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ADC 303a's have to be opened. How?

You're right... the coil IS in parallel with the tweeter. So that means the woofer is running full range. Hmmm, I thought that was to be avoided...

I did look at at those Goldwood woofers but Zilch indicated the specs for my sealed 1.4 cu ft box were better suited to a few other models. I'm making a note of the 12" version of that woofer- it looks like a good fit for one of my other systems. I see they put ALL the Goldwoods on sale the day AFTER I ordered mine. It figures...

I'm not sure how the original tweeters would come out. Maybe from the front? But I'm leaving the originals in so it doesn't matter.

I made wood "caps" for the back and built the crossovers. I used the original resistors and coil and added a new jack plate, switches and capacitors:

20100110 ADC 303a bought at estate sale for $20 2 crossover.jpg
 
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Great work!

These speakers have been in the back of my head for awhile, I think I'm most likely going to try the econowave project with them but I have no idea how that would compare to the original sound.

I'll let the others with more experience chime in, but I think full-range woofers is ok and maybe even typical of 2-way speakers of this era... pretty sure the EPI 100 line is like that since the "crossover" is just the one cap in-line with the tweeter.
 
Thanks, beekeo! You made me feel better about the full range woofer- I'm going to leave them wired as they were originally.

The job is finished, the backs are on, the speakers are playing and I'm very happy with the outcome. Bass is smooth and abundant. The Goldwoods are an asset to the system.

20100110 ADC 303a bought at estate sale for $20 6 finished back.jpg

Even though you can't see the backs when set up properly I may get some darker paint. All I had laying around the house was tan.

On to the next project- Realistic MC-1000's worked over as Indignias: https://audiokarma.org/forums/index.php?threads/more-karma-indignias.398876/
 
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How would you describe the sound? I'm trying to decide if I want to start with the relatively cheap and easy restoration or just move to E-Wave.
 
I wonder if an inexpensive speaker like the 303a or ax is really worth the cost of econowaving -- the econo part of the name is a relative thing. Certainly compared with equally capable horns it may be cheap, but its still significantly more expensive than a replacement dynamic tweeter would be. And I wonder what the effect of the change in volume of the enclosure would be on the woofer.
Obviously if you are eager to econowave a speaker, go for it. But I think you might find a better candidate (and if you have any local and historic sentiment, the ADCs were made in Connecticut back when we had a vigorous audio industry here).
 
Nat - ok, I guess I'll refamiliarize myself with the econowave concept and weigh what I learn about it in regards to the 303ax against the other speaker projects I have piling up. :)
 
Its possible that the econowave might not have much of an effect on enclosure volume since you have to cut out a portion of the front baffle, so that volume becomes part of the internal volume, and may compensate for the horn and driver's volume. I'm sure this must be a topic that has been discussed with regard to other smaller enclosures adapted for this purpose.
 
beekeo said:
How would you describe the sound? I'm trying to decide if I want to start with the relatively cheap and easy restoration or just move to E-Wave.
Click to expand...

I haven't followed the E-Wave thread so I don't know if that's feasible for the 303ax, or not. Beekeo- you talked about bum switches and, of course, the capacitors need to be replaced but do all your drivers work?

I haven't done 'formal' listening tests to these. I've only had them hooked to my Realistic SA-900 which is about 20w/ch. They are sitting in front of my desk which is essentially out in the middle of the room. I also have a pair of sealed 3-way Fisher with 10" that are original, other than a re-foam. I will be comparing these speakers as soon as I can.

Keep in mind I'm a 'rock 'n' roll' guy. Ported is my style for crankin' but I also like sealed because I don't 'crank' all the time. And I'm looking for variety right now. I'm really liking the smooth bass from these. Sometimes I mind that bass seems to overpower the tweeter. I'm sure the woofer is more efficient than the original that was still working. Sometimes I think that I'm going to go back in to replace the tweeters. But they appear to be screwed in from the front and I am NOT touching the grills. So when I think of it that way the speakers will stay as they are. I have many pair of speakers so I have many different sounds to choose from- I don't need to change these any further.

But don't your 303ax have 10" woofers? Your mileage is going to vary from mine. Like Nat said and I agree, you may not want to change anything too drastic. I only did to mine what it took to make them work reliably. People suggested I bust into the grills and build new ones. But I liked the way they looked which I why I wanted them to work again. If you owned 303a's and told me you were wanting more performance and didn't care what they looked like, I'd suggest you go in through the grills and replace the tweeters, as well. But I don't know enough about the 303ax to compare them.

Beekeo, if you decide to rework them, post it. I'll be curious to see how it goes and what you think of them after the change!

Brian
 
It's been a long time since I first tore into the crossovers so I actually don't remember if anything was coming out of the tweeters, but I think they must have had the typical muddy sound of bad caps or I wouldn't have bothered.

The tweeters in the 303ax are much easier to remove than the other 303's so customization is possible.

I guess I'll have to play around!
 
Thread Resurrection!

I recently wandered into a local electronics hobby store and picked up some caps to replace the original 6µF (nothing as nice a Daytons though) as well as some new terminal cups. (Cables and Connectors on the Berlin Turnpike in CT -- no affiliation, and not a PE replacement but was happy to see someone with at least a few Goldwood drivers in stock.)

I got everything wired up to the original crossover (albeit clumsily) and then taped the panel to the inside of the cabinet.

Got --nothing-- from the tweeter, but the sound from the woofer was pretty good, nice and mellow, albeit lacking punch (no insulation stuffing, didn't get an airtight seal). Definitely encourages me to keep going.

Next I'll eliminate the old circuit and my kludgey connectors and using maybe only the 6µF cap inline with the tweeter, see if I can get any sound from them. If they're good I'll have to go back through my connections in the old crossover circuit and look for loose wires.

If the tweeters are toast, I might cannibalize parts from my BeoVox 4702's (which seem to require unobtanium woofer foam).
 
Tried simple circuit, just 6µF between the signal and the tweeter, still no sound.

I think the woofer sounded even better, very nearly full range with only the very high end missing.

I'm going to try swapping in some spare 10µF Dayton caps, just in case there was an issue with the caps I got from the local store, but I think I'll probably be moving on, maybe try the mid-tweeter from the 4702's (if they fit) and then designing a crossover circuit for that.
 
Some more progress here, although I'll likely make a new thread for build progress and discussion specific to this new frankenspeaker since only the cab and the 10" woofer are still ADC.

I've swapped over the two tweeters and the crossover from my BeoVox 4702's (cut a hole in the cab to add the 2nd tweeter). I got good sounds from all 3 drivers, but I still need to stuff the cab and seal the back before I'll get good bass.
 
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