This ebony classic is the Yamaha CR-840 receiver. It was produced from 1979 to around 1981 and retailed for about $500. It was a mid range receiver in Yamaha’s CR-XX40 lineup. It puts out 60 watts per channel into 8 ohms.
The CR-840 has the big flat toggle switches as do many of the other Yamaha models. Overall it has a very nice sleek hi-tech look to it, though some think the Yamaha models look somewhat sterile.
The CR-840 has a built-in AUTO-DX circuit that monitors the signal strength and amount of interference present. If needed it will automatically switch to the DX Mode IF Stage to increase the selectivity to 83dB.
It also has continuously variable loudness control which means that the frequency balance and volume are adjusted simultaneously to compensate for the ear’s insensitivity to high and low frequencies at low volume settings. So, a natural-sounding balance is maintained regardless of volume level. It weighs about 30 pounds and measures 20″ x 6-9/16″ x 15-1/4″.
One problem with the Yamaha CR-840 is that it uses output modules rather than discrete output transistors. These modules have a tendency to overheat and die. Unfortunately, original replacements are difficult to find and newly made versions tend to be out of spec and perform erratically. It has been speculated that the Yamaha IG 02970 output module was in fact a rebadged Sanyo STK 0060-II or STK-0080-II. The STK-0080-II is fairly easy to find which would make repairing these units far easier.
The Yamaha receivers have never garnered as much attention as the Pioneer and Marantz receivers but perform just as well. They do emphasize a “Natural Sound” so they tend to have a more accurate representation of sound which some find to be a little harsh. Prices are rising for these receivers though – especially the higher end models.
Love your page
Please get your hands on a couple of Akai
units 10XX and 11XX series
Always look forward to your reviews! Love the old vintage stereos. Keep up the good work!
Nice website! Informative and convenient.
I have acquired a nice, clean Yamaha CR-840 which I hope to clean and change the bulbs before long.
But I have noticed there is no clear lens or glass in front of the AM/FM dial. Surely there was one, yes?
Yes, there is supposed to be a glass panel.
No there isn’t (a clear glass lens in front of the AM/FM dial) . I’ve had my CR-840 since new…still works great.
The dial was designed that way…..on a tilt….and the only place there would be glass or clear lens would be
the very narrow section where the dial pointer travels. So worry not. It’s a really nice receiver.
I recently purchased a CR840 in mint condition the fellow I bought it
from had it since new he had it cleaned and checked over prior to sale
The only issue is the backlight for the tuner display is out which I’m not sure if the signal meter shares the same light is that an easy fix?
Love this receiver! Found mine in the junk bin at the local Goodwill. Cleaned it up and perfect sound! Great find for $30. Your page is spot on, thanks!
Which is the correct replacement for the Yamaha IG 02970 output module in my Yamaha CR-840? Is it the Sanyo STK 0060-II or STK-0080-II? Or would either work? Also…could this be my problem that is causing my CR-840 to not click in the relay and have any outputs?
Thank you in advance for your help.
Hi, I would try the guys in the Yamaha forum at audiokarma.org. There are a number of techs over there that should be able to give you a definitive answer. The forum is HERE.
Yes, these work. I replaced both with the Sanyo STK 0060-II and the receiver worked for about a year before one of the modules failed. Since i like the CR-840 for all its control and switching, i decided to replace the entire power amp stage with a “Class D” amp module. The chassis has +/- 53V available. If you remove the power amp modules, their heat sinks, resistors, and caps, that leaves plenty of space to mount a suitable module. You could buy Hypex if you want but these are expensive and maybe a bit overkill for a 1979-era receiver. I used Sure AA-AB32313 from MCM Electronics because the specs are pretty good and the price is right. You can get the audio from pin 1 of IC701 and IC702, and route that into the amp module. You will lose the headphone capability so a separate amp will be needed if you do headphone listening.
Use the larger of the two, the STK-0080-II in a Yamaha CR-840 with a failed IG02970, it works.
Upon application of power it actually exceeds spec for power output with excellent distortion characteristics with 0.04% THD+N at 65W into 8 ohms! 1% THD power, one channel driven, into 8 ohms using this module is 100W.