604 8g

[stutrex]

hello does anyone know what production year altec used the tangerine phase plug on the 604-8gs? also how can I tell if I have them in my 604-8gs? is the tangerine plug better in performance? thanks for your input stu

[billfort]

I was told the 604-8G was produced from 1974 to 1978 and they started installing the tangerine phase plugs in 76. You can tell if they have them by looking down the horn throat with a bright light ? here?s a shot down the throat of my G?s which have the tangerines.

[kevf]

While we're on the 604-8g, does anyone have any experience comparing it with the 604-16x? I've came across both for sale for similar prices. Which one is generally preferred? I know the 604-8g has alnico while the -16x has ferrite, but does that mean anything? Looking forward to hear your opinion. Thanks.

[stutrex]

Thanks for the info but I still don't know what I am looking for. your pic is a little blurry.

[dgwojo]

Maybe this image of the phase plug in an 802 will help you;
http://www.lansingheritage.org/image...ome/page08.jpg

[billfort]

The image is blurry because the orange tangerine phase plug down the throat is in focus, seems kinda obvious to me in this picture.

[thinking]

When you're shinning a light down the throat of the horn, there is a very fine mesh screen placed between the phase plug and the outer end of the horn, you have to look at what is behind the screen. If you see rings (circular), then you don't have the tangerine phase plug, if they are radial (like spokes on a wheel) then it is. There are some later radial plugs that are black instead of orange.
Nobody that has done it will ever recommend that you take off the diaphragm to see the phase plug, although it can be done, unless you are planning on buying a replacement. There are several ways to screw it up, and don't say you weren't warned. After you disregard this warning, call Bill at Great Plains Audio and talk to him about the replacement.

[stutrex]

Thanks everyone for all the great info. I know what I am looking for now unfortunately one has the tangarine phase plug the other does not. Will that be a problem they both sound great.

[gearjammer]

Hi Where did you pick up a mismatched pair of 604-8g,s??

[joyspring]

Rexypoo,

Don't want to come off all too negative but I feel that you should be aware of the impact of the phasing plug mismatch on stereophonic imaging...

The 604-8G with the Tangerine(tm) will have greater HF output and a different response curve than the one equipped with a standard circumferential slit phasing plug.

The greater output cannot easily be compensated for by attenuation/pads.

Try listening equidistant from both 604s (60 degrees) and send a single pink noise signal to both channels, using the same electronic gain and crossover attenuator settings. You'll probably note that the sound may `spread' towards one side when it ought to remain dead center at all frequencies.

Even adjusting the crossover HF attenuator will not resolve this as the HF response curve will differ between the two 604s.

I'm quite familiar with the imaging shift that occurs with the demagnetisation of Alnico 604s in studio control room monitors and I'm quite certain that the mismatch of phasing plugs will yield the same if not more pronounced result.

This defeats the main reason for using the coaxial point-source 604: superior stereophonic imaging!

If you seek out a replacement for one of your 604s, I'd look for a Tangerine(tm) equipped 604-8G, or perhaps a 604-8/16HPLN that may be reconed/remagnetised to 604-8G spec.

Hope this helps,
BobR