Another Altec Build

[rajagopal_j]

Just Arrived from accross the globe

Just arrived via DHL from our good friend Bill at Great Plains Audio.

Two shiny new Diaphragms for the 288-16ks (but with 8Ohms imp)

Two Recone Kits for the 416-8A complete with glue and bonding agent.

All just in time as I will most probably be getting my repaired HF units today as well.

B Rgds,
Raj.

 

[anilva]

I am surprised that GPA managed to send the surround goop. It is highly inflammable and is not allowed in freight or courier.

Good luck on the restoration.

 

[rajagopal_j]

I had Bill ship it to my friend in Seattle who in turn shipped it through DHL lower valued and without insurance.

B Rgds,
Raj.

 

[rajagopal_j]

the HFs are back as well.

Pole piece fixed, Voice coil gap adjusted, wired brushed, emeried, zinc plated to 0.6 microns.

B Rgds,
Raj.

 

[stevieboy]

Cool! My kit and a pair of HFs for santhosh too are on the way. Thanks for the tip on the goop. Was figuring out borderlinx with santhosh. Now I guess it will work!

 

[himadri]

the HFs are back as well.

Pole piece fixed, Voice coil gap adjusted, wired brushed, emeried, zinc plated to 0.6 microns.

B Rgds,
Raj.

Great going Raj .I have the sneaky feeling that the altecs with SE tubes might be the ultimate nirvana.
Well, fortune favors the brave and the industrious and you are on your way. best of luck.
himadri

 

[santhosh]

Hi Rajagopal,
Good to know that your 288s are fixed. Now you are all set .

Thanks to Rajiv, I too managed to find a pair of Altec 288Cs. First he found one and few days later managed to find another C. I have ordered 16ohm diapraghms alongwith Stevie, can't wait to try them with my 805s.

 

[rajagopal_j]

All the best santhosh, i do have 1 Altec 288c and I am looking for one more. should be able to find one in another 10 days or so, just that work is keeping me super busy. Right now I am hunting for a good wooden round horn.

B Rgds
Raj.

 

[Rajiv]

Hi,

Rajagopal, Ali seems to have done a good job on the Altec 288. Worth the time and effort .

Regards
Rajiv

 

[rajagopal_j]

Finally on Sunday I got around to setting up the altecs on a couple of chairs, with a couple of capacitors (in parallel to total 20uF) for the HF and a 1.3mH inductor for the LF connected straight to the wires. The horns are local fiberglass horns, a temp till I can decide which horns to go with.

Was thinking its going to sound really awful but then it was really surprising to hear them do very well. Music was flowing effortlessly and there was a lot of detail, though sometimes the string instruments were in the backgroud rather than in the front. The high were a little harsh, but there was surprisingly good bass, not the really tight and heavy hip hop kinda bass but then enough for the blues that I listen to.

The Setup

Left Channel

Right Channel

Still running on Ali's Diaph on the HF and Local Paper on the LF.

B Rgds,
Raj.

 

[santhosh]

Hi Rajgopal,
Good going, I have seen those FRP horns here in Bangalore, the ones I saw were flimsy and huge. Your horns look pretty compact, would you know what is the cutoff frequency? While you are waiting for horns, try and reinforce it using tar sheets.

Those pics remind me of when I had working drivers but had not yet built the cabs. Here's a pic from then:

I too had the same timing/phase issues, they reduced to a great extent when I aligned the drivers such that their voicecoils were in the same plane.

Which TT is that? Seems to have a custom plinth? I also see a 288C sitting there

 

[rajagopal_j]

Hi Rajgopal,
Good going, I have seen those FRP horns here in Bangalore, the ones I saw were flimsy and huge. Your horns look pretty compact, would you know what is the cutoff frequency? While you are waiting for horns, try and reinforce it using tar sheets.

Thanks Santhosh. The horns are from Ali apparently chinese imports though I don't believe. Also I don't think these guys will have any idea on the cut-off frequency. If there is some way to measure let me know I can do it. The horns are fairly well built for being made of fibre, it did take me a good 5 hrs to drill 3 mounting holes on each of them with my bosch drill.

I too had the same timing/phase issues, they reduced to a great extent when I aligned the drivers such that their voicecoils were in the same plane.

Yes I will have to align the voice coils, but then the acoustic center is different for horns right?

I think attenuating the signal for the HF will help for one and once I am done with a proper crossover that should sort out a lot of the issues.

Which TT is that? Seems to have a custom plinth?

The TTs near the Right Channel Chair are a Cosmic 2000 BD on top of which is a Dual 1229 (looking for a headshell mount for this one though).

I also see a 288C sitting there

Yes that is a 288C have to find another to pair.

 

[Rajiv]

Hi,

Still running on Ali's Diaph on the HF

Alitec :lol:

A word of advice to all you guys getting the woofers reconed. Please don't ask the reconing guy to apply the damping compound(goop) on the surround. They tend to make a hash of it. While the reconing part is very good they are not careful while spreading the goop and it is lumpy in places which affects even pistonic motion of the woofer.

You can apply the damping compound yourself, very simple and not difficult at all.

Regards
Rajiv

 

[Rajiv]

Hi,

I think attenuating the signal for the HF will help for one and once I am done with a proper crossover that should sort out a lot of the issues.

The Altec 288K will need to be attenuated at least 10-12dB to match the Altec 416 woofer .

Regards
Rajiv

 

[asliarun]

The Setup

I'm quite amazed at what you are doing! That's one massive driver as well.

If you don't mind me asking, what are the tall towering speakers in the back?

Thanks,
Arun

 

[rajagopal_j]

If you don't mind me asking, what are the tall towering speakers in the back?

Arun, those are Lyrita Audio's Harmony One.

B Rgds,
Raj.

 

[kuruvilajacob]

Rajiv,
What damping compound can I apply on the cloth surrounds of my KLH ? I have seen on many forums that Butyl diluted with toluene is applied to the cloth surrounds

Regards
kuruvilajacob

 

[Rajiv]

Hi,

What damping compound can I apply on the cloth surrounds of my KLH ? I have seen on many forums that Butyl diluted with toluene is applied to the cloth surrounds

I am not sure of the exact compound used by KLH but Butyl diluted with toluene should suffice .

A word of caution ,using the wrong type of damping compound can change the specs( F's) of the driver. Also, unless the surround has dried up, or stiff/brittle I would not tamper with it.

You can post your question on the forum linked below or on Audio Karma.There are bound to be guys on these forums who can tell you the exact type of damping compound used by KLH.

The Classic Speaker Pages Discussion Forums

Regards
Rajiv

 

[rajagopal_j]

After some very very busy time I finally managed to sneak in about an hour to haul my LFs to the reconing guy about 3-4 days back.

And today just in fresh from the speaker reconing guy

Close ups

What a difference the GPA paper is making. Its so light and responsive now. I cant believe the sound coming out of these 15" woofers.

Anyway I think the reconing guy did a great job of putting the whole this together and the damping compound has been spread neatly as well a little lumpy but not a bad job.

Hope fully I will find the time and a good carpenter to finish rest of the build soon. The most painful part is finding a carpenter. Spoke to three of them and none of them are comfortable taking up the job as they are simply not confident enough to give an exact inner volume measurement.

B Rgds,
Raj.

 

[santhosh]

Good to see progress on your build buddy. What plan have you finalised?

Yes, the altec paper is very light compared to the replacements that the theater chaps may have used to recone earlier. This helps in very fast response and decays.

It was nice to meet you in the Chennai meet, put a face to the name after so many emails and phone call exchanges.