Yamaha MX1000

JerryD99

Member
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I now have purchased 2 of these unit and trying to figured how much power will be needed to supply them. At moderate power maybe 90 db listing level. Power rating usage on back of amp states 1100 Watts and I am sure that is max power at 2 ohms or so. I am hoping that both of them together will pull no more than a 1000 watts if I don't crank them. However 1 of them will be driving a set of Maggie MG10 speakers. 2nd one should be here Monday.

Thanks for your thoughts....
 
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Nice speakers, couldn't find the specs on those speakers so be careful not to over amplify those speakers with that monster amp. I bought an MX-1000 new and used it in the Army barracks for stereo wars which I always won. That amp will blow a fuse in a speaker faster than cancer spreads. The capacitors in the MX-1000 have the nasty habit of leaking their acidic contents all over the circuitry and destroying everything. Then to find someone to replace all of the caps is going to be a job because of the difficulty of repairing the amp. But I will tell you that, that amp severely overpowers those speakers. That amp will easily pop the fuse in 400 watt speakers like popcorn. I would think that a 250 watt tube amp with a tube preamp would be the route to go. Enjoy.....
 
Yes it is very powerful and more than I need but those MG10 recommendation at least100 to 250 at 8 ohms. I do know how to use the volume control and I really don't play them as loud as I use to.
I am hoping they don't draw to much power. Thank for your feedback.
 
I'd recommend one of those Killawatt things you can buy on Amazon to see what the power draw is. I doubt they would be anywhere near close to 1000 watts idling along at a 90db listening level.
 
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I now have purchased 2 of these unit and trying to figured how much power will be needed to supply them. At moderate power maybe 90 db listing level. Power rating usage on back of amp states 1100 Watts and I am sure that is max power at 2 ohms or so. I am hoping that both of them together will pull no more than a 1000 watts if I don't crank them. However 1 of them will be driving a set of Maggie MG10 speakers. 2nd one should be here Monday.

Thanks for your thoughts....
They idle at just over 70w (tested), but they will trip a 15amp braker frequently during power-up. That is because the two massive transformers and 4 large PSU capacitors. The in-rush current is substantial. I have yet to test what the current draw is at power-up.
I am not sure what the continuous max power is on these, but It is well over the rated power.
I strongly suggest you refloat all solder joints if you can. Recap is also strongly recommended.

I would not worry at all about the four large PSU cans. They are most likely ready for another 30years. That will not be the case for the rest of the caps in these amps. Those I strongly recommend you replace.

Good luck!
 
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The capacitors in the MX-1000 have the nasty habit of leaking their acidic contents all over the circuitry and destroying everything. Then to find someone to replace all of the caps is going to be a job because of the difficulty of repairing the amp.

I have been inside over half-dozen MX-1000 amps, some abused that went through a Cernobyl disaster, some that were mint as if the just left the factory floor.
In no case I"ve seen can juice anywhere. These are some of the most robust capacitors I have ever seen.
I test all large cans in all of my amps with a calibrated Sencore LCR meter for capacity, ESR, dielectric absorbtion and leakage.
I have yet to see any of these caps to be out of spec in any of the MX-1000 units I have/had. If you search the forum, you will find at some test results I posted from one or two of the tests.

To draw a parallel, I have yet to see any other vintage amp (with the exception of my beloved Sony ta-n7) where the main caps were still on spec. The Yamaha B-2 cans are notorious for spilling juice.
 
Thanks everyone for your advise. Yes these amps are around 30 years and a re cap will be good. However both of them were serviced before I purchased them, but can't find out what was done. I would like to get good parts to do the job and I have seen that mouser is a good place to purchase them. I have heard some name brand in other threads, but don't remember the brand. will have to go back and see if I can find it... If I may be so bold to ask..DO you have a parts list for a recap on this amp?
Thanks
 
Thanks everyone for your advise. Yes these amps are around 30 years and a re cap will be good. However both of them were serviced before I purchased them, but can't find out what was done. I would like to get good parts to do the job and I have seen that mouser is a good place to purchase them. I have heard some name brand in other threads, but don't remember the brand. will have to go back and see if I can find it... If I may be so bold to ask..DO you have a parts list for a recap on this amp?
Thanks
I would have to look for it. If I do not find it, I will put one together for you.
There's a kit for sale on the auction site. Not my choice. Most caps in that kit are bi-polar...

I will say this once more: even more important than recap, is to resolder all solder joints in the unit.
This is the Achilles hill in most Yamaha equipment of that period. The MX-1000 is particularly bad. I found cold joints through the entire unit. Worse are the amp sub boards.
 
However both of them were serviced before I purchased them, but can't find out what was done.
I would be very cautious of such marketing claims. Shooting some deoxit into the attenuator pots is what some sellers will claim as service. If you do not know what it was done because you were not told, I would be very cautious about giving any weight to that sale's pitch.

Pop the cover open, take some photos of the inside, top and bottom, and we should be able to tell easily what was serviced.

Oh, I meant to say this earlier: if they were my amps, I would not keep them in that cabinet.
MX-1000 runs relatively cool comparing to other Yamahas, I have, but place anything above and it will slowly cook itself to death.
Not sure what that optimal above space is, therefore, I ran my units with nothing above.
I noticed substantial difference in temp on the unit when placed inside a cabinet/ rack or when there is free space above. I learned this quickly with my first one
 
You should be okay in terms of power consumption. My 6 Yamaha amps all going simultaneously, cranked exceptionally loud, do approach 1800watts power consumption but I've only popped the breaker once. With two amps, the only thing you should have to worry about is in-rush current. You could easily pop a breaker turning more than one amp on at a time.
 
Thanks Everyone.....Yes I plan on touching every solder point on the amp when I do the recapping and of course I want the better part not just the run of mil parts. Want the good stuff. Not planning to put anything above the amp, keeping that space open and will be moving them to a open cabinet....
I will be using a sequencer to power them up one at a time....Using a Adcom Ac-515 one per amp.
Thinking about these cabinet.....
http://www.bushfurniturecollection....MI25Xoqcrh1QIVEySBCh05yw6-EAQYASABEgJBEvD_BwE


Thanks
 
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Lord sweet Jesus ... I believe you found Yamaha heaven. Do yourself a favor ... 20 amp dedicated circuit. They deserve it ... I did it for my Class A Threshold SA/6e monos ... it was a very good move.
 
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I would be very cautious of such marketing claims. Shooting some deoxit into the attenuator pots is what some sellers will claim as service. If you do not know what it was done because you were not told, I would be very cautious about giving any weight to that sale's pitch.

Pop the cover open, take some photos of the inside, top and bottom, and we should be able to tell easily what was serviced.

Oh, I meant to say this earlier: if they were my amps, I would not keep them in that cabinet.
MX-1000 runs relatively cool comparing to other Yamahas, I have, but place anything above and it will slowly cook itself to death.
Not sure what that optimal above space is, therefore, I ran my units with nothing above.
I noticed substantial difference in temp on the unit when placed inside a cabinet/ rack or when there is free space above. I learned this quickly with my first one

Here are the Pictures:
 
I am assuming these are pictures from only one amp.

here is what I see:
One channel was repaired...the one without the Toshiba transistors...pink emitter resistors marked with red dot.

I see all original caps, original trimmers...I doubt any work was done to the rest of the amp. It needs rehab.
please post the part number on the replaced power and output transistors...the ones on the aluminum heat sink where the transistor casing has metal showing at the top..not the Toshibas
 
The replacements look like 2SD2053 / 2SB1362 T03 transistors
these check out at 100W originals were rated at 150W and there are better replacements available. If that was my amp, I would replace them....in both channels if I am already in the surgery room.
 
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