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JPW AP2s - worth repairing or not?

eguth said:
I came dangerously close to purchasing these decades ago but instead decided to continue modifying my DIY Peak Baxendall's.

However, I would suggest that you consider, in due course, removing the crossovers from the boxes and doing a Colloms passive parallel bi-amped job on them (see the two Colloms articles from Hi Fi News scanned on Mike Snowdon's thread). I imagine that with that done they would become simply stunning.
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Can we have a link to that thread of Mike Snowdon's?

The Peak Sound Baxandall's are going back a bit. Did they not use an Elac elliptical? I built something that may have been similar, Hi Fi News design "Cheap But Not Nasty". They were quite good, also using Elac elliptical.

Not sure that there would be much to gain putting crossovers outside/ bi amping AP2/ AP3.

The AP3 has a bi amping facility. The original crossovers are quite simple, certainly the inductors are of good quality and the connecting wire is not too thin.
 
Radfordman said:
Can we have a link to that thread of Mike Snowdon's?

The Peak Sound Baxandall's are going back a bit. Did they not use an Elac elliptical? I built something that may have been similar, Hi Fi News design "Cheap But Not Nasty". They were quite good, also using Elac elliptical.

Not sure that there would be much to gain putting crossovers outside/ bi amping AP2/ AP3.

The AP3 has a bi amping facility. The original crossovers are quite simple, certainly the inductors are of good quality and the connecting wire is not too thin.
Click to expand...

I can see that providing a link to Colloms article is going to become a recurrent and time- consuming demand; but its worth the effort.

If you are interested, search MIKE SNOWDON in the member's list. Go to his threads. You will see, not long ago, his thread: "BI-AMPING WITH 2 DIFFERENT TYPE AMPS?" Go to post #38 which is on p.3 of the thread. That gives you the link to Colloms articles.`

I am certain it is worth trying to parallel bi- amp. When I did this on my speakers I took the opportunity to upgrade all xover components; well worth doing. I also upgraded and optimised the cables; this need not be an expensive proposition. There are air core inductors around nowadays that give dramatic aural improvements compared with the old stuff; ditto for caps. Yes, the Baxendalls use Elac 9x5" ellipticals; I still have a stock of these drivers, new, that Malcolm Jones suggested were suitable for experimental line array designs.

valveheaduk

Be very clear that the Colloms mods I suggest you try do not involve active crossovers at all. It is PASSIVE CROSSOVER parallel bi- amping.

My SEAS drivers have rubber surrounds, and after- I can't recall offhand how many decades of use- they are still in new condition. However, you are best guided by the expert- Pure Sound. I would take his advice on everything to do with JPWs- not mine!

Personally, if I were doing it, I would parallel bi- amp (passive) in the Colloms manner, then add a subwoofer, dedicated home- built one, and use an ACTIVE crossover to ensure that the rollon frequency and slope could be easily optimised so as to crossover smoothly into the midrange.

Please, if you are going to play around with passive parallel bi-amping, read the Colloms articles thoroughly again and again. Much confusion and misunderstanding on Mike's thread could have been avoided- at least some of it- had this been done. The Colloms articles are not technical. They are well written in plain English, but are packed with information. They need careful consideration and to be well understood in detail before experimenting begins.

I would suggest, also, that you read Mike's entire thread. There are various viewpoints and comments that you may find of interest.

Best of luck, and do let us know how you get on!
 
Vifa themselves changed from foam surrounds to rubber later on in the production of these drivers. And the advice to go for the rubber surrounds was given to me from the guru's who run this website:

http://www.speakerrepairshop.com/index.php?action=home&lang=EN

That plus what's left of my perished surrounds looks very much like rubber and not foam. I'll go with rubber. At any rate for only £15 to upgrade I can always switch to foam at a later date if I'm not happy with the sound.

I mentioned active use as a future possibility because on the rear of the speakers there is an extra pair of terminals marked 'for active use only!' so I may investigate that at some point. With various other things on my plate at present I probably won't have time to try out the mods mentioned in Mike's thread, but thanks for drawing my attention to it. It's saved for future reference ;)

- John
 
To get the gist of these mods you need to read Colloms two articles, the LINK TO WHICH is on Mike's thread. You don't have to read the thread first; in fact it would probably be best to read it only after you have read the Colloms articles.
 
Back in the late 70's and early 80's there were a number of companies, Arcam, Nytech and others offering active crossovers. Quite a few companies provided speakers which allowed (fairly simply) a direct connection to the HF & LF drivers. The AP2's and AP3's were such speakers.

All of the M21 WG-09-08's I've seen (since the mid 80's) have had foam surrounds. Current production ones still do. It is really an expanded foam rubber sheet formed to give the correct roll shape. I'd agree that the surrounds of old deteriorated drivers do have the appearance of sheet rubber. It changes in character quite markedly prior to disintegration! I see alot of them.
 
The AP2 had a whole load of bituminous damping sheet applied inside the cabinets and earlier ones had the extra two pairs of terminals to allow for direct connection to the drivers. (I imagine you'd still have had to disengage the passive x-over though)
Later they removed that option & just made the more conventional provision for bi-amping but via the passive crossover. P1's were also sometimes available in vinyl wrap cabinets whereas AP2's & AP3's were always veneered iirc.

On all three models there's some scope for improvement by changing the 4.7uF np electrolytic cap feeding the tweeter for a film cap.
 
Just gotten around to ordering the replacement foam surrounds for my AP2s. In the meantime I'd like to order a pair of film caps to replace the aged (and cheap!) electrolytic type in the crossover. Only problem is they are both glued label side down :s

I don't want to prise them out just yet as will want to listen to the speakers as soon as I have refoamed them, however would be nice to be able to order the film caps whilst waiting for the surrounds to arrive. So does anybody know the value of the single electrolytic cap in the crossover please?

Looks nice and simple in there - just two coils and one cap. Should bode well for decent sound if the drivers are good quality I guess. I hate complicated crossovers.

Cheers,

- John
 
I have a pair of P2s as emergency back up speakers when other things are loaned out (I am using them at the moment) They are OK but a bit woolly and ill defined compared with what I am used to, but they do the job especially for £30 off ebay.
 
I've been told by several people that a speaker with the same performance as the AP2s would likely cost around £1000 today, which sounds good enough for me being as they were free ;)

Haven't heard/seen the P2s - I take it they're similar?
 
Well as in all things Hi-Fi, I shall let my ears decide once I have them refoamed. If they do sound pants they only cost me £15 for the foam surrounds, and I'll sell them on.

Does anybody know the value of the electrolytic cap in the crossover please? Ta :)

EDIT: just re-read this thread again and Pure Sound provided the answer on page 2; 4.7uF :) Now to order a pair of film caps...
 
Ordered a pair of 4.7uF caps from World Audio Design, made by Clarity Caps - was very impressed by these caps used in a VTA board for a Dynaco ST70. Preferred them to the copper foil Jensen caps, as well as Jupiter beeswax caps too. £10 for a pair - not bad. Should be an improvement on the existing electrolytic caps. Even brand new they must have held some of the performance back, and now they're approx. 22+ years old so are probably drying out too. Bet this cap did the treble performance no favors at all...
 
I have a 20 year old pair of JPW P1's, similar in size to the AP2's which I believe had additional damping material to the inside face of the cabinets, as expected the rubber surround to the mid-base driver perished and needed repair.

I replaced mine with a new pair of high quality Danish drivers from Guy Sergeant of Puresound. He also recommended fitting dedshete to the inside of the cabinets (available from Wilmslow Audio) and replacing the original electrolytic capacitors in the cross over with polyproylene ones (I used Clarity Cap ESA type).

The repair and upgrades are easy to carry out and greatly improved the speakers, they sound wonderfully natural, detailed and delicate but with plenty of life. Unlike many modern speakers I auditioned (priced between £700 - £1500) they have an effortlessness to their presentation. Particularly strong on vocals and acoustic material which has amazing realism and presence.

I was told the new capacitors would 'clean up' the top end and indeed the treble is now sweeter and brings a clarity and separation throughout the mid-band. The bass was and always will be a tad shy, they are in no way bright or harsh and being a sealed cabinet design bass is fast. Good open 20" stands are essential.

I recently visited the Bristol show and can honestly say I did not hear a finer sounding speaker there! - Definitely worth getting them repaired and the upgrades suggested by Guy Sergeant of Pure Sound made a significant improvement - he was very helpful.
 
You're the fourth person to suggest they can hold their own with modern speakers around that price bracket, so really am looking forward to getting these up and running again I must say. I'll have to get a pair of open stands for them on fleabay if they do sound good as I currently only have a pair of single pillar Target stands from the early 90s which are probably a bit too high for these speakers.
 
Please, if the person who originally posted still reads this forum could you let me know the exact measurements for those AP2 speakers? I need to order a repair kit for mine but have no idea how to go about measuring them accurately.
(Sorry for being a helpless, hapless ignoramus who stumbled upon a site for people who actually know what they're doing.)
The picture posted here is in much, much better condition than my speakers. In the 1990s I spent at least $800 Australian, maybe even $1000- they were my pride & joy. The rubber has now perished to absolute shreds. But after reading this thread I'm worried that other work will need to be done that I don't even know about: what's a voice coil? what's a driver? what's a woofer? and how do I know if mine are okay? eek! It's overwhelming.
Frankly, is it even worth getting the repair kit, given my inability to assess these other attributes?
Any feedback welcomed....
 
Sorry the speakers have long gone so I cannot offer help with dimensions. Have you done a Google search? I'd be surprised if you couldn't find this information fairly easily...

Perhaps somebody else here has a pair and can help.

Probably best to email one of the repair kit providers for further details. And if you order a repair kit for an AP2, you don't really need to know the measurements anyways - they'll fit ;)

Best of luck with it - a fiddly job and one I wasn't happy with after doing alas.

John
 
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