AR-303 crossover parts upgrade ?

[thiptoman]

I have a few questions concerning the AR-303 loudspeakers .

#1. Is it worth the effort to upgrade the crossover parts in this speaker ? Is there an audible difference ( stock vs upgrade )?

# 2. I took a look at the crossover network in my speakers . Does anyone know the exact values of the various crossover parts for this speaker ? If so please list them .

I realize this is asking much but info will be greatly appreciated . Thanks !

[Guest Bret]

>#1. Is it worth the effort to upgrade the crossover parts in this speaker ? Is there an audible difference ( stock vs upgrade )?<

I cannot help with the second part of your question.

So in "big general terms" then;

Your speakers are modern enough that the parts-problem found during the "vertical series" should not apply to you.

The tweeter capacitor used is the mylar type in your speakers - it should still be good after we are dead assuming nothing weird happens.

The resistance of the inductors was used in various calculations and measurements (and likely the capacitors as well) so changing those might not be a good idea.

If they were mine, I'd leave them alone.

Bret

[kkantor]

Hi...

There's a circuit for the 303a in the library here. The 303 uses the same crossover, just no bi-amping option. Naturally, my own opinion is that the crossover is optimized as is. As Bret says, pretty good parts were used, so I doubt you are going to get much improvement with replacement. On the other hand, it can be fun to try.

-k

kkantor.spaces.live.com

[onplane]

Ken,

While we are on the topic of the 303, one of our favorite speakers , any chance we can get you to comment on:

1. the addition of bi-amping capability in the 303a (why, what are your impressions of bi-amped 303's, disadvantages, etc.)

2. why only "passive bi-amping"?? Many competitors offered the option of switching out the passive components and operating under ACTIVE bi-amping (aka ACTIVE operation).

3. the xover for the mids and tweeters is significantly more complex that the xover for the venerated AR-3a. What were you striving to accomplish with this added complexity?

4. xover for the woofer is pretty similar to 3a, except for the 5 ohm resistor in series with the 80 mfd cap. Can you comment of the function of that resistor?

Regards,

Jerry

PS: Ken, answering any or all of the above may be dangerous to your health, as it may breed ... more questions!!

[kkantor]

Arrgh. The internets seem to have munged my earlier reply, so here's another.

0- Questions are good. But, I generally tend to prefer only one or two per post. Otherwise, the ratio of answering effort to asking effort grows exponentially.

1- When the 303 came out, the bi-wiring mania was taking hold. Our dealers put a lot of pressure on us to accomodate this. The advantages and disadvantages of bi-amping are well-worn territory in audio. I have no particular impressions of about bi-amping the 303's other than the usual issues about power allocation.

2- I would *never* consider this seriously. The crossover is a critical part of the sound of any design, and takes months to get right. Bypassing it is not only very risky to the health of the drivers, it also renders the design moot. Anyone who has one-tenth of the skill necessary to make a decent crossover already knows more than enough to open the box and bypass the existing network. Putting a switch on the speaker to bypass the crossover would do nothing but lead to trouble for the other 99.999% of users.

I work hard on my designs. If I do my job properly, I've made the right crossover in the first place. Why would anyone buy one of my speakers if they wanted a completely different sound? I support DIY, but it is important to remember that a DIY design is not the same thing as an improvement to an existing design. Changing the crossover is no different than changing the drivers. It becomes a new system.

3- Hmmm. My design goals for the 303 are posted somewhere on my aural.org website. I'll look around for them and post a link. The goal of designing any crossover is to achieve the target acoustical response, and protect the drivers from out-of-band signals.

I don't think about circuit complexity, per se, unless there are tight cost constraints. In a design like the 303, all the attention goes to the acoustical response. "I need half a dB less at 3 KHz, but move the main lobe down 15 degrees." A computer spits out a new circuit in a matter of seconds, and it is what it is.

In the old days, there was a lot of trial and error in crossover design. So, adding more than a few components was futile, since it wasn't practically possible to optimize them. Simplicity yielded better optimizations.

4- See the above comment. The individual crossover components usually don't have functions in a way that can be isolated. A crossover is a filter network that implements a transfer function as a result of all of its parts. Sometimes it is possible to generalize and say, "Oh, this resistor adds damping." Or, "This network compensates for a resonance." But, really, the better a crossover design is, the more the parts work together, symbiotically.

Hope this makes sense?

-k

kkantor.spaces.live.com

>Ken,

>

>While we are on the topic of the 303, one of our favorite

>speakers , any chance we can get you to comment on:

>

>1. the addition of bi-amping capability in the 303a (why,

>what are your impressions of bi-amped 303's, disadvantages,

>etc.)

>

>2. why only "passive bi-amping"?? Many competitors

>offered the option of switching out the passive components and

>operating under ACTIVE bi-amping (aka ACTIVE operation).

>

>3. the xover for the mids and tweeters is significantly more

>complex that the xover for the venerated AR-3a. What were

>you striving to accomplish with this added complexity?

>

>4. xover for the woofer is pretty similar to 3a, except for

>the 5 ohm resistor in series with the 80 mfd cap. Can you

>comment of the function of that resistor?

>

>

>Regards,

>Jerry

>

>

>PS: Ken, answering any or all of the above may be dangerous

>to your health, as it may breed ... more questions!!

>

[mluong303]

Hi Ken

By any chance you still have the original AR-303 crossover schematic(International Jensen AR) on file or would you be able to contact William H. Bush to request a copy from him? The AR-303A schematic in the Library is the last revision for the rosewood AR-303A speaker from Bill Bush(Recoton AR).

I do think the AR-303A crossover had minor modification compare to the original AR-303 crossover. I don't know if Bill Bush had done this without keeping you informed? The AR-303 and AR-303A crossover boards don't look the same to me but they both hold the same crossover points at 650Hz and 5500Hz. The terminal cup of the AR-303 is much bigger than the AR-303A terminal cup with one set of red and black plastic coding terminals. The smaller terminal cup on the AR-303A has two set of heavy duty gold plated brass terminals for bi-wired application. AR-303 uses 18 gauge hook up wires and AR-303A uses 14 AWG.

I have pictures of both crossovers somewhere but can not locate them at the moment. I had own AR-303 in cherry veneer, AR-302T which I upgraded to AR-303A crossovers with modification to the larger AR-302/303 terminal cups to hold 4 terminals and the AR-303A Xovers. I also own two pairs of rosewood veneer AR-303A. I listen to them for few years and eventually let them all go to new owners.

Minh Luong

[onplane]

>A computer spits out a new circuit in a matter

>of seconds, and it is what it is.

>

>In the old days, there was a lot of trial and error in

>crossover design. So, adding more than a few components was

>futile, since it wasn't practically possible to optimize them.

Ken, thanks for answering all of my questions!!

On the ACTIVE bi-amping, I think it was ADS that had the switch to disable "parts" of the passive network. It was more than that, however, as ADS then sold the active network as an "upgrade" that went between the pre-amp and the power amps.

I believe what they did with the switch was disable the low pass filter on the LF driver and the high pass filter on the mid driver. Everything else remained (low pass on the mid and complete xover for tweeters).

From a marketing standpoint, I don't think was a huge success. It did, however, offered ADS a way to get aditional $'s a few years down the road from customers, who sought the next "level".

One last question, after you got the computer models for the xover, I assume you then actually measured the results and "tweaked" where necessary? I mean nobody really leaves design to a computer. Further, in my own painful experience, this "tweaking" can take hour upon hours, because NOW we are operating in the real world.

Regards,

Jerry

[kkantor]

I don't have any of that documentation anymore, but I will drop Bill a note to see what he has, or remembers. There are some other people at NHT I could ask also.

I'm not remembering any changes in the circuit, but I could easily be wrong. Do you recall anything about the kind of changes that might have been made?

-k

kkantor.spaces.live.com

[kkantor]

Of course... it still takes as much listening and measurement as ever. It just that humans get to concentrate on the hard part, like solving problems, balancing sonic factors, etc. No more need to spend 2 or 3 hours with a calculator and graph paper every time one wants to play "what if" with a crossover design.

-k

kkantor.spaces.live.com

[soundminded]

In 2007, one would think that at the very least, a speaker designer selecting crossover frequencies, slopes, and loudness levels would be performed using active crossovers and mult-amplification. Rather than building a lot of test circuits of passive equalizers, this allows simple switching from one to another in both the anechoic chamber and in the listening room. You should be able to select quickly between literally thousands of possible combinations. Then if you must have a passive crossover network to market a speaker, you'd just design one with the same final FR as the active network selected as optimal. Frankly, given the low cost of amplifiers and active crossover networks, I find it difficult to understand why at the very least, the high end speaker market hasn't gone this way. They dip their toe in it with a separate subwoofer and plate amplifier but that's as far as it usually goes. Back in the 1970s, Phillips marketed their "Little David" speaker which was a tri amplified three way speaker with built in amplifiers. I don't know if the crossover network was active, passsive or both but the trend never seemed to catch on. Were I to build my own "best design" I wouldn't consider any other option. By now passive crossover networks should be as antiquated as vacuum tubes and phonograph records.

[rrcrain]

My gut reaction is this idea would be acceptable for a small percentage of the high end audiophile market but quite well received at the mid to bottom end.

At the top end, you have people who swear they can hear differences between wire and capacitors and can identify male and female gnats by the pitch of their sneeze at 20 paces. I suspect these people would never limit themselves to speakers with built in solid state amplifiers.

As for myself, I have a preference for the sound of a tube amp on the mids and highs but prefer what a robust solid state amp does in the bass region.

[mluong303]

Hi Ken,

The AR-303A crossover components are marginal better quality compare to the original AR-303 Xover. I think it was slightly modified for bi-wired design compare to just cutting couple of wires and add on an extra pair of terminals as done by the DIY people at home!

I did write to you, the President and VP plus the Marketing Director regarding how to improve the AR-303 speaker for marketing strategy in Hong Kong market right after I attended the AR 40th Birthday Party in NYC. The only response to my letters was you for couple of times and I Thank you for not egnoring me.

If International Jensen AR did listen to me at that point, AR might have been continue its Legacy and likely to break into the Chinese market in Mainland China today which will keep the real AR fame for another quarter of the Century or so...! Unfortunately, no one take me seriously or believe me of the determination of AR future is base strictly in Hong Kong / China markets and not the U.S. market anymore.

After you pass on my correspondence and suggestions plus pencil drawing of my suggested Super 303A(two tweeters, two midranges and a single woofer) to the marketing group, the AR-303A came out months later with some of my suggestions which include expensive veneer, gold plated bi-wired terminals and better parts for the crossover plus thicker wires but they still didn't listen to me close enough to spend few extra dollars for polypropylene caps with air cored inductors and pure copper wires on bigger Xover boards. The marketing people disregard my suggestion of the center bracing of the cabinet so the outside of the AR-303A looks much better compare to the cheap looking cherry veneer AR-303 which is not even real cherry veneer anyway but internally there is no change at all!

I even flew to Hong Kong and knock on the door to the Editor of Audio Land magazine, Jimmy Lam and ask him to review the AR-303A who had no good thing to say about the cherry AR-303 speakers but did enjoy his AR-10Pi and AR-3a Limited. He was surprised by my level of enthusiast and personal love and knowledge of AR speakers that he did follow up and say few good words about the AR-303A speakers in his magazine in the following month but by then it was too late to patch up the damages that had been done by the cherry AR-303 speakers!

Pictures below are the AR-303A and AR-338 which I let go at the very end due to the need of money to pay bills! If I locate more pictures of the AR-303, AR-303A and AR-302T speakers and Xovers, I will post them.

Minh Luong

http://www.classicspeakerpages.net/dc/user_files/2069.jpg

http://www.classicspeakerpages.net/dc/user_files/2070.jpg

[Guest John Faulkner]

a question for Ken Kantor:

Are AR-303 or 303a tweeters a reasonable substitute for AR-3 or AR-3a speakers, considering of course the difficulty of finding OEM replacements for either? If used in an AR-3 what crossover modifications would help. Or, if used in an AR-3a what changes? Or even in an AR-2a in place of its AR-3 tweeters?

thanks for any help.

John

[genek]

a question for Ken Kantor:

Are AR-303 or 303a tweeters a reasonable substitute for AR-3 or AR-3a speakers, considering of course the difficulty of finding OEM replacements for either? If used in an AR-3 what crossover modifications would help. Or, if used in an AR-3a what changes? Or even in an AR-2a in place of its AR-3 tweeters?

I think we beat this one to death a while back.

http://www.classicspeakerpages.net/IP.Boar...ost&p=58766

[Carlspeak]

That PE 4 ohm tweeter is looking better every day!

[Guest rbrumett]

That PE 4 ohm tweeter is looking better every day!

The PE AR tweeter is $8.00 in quantities 0f 4 or more(plus shipping),plus the adapter ring from Carl($10.00) and the coil also from PE(cann't remember the price). Am I missing something-lol. These tweeters are very,very resonable substitues for the Classic AR speakers. It appears that there are no EXACT new replacemant tweeters available, at least I have not been able to find them!!

Thanks,

Rick Brumett