Description

This device has been tested as described. This device is offered without its Mic input transformers; however, with its output transformer. Except for the Master volume control, all switches are mechanically sound and the controls rotate smoothly. The interior appears to be unmodified; except for two power supply capacitors, all components look to be original. This is a very late production model offered without a panel meter; manufacturing codes indicate 1970. Meter lamp leads are disconnected as a precaution. I am offering the vintage ALTEC 1567A 5X1 Vacuum Tube Mixer Preamplifier - without input transformers - displayed in the photo as tested . This device was acquired as industrial excess from a facility that had purchased it in 1971 ; it has not been in service for many years. Except for the two Sprague 33.0 mfd/250 VDC power supply capacitors - see photo , all components look to be original and appear to display no signs of stress due to excessive heating or arcing. Testing was limited to the high level input stage , the tone equalization stage , and the line output stage . Testing this unit powered at 117 V was comprised of verifying that the measured voltages were approximately correct, that the carbon composition resistor values were within their specified tolerances, and that the unit delivered stable and undistorted audio over the course of a two hour listening session. With all four MIX microphone levels set fully CCW (minimum), program audio was provided to the input of MIX 5 ; the audio output was sourced to a solid state commercial grade audio amplifier from the 600 ohm output terminals . Under these conditions and over the course of several hours, this unit provided a stable and undistorted audio presentation of a variety of modern and vintage recordings with surprising richness and fidelity . The lack of any noticeable hum was undoubtedly due to the replacement of the failing consumer grade 60 mfd/250 VDC (C21) axial electrolytic capacitor forming one leg of the voltage doubler. Bass and Treble controls, the MIX 5 control, and the MASTER Volume control each functioned properly. Date codes indicate this unit was manufactured in 1970, making this a late production model. Two of the 12AX7A/7025 input tubes are General Electric (Great Britain) - see photo - a sample of the Great Britain 12AX7A tested at approximately 40 above the 32 minimum on my TV-7D/U tube checker . The other 12AX7A/7025 is a NOS GE (USA). The 6CG7 output tube is a NOS (USA) branded Zenith - see photo . Except for the Master volume control, all controls are mechanically sound and rotate smoothly; the Master volume control is a bit stiff and a slight mechanical scrapping sound is audible when rotated ; however, this scrapping sound is not heard in the audio playback as the Master volume control level is varied. Only the Peerless 15095 output transformer is included with this sale - see photos. The original meter cover is unavailable, hence the meter lamp leads will be disconnected as a precaution. This device has been kept in a controlled environment; besides some internal dust, the interior is in very good cosmetic condition - see photos . There is some rust to the steel transformer bells - see photo ; besides this minor issue, this device is offered both in good physical and cosmetic condition. Photos taken in natural daylight are provided for your inspection . This device would serve as an excellent candidate for a full restoration. Feel free to contact me should you require additional information or clarification . This device is offered as tested as described, and as displayed in this listing. Offers that include local pickup are welcome. Images sell! Get Supersized Images & Free Image Hosting Attention Sellers - Get Templates Image Hosting, Scheduling at Auctiva.com. Track Page Views With Auctiva's Counter