[Picked up some more AR speakers]

I'm starting to make an order list of caps and resistors for the 10Pi speakers. I'm going to use all NPE caps and the only one that is an issue finding is the 20uF. I can get 18uF and 22uF but NOT 20uF. This cap appears to be a woofer shunt cap that can be added, via an attenuation switch, to the 100uF cap. I'm not sure at what switch position the 20uF comes into play. I want to run the woofers in the 4TT position.

> Does anyone know if the 20uF is in the circuit when 4TT is selected AND will the 22uF be OK to use?

> Also, what is the 10 ohm resistor doing to the xover circuit where they put it across (parallel) the cap leads of the 2500uF cap?

[The Venerable Bose 901 Discontinued After 50 Years]

Like 'em or not the 901 was the largest selling speaker ever.

I prefer the acoustic suspension models way more than the ported ones.

Even though they don't have the detailed treble and nicely defined bass of my big AR's there's just something about listening to a full range driver system. I found recapping the EQ with modern day electrolytic, film and silver mica caps will enhance the treble range a lot.

 

[Picked up some more AR speakers]

2 hours ago, harry398 said:

What is your plan on surrounds....ie type and which seller?

All surrounds are good. The LMR with the round magnet is original and won't last long. Will use the BA filleted foam from Rick Cobb

2 hours ago, harry398 said:

what differences are there in the 8 inch 20027 and the AR18 woofer?

Square magnet vs round magnet. Both have the AR 20027 (and 20027-0) label.

[Picked up some more AR speakers]

Good to know about the woofers. I was ready to give up.

The square magnet LMR is like an original but has the replacement sticker. The round magnet is way more modern and has the modern AR symbol. Most likely a Tonegen driver. Both have the AR replacement sticker. The round magnet/more modern still has the original surround with the bead of rubber around the edge.

I think the original owner may be the reason for blown drivers. All of the screws holding the drivers were loose and he was playing both the 10pi and 9's with one amp and hitting them hard. I also think he used them outdoors a lot.

[Picked up some more AR speakers]

I finally recovered from the flu and took some time to pull all the drivers from the 9's and record the part numbers and voice coil DCR (below). (FYI: I always label/choose a left and right speaker when restoring).

All the drivers except one tweeter had replacement stickers on the magnet (WTF?).

Since three of the woofers are late production models will I loose bass? Or can I expect them to perform as if all drivers were the originals?

[Driving these AR3a speakers]

Thread title should be "Releasing the Magic Smoke"

<sorry, couldn't resist>

[Picked up some more AR speakers]

Luigi, thanks for the drawings.

Unfortunately I have no means of weighing the polyfiber.

I have a bathroom scale - not sensitive enough and a jewelers scale 0 to 100 grams and its small.

[Picked up some more AR speakers]

Adding a few more pics...

[Picked up some more AR speakers]

They are/were leaking and have a light brown crusty gunk on the ends. Feared a short.

That's exactly what my woofers read. I felt that was a bit low.

Thanks again Roy

[Picked up some more AR speakers]

I did some exploring. No work done to the  crossovers and it looks like their age has caught up with them. I'm glad I only hooked these up to an inexpensive amp.

Does anyone know what the DCR of the woofers should read?

[Picked up some more AR speakers]

I was thinking it was more of a satin. I knew it wasn't a flat black.

[Picked up some more AR speakers]

Could you give me a little more info?

LOL

Thanks Stewart

[Picked up some more AR speakers]

Does anyone have the spec for the black paint used in the 9 series speakers? Mostly used on the backs of the speakers.

[Picked up some more AR speakers]

Thanks Roy. You are a plethora of information and your knowledge is greatly appreciated.

[Picked up some more AR speakers]

My AR10pi speakers are the MkII version. They have polyfiber and not fiberglass stuffing. Could this be original?

I still need to peek at the crossovers and see what's in there for caps. Hoping for Sprauges but I've seen pics with Callins caps in some.

[Picked up some more AR speakers]

Thanks alkermes.

I need to AB the AR91 vs 10pi. I have a feeling the bass of the 10pi will easily surpass the 91's.

It maybe a while before I get to the 9's. At least I don't have to refoam any drivers.

[Picked up some more AR speakers]

Thanks so much for the tips Glenn. In case I can't find ZPoxy Stimpy mentioned Minwax wood hardener. Any experience with that?

I'll have to see if I can get a donor speaker from my brother inlaw for the veneer. He has a lot of oddball speakers he picks up at the town recycling center. He owes me for the AR94 restoration and a pair of small Infinity speakers.

[Picked up some more AR speakers]

Thank you for the pointers and schematic Luigi

[Picked up some more AR speakers]

I used a digital VOM on the ohm setting and measured the speaker output terminals.

Thanks for that info and that's what I thought. I hooked them up to a class H amp with the switches in 4 ohm position. Bass was EXCELLENT, Mids are great, tweeters do not stand out well.

[Picked up some more AR speakers]

I need some help understanding the 10pi ohm readings I'm getting. I want to run the 10pi speakers on my tube amp that is wired for 4-ohm speakers. I have the 10pi switches as follows: woofer> 4pi, mid> 0dB and tweeter> 0dB. I get an ohm reading of around 16 ohms ???? If I flip the woofer switch to pi and the ohm reading goes up to around 26-ohms. I know they have a transformer in the xover so this is probably giving me these high readings.

[Picked up some more AR speakers]

21 hours ago, larrybody said:

You must have a large vehicle to haul all that.

Nope. Just a Subaru Outback. Had the back seats down and both 9's on their backs. Pushed one way up and placed a 10pi on its side and the other pi on the front passenger seat.

I'll have to look for that cleaner. I've never seen it before.

Finally got a pic of the 9's to successfully load.

[Picked up some more AR speakers]

Thanks Glenn.

All of the foam on both speakers are good.

57 minutes ago, GD70 said:

The 9 veneer repair may be a bit tricky. What's your plan to tackle that?

Since you're the expert in this  area I was hoping you'd give me some pointers.

I've been told there is a product that will harden up MDF so I'll be looking for that.

What product do you guys use to clean dirt and grime from the wood. I use Murphy's Oil Soap but don't know of any other product that might be better.

 

[Picked up some more AR speakers]

The serial numbers are obliterated on the 9's.

I'm curious about the 10pi speakers (they are MkII models) as well. I have not had time to hook them up.

Spent most of the remaining daylight hours with compressed air and a vacuum cleaning all the grilles. Dust, dirt and dog hair. I usually clean grilles by first blowing off with compressed air, vacuum and then the garden hose followed by compressed air again. BUT with the frames being wood (and not plastic) I doubt I'm hitting them with water. It did work on an old pair of Polks though.

[Picked up some more AR speakers]

A 100 mile drive (each way) made me the proud owner of a pair of AR9's and 10pi speakers.

The 10pi are almost perfect. Just a small back corner chip on the top of one and dirty and thirsty for oil. They should clean up nice.

The drivers in the 9's are all good. One speaker has lifting of the veneer on the side/bottom. The MDF has swelled some. These too need a good cleaning. The side grilles are original and all but one has a small hole in the fabric. The front grilles have been replaced and need to be stretched better. Its odd but these have the plastic pegs reversed - mounted to the cabinet and plug into the grilles. Also, I have a few broken ones. A few small nicks here and there but not significant. They are beasts and my back will attest to that.

Having trouble uploading the full pic of the 9's

 

[Are these genuine AR 10pi or replicas?]

Thanks Roy. I pick them up tomorrow along with another pair of speakers provided all is good with them.