work optimally in the chosen sealed cabinet.
It will sound superficially and initially better projected and livelier, forward in presentation with an accent on harmonics over fundamentals which sounds exciting, but will have completely farked the correct balance and distorted the correct relationship between the different parts of the spectrum.
Also this is a sealed box design and the cabinet wadding is part of the bass driver loading and alignment. Removing it alters the bass response and transient response (for the worse) and will also encourage mid-band sounds to bounce off the internal wall and pass out the the bass driver cone.

More mass in the cabinet isn't automatically better - nor is bracing so while it might give a better sound, you might also make it worse.
These weren't expensive loudspeakers but they were designed with care and understanding of how to balance the inevitable compromises.

Use a Solen cap from Falcon acoustics - http://www.falconacoustics.co.uk/al...capacitor-nonpolarised-reversible-series.html
 
Thanks Robert, I should have said I will be doing the mods one at a time and listening .

I will take it as read you don't consider a more expensive cap to be worth it , any point in your opinion on paying extra for higher tolerances ?
 
Good, definitely don't do them all at once! :)

There's benefit in going for a film cap over an electrolytic but for this application the type of film makes no real difference. Depends on the usage. For a power supply application you'd be looking closely at things like ESR, but in this type if circuit where you are feeding an 8 Ohm driver is doesn't matter a bean. The Solens are good quality and consistent. Might as well pay the extra £2 for 1% matching, I usually do.
 
Gerald said:
Okay these have arrived.

cabinets very well built , the light wood venner is top quality and matches my PT .

Ordered the foam surrounds and I am to do my usual modifications - remove damping , line inside of cabinets with steel plate , add internal bracing and modify the crossover .

So issues to debate are , all opinions welcome

1. There is an inductor on the bass unit positive lead - remove this and hard wire speaker cable direct to the driver or leave it in circuit on the + or - terminal . Either way I will be removing the speaker terminals and hard wiring the cables to the drivers .

2. What 4.75uf cap to use instead of the cheap bi-polar , they range from pennies , to hundreds of pounds , when does the law of diminishing returns kick in £10, £20 £100?
Click to expand...

I use Jantzen cross-caps for low cost PP's, really good quality & always fantastic service from audio-components.

http://www.audio-components.co.uk/store/SubSubCategoryList.asp?SubSubCategoryID=105
 
You are perceptive , but after I talked to him , I listened and have done it on four speakers now and prefer it . . But as I said , it will be one mod at a time .

Robert as offered me an explanation vis-à-vis inductor and wadding , as usual it is clear concise and easy to understand , I will bear it in mind when I listen .

Seems to me , you are both suggesting I keep certain characters of the speakers as
my modifications will introduce other characteristics that you don't like , ie a none flat anechoic frequency response .

We shall see gentlemen , but I appreciate your comments in any event .
 
I don't know who the "bloke from Epping" is, but if he gives advice like this, it is best taken with a pinch of salt.

As mentioned, there is absolutely no point in removing the inductor or the wadding. They are both there for a reason and the original designer wouldn't have put them in "just for the hell of it".

Definitely re-foam them; by all means replace the capacitor with a better one and re-wire them with something a bit chunkier if you feel so inclined. However I'd stop at that point and just enjoy them - they're damn good speakers.
 
Wouldn't be hi-fi if there wasn't disagreement . To be fair to the bloke from epping {nva} his approach is much more professional than mine and encompasses doping the cone . I merely tried out a few ideas he kindly gave me and he encompasses in his own NVA speakers , as I was not happy with the sound of my speakers . They worked to my utmost satisfaction .

And as stated , the wadding/inductor appear to be their for an anechoic flat frequency response , I consider - in my previous mods of off the self speakers - x-over on the bass robbed the music of detail, life and rhythm and caused phase issues . Rob is of the opinion that 1 inductor on the bass will not cause phase issues , I am happy to listen and learn .

I did of course start a thread on why an anechoic flat frequency response was desirable and all I got was waffle , dogma and prejudice .

Modifications are enjoyment dependant , if I like them re-foamed and hard wired only they will stay as they are . I will listen and learn .
 
Beobloke said:
they're damn good speakers.
Click to expand...

Indeed they are, in fact RD of NVA highly praises AP2's himself. He also manufactures highly regarded equipment of his own and has many loyal customers as a result. I believe there would be good reason for RD to mention his modifications as they would not have been undertaken haphazardly.

Regards

John R.
 
In the designs in question (Cube) the bass driver fires upwards and the rising on axis response is smoothed becasue the listener doesn't get the direct forward response. It's a mechanical/acoustic crossover and certainly an interesting approach in that context with some similarity to smaller Allison designs.

In the JPW the Vifa bass/mid when used 'open' has a very obviously rising response with considerable peaking. Used face-on it sounds very 'wrong' without an inductor to flatten things out. The rising response exists in anechoic and normal room conditions.

Worth noting that changes will also impact transient and dynamic behaviour, not just the forward response.

If the changes are preferred then that's of course absolutely fine, I'm simply pointing out what will happen since it won't be subtle and you'll end up with something very different to a JPW.
 
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