MarcAL

Yes to the first question some with great results. The very best single driver in my opinion based on testing every single Altec driver is the 416-8A/416A/803B/416-16Z in the standard Onken cabinet. I have tested others and took measurements however some drivers require the cabinet to be tuned. When I built my cabinets I allowed for port extensions to be fitted if required to get the cabinet tuning lower.

I expect that the autotransformers would be okay for the crossover points but I would stick with a good quality air core choke for the filter network. The choice of good quality components made the biggest difference for me.

You can't go wrong with large format Altec horns and Onken cabinets. If you go with passive crossovers, the Hiraga crossover network is definitely a winner. Welcome to Stereonet

On the subject of recycling Hitachi TO3 Power Mosfets...

Hi acongdon, I do not have the files for the PCB's however Leinster Lad might. He may have some PCB's as well but I am not sure if he has any more for sure. The old school approach would be to make a plastic scan using the original artwork from the article. Use photosensitive PCB material, UV light and the rest with chemicals etc....then drill them out yourself. It is time consuming but it is doable. My Series 5000 amplifier is still performing well by the way and I will never trade it for anything. Sentimental.

Hi nedee, the simplest way to keep your Santana speakers in service is to keep your current system and tweak the crossover networks to suit your needs. There are several other ways you can get more out of the 420-8B drivers but that would involve new cabinets, small format compression drivers such as a pair of 902 drivers with small format Mantaray horns and newer two way crossover networks for example. Obviously this is a new build so some research would be involved and a fair sum of money and time also. The 420-8B really does have potential if you are interested in experimenting with various scenarios and believe me there are many. All the best MarcAL.

If you have to recone an Alnico driver pair then definitely get them regaussed. A saggy spider, torn cone and damaged surround is warranted for a recone. Do you need 8 or 16 ohm at the end of the day? Are the existing voice coils still good?

What is actually wrong with the existing Altec 803B's?

Unfortunately the ports for cabinets back in the early Altec days were not tuned using TS parameters. So you may have to tune your port once you have built it or better still work it out with a port calculator before you start cutting the port in your baffle. Really it is not hard to do once you have all your driver and cabinet parameters, but do try a few to cross reference as some port calculators are bogus. It will make a big difference to the bass response and is highly recommended. Like any instrument/device that is used to produce/reproduce musical tones it needs to be tuned.

Ah yes, the tweeter repair. Feel free to bring them over sometime.

Is that your next restoration project that I can see in the distance, Powerglide?

Congratulations to an excellent find Simon. Grand idea with the longer term Onken plan, can't go wrong there. For now the 612 cabinet built to the original 1937 plan is a winner and totally agree that it does look badass. Please feel free to keep us posted with your build.

Ditto

Another excellent restoration project Powerglide. Very much better than the originals in so many ways. Thanks for sharing the journey with us and keep up the fabulous work.

Hey tygersmoke that sounds like a great idea. Have four different vintage mono setups one for each corner. Then there is all the other corners of the house that are idle. A new direction with all that classic vintage gear that is hard to pair up, you might be onto something.

This latest build is very well executed, worth the effort and will last a lifetime of listening enjoyment without any doubt. Seriously excellent work all round guys!

For this type of push pull amplifier these Altronics output transformers will do the job. I have given a few amplifiers a new lease of life the same way. Excellent, keep up the great work!!

I am currently running a pair of Onken cabinets made from solid Kari timber fitted with 416-8A drivers. The horns are MR94B fitted with the larger format driver 291-16B fitted with 24 ohm aluminium diaphragms essentially a 288-G. The crossover networks are customised Hiraga crossover networks with 8 ohm low pass and 24 ohm high pass filters with Mundorf SGO capacitors. The sound is superb. I have two mates with A7's and a third mate going A7 with the help of powerglide. There is another mate running an Onken cabinet fitted with two 411-8A drivers in each that makes the smoothest low bass with ease. Remarkable!! All systems are fitted with large format horns and drivers with customised Hiraga crossover networks. All in Sydney.

What kind of Altec speakers may I ask?

Excellent work so far! You may be able to get away with only one layer if it is about half an inch thick. Two layers may end up being more than enough but give it a go on one cabinet anyway. But the deciding factor is how does it sound now and then how much better with more added.

Yes, you can try that for now however avoid putting any on the baffle itself as it is unnecessary and definitely use generous amounts on the rear panel. Add layer by layer on the side walls and test how it sounds per layer. (Test by speaking inside of the cabinet works for me) Less is more as you don't want to overdo it and kill the midrange. If you want to experiment by putting it on the lower part of the cabinet do so. Some people do, some don't and you can always remove the stapled down wadding easy enough. It is up to you and they are your cabinets, experiment to your hearts content. Feel free to let us know how you go.

This is the felt that we used in our A7 and Onken cabinets. Pictured 3 X 5mm thick woollen fibre carpet underlay. The same kind of felt that Altec used in their compression driver rear covers.

Try the 5 to 15mm woollen fibre carpet underlay it can be found easily enough, its not ok, it works! Most of us Altec enthusiasts on this thread are using it and would highly recommend it, you won't be disappointed, trust us.

For what it is worth ... if it is hazardous to your health and is going to be used in a vented enclosure then don't use it as the fibres will probably become airborne. I used a similar material which was recommended in the original Onken build back in the day and swear by it. If you can source this or something very similar such as 5 to 15mm woollen fibre carpet underlay then use it to start with. Don't glue it in, just staple it. Experiment with one enclosure by adding amounts layer by layer then by speaking inside of the enclosure and see how it sounds. Your ears will tell you when you have reached the correct amount so there is no need for fitting the speaker at this stage. Go by ear first as you really only want to reduce standing waves within the cabinet. If you use too much wadding you will kill your cabinets midrange response and it will sound dead. 15mm was the optimum thickness used in my Onken cabinets however I would expect a similar result in an A7 cabinet.

Considering that they have been in storage for 25 years in your grandpa’s garage the surrounds on the 411-8A bass drivers will have surely perished and are in need of replacement / re-foaming. If anyone attempts to use them in their current condition the voice coils will surely be destroyed and then they will require a complete recone by a skilled technician. The cabinets look okay for their age and you can probably restore them yourself by hand if you are careful but I advise you not to do this by machine. If you take the time and perhaps do some research on the internet on how to do this first that may save you some money. The crossover network capacitors have to be tested and most probably need replacing, advisable if you want them to sound better as better parts are available today. The same goes for some of the other parts of the crossovers (such as the attenuators which may drop out or sound scratchy) if they are to perform at todays standards. The horns compression drivers should still be fine if they have been used at sensible listening levels in the past, otherwise the diaphragms may need replacing due to metal fatigue for example. The internal of the cabinets and around the horns are lined with fiberglass. This is somewhat a serious health hazard so be careful and wear appropriate PPE when handling and disposing of it if you decide to replace it. You can get all of the above works done but it would require more money than what they are worth now as is. The reasonable going price for a pair that are located in Australia and in desperate need of repair would be between $1000 and $2000. Depending on how far you go and the quality of the restoration work they may fetch $5000. Good luck with any sale or restoration works as you will require a truck with a decent tray whenever you decide to move them around at 67.6Kg each. However before you do anything I would seriously consider asking your Grandfather if it is okay with him first. I know that I would not appreciate it one bit whatsoever if my grandson touched or sold my Altec gear without my permission!