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pjanda1 2nd November 2007 02:53 PM

Philips AD3800 in nice boxes, what are these?
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I found a nice pair of boxes at the thrift store yesterday, and I was happy to discover they have a pair of Philips AD3800AM 8" Alnico fullrangers in them. Luckily they are 8 ohm. It appears a bunch of these were 800 ohm. The cabs are really well made: 3/4 inch ply all the way around, except for a thin back, nice veneer, ultra cool grill cloth, fiberglass on the back and top. There is a big rectangular port in the front, also built from the ply.

They have no identifying marks anywhere. Were these packaged with some amp/receiver?

I've got 'em playing now, and they sound allright. You'll think I'm silly, but they have great PRAT. They have more HF than I'd expect, with perhaps a peak around 10 or 11K, as they are kind of sibilant. I think they extend quite high, though I've yet to test it. My guess is at least 15K, but they could be fooling me. I think they are done below 80hz or so. Midrange is fine, just not as pretty as I'm used to. They seem quite efficient. I bet they'd be perfect up against a wall with a little tube amp. I'm guessing the underdamped bass and very present HF make sense with whatever the intend amp was. If I get bored, I'll try some ultra thin speaker wire.


pjanda1 4th November 2007 06:00 PM

Nobody has seen them huh? I found some pics of Philips cabs that were sort of similar, at least in construction technique. They had badges, and some shiny trim, though. I wonder if these were a diy project.


markanica 4th November 2007 09:38 PM

2 Attachment(s)
Hi PJ,

I have some readymade enclosures for these speakers.
It says AD5053 on the back.
The enclosures measure 40x20x15 cm inside. They were made in the early sixties.
Inside is an AD3800AM, the -A suffix means that this is an 800 Ohms unit, suffix -M means whizzercone
There is a 7 Ohms unit as well, it can be coded as AD3800M or maybe AD3800M7

I mate them with a 1959 Philips AG9015 stereo OTL Amplifier
Alltogether it gives a sweet and mellow sound, no bass to speak of but very enjoyable to my ears.

pjanda1 4th November 2007 10:22 PM

That is indeed the same driver. Those enclosures look aperiodic, which would make sense given my guess about the Q of the driver. Yours must be 800ohm versions huh?

The boxes I have are proper BR's, with a big rectangular port. When I open 'em up, I'll measure it. My guess (based on exterior dims and my quick view of the length) is that these are tuned around 80-90hz. I'm not sure if that is ideal or not. I've seen the Fs of these drivers listed as 72. I'm guessing the Qts is high, but I don't know if that means .7 or higher. I haven't any idea what the VAS is. I'm trying to figure out how optimal the enclosures are, thus why I'm wondering if anyone knows anything about them.

What do you think of the drivers?


Zen Mod 4th November 2007 10:58 PM


Originally posted by pjanda1

What do you think of the drivers?


those are worthless ; send them to me for proper disposal ;

go to and look for his last few speaker projects ;

you have a gem here

markanica 5th November 2007 08:45 PM

These units were also sold for diy purpose. Philips published several books on speakerbuilding. One of them is here:

When you go to image 12, the AD3800 is mentioned as well

That's all I can find atm.

I'm glad I kept these units, It is fun to play with them.

They work well on OB

edit: I just spotted an fr-plot on image 19 and a BR proposal on image 34

pjanda1 5th November 2007 09:46 PM

That's the box allright! Amazingly, their graph shows similar response to my results inputting guesses about the driver specs into WinISP. That sure is a strange looking 10db step from 2k to 3k. It doesn't sound like that, nor does such a thing seem physically possible. Weird measurement?


pjanda1 5th November 2007 09:49 PM

I'm thinking of stuffing some polyfill in the port, making it sort of aperiodic. I imagine that will allow the driver to get down a little closer to its Fs, and smooth some of that peak around 150hz.


markanica 6th November 2007 04:58 PM

I had my speakers near the corners of the room for some usefull basslift, that was common practice those days anyway...
The simple way to deal with the excessive hf lift is to use a lot of toe in. It never gets perfect but a pleasant listen at the least
Right now I have a set of AD3700 playing in a largish closed box.
They sound large as live for their 3 Watt Max.

sure it is possible to get a better sound with modern drivers, but I find these old speaker just irresistable somehow.
I do have Fostex 103 and 207 to play with as well but these lack nostalgia I guess

e_fortier 28th August 2008 03:07 PM

Hi Zen mod,

I looked at the web site you mentionned and did not see any OB project with AD3800M. Please tell me which project you are refering too.


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