• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Yamaha CX-830 Project

I

ic-racer

Super Member
I got my M-45 many years ago and have restored it in a prior thread. For years I have been wanting to pair it with a Yamaha preamp. I would not have minded a C-45 low-end unit but, for some reason, the price of Yamaha preamps is a little crazy for 1980s gear. New preamps are out; I can't pay $2000 for a preamp to mate with a power amp that cost me $75.

One day last week I entered my ebay "Yamaha Preamp" search wrong. I got a hit on a "Yamaha Control" amp; a CX-830! The listing had no followers and no bidders at less than $100 starting bid. Seemed to be 'under the radar' of others looking for Yamaha preamps. I bid $133 with 4 days to go. Anyway, I won the auction at the starting bid no other bidders or snipers or watchers!

It is said to be a working unit, but I was looking for a new project, so I don't really care if it works or not.

It came today....
 
Register to hide this ad
The outer cover is scuffed and has a few dents.

I don't know about all you, but to me, the rarest and most desirable projects are ones that HAVE NEVER BEEN OPENED! This was the case here. The cover had never been removed, the original plastic was still under the screws. I used my $35 Tamiya JIS screwdriver to remove the screws to keep them in perfect condition.
Screen Shot 2018-12-10 at 10.02.50 PM.png
 
Test points for Bias adjustment are within normal limits. So, nothing to do there.

A little 'smell of heat' from the unit, but the Temp gun found nothing unusual. The two TO-220 transistors on heat sinks were warm but, expected.

First listening check was with an iPad connected to the RCA inputs and a listen with headphones.

Initially the DIRECT sounded fine but the preamp had a weak R channel when DIRCT was disconected. I thought 'now I have a project.'
Also, I had a 60hz hum on unused inputs. (There is a thread about tracking down this hum out there).
However, after de-oxit of the pots, it came back to life. It was actually the 'Loudness' pot that was the culprit. Also, after the de-oxit the hum went away.
I was also glad it was not stuck in "MUTE" as it did not come with a remote (there is a thread here about a Yamaha preamp stuck in "MUTE" with no remote).
 
So, really nothing to do here, not even ugly glue to remove.

Other good news. I just found the remote that was supposed to come with this! It is on its way.

Although, to look closely at the buttons, most are useless for "HiFi" use. For example the bass, treble, balance, shelf, filters, direct, etc can't be controlled. It is mostly a A/V controller. At least I get to choose inputs and control volume with the motorized volume knob.

The blank buttons are programmable, so I can program my CD player controls.
Screen Shot 2018-12-12 at 9.07.50 PM.png
 
Last edited:
I have a stack of L19 & 4311B that can be powered together (4 ohm in series) and the 590 to run separate ( 6 ohm).

For power I have the integrated Yamaha A-1000 vs the M-45 & CX-830 combo.

So, how to choose who gets what.

Rather than flip a coin, I scanned the specs. from the owner's manuals. Of course, who knows if my units actually perform to specs at this time. Anyway, it turns out that even though the M-45 is older than the A-1000, it has betters specs than the A-1000's power amp section. In terms of Control Amp, the CX-830 again beats the built in Control Amp of the A-1000.

So, the 590s get the M-45 & CX-830 and the vintage JBLs get the A-1000.
 
Thanks for the help mates I plan to dig into it tomorrow. The wife has duties for me to do today and have to take grandson to guitar lessons this afternoon . I will keep you posted. And Yes, the print from HFE is the pits
 
Ic-racer, the cx-830 looks great after being repainted. I have the same unit plus a MX-2 that need to be repainted. Can you please let me know what type of paint you used, if you used primer, etc?

Thanks a lot in advance
 
comish4 said:
Thanks for the help mates I plan to dig into it tomorrow. The wife has duties for me to do today and have to take grandson to guitar lessons this afternoon . I will keep you posted. And Yes, the print from HFE is the pits
Click to expand...
Did you post in the right thread ?:biggrin:
 
I really like my CX-830TI. It matched up visually well with my other Yamaha Titanium units, but then I obtained a TOTL CX-1000U of that era that caused the CX-830TI it to be set aside for some time. After both were set aside for a while, I went to try both, and the complicated/high-end CX-1000 is malfunctioning, but the CX830 works perfectly fine. Here is an image of the CX-830TI with MX-830TI...

image;s=1000x700
 
Are these cx-830 hard to work on? I just bought one online so not in my hands yet i was just thinking i liked these and i might want it rebuilt.
 
gentlejax said:
Are these cx-830 hard to work on? I just bought one online so not in my hands yet i was just thinking i liked these and i might want it rebuilt.
Click to expand...
Shouldn't be hard. Probably cleaning the volume pot would be the biggest challenge. IIRC they use a motorized ALPS? I have several C-80's, 60 and 65, the volume pot is my biggest concern with these.
 
gentlejax said:
Are these cx-830 hard to work on? I just bought one online so not in my hands yet i was just thinking i liked these and i might want it rebuilt.
Click to expand...
Did you get your CX-830 and do any work on it? I have one inbound, would be interested in anything you have learned about them.
 
You must log in or register to reply here.
Back
Top Bottom