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View Full Version : Altec model 18 with the 604-8 H



big speaker
09-26-2015, 06:25 AM
672166721467215 hi every one, i bought theses Altecs some time ago. and they were in really bad shape. i managed to sand a repair the cabinets back to a nice finish. what i am wondering i was told they were the model 18's can any shed some light this. one of the 604 drives i have remove the tweeter and when i refit it i find it, a really snug fit. i found this inadvertent with i this is for my speakers. :blink:

http://audio-heritage.jp/ALTEC/speaker/620bmonitor.html6722167222

Alien_Shore
09-26-2015, 09:50 AM
That does not appear to be an Altec Model 18 (http://www.lansingheritage.org/html/altec/specs/home-speakers/model-18.htm). It also does not look like a 620 enclosure.
I'm not an expert in cabinetry, especially for the 604 drivers, but I don't recall ever seeing an Altec enclosure with the port and crossover slots arranged like that. Is there any labeling or numbers stamped on the cabinet?

Another thing that makes me suspicious is the use of the 1209 crossover with a 604-8H. That speaker is supposed to cross over at 1500 Hz. The 1209 network is a late-1970's pro sound unit typically used for larger separate 2-way systems like the 1235 system (http://www.greatplainsaudio.com/vintage_altec/1235C_MI_System_spec_sheet.pdf).

As for your comment about the HF diaphragm, I'm not sure what you mean about snug fit?

big speaker
12-15-2015, 12:57 AM
That does not appear to be an Altec Model 18 (http://www.lansingheritage.org/html/altec/specs/home-speakers/model-18.htm). It also does not look like a 620 enclosure.
I'm not an expert in cabinetry, especially for the 604 drivers, but I don't recall ever seeing an Altec enclosure with the port and crossover slots arranged like that. Is there any labeling or numbers stamped on the cabinet?

Another thing that makes me suspicious is the use of the 1209 crossover with a 604-8H. That speaker is supposed to cross over at 1500 Hz. The 1209 network is a late-1970's pro sound unit typically used for larger separate 2-way systems like the 1235 system (http://www.greatplainsaudio.com/vintage_altec/1235C_MI_System_spec_sheet.pdf).

As for your comment about the HF diaphragm, I'm not sure what you mean about snug fit?
theses speakers are Altec 718 A monitors . 1960 cabinets with the cross over order the way it is for the recording studio it had new drivers fitted in the 1980 i have proof theses are 100 % original

http://audio-heritage.jp/ALTEC/speaker/620bmonitor.html

speakerdave
12-21-2015, 11:39 AM
. . . . I have proof . . . .

Well, no you don't. The two crossovers, the one in your photo and the one in the link, look different. What you have may be an attempt to copy a 718, but it is not a 718.

The crossover you have, the 1209, is not correct for a duplex driver.

Also, the duplex driver you have does not appear to be a 604-8H. Those had Alnico magnets. From the photo it appears yours has ferrite magnets. If that is true it is probably a 604-8K.

Since the speaker system you have appears to have been cobbled together it might be worth your while to have it looked at by a knowledgable Altec tech, if you can find one. Failing that you could try the guys over at the Altec User's Board. They'll sort you out.