Help Restoring My AR-3a's

[JKent]

1 hour ago, Edward said:

The replacement components had that same thin wide foam with a circle painted on it prior to it dissolving into powder.

Edward,

I admit I've never actually seen an AR-11 tweeter. Is the thin wide foam you refer to a diffraction ring on the face of the tweeter? If so, they can be replaced with these: https://www.madisoundspeakerstore.com/acoustic-damping/dampers-felt-defraction-ring-for-tweeters/   They are $2 each. Ebay seller "Vintage AR" sells the exact same rings for $15/pair.

There are 2 ways to go with the tweeter cap. The simple way (that Roy described) is to chuck the 6uF and put in 2uF. What you described, i.e. replacing the old 6uF with a new film 6uF on the board and then adding a 3uF in series with the negative terminal is another way to go and in a sense more "authentic", since the factory would have done it that way. But unless you plan to find original 3a tweeters and have them rebuilt to replace the 11 tweeters in there, why go to that trouble? I think we all agree that Roy is the 3a guru and if he said just replace the 6uF with a 2uF you can take that to the bank.

It is wise to have your '70s era components checked periodically and it sounds like your tech, like mine, believes "if it ain't broke don't fix it". A total re-cap is a really big job.

Kent

[RoyC]

10 minutes ago, JKent said:

Edward,

I admit I've never actually seen an AR-11 tweeter. Is the thin wide foam you refer to a diffraction ring on the face of the tweeter? If so, they can be replaced with these: https://www.madisoundspeakerstore.com/acoustic-damping/dampers-felt-defraction-ring-for-tweeters/   They are $2 each. Ebay seller "Vintage AR" sells the exact same rings for $15/pair.

There are 2 ways to go with the tweeter cap. The simple way (that Roy described) is to chuck the 6uF and put in 2uF. What you described, i.e. replacing the old 6uF with a new film 6uF on the board and then adding a 3uF in series with the negative terminal is another way to go and in a sense more "authentic", since the factory would have done it that way. But unless you plan to find original 3a tweeters and have them rebuilt to replace the 11 tweeters in there, why go to that trouble? I think we all agree that Roy is the 3a guru and if he said just replace the 6uF with a 2uF you can take that to the bank.

It is wise to have your '70s era components checked periodically and it sounds like your tech, like mine, believes "if it ain't broke don't fix it". A total re-cap is a really big job.

Kent

I agree with Kent (so often the voice of reason ). Going with the series 3.3uf/6uf arrangement allows you to more easily return to the original tweeter should the opportunity arise, which is well worth taking into consideration. There is no need to use the tweeter faceplate (foam or felt) treatment for the 3a.

I also agree with Jeff (lakecat), the later pots were much less prone to the typical debilitating corrosion.

Polarized capacitors in your electronics are not really in the same category as your non-polarized crossover filter capacitors...though, imo,  too much confidence is placed in "vintage" amps, etc, which have not been completely restored.

Roy

[JKent]

PS
I'm with you on the evils of streamed music (but don't let Frank catch wind of your comments on vinyl ?)

Good advice from Lakecat. Maybe pull out a pot, open it and post photos. I'd still go with L-pads myself though.

Those Sony components are beauties from the heyday of Japanese electronics. If you want manuals etc. check here for the TA-2000 https://www.hifiengine.com/manual_library/sony/ta-2000.shtml  and here for the 3121 https://www.hifiengine.com/manual_library/sony/ta-3120.shtml  You'll have to "join" but it's free.

It's been noted here that the AR-3a likes a lot of power. Although the Sony's rating was "big watts" you may still be better off with more power--either a second 3121 or, many members here have praised the new cheap and powerful Crown or QSX power amps.

[Edward]

2 minutes ago, lakecat said:

Don't be so quick to throw away those pots. There is a double swipe in those later models...and have found them to be in pretty good shape. You have some of the last built speakers with those serial numbers.

lakecat,

After replacing pots for lpads I will no longer have any use for the four pots removed.  You are correct there does seem to be two layers of metal swipes, with the top one extended out to contact the coils.  If there is interest in them, I would give first refusal options to the individuals who have responded to my forum posts, and the order they responded. I'm not $$ grubbing but it would be nice to receive something to offset the costs for repairs discussed and postage.  Just some white powder on metal surfaces (sulfur?).

[Edward]

55 minutes ago, lARrybody said:

Not even FrankenAR. Now replace your woofer with Radio Shack woofers and your tweeters with Peerless soft domes then maybe. You want to install new L-pads because the original aetna-pollak pots are past their life expectancy. Your 20001-1 tweeters are ferro -fluid and will handle more power.  Just do the crossover mods. If you must have the original 3/4 in. hard dome tweeters they can be found and rebuilt by either RoyC or Chris1 to like new condition. 

Great news !!!

[Edward]

57 minutes ago, RoyC said:

As official spokesman for the " "Help Restoring My AR-3a group", the L-pads are fine with the 25 ohm parallel ohm resistor on the mid, and a 2uf capacitor on your AR-11 tweeters.

Roy

Thanks RoyC,

25 ohm parallel ohm resistor on the mid, and a 2uf capacitor on the AR-11 tweeters -- duly noted. 

Added to list.  The AR-3a restoration manual is truly a classic.

[JKent]

This QSC amp will provide 425wpc into 4 ohms. It's new, warranteed and costs $350

https://www.sweetwater.com/store/detail/GX3--qsc-gx3-power-amplifier

The Crown XLS line has been praised by Tom Tyson (of Restoring the AR-3a fame) and others. The 1002 delivers 350wpc into 4 ohms and costs $340. https://www.sweetwater.com/store/detail/XLS1002--crown-xls-1002-power-amplifier

Just a thought for down the road. 3a's like 100wpc or more. More importantly, they are 4 ohm speakers and your Sony is only rated for 8 to 16 ohm loads. I know that combo has worked for you for decades but I'd say "danger Will Robinson".

btw, found an interesting writeup on the TA-3120 here https://forums.stevehoffman.tv/threads/from-the-vintage-solid-state-vault-the-sony-ta-3120a.329715/  He commented; "making a decent - for the time - 50 watts per channel this amplifier will have enough moxy to drive most speakers, provided the they don't dip below 4-ohms impedance".

Kent

PS: Hey Steve! It's Moxie!

[Edward]

21 minutes ago, JKent said:

Edward,

I admit I've never actually seen an AR-11 tweeter. Is the thin wide foam you refer to a diffraction ring on the face of the tweeter? If so, they can be replaced with these: https://www.madisoundspeakerstore.com/acoustic-damping/dampers-felt-defraction-ring-for-tweeters/   They are $2 each. Ebay seller "Vintage AR" sells the exact same rings for $15/pair.

There are 2 ways to go with the tweeter cap. The simple way (that Roy described) is to chuck the 6uF and put in 2uF. What you described, i.e. replacing the old 6uF with a new film 6uF on the board and then adding a 3uF in series with the negative terminal is another way to go and in a sense more "authentic", since the factory would have done it that way. But unless you plan to find original 3a tweeters and have them rebuilt to replace the 11 tweeters in there, why go to that trouble? I think we all agree that Roy is the 3a guru and if he said just replace the 6uF with a 2uF you can take that to the bank.

It is wise to have your '70s era components checked periodically and it sounds like your tech, like mine, believes "if it ain't broke don't fix it". A total re-cap is a really big job.

Kent

Foam: I believe I read in the AR3 restoration manual that it is to reduce unwanted dispersion.  For a few buck I'll order them.  Thanks for the options. Otherwise I may fabricate them matching thinness.

Caps: Had I diagrammed these alternative I would have conceptualized these options earlier.  I'm going with the Roy suggestion: replace the old 6uF and put in 2uF. (vs replacing the old 6uF with a new film 6uF on the board, then adding a 3uF in series with the negative terminal).

You all have been very patient with me. Closest to original sound driven by logic is my priority , over the "authentic" option I was inadvertently stating.  Future owners will understand. Can't wait to run some Stravinsky and Miles Davis through them once completed.

[Edward]

20 minutes ago, JKent said:

This QSC amp will provide 425wpc into 4 ohms. It's new, warranteed and costs $350

https://www.sweetwater.com/store/detail/GX3--qsc-gx3-power-amplifier

The Crown XLS line has been praised by Tom Tyson (of Restoring the AR-3a fame) and others. The 1002 delivers 350wpc into 4 ohms and costs $340. https://www.sweetwater.com/store/detail/XLS1002--crown-xls-1002-power-amplifier

Just a thought for down the road. 3a's like 100wpc or more. More importantly, they are 4 ohm speakers and your Sony is only rated for 8 to 16 ohm loads. I know that combo has worked for you for decades but I'd say "danger Will Robinson".

btw, found an interesting writeup on the TA-3120 here https://forums.stevehoffman.tv/threads/from-the-vintage-solid-state-vault-the-sony-ta-3120a.329715/

Kent

I have been coming across references to QSC amps as of late but was not familiar with them.  I am not stuck on the Sony separates as I am with my AR-3s.

Seems like I may need to look into this ohm aspect of the Sony amp.

[Edward]

37 minutes ago, RoyC said:

I agree with Kent (so often the voice of reason ). Going with the series 3.3uf/6uf arrangement allows you to more easily return to the original tweeter should the opportunity arise, which is well worth taking into consideration. There is no need to use the tweeter faceplate (foam or felt) treatment for the 3a.

I also agree with Jeff (lakecat), the later pots were much less prone to the typical debilitating corrosion.

Polarized capacitors in your electronics are not really in the same category as your non-polarized crossover filter capacitors...though, imo,  too much confidence is placed in "vintage" amps, etc, which have not been completely restored.

Roy

And there are folks that will pay good money for these very Sony separates. They are in great shape, well sort of, they are old.  Hmmmmmmm.

[Edward]

43 minutes ago, JKent said:

PS
I'm with you on the evils of streamed music (but don't let Frank catch wind of your comments on vinyl ?)

Good advice from Lakecat. Maybe pull out a pot, open it and post photos. I'd still go with L-pads myself though.

Those Sony components are beauties from the heyday of Japanese electronics. If you want manuals etc. check here for the TA-2000 https://www.hifiengine.com/manual_library/sony/ta-2000.shtml  and here for the 3121 https://www.hifiengine.com/manual_library/sony/ta-3120.shtml  You'll have to "join" but it's free.

It's been noted here that the AR-3a likes a lot of power. Although the Sony's rating was "big watts" you may still be better off with more power--either a second 3121 or, many members here have praised the new cheap and powerful Crown or QSX power amps.

I have A/b d vinyl vs quality CDs.  I'm in favor of the wider frequency response of the compact discs and no background noise.  You see I tend to drop things including the finest of vinyl records. And it is so easy to insert a disc vs pull out a record and place on turntable. And with a CD you can listed from beginning to end without flipping the plastic.  I'm so glad to be rid of those cumbersome crates and the drying out of the cardboard slip covers, ...

The pots are in great condition, just need to have surfer reaction powder cleaned off and cleaned.  Maybe Ill just keep the pots.  Easier that way initially.

[JKent]

You could still use the Sony preamp with the Crown or QSC (or whatever) power amp to keep things looking vintage.

I'll give a plug for Akitika kits. I used one to rebuild my old Dynaco ST-120. He (Dan Joffee) now offers a nice preamp kit https://www.akitika.com/PR102.html

Of course, since you are using a CD player as a source you don't need a phono section (it's optional on the Akitika) so there are nice passive preamps available. Anything from a $49 Schiit (really--that's the name) to some very fancy units.

One of our members is a big fan of the Adcom SLC-505. I see those on ebay for $75-ish. Then there's Creek, Superphon, etc. Some guys like tube preamps. I use an old AR-SRC on a CD-only setup.

Got to get ready to go out. Happy New Year to all!

[lakecat]

CD guy myself. Got a nice ES Sony that weighs 45lbs. A little dielectric grease on those pots and they should last. Mine have...

[RoyC]

I try not to post personal preferences...but well recorded or re-mastered digital files of older recordings (WAV/CD or FLAC) are my favorites as well.

Roy

[Edward]

56 minutes ago, JKent said:

PS
I'm with you on the evils of streamed music (but don't let Frank catch wind of your comments on vinyl ?)

Good advice from Lakecat. Maybe pull out a pot, open it and post photos. I'd still go with L-pads myself though.

Those Sony components are beauties from the heyday of Japanese electronics. If you want manuals etc. check here for the TA-2000 https://www.hifiengine.com/manual_library/sony/ta-2000.shtml  and here for the 3121 https://www.hifiengine.com/manual_library/sony/ta-3120.shtml  You'll have to "join" but it's free.

It's been noted here that the AR-3a likes a lot of power. Although the Sony's rating was "big watts" you may still be better off with more power--either a second 3121 or, many members here have praised the new cheap and powerful Crown or QSX power amps.

To all,

 Yea lots of chatter about old classic amps that, however, contain tiring capacitors.  I'm now clearly seeing that I do need to move to a more compatible amp for my AR3s.  Interesting suggestions with good specs and not that costly.   Does this mean that a newer amp will contain circuit boards with chips ???

[DavidR]

Have you considered a tube amp. I run a Bob Latino VTA ST-120 with my 10Pi. SWEET !

I know someone selling some M125 monoblocks. Similar to the pic below.

 

[Edward]

I would love twin tube amps, but @ 61 yo I'm looking for something small and little to no maintenance.

However they are great looking set.

Thanks, EE

[genek]

3 hours ago, Edward said:

Yea lots of chatter about old classic amps that, however, contain tiring capacitors.  I'm now clearly seeing that I do need to move to a more compatible amp for my AR3s.  Interesting suggestions with good specs and not that costly.   Does this mean that a newer amp will contain circuit boards with chips ???

There are very few modern amps that don't contain a chip somewhere. Even if the output stages are discrete, there will probably be some in the protection circuits.

[Aadams]

5 hours ago, Edward said:

But unless you plan to find original 3a tweeters and have them rebuilt to replace the 11 tweeters in there, why go to that trouble?

One reason would be it is the most flexible approach. In the event one of the old Ar11 tweeters fails the easiest, least expensive and most expedient path to a matched pair would be a Hivi QR1 mod which is based on having a 6mf cap in place.

Adams

 

[JKent]

1 hour ago, Aadams said:

One reason would be it is the most flexible approach. In the event one of the old Ar11 tweeters fails the easiest, least expensive and most expedient path to a matched pair would be a Hivi QR1 mod which is based on having a 6mf cap in place.

Not necessarily. I believe Roy's current thinking on this is that the Hi-Vi tweeter should have a lower value cap. Check this thread:

Trouble is, you'd have to put a 30uF cap on the tweeter to make the total capacitance 5uF (I don't really understand this, I'm using a calculator). OTOH, it would be adventagious if Edward ever went back to original tweeters. But there seems to be little reason to do that.

[Aadams]

18 hours ago, JKent said:

Not necessarily. I believe Roy's current thinking on this is that the Hi-Vi tweeter should have a lower value cap. Check this thread:

That thread has several opinions.

If these excellent examples ever come up for assessment against a normative 3a , originality will always require the least amount of explanation.  To a knowledgeable observer the AR11 tweeter is an immediate sign of a non-standard configuration that should raise skepticism.  Keeping the original internal configuration and putting the mod on the tweeter makes this more of an expedient adaptation that is easier to explain.  Without this thread as provenance, an objective, knowledgeable buyer of 3as would discount the value based on appearance alone and even more if the crossover is modified, unless, perhaps, the owner could show the page in the restoration guide on how to electronically reconfigure the crossover to take make an AR11 tweeter compatible with an AR3a.

From a performance standpoint,  the only tweeter that bridges the 4k to 8k octave across the classic mid and tweeter combo while maintaining the power response of the midrange unit, is the original tweeter.  All subsequent tweeters are stronger on axis and yield a different sound when the harmonics and overtones are strong in the 4 to 8 range but the superiority of the 3a tweeter power response can only be heard by using a rebuilt unit that has been tailored to crossover correctly at the 5k point AND if you are listening to source material that contains the information. 

Adams

 

Edited January 2, 2020 by Aadams
for clarity

[DavidR]

14 hours ago, Edward said:

@ 61 yo I'm looking for something small and little to no maintenance.

Have you considered Emotiva:

https://emotiva.com/collections/amps

[ar_pro]

This is shaping up to be a fine restoration, with lots of excellent advice & direction from guys who have been down the same road.

I had a friend whose brother once owned the very same Sony equipment, along with an early Sony direct drive turntable (maybe the PSE-4000) that he used with enormous custom JBL speakers; the guy was kind of a jerk, so we only got to hear the system once or twice, but it was pretty impressive. This particular Sony equipment has some classic Japanese design elements that make the preamp especially desired - they commonly sell for close to a thousand dollars, depending on condition. There's a review of the TA-2000 in the December, 1968 issue of Audio magazine that can be found at the American Radio History site: https://www.americanradiohistory.com/Audio-Magazine.htm

The power amplifiers suggested all have their merits over 50 year old equipment, especially when it comes to increased power output and the ability to handle low impedance loads like your restored AR-3a systems with ease. 

[Edward]

Thanks for that.  just cannot see those old Elna caps in my Sony power amp living that much longer and remaining with acceptable tolerance.  As previously mentioned in the forum under this thread, the QSC amps were suggested as an option.  I really do not have all that much mula allotted for home audio.  They certainly meet all my requirements. However, I am digging the preamp.  I 'm looking for clean, simple, and reliable power source with power to spare so I'm remain lower on the dial.  For a short period of time I owned pairs of both the AR-3 and JBL 100s (waffle grills) having the opportunity to A/B them.  The ported JBLs were louder given a volume setting compared to the ARs.  But the AR3 were much smoother (flat) to my ears with symphonic strings, jazz horns, and vocals.  All my friends liked the JBLs better.  I easily sold the JBLs for what I paid for them because I had ordered them from a catalogue sales company at a significantly discounted cost.

Yea the Sony TA-3120 seemed to power (stated 50 wpc rms) the AR-3 s just fine for a few decades.  But those QSCs would also fit under the preamp much better.

[JKent]

Yes, that Sony preamp is a beauty and as long as it has been checked and serviced it is a cool vintage piece to use with a new power amp. Of course there are many options and if the old Sony gear can be sold for a good price the options discussed above are all good. And there are more, depending only on taste and purse.

For my own vintage setups I like to keep it All American (where possible), not because the Made in USA gear is superior to imports (often it's not) but because as an aging boomer I'm nostalgic for the time when we did lead the pack when it came to hi-fi.

One of my vintage systems uses an Adcom amp and pre, both made in my home state, NJ, to drive AR-91 speakers. That system has a Henry Kloss designed (but Chinese built) Tivoli CD player. The second system uses a DB Systems preamp (NH) and a modded Hafler amp (also NJ). That system includes an AR 'table and AR-3a speakers. The third vintage setup uses an AR-SRC stereo remote control as a passive preamp and a rebuilt Dynaco ST-120. This one is not truly American--the SRC was designed by Ken Kantor but built in Taiwan, and I use a cheap bluray player for CDs. The ST-120 was gutted and everything but the transformer is from updatemydynaco.com. Speakers in that setup are also Ken Kantor designs: NHT Super Zeroes. And finally a completely rebuilt Scott 299a integrated tube amp is hooked up to Cizek KA-1 speakers. Source for that is an HK T-60 'table with a Shure V-15 V cart but "one of these days" I'll rebuild a spare AR 'table and put that in there.

The point is, there are many options and you don't have to spend a fortune.