Latest aquisition - AR91s

[valkyrie]

Ra.ra - thank you for your help.  And the link!!!

AR_Pro - I plan on using the "holes" that the slide switches currently (no pun intended) occupy on the Nine attenuation control panel.  Not sure - I may have to do some mods to get the switches mounted correctly - airtight and all.   I just like the feel of the switches on the 91 - and feel that the switches on the 9s are - at best - somewhat cheesy.  I guess AR was trying to save a few bucks in production.  I do want to save the original sand cast resistors on the 9 - why remake the wheel?

I will post pictures when I am done.  

Thanks guys for your timely and helpful reply!!!

[Stimpy]

1 hour ago, valkyrie said:

Ra.ra - thank you for your help.  And the link!!!

AR_Pro - I plan on using the "holes" that the slide switches currently (no pun intended) occupy on the Nine attenuation control panel.  Not sure - I may have to do some mods to get the switches mounted correctly - airtight and all.   I just like the feel of the switches on the 91 - and feel that the switches on the 9s are - at best - somewhat cheesy.  I guess AR was trying to save a few bucks in production.  I do want to save the original sand cast resistors on the 9 - why remake the wheel?

I will post pictures when I am done.  

Thanks guys for your timely and helpful reply!!!

You could always wait for a set of AR90 crossovers to pop up on eBay.  The upper range boards are the same as the 9's, and already have the heavier duty toggle switches in place.  Just swap the boards. 

But, I've do admit that I've never seen the rear panel of the 9's.  Is the cut out the same size as the 90?  Would it accommodate the 90 board, and switches?  Plus, you'd need to add back the extra set of binding posts.  Hmm, now that I think about it, too much work? 

[DavidR]

The AR90 upper board has the same caps as the 9 but the boards are not exactly the same.  The caps are laid out differently and the wire color for pos and neg is different/reversed for the 90 due to it being wired out-of-phase. But you could make it work.

[Stimpy]

The phasing differences between the 9's and 90's still makes me crazy!  I guess I don't understand the need for the difference?  I do know the 9's bass crossovers are different.  Do those extra components shift the phase?

[DavidR]

There is no "shift" in the phase. It is hard wired on the 90 for the LMR/UMR and tweeter to be out-of-phase. 

[AR surround]

In the AR90's the toggle switches for the attenuation network are mounted on the rear of the speaker.   In the AR9's, they are mounted on the front.   That board in the 9 is easy to remove...at least with the serial numbers that I have.  Just remove the nuts from the toggle switches; pull the resistor board (with attached toggle switches) into the speaker; disconnect the spade lugs and work on the board at the workbench.

I replaced all of the resistors in the AR90's and AR9's except for those in the LMR attenuation circuit because I haven't attenuated the LMR in about 30 years.   Upon checking the removed sand cast resistors, almost all of them measured close to right on.   But there's always a trouble maker and that one was off by about 20%.

I used a couple of the sand cast resistors taken from the AR9 to do some attenuation in my AR915.   I wasn't concerned about close matching resistors because I only use a single 915 as the center channel speaker in my HT.

Lastly, I did some phase testing with my AR9 front speakers and AR90 surround speakers and confirm that both pairs play in-phase to each other.

[Stimpy]

1 hour ago, DavidR said:

There is no "shift" in the phase. It is hard wired on the 90 for the LMR/UMR and tweeter to be out-of-phase. 

I must not be doing a clear job of explaining what I mean?  On the 90's, the upper range drivers are out of phase to the woofers, as we've discussed.  On the 9's, all drivers are in phase.  That's what I refer to as phase "shift".  This difference in phase, between the 2 models of speakers, is what I don't understand?  Why the need?  What's different in the 90's, compared to the 9's, that required this difference?

[ar_pro]

Those switches on the AR-9 have been a pita since forever, and it's a shame that AR ever used them, especially when the more robust switches from the AR-90 and AR-91 designs were available.

That said, how often do current AR-9 owners here find cause to adjust the output levels of their speakers? I believe my long-standing default position was always the "0 dB" setting. If this is true for others, then perhaps just bypassing the level controls - while leaving the front panel switches & board undisturbed - would be the better solution, no?

[DavidR]

1 hour ago, Stimpy said:

I must not be doing a clear job of explaining what I mean?  On the 90's, the upper range drivers are out of phase to the woofers, as we've discussed.  On the 9's, all drivers are in phase.  That's what I refer to as phase "shift".  This difference in phase, between the 2 models of speakers, is what I don't understand?  Why the need?  What's different in the 90's, compared to the 9's, that required this difference?

Oh, OK

 

It probably sounds better.

PM Ken and ask him. He may know as he was a young engineer at AR at that time IIRC. --OR-- wire your 90's all in phase and tell us the results.

[Stimpy]

3 hours ago, DavidR said:

Oh, OK

 

It probably sounds better.

PM Ken and ask him. He may know as he was a young engineer at AR at that time IIRC. --OR-- wire your 90's all in phase and tell us the results.

Don't roll your eyes at me!  Just because my 90's aren't currently available, doesn't mean that's a permanent condition!    And in actuality, I do plan on testing the drivers all in phase.  One day...!  Soon?  

[DavidR]

I may have to come down for a few days and help you get them up and running.

My audio to do lIst:

1) Listen to the 91's way more

2) Get the AR94 drivers and xovers ready for sale on eBay

3) Recap 10 Pi

4) work on  9 cabinets

5) Recap 9's

6) Recap 90's

[Stimpy]

That's a busy To-Do list.  It should be fun.  Any caps in mind for the 10's, 9's, and 90's?  Clarity, or Mundorf E-Caps, or...?  Solen perhaps? 

Also, I've liked my AR58S speakers so much, that I think they're part of the reason that I haven't started back on the 90's.  The 12" AR woofers sound too good to give up!

[DavidR]

The 10 Pi and 9 will have all NPE. Mundorf ECap70 on the smaller values and Bennic on the larger.

The 90's will have Mundorf ECap70 + vishay bypass on the 4, 6 and 24, The 80 will be a Jantzen + CD 940C bypass. I believe all the other caps will be Dayton polypro for the shunt caps (1% on the 8 and 5% on the rest) - only because I already bought them. Oh, and a 200 + 150 Solen for the 350Uf cap.

[ra.ra]

6 hours ago, ar_pro said:

Those switches on the AR-9 have been a pita since forever, and it's a shame that AR ever used them...

I should probably stay out of this discussion since most of this does not apply to my own speaker collection, but I assume here that your complaint has to do with the quality of the particular switch which was used in the AR-9, and not the concept of a three-position switch in the crossover for these drivers.

And is that the same reason why member valkyrie is thinking about replacing them with a more robust switch component? 

[ar_pro]

48 minutes ago, ra.ra said:

I should probably stay out of this discussion since most of this does not apply to my own speaker collection, but I assume here that your complaint has to do with the quality of the particular switch which was used in the AR-9, and not the concept of a three-position switch in the crossover for these drivers.

And is that the same reason why member valkyrie is thinking about replacing them with a more robust switch component? 

Yes - quality. The AR-9 switches are feeble, and it's even possible to wiggle them from one contact point to another, getting the kind of "static" sound that plagued the pots from the Classic Series.  It doesn't instill confidence, that's for sure.

On the other hand, the AR-90/91 switches are very solid & reliable, and should have been used in their top speaker.

[ra.ra]

15 minutes ago, ar_pro said:

...and should have been used in their top speaker.

Yep, makes good sense to me. Thanks for clarifying.

[harry398]

On 3/30/2018 at 9:36 PM, ar_pro said:

Yes - quality. The AR-9 switches are feeble, and it's even possible to wiggle them from one contact point to another, getting the kind of "static" sound that plagued the pots from the Classic Series.  It doesn't instill confidence, that's for sure.

On the other hand, the AR-90/91 switches are very solid & reliable, and should have been used in their top speaker.

I have the opposite experience.   90's I have here now have a bad-scratchy switch.   I wd-40 it, big improvement.   They sat for 18 years in a guys house........in pieces...

I guess they all get corroded, but I havent had any issues with the 2 sets of 9"s I own.  

[DavidR]

How do you go about spraying WD-40 or De-Oxit inside the switch ? My 90s are stiff but the 9's move like silk.

[harry398]

Well,

The easiest way is to tip the speaker and hit the toggle area with a little wd40 and let it seep inside the switch assembly.   work the switch..........and add wd40....keep doing it ....you will get a positive result.