Sony APM Questions

[Stoffie]

if i remember correctly, the true apm woofers have 5 divets on the cone . the ones with 4 divets have a traditional voice coil with bracing extending from the center outward on the back of the cone. i'm sure there are exceptions and someone else will know better than i.

i couldnt tell you exact model numbers other than the apm 77 is a true apm, the apm 66 is not

if you aren't familiar...real apm

"fake" apm.

The 'fake' APM you are referring to is actually from an APM-66ES which I'd hardly call 'fake'.
Those are a far cry from the cheaper made triple digit series which had the looks but not much of the high-end tech of the 'real' APM's.
It's simply the last iteration of the APM development as you can read here from the very knowledgeable Romain (from Sound Oddity) which is probably one of the very few people in the world that could be called an actual APM expert.

A little excerpt:

When comparing the woofers magnets, one could think the 66 are down scaled 55 but they aren’t at all. The 66 have in fact a much more evolved driver’s design, with T shape pole pieces, a strontium magnet material, flat wire OFC copper voice coil, a thinner magnetic gap and an aramid spider. For the same measured MMS of about 65 grams, the measured BL of the 66 is 1.5 points higher with a value of 14.5 against 13 for the 55. It doesn’t mean ether that the 55’s woofers are less good, it’s just that the 66’s woofers are more optimized for less weight.
The driving system of the 66’s woofers is the last APM evolution using 8 points driving instead of 4. It allows to get rid of the 9th order resonance mode of the 4 points driving system originally designed for the APM-8. Consequently, the frequency response of this woofer is flat until 4KHz! Which is kind of unbelievable for a diaphragm equivalent in area to a 25cm diameter cone. The result is an incredibly clear and fast bass response, so detailed and powerful.
I will agree though that the 4-magnet design of for instance an APM-77 woofer does speak to the imagination more

 

[painttoad]

The 'fake' APM you are referring to is actually from an APM-66ES which I'd hardly call 'fake'.
Those are a far cry from the cheaper made triple digit series which had the looks but not much of the high-end tech of the 'real' APM's.
It's simply the last iteration of the APM development as you can read here from the very knowledgeable Romain (from Sound Oddity) which is probably one of the very few people in the world that could be called an actual APM expert.

A little excerpt:

When comparing the woofers magnets, one could think the 66 are down scaled 55 but they aren’t at all. The 66 have in fact a much more evolved driver’s design, with T shape pole pieces, a strontium magnet material, flat wire OFC copper voice coil, a thinner magnetic gap and an aramid spider. For the same measured MMS of about 65 grams, the measured BL of the 66 is 1.5 points higher with a value of 14.5 against 13 for the 55. It doesn’t mean ether that the 55’s woofers are less good, it’s just that the 66’s woofers are more optimized for less weight.
The driving system of the 66’s woofers is the last APM evolution using 8 points driving instead of 4. It allows to get rid of the 9th order resonance mode of the 4 points driving system originally designed for the APM-8. Consequently, the frequency response of this woofer is flat until 4KHz! Which is kind of unbelievable for a diaphragm equivalent in area to a 25cm diameter cone. The result is an incredibly clear and fast bass response, so detailed and powerful.
I will agree though that the 4-magnet design of for instance an APM-77 woofer does speak to the imagination more

best way to say it is that we have a difference in opinion of what we consider a real apm.

 

[Max cando]

Hi All APM speakers made in Japan and in Germany are truly APM. All APM 930.790 etc made in USA are a shame to Sony with crap woofers ,drivers frames made of tin instead of Aluminium .All plastic cheap driver covers too.
The cabinets of usa made are pure rubbish.poor finish and thin cabinets .The stands are crap too .
The APM 66 ES are top end speakers with a rare and fantastic big mid drivers.
The eight pillars on the woofers give more support but the sound is the same of the APM-55 gems unless you have a dog or superman hearing to see the difference.
The tweeters of the APM -55 are bigger than the 66 but the 66 mids are bigger than the APM:55/77 and this element gives the APM -66 an advantage as the sound coming from the mids are superb !!
The 66 mids are nearly the same size of the APM-6 tweeter .
Got APM-700/33/55/66/77/ and my gems APM- 6 Esprit .
However ,the APM-12ES /20/22/141/181/X300
Are all fantastic ! I’ll keep the APM-55/77/6/33
And sell the rest including the 66ES.
Max
The Sony Guy Uk
Note :I know Romain I sold him a AR-3a and sent them to Reunion
Any faulty APM tweeters or woofers can be fixed by:
Speakerfix in Belgium by Galip

 

[Ds2000]

Hi All APM speakers made in Japan and in Germany are truly APM. All APM 930.790 etc made in USA are a shame to Sony with crap woofers ,drivers frames made of tin instead of Aluminium .All plastic cheap driver covers too.
The cabinets of usa made are pure rubbish.poor finish and thin cabinets .The stands are crap too .
The APM 66 ES are top end speakers with a rare and fantastic big mid drivers.
The eight pillars on the woofers give more support but the sound is the same of the APM-55 gems unless you have a dog or superman hearing to see the difference.
The tweeters of the APM -55 are bigger than the 66 but the 66 mids are bigger than tje APM:55/77 and this element gives the APM -66 an advantage as the sound coming from the mids are superb !!
The 66 mids are nearly the same size of the APM-6 tweeter .
Got APM-700/33/55/66/77/ and my gems APM- 6 Esprit .
However the APM-12ES /20/22/141/181/X300
Are all fantastic ! I’ll keep the APM-55/77/6/33
And sell the rest included the 66ES.
Max
The Sony Guy Uk
Note :I know Romain I sold him a AR-3a and sent them to Reunion
Any faulty APM tweeters or woofers can be fixed by
Speakerfix in Belgium by Galip

Is Galip able to fix the delamination exhibited by the APM-6 woofer in its old age? I had a pair and sent them to Japan where one shop was able to do the work well enough that you could not tell the difference. And was neat enough to not need to silver paint the diaphragm.

 

[Max cando]

That’s fantastic news too!!!
When you say delamination do you mean the honey comb front face plate?.
I sold a APM-6 set with fixed tweeters .Galip was the only one in the globe to fix them.The central piston went sideways after a short incident .According to Romain ,the tweeters needed to get demagnetised first. In the meantime I fit the APM-66 mid drivers as a tweeters on the APM-6 and sounded superb !!
So the APM-66 mids 30W-6 ohms can replaced the tweeters on the APM-6 -20W/8ohms if 6 tweeters not available
Max

 

[Ds2000]

That’s fantastic news too!!!
When you say delamination do you mean the honey comb front face plate?.
I sold a APM-6 set with fixed tweeters .Galip was the only one in the globe to fix them.The central piston went sideways after a short incident .According to Romain ,the tweeters needed to get demagnetised first. In the meantime I fit the APM-66 mid drivers as a tweeters on the APM-6 and sounded superb !!
So the APM-66 mids 30W-6 ohms can replaced the tweeters on the APM-6 -20W/8ohms if 6 tweeters not available
Max

That is a good tid-bit there. Having a backup driver is good news for APM-6 owners.
The woofer issue relates to the cardboard spacers and the aluminum rings they attach to in the honeycomb. Those loosen and sometimes the cardboard cracks and needs replacement. The loosening rings can unglue the top aluminum panel on the honeycomb and the net result is distortion from the non linear surface and the now mis-aligned coil.
Repairing this is a delicate process, beyond delicate. One doesn’t want to add too much stiffness or mass. The sound characteristic would change. He would not divulge specifics, but they have worked for 15 years without further issue. The tweeters never had an issue.
I sold them but I keep in touch with the owner.

 

[Stoffie]

Any faulty APM tweeters or woofers can be fixed by:
Speakerfix in Belgium by Galip

Interesting to know there's a guy I can just drive to that can deal with APM repairs.
Have not seen this guy's work contrary to the meticulous job Romain always does but sure beats having to send precious APM units overseas.
Romain from Sound Oddity is currently developing a DIY surround kit and also working on a diaphragm/membranes repair kit which will also include said surrounds, I'm very interested to see what that will turn out to be.

 

[{tpc}]

Great information in this thread! I still have not located a set I want, though I have seen some around. I get nervous because even reputable ebay sellers sometimes don't know what they have, and your buying them on a picture alone, which is tough.

 

[Max cando]

Great information in this thread! I still have not located a set I want, though I have seen some around. I get nervous because even reputable ebay sellers sometimes don't know what they have, and your buying them on a picture alone, which is tough.

Hi
I’ve been collecting Sony APM since the nineties.I’m the only one who has original Sony APM-33 surrounds made in Germany /Wega
Not Russian ones .and sell them on ebay
Sold lots of them not only to repair apm/33 but
66/77/6 by cutting the 33 in quarters and spreading the corners on the woofers, then cutting same size pieces to cover the gaps .
The speakers have to be in lay down position when fitting the surrounds ,not standing up as the piston has to be balanced in the middle.
I do prefer original rubber surrounds to made ones .