Goodmans ARU/Audiom60/Midax/Trebax

[Donnie2112]

I have a set of Goodmans that my grandfather loaded into custom teak veneer cabinets way back in 1958. One of the boxes sounds good in mono, the other has a non working tweeter.

I want to make them sing again. Planning on using a Scott 222C to make them go.

Anybody have any experience with these speakers? Any general advice, or advice on potential tweeter replacement would be appreciated.

 

[Donnie2112]

Bump

 

[Sandstrom]

Hard to comment specifically on that setup as I have not heard early Goodmans 3 ways but I would imagine they would sound amazing once you get them sorted. I have had an early full range 12" Goodmans in a large mahogany cabinet w/ARU that I used for a mono setup that sounded wonderful. I do see the trebax units pop up from time to time, but probably aren't the easiest replacements to find. You'd probably want to check the crossover components to see how far they've drifted over the last 60 odd years.

In my opinion WELL worth bringing back to their former glory, that 222 would have plenty of juice to make them sing. Would love to see pictures of these once you have them, the cabinets sound very interesting. Often these ARU cabinets had a series of "blankets" hanging from the inside tops of the cabinets to dampen sound waves.

Add to that the fact that they were your grandfather's and you can't lose! Best of luck and looking forward to hearing about your progress with them.

 

[Donnie2112]

You'd probably want to check the crossover components to see how far they've drifted over the last 60 odd years.

We pulled the crossovers out and measured some values, they were both pretty close to one another. Is there a specific place where I can find out what the caps should be reading? Otherwise they seem like good quality (no electrolytics) and working.

Lemme show some photos

My grandfather built these Teak veneered cabinets in England in 1958 before my father was born. He was a fighter pilot over there flying F-101 VooDoos.

Anyway, As you can see, it’s some sort of folded horn design for the woofers, the mid and tweeters are recessed behind another piece of wood. I have not had the opportunity to tear them all apart to go looking for the problem with my tweeter. I plan to take them both apart if for no other reason than to replace the 60 year old wire

Not planning on using the Garrard table, but that’s part of the solid Teak electronics cabinet that he built to go with it. (Actually, I think the original was stolen at the base wood shop and the other guys in the squadron got together to build him a replacement because they felt bad.)

 

[thomo57]

I bought a self built cabinet built around the same time as yours with the exact same cream fabric, like nylon?
They had the ARU and Goodman 12" Triaxiom 212C inside
As was mentioned they had 2 curtains of damping material hanging from top to bottom of the cabinet about half way in the cabinet.
They sounded OK but when l put the drivers into a folded horn cabinet they sounded more than fantastic

 

[Donnie2112]

I bought a self built cabinet built around the same time as yours with the exact same cream fabric, like nylon?

Yes, I assumed that this was once a lighter color because of how much my grandparents used to smoke. Planning on changing out this grill cloth.

I have law school finals starting next week so I’m planning on trying to focus on that but as soon as I can start taking these boxes apart I’m stoked to do so.

Which mids/tweeters did you have? Any ideas about potential replacement for my tweeter?

 

[thomo57]

Test your tweeter, it maybe ok.
I had a mate listen to mine which is a Triaxiom so no seperate tweeter and he loved mine so without telling him l put a wanted to buy advert up and just by chance a guy contacted me saying he had the Goodman 301 with horn and trebax for sale so my mate bought them and had the cabinets built and they are the love of his life using a valve amp.

 

[Donnie2112]

Hard to comment specifically on that setup as I have not heard early Goodmans .

I am replying to make sure you see my previous response to your comment, I may have pulled a noob move by failing to reply/quote.

 

[Donnie2112]

Test your tweeter, it maybe ok.
I had a mate listen to mine which is a Triaxiom so no seperate tweeter and he loved mine so without telling him l put a wanted to buy advert up and just by chance a guy contacted me saying he had the Goodman 301 with horn and trebax for sale so my mate bought them and had the cabinets built and they are the love of his life using a valve amp.

I am hoping that tweeter is still ok. I tested the wires to all of the XOs, good continuity and sound out of every driver except the tweeter from one of the cabs. Hoping it’s a broken solder joint or something. I have not had the time to tear down the cabs. I want to do it anyway, if for no other reason but to solder in new/better wire and to replace grill cloth.

If I get in there and find that tweeter is still ok, well game on.

Scott 222C plus some sort of graphic eq and I think this thing will sound badass.

 

[Sandstrom]

I am replying to make sure you see my previous response to your comment, I may have pulled a noob move by failing to reply/quote.

My vision may be shot by I am not seeing the ARU in these shots. Looking at where you have the grill cloth peeled back this almost seems to have a sort of Onken cabinet porting around the perimeter? May be that it is on the back you've removed there, they look like this:

If you have an electrical meter you can use it to test the non working tweeter to see if are getting a resistance reading on the coil (disconnect the wires to the tweeter first and set your meter to 'ohms') Maybe if you are lucky the tweeter is ok and there is a short somewhere further back in the circuit.

If you can get into the network box you can examine the condition of the capacitors and if your meter has a capacitance setting you can get an idea of where they are at. While you are in there you can record what the values are of the individual capacitors, may not be a bad idea to just source new replacements and swap them out if are comfortable with soldering. The values of the capacitors should be printed on them and hopefully will be legible.

 

[Donnie2112]

My vision may be shot by I am not seeing the ARU in these shots. Looking at where you have the grill cloth peeled back this almost seems to have a sort of Onken cabinet porting around the perimeter? May be that it is on the back you've removed there, they look like this:

If you have an electrical meter you can use it to test the non working tweeter to see if are getting a resistance reading on the coil (disconnect the wires to the tweeter first and set your meter to 'ohms') Maybe if you are lucky the tweeter is ok and there is a short somewhere further back in the circuit.

If you can get into the network box you can examine the condition of the capacitors and if your meter has a capacitance setting you can get an idea of where they are at. While you are in there you can record what the values are of the individual capacitors, may not be a bad idea to just source new replacements and swap them out if are comfortable with soldering. The values of the capacitors should be printed on them and hopefully will be legible.

Yeah, damn, that is some good insight. I suppose I was just thinking that “ARU” “acoustic resistance unit” was some old school ratchet name for a crossover. Not sure if those devices are some where within the cab or not.

I have tested the wires that go from the tweeters to the XO, no dice there.

When we pulled the XOs we did not notice any values printed, everything tested more or less the same too. I think the XOs are ok.

I guess the next step is getting these Bad Larrys torn apart to figure out exactly what I’m dealing with.

 

[Donnie2112]

So I have the drivers out on my afflicted speaker. I made a stupid mistake initially because I was thinking I had to take apart the box to get at the mids/tweeters. Dumb mistake and I’m going to have a fun time screwing the motor board back into the front baffle. It won’t be impossible but it’s not gonna be fun either.

My tweeter is, in fact, open. So I found another one in England advertised on EBay and I have sent for it.

When that tweeter gets here I will reassemble the whole thing with new speaker wire. The Scott 222C I’m having restored will be done soon as well.

More to follow.

 

[Donnie2112]

So here’s my new stereo set up. Bluesound Node 2i, Pro-Ject Carbon DC turntable, going into a Scott 299 for now. I will be replacing the 299 with a 222C.

The speakers are Goodmans Audiom 60 loaded in the back facing forward. Right in front of those are a Goodmans midax and trebax. Folded horn design with compression mids and tweeters. XO points are 800 and 5000, 15 ohm speakers.

I feel like they image nicely, they are pretty detailed without being exhaustingly harsh.