Introduction

[tgroendahl]

Dear Audio Friends!

I work as a free-lance photographer. Music has always been my truly great passion. Main interest is jazz and classical. I only play vinyl (becoming an analogue addict..!) The past few years I got more and more interested in audio. By surfing the net looking for speakers, my attention was soon drawn to vintage speakers with alnico magnets. In Germany I then found a pair of 12" Philips drivers from 1952, taken from a cinema installation. They play wonderfully up to around 4 Khz, from where they fall evenly so that no filter is required. The sound is very resoluted and natural. Above 4 Khz I use another vintage driver, Fostex T-825A with a 5uF Jensen Pertinaxshell PIO capasitor plus a few carbon resistors as filter. In december I was lucky to get the very musical EMT 930 turntable, now fitted with a Denon DL-103. Amp is a 2A3 single ended tubeamp. Currently I´m working on getting speaker cabinets constructed, since drivers for some time has been mounted in open baffles that do not support low levels enough (strongly considering large closed cabinets or eventually the aperiodic principle).
I am looking much forward to participate in the interesting forums on DIY Audio.

Sincerely,

Thomas Groendahl

Copenhagen

http://www.thomasgroendahl.dk

[Cal Weldon]

Welcome Thomas,

I think you'll find this is a great place for getting whatever info you need.

Cal

[EC8010]

Welcome to the forum. That system sounds interesting. Can you post some pictures, or are you medium format?

[tgroendahl]

Thanks for the welcome.

Currently I don´t have any pics of my system, but will make.

Instead I post photos of the lovely Philips 2278-00 driver. It is a 12" driver manufactured in the beginning of the 50´s for use in cinema.
It has a quite large magnet and phenol-spider. There is no available information about this unit on the net. I guess that it was probably
not made in very great numbers. One of the three units I have measures: Fs=50Hz Qms=14,55 Qts=0,27 Vas=155 Impedance=16ohm.
The driver is not a real full range driver, but extends with fine resolution to around 5Khz.

The sound with these drivers is very present and brings me close to the music.

[tgroendahl]

Front photo

[planet10]

Welcome to the forum.

Those are really sweet looking drivers...

Some very nice photos on your site... the flash UI makes it next to impossible to read any of the accompanying text though -- to small for my eyes.

dave

[tgroendahl]

Hi Dave, Thanks for the welcome.

You´re right about the text size on my website, it´s to small. Anyway it´s just a list of some of the clients I worked for here in Denmark. Some people also find that the photos are pretty small for a photographers website... I will be redesigning the website later this year.

It´s a very informative website you have on T-line speakers. I don´t know much about this kind of design, very interesting reading!

For my Philips 12" drivers I´m considering to make a large sealed cabinet or eventually an aperiodic box. I´m currently reading the threads on these subjects on the speaker forum.

What an interesting FORUM this is!

Thomas

[planet10]

Originally posted by tgroendahl
For my Philips 12" drivers I´m considering to make a large sealed cabinet or eventually an aperiodic box. I´m currently reading the threads on these subjects on the speaker forum.

My receipe for building an aperiodic box is a sealed box that isn't quite big enuff (in some cases just a box as big as you can live with) and then add an aperodic port.

dave

[EC8010]

Interesting driver. Does it really not have a dust cap, or are my eyes deceiving me?

[tgroendahl]

Hi EC8010,

The drivers do not have dust caps. A diminutive circle that looks like old glue next to the voice coil, suggests that maybe once there was dust cap. It is however quite usual to see this kind of drivers (Siemens/Klangfilm etc.) without no dust cab. They are, as far as I know of, removed in order to improve high frequency extension. And indeed this driver plays with good resolution to around 5Khz, which is quite high for a single cone 12" (?). This Philips driver is quite rare, I haven´t seen it on the net. I checked with the danish Philips full-range expert mr. Ole Chistensen (http://www.sitecenter.dk/otc/nss-fol...lipsfullrange/), he didn´t see this driver before. They remind more of the mentioned German drivers, that came in 8", 10" and 14" sizes, than of the well known other Philips / Norelco drivers 9762M / AD5200 driver with whizzers, and the alnico magnet on the 2278-00 is also slightly larger and has phenolic spider.

I will be soon be making large sealed cabinets, and then eventually experiment with an aperiodic port.

Sometime I would like to try a real full range driver. Saw the Exact 6" driver on the full range speaker forum. They look pretty exciting...

Regards, Thomas



Thanks Dave for your input yesterday regarding aperiodic principle.
Regards, Thomas