JPW AP1 Speakers

On loan from a friend while he is on holidays is a pair of JPW AP1 speakers. These speakers were rated as a best buy in Britain during the mid 80's due to their quality components and the low retail price.

From what I read the PW stood for "prison workers" in the fact that these were made by inmates. I don't know how true that story is.

The AP1 is a simple acoustic suspension featuring Seas/Vifa woofers and tweeters, air core inductors and what looks like a 1st order cross on the woofer and a second order cross over on the tweeter, there is a resistor to tame the Vifa D 19TD tweeter.

This pair had been re foamed in the past 5 years.

Pioneer HPM-60

I just picked up a pair of Pioneer's legendary HPM series speakers, the HPM-60.

In the golden days of vintage audio 1975-1979 (I think continued into the late 80's) the war for domination was lead by Pioneer. The king daddy no budget spared receiver of the day was the Pioneer SX-1280 and SX-1980 which competed with the Yamaha CR-3020, Sansui G-3300, Sony STR-V7 and another legend, the Marantz Model 2500. This was in the day of real "watts per channel" as in 200+ watts continuously, not peak power for micro bursts as receivers are marketed today.

It is fair to say that Pioneer and Marantz won the vintage war as today their receivers still command a big premium over their rivals, a true testament to their quality 35 years later. Here is an interesting article on why 30 year old receivers sound better than today's crap. And another interesting shootout between a Pioneer SX-1980, a Sony STR-V6 and a newer Yamaha RX-V1800.

Back to the Pioneer HPM Series speakers, 1n 1975 Pioneer scooped JBL's Vice President of Engineering, Bart Locanthi who developed JBL's most famous loudspeaker the JBL L100 Decade, remember these where the days when no expenses were spared to gain market share.

The Pioneer HPM-100 was a direct competitor to the JBL L100 with hints of the JBL 4311, the HPM-60 was designed to rival the JBL L36, the HPM-40 was targeting JBL's L26 and the HPM-30's was targeting the JBL L16.

Pioneer had to differentiate themselves from JBL so they added the "Super Tweeter" which was probably more of a marketing schtick than anything else. The Super Tweeter is a thin film foil over foam with to leads attached, no magnet just a current across the film. They do make noise but their output is very low, I bet the sales pitch was that it works but you just can't hear it.

The Pioneer HPM-60 have been playing for the past 24 hours and I can hear the JBL low end in these speakers, they sound like the JBL L26 in that sense but the mid range is there and the tweeter is not a harsh as the JBL tweeters.

I can understand why the HPM 100 and the HPM 60's still command JBL prices in the vintage market.

Update: I have been running these speakers all weekend and these are awesome monitors, very forward sound. Very much like JBL's.

Mission 700S update

I sourced a couple Vifa D 19 TD tweeters from a pair of Mission 70 speakers, They were installed and sound better than I thought. There is  a couple of resistors on the crossover which tames the shrillness of the Vifa tweeter. When I was listening to the Mission 70 speakers, they have a simple 2nd order cross on the tweeter and the woofer rolls of naturally, the shrillness was evident.

The Philips tweeters ended up in the Mission 70 which sound good.

Now these Mission 700S are 100% original and sound fantastic, no wonder I bought these as my first speaker ever.

Visonik David 4000

I just stumbled upon another mini speaker this time it is a pair of Visonik David 4000's. These little guys were made in Germany and were the predecessor of the Visonik David 5000.

The DAVID 4000, presented in 1978, was particularly innovative because its case was cast in aluminium. It resulted in new benchmarks for machining, resonance-behaviour and stability of the case. The DAVID 5001, nowadays still in production, endues over these exclusive technological features.

These guys will need to be re foamed as the foams are cracked, while I am at it these speakers have a 1st. order crossover to the tweeter with 6.8uf cap, so I might as well upgrade that as well.

Update: Unfortunately this project has come to an abrupt end as one of the tweeters died. I managed to re foam the woofer and re cap the crossover and upon testing it one tweeter died. Looks like I will part these out on Ebay.

Another Energy 22 option

A follow up to my post from Saturday here is another drop in replacement.

JBL 033 Tweeter: From JBL L40 or L110. Faceplate is 5 3/8" crossover was 1800hz. I believe these were made by Audax and found in Infinity speakers also.

Energy 22 tweeter replacement

The mid generation of Energy 22 speakers are currently finding that a lot of their tweeters have failed. I have an early generation Energy 22 the one with 3 posts for attaching the speaker grill, and a mid generation with the four inverted holes for the speakers grills and the post were mounted on the grill verses on the cabinet. The third generation before the Energy 22.2's saw the tweeter deviate from an aluminum plate to a 1/4 thick plastic plate.

Unfortunately Chris Coote from ABI Tech is no longer rebuilding the tweeters, Vancouver Speaker Clinic can re tinsel the leads going to the voice coil if this is where your failure is. If you have a burnt voice coil then you are out of luck. By the way the guys at Vancouver Speaker clinic do excellent work and I have had them fix a JBL T35i tweeter.

The Energy 22 tweeters that I used for this project the guys at Vancouver Speaker Clinic tried to fix for me and if you look close enough you can see the tinsel leads they tried to use. So these are my guinea pigs.

So owners have scratched their heads on how to solve 2 problems with finding a replacement, one is the 1500hz crossover point and the other is the face plate is 5 3/8 in diameter. Most modern day replacements do not have a face plate that size leading to further modifications.

A few tricks that have been tried including myself is using an EPI or Epicure tweeter, the Epicure tweeters were crossed over at 1800hz and almost fit the front baffle cutout.

Another talked about replacement is using Sound Dynamic tweeters as straight drop ins but from what I have read the Sound Dynamic tweets are a bit hot for the 22's.

The most talked about off the shelf replacement is a Dayton Audio RS28F-4 silk dome or a Vifa Dual Ring Radiator Tweeter. Both would require extensive baffle work to get them to fit.

I was always looking for a solution and finally one popped into my head the Vifa OC25SC65-04 tweeter, although it runs at 4 ohms the rest of the tweeter could work. Below are the specs for the tweeter. Here is the Tymphany PDF.

Specifications: • Power handling: 25 watts RMS/50 watts max • VCdia: 1" • Impedance: 4 ohms • Re: 3.2 ohms • Frequency response: 900-28,000 Hz • Fs: 1,520 Hz • SPL: 90 dB 2.83/1m • Dimensions: Overall diameter: 1.6", Cutout diameter: N/A, Depth: 1".

So I did no mods to the crossover and I am sure there is some shift there upwards in the frequency as the tweeter is 4 ohms and the crossover is designed around a 8 Ohm driver. The Energy has a 3rd order cross with an 18db slope and the Vifa tweeter has a resonance frequency around 1500hz so I figure this could work.

Anyway of on with the walk through, after all that's why you clicked this story.

First up we have the tweeter pulled apart, as above.

Next is sizing up how it is going to look mounted on the back or should I mount it on the front?

Next I had to fill the old screw and lead holes with silicone.

While the silicone was drying I added new connectors to the speaker wire, blue is negative and yellow is positive.

Next I pinched the soldered leads to the post for a better fit for the face plate modification. I decided that I wanted the tweeter mounted on the front and not the back for diffraction issues.

Next was filing the plate to mount the tweeter.

Tweeter now fits in.

Next I added silicone to glue them in and seal any gaps.

I bought some 1/8" closed cell foam similar to the original foam on the plates and added a felt ring around the tweeter to help cosmetically.

I have them installed and I am really enjoying my Energy 22's again. I have A/B them against my other Energy 22's that are stock and the modded pair are have a bit more energy in the highs but they sound fantastic and image great. No they don't sound like the originals but they do sound close.

Email me if you have any questions.
 

Mission 700S update

The Mission 700S have found a spot in with the Mission 770 Freedom IV and the Dual CL390's. The Philips tweeter works really well and I prefer it over the Vifa D19-TD in which is stock in this model.

I re-foamed a friends pair of Mission 707's awhile back on the premise I get to listen to them for a few weeks. I found the Vifa tweeter very open at first but after an hour listening I found the Vifa fatiguing. I ended returning the 707's early.

These 700's are a great sounding little speaker.