Tuesday, August 01, 2017

Vintage 755a speakers + Modern Elekit Tu Tu amplifier + Western Electric 111c

I was back Singapore last week to attend JJ's army open house and to have breakfast and dinners with parents and to bring Mel for medical check up.

When I was home alone, I have decided to listen to some music using my Elekit Tu Tu amplifier together with my 755a fullrange (全音)speakers and the sound was wonderful. Full range speakers excel in coherence & transparency. These two simple combination are perfect fit and listening to the music is a truly enjoyable experience.

全音域的好處,是可以不經分音器,完全正確地重播聲音!前人留下的755a全音單元,有相當好的作品,全音喇叭是沒有分音喇叭的壓縮感,無分音元件音染、高效率、單點音源、高訊變等特性希望更貼近原音,发烧友的系统就像女人的衣柜,永远少了一件衣服, 如果能夠親身感受一下,相信對音樂的感覺,另有一種新的反

In the late afternoon, I have brought out my Western Electric 111c in the box to connect with my cheap CD player and the sound was further enhanced. The 755a is really superb for vocal and light instruments and a small power amplifier is able to do the job nicely.

The following information is a from the internet on Western Electric 111c:

"Long known for their superb sonic integrity and ample headroom capacity, the Western Electric 111C still can outperform most, if not all, the audio transformers of its type made today. There are not many remaining on active duty around the US at radio stations. The changeover to dedicated digital audio telephone circuits over fiber as well as ISDN lines for special “remote” broadcasts has removed the need for these coils.

The 111C is a toroidal type repeating coil was designed for dependable impedance matching applications and for line isolation at circuit transfer points. It is intended for use with amplifiers for program transmission over long or short cable or open wire circuits equipped with proper loading. It was the Bell System standard coil for broadcast radio lines for 50 years.

The factory specifications call for a frequency range of 30 to 15,000 Hz. with an insertion loss of less than 0.5 dB. The maximum power capacity at 30 Hz is 1.1 watts (+30dBm).

In actuality, the Western Electric specifications are quite conservative. Using a Hewlett-Packard 3551A Transmission Test Set on 6/1/2007, the actual measurements are a bit better. Overall loss is 0.4 dB at 1,000 Hz. The frequency response is +0, –0.2dB 28 to 20 kHz referenced to 1,000 Hz. The oscillator in the test set does not go below 28 Hz. The high end was down 0.3 dB at 24,000 Hz. At the upper limit of the test set, the response was down 2.0 dB at 65 kHz.

Input impedance is 600/150 ohms. Output impedance is 600/150 ohms.

Each unit weighs 4.5 lbs. It measures 2-9/16 inches x 4-3/16 inches x 4-17/32 inches. These units are ideal for eliminating ground loops and other electromagnetic hash. They have an inter-winding electrostatic shield that can be connected to the audio ground."



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