From Yamaha to NAD to...? What's my next move?

ADClosson

ADClosson

Member
Greetings all,

In a budget-minded attempt to improve my modest 2 channel system I've managed to take a step backward and could use some counsel on how to proceed from here. I started with an 80's Yamaha A-1000 integrated (not to be confused with the newer A-S1000) boasting 120 watts, considerable heft and seemingly high-quality construction. It sounded good through my ADS L520s, although sibilants were an issue with my Dual 606/2M Red combo, and generally the high end could be a bit grating in my lively room. Because I had no point of reference - this was my first stereo system - I decided to grab a vintage NAD 3140 to compare the sound. I had read that NAD tends to be warmer, so I hoped that it might smooth out some of the fatiguing high frequencies I was getting from the Yamaha.

Upon first listen, I liked the NAD. While much brighter than I expected, it imaged well, probably better than the Yamaha, and seemed also to present a more balanced soundstage (more on that observation in a moment.) But after a few days I began to suspect that I was missing something, and reverted back to the A-1000 to revaluate its performance. Sure enough, I was immediately struck by a richer and more substantial low end, a deeper soundstage with better differentiation of instruments and added dimensionality over the NAD. Simply put, the Yamaha delivered more body and weight to the music. I did notice, however, that the Yamaha sounded out of balance, with the left channel dominating the stereo mix. Despite this imperfection, I concluded that the Yamaha had a more robust, authoritative sound that I preferred, leaving me to wonder what to do with the 3140.

Unfortunately, a day later the Yamaha's right channel began to intermittently emit a horrible static distortion, which I interpret to mean that that channel is indeed defective. The distortion occurred even with the amp's volume dialed to zero, and irrespective of input selection. Shame, as it was a pleasant-sounding unit. I should have left well-enough alone.

Now I'm left with a much "thinner" sounding 3140. My options appear to be: 1) Repair the Yamaha 2) run the 3140 as a preamp and upgrade to a more robust power amp in hopes of regaining the lost heft delivered by the Yamaha 3) start over and buy a new integrated. I'm leaning towards option 2, but am looking for advice on whether the difference in sound might plausibly be attributed to the disparity in power between the 3140's 40 watts and the Yamaha's 120 watts. Or do the units just sound fundamentally different and no addition of power will change the 3140's preamp sound signature?

Thanks in advance for any suggestions.
 
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Clean the A-1000 controls. Tech in the can aka residue free contact cleaner has cured a lot of expensive sounding faults. Brand D is not necessary, I use MG Chemicals from Fry's. CRC is good as well.
 
Hmm, ok SoCal, I'll give things a good lubrication/cleaning. From the nature of the distortion I'm getting and the imbalance in channels, I suspect the problem is more serious than that, but I'll admit to having no experience in such matters. To clarify, I'm not getting the bursts of distortion while adjusting balance, EQ or volume - this isn't dirty pots - but just spontaneously and even without signal input. It's a horrible lacerating sound that I was certain would destroy my speakers.

Any recommendation as to what components I should clean?
 
Yes, do clean the back panel jacks (small amount of de-ox - I usually spray on a paper towel and wipe)and then gently "work" the various pots and switches. A very small amount of de-oxit on the volume pot and the tape monitor switch would be the next thing I'd try. Let a couple of hours go by before you recheck, just to make sure all is dry. The A-1000 would be worth repairing if it is something more serious - in my view. Especially given that you liked the sound. Don't risk those L520s on a bad amp, though - they are superb, I love mine and connect to only my most trusted amps.
 
Thanks, J English. I agree, the L520s do sound very capable. I've got a pair of Realistic Nova 10s on hand that I can test the Yamaha with. I'll give it a thorough cleaning. Appreciate the suggestions.
 
After cleaning the contacts controls, you could check the "DC offset" at the amps speaker binding posts. There is a sticky thread in AK on how to. May be in DIY section. Would need a multimeter. Excessive DC can damage speakers.
 
The A-1000 is one of my all time favorite amps. I've had experience with it all the way back when my father bought one new in 1984.
I'm currently running one in my main system and love just about everything about it. It powers my inefficient B&W speakers well and never fails to put a smile on my face.
Unfortunately they don't age particularly well and suffer from aged capacitors and especially from cracked solder joints. It sounds like yours has hit the point where reliability is an issue and that its time to have it looked at.

I'd say a good improvement to your system would be to get the A-1000 restored (I'll extend the offer to go through your A-1000 if you don't take Lee up on the NAD) and then work on some room treatments to knock the brightness down.
 
Yamaha units of this era also used glue to hold down larger components that has dried out and turned brown by now. This glue can become conductive and corrosive. It literally eats the leads off of components on the board.

I would pop the cover off the amp and check for damage as shown in the photo.

corrode4.jpg
 
The A-1000 does have glue on a few caps but it's in spots where it shouldn't damage anything. The smaller A-700 will have 5 or so corroded resistors and a diode with damage.
More than likely one of the smaller transistors or the power resistor on the small board is wiggling around loose due to cracked solder joints. The only way to fix these amps for sure is to just go over ever single joint. I bought a Hakko desoldering tool to get rid of the old solder as it seems to be a pain to get new solder to wick properly sometimes when there's old, oxidized solder still present.
Lots of work but they sound so nice when done.
 
Not for nothing, I run a Crown XLS 1502 amp and a Rotel pre-amp. It would be hard to do incrementally better without spending MUCH more money. I'd like to borrow Mac and Bryston gear to see if it is a dramatic change, but I doubt it.
 
Thank you all. Now the Yamaha is hesitating to come out of protection and sometimes doesn't at all. As for repairing, I'm not afraid of a little soldering, but I am daunted by the prospect of dismantling the A-1000. Perhaps I'll get lucky and detect a visible defect of some sort. It really is a beautiful sounding amp. People refer to Yamaha as bright and sterile, but the NAD 3140 is far brighter. Perhaps it's in need of repairs, too.

The NAD doesn't sound bad, I just feel like it's missing the muscle to bring the L520s to life.

Thanks OMGCat! and leesonic for the offers to repair. I wish you were nearer to Dallas, as I'd hate to ship amps cross-country. I'll keep your offers in mind as I deliberate options.
 
Bad news. I just received an email from Frank Mufich, a local tech mentioned elsewhere in these boards. He told me to let the A-1000 go, as the restoration costs would be $650. Sorta heartbreaking.

From what I understand the A-1000 is the integrated version of the M-2 power amp. Would the 3140 pair well with the M-2? Perhaps I should be seeking out a power amp with higher wattage to approximate the sound I achieved with the A-1000. I'd like to put the 3140 to some good use, as I've got a matching NAD 5330 CD player. But then I'd be dealing with another vintage amp prone to failing. Thoughts?
 
The A-1000 doesn't have much at all in common with the M-2 aside from a familial resemblance in the topology.

It's also older so will likely need repair as well.

If you decide to poke around yourself I'd wiggle the big power resistor in the front right hand corner (amp controls facing you). They will get loose and cause issues. Otherwise look around at the smaller transistors on the main amp board and try and wiggle them as well. Likely some are loose. If you have any other questions feel free to PM me.
 
I opened up the A-1000. Does this look like damage, or just discoloration caused by heat over time? That's the only sign of a problem I could see.

Yamaha_A1000.JPG
 
That's just how they look after time. The board with all of the resistors is typically called the BBQ board because it gets cooked like that. The other board with the three cement resistors ends up looking the same way. All four of those cement resistor solder joints are very suspect.

Since it seems to be going into and out of protection, I'd power it up and use a chopstick or something and poke around on the main amp board and see what general area is causing the issue.
The A-700 I had was absolutely full of cracked joints and it had similar issues with going into and out of protection even after I took care of the obviously bad joints. After going over the whole board it's been working fine.
While you're in there it wouldn't be a bad idea to change out the 680uF caps in the center. There are a few others that tend to go down in value over time but those are the worst.
Replacing those caps and reflowing the joints will get you back to good I'd almost guarantee it.
 
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I've had the M-40, and it was an excellent amp. I think those zero distortion rule amps were my favourite of the Yammys I've tried. I have an R9 right now that I also like quite a bit. I think that family of integrated NADs don't have bad preamp stages, but there are many others that are better. I've had quite a few of that family. I find they are not bad at giving that umph to music, if a little dark. It is definitely an option to find yourself a power amp and use the NAD as a pre until you figure out what direction you want to go. I would hang on to the A-1000 and try fixing it yourself. After all, you wouldn't get much for it if you tried to sell it in this state, and it might be an easy fix.
 
Personally, I'd just have the Yamaha serviced--by a different tech than the one that quoted you $650--that is outrageous, even for a complete restoration. If you want to go down the path of mixing and matching preamplifier sections and power amps, save your pennies and go for separates.
 
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