Onkyo Tx2500 User Manual Site Audiokarma.org
Pioneer's original forte and original business was loudspeakers, Onkyo made it with receivers : properly integrating three separates into one enclosure.
Onkyo is nowadays only working around mini-components, integration toward reduction, and home-theater, the latter being integration pushed to the limit : intergalactic battleships, earthquakes and super-heroes all in one room !
Whatever the brand, most receivers made in Japan were export-only : Japan never really cared for receivers although integration would've been practical for most japanese audiophiles and their... small rooms.
The TX-2500 hides behind its very conservative front what was beginning to be common features in 1976 : PLL MPX decoder, tuning servo-locking and 'Accutouch' tuning knob.
Accutouch temporarily inhibits the locking circuits for manual, large-scale, tuning : hands-on ; when released, hands-off, the locking function clicks back in and fine-tunes on its own the locked station until the TUNED indicator lights up.
A variant of Accutouch was also used by Luxman at the time for temporary volume muting.
The TX-2500 tunes in AM or FM with a 3-gang varicap, two IF amp stages, 4-elements ceramic filters and an Onkyo-made low-pass filter.
One-step on/off muting is at hand, just like a (potential) Dolby FM adaptor (in the future) for the (upcoming) Dolby FM (maybe) broadcasts which reduces deemphasis to 25µs instead of 50µs.
The latter feature was removed from the 1978 MKII version but the actual 25µs / 50µs function was still there ; it just wasn't labeled DOLBY anymore and the back loop was scrapped.
The main section of the 2500 boasts a beefy transformer (we're in 1976, not 1979), fairly low distortion, and square-wave response worthy of an H/K product : only 5% tilt at 50Hz.
The preamp section had two RCA & DIN tape loops, the Dolby FM loop, one phono MM input, hookups for two loudspeaker pairs and dubbing from tape 1 to tape 2. It is simple, it works, it makes music.
The TX-2500MKII is a visual redesign in 1978 style with however much better specifications for the preamp and tuner sections and quite a bit more output power, too. So the inside of the two versions must be rather different...
A TX-2500MKII restoration here.
Instruction Manual
This is a great amp.Some say its power supply is overbuilt.Mine makes my Klipsch RF-82 so loud its got to damage my ears.Cant turn volume past halfway in my room.I don't go halfway much as its to loud.But even very loud it sound wonderful.Very good combination. Reviewed May 21st, 2014 by Rizal This. Sep 06, 2014 My thought is that it is cheaper for comparable or better to use a receiver to power DIY non-amplified speakers, eg. Onkyo TX-8020 with parts express Tritrix speaker kit. Anyone disagree with the above statement? Is the Onkyo garbage or is there a better alternative? It is my intent to use an input for Lyr 2 as the source.
Onkyo Tx 2500 User Manual Site Audiokarma System
This is one of the less common receivers – the Onkyo TX-6500 MK II. It was made by Onkyo from around 1978 to 1981. They made a series of receivers with the entry level unit being the TX-1500. From there was the TX-2500, the TX-4500, the TX-6500 and the monster TX-8500. I believe they were 40, 60. The Onkyo TX-6500 MKII featured a smoked glass front dial cover with 4 heavy duty looking bolts holding it in place. The receiver is really a very nice looking unit when it is lit up. It also features a very good phono preamp circuit. The TX-6500 measures 540 x 190 x 435 mm or 21.3 x 7.5 x 17.1 inches. Aug 10, 2015 Is is an automatic table, so there are lots of tiny additional electronic components in the way not found on manual tables. I have the service manual but was wondering if anyone who has personally worked on a 1600 Mk2 could chime in or offer helpful tips, link and advice for restoring this great table and accessing the necessary components. May 03, 2010 Onkyo tx-2500 mk II oops. Another poster kindly sent me a pdf of the service manual, and after checking dummy-load dc (under 10mv even after 30 min warmup) all.