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    M-125 Review

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    TMadden

    Posts : 99
    Join date : 2011-12-22

    M-125 Review

    Post by TMadden on Thu Dec 22, 2011 10:37 pm

    Hello to all on the forum, and Merry Christmas!

    I'm posting tonite beacause I have been listening to the M-125's for several weeks now and I feel compelled to share my impressions. I feel that Bob has set a benchmark for value and performance with these amps. Let me tell you about the system they are in to give you some perspective. It's a bi-amped system that serves as a home theater and a music system. The source for music is generally a Marantz CD5003, the digital output of this connects to a Behringer SCR2496, this serves as a digital source selector, removes jitter and reclocks if needed. The digital signal from this feeds a modified DCX2496 with Jan Diddens excellent 6- channel analouge output board in it. It's functions are digital crossover, EQ, preamp, and DAC. The high output from this feeds the M125's, the lows are amplified by a 1200W 100+lb current dumping monster SS amp, hehe, I like plenty of bass when watching action movies, this thing has it's own 240VAC feed. Speakers are modified Ascend Acoustic CM340's on the high end, and Dayton Reference 12" subwoofers in sealed boxes for tight, fast bass on the low end.

    Ok, how does this sound? Well, my friends tell me they have never heard better sound reproduced in a home. It destroys their mid-fi systems. Lyle Lovette is in the room with you, so real you get goosebumps. You sense the space of the studio, you hear his lips, his tounge, his breath, his stool creak. Steely Dan Aja is spellbinding, live, dynamic, amazing! Telarc discs are stunning, my guests are amazed at the realism and dynamics. The Mobile Fidelity Labs version of Pink Floyd The Wall is mesmorizing, transfixing, haunting. The M125's are incredible sounding.. transparent, dead quiet, dynamic, powerfull, revealing, natural, smooth, detailed. I have tried a lot of high dollar amps in the system (including a Class A SS amp) and I have no desire to replace the M125's. Any further upgrades with be focussed on the speakers, and possibly a DEQX if I can find a deal on one. Oh, must mention the tubes in the M125's, I did some rolling and ended up with JJ ECC 802S and Westinghouse 12BH7's in the driver boards, and EI KT90 power tubes. I carefully balanced the phase splitters with a 'scope and set the bias per Bob's recomendation. I hope I didn't come off too strong, but I wanted to try to convey just how good these amps are. Thanks Bob! Below is my system with the two M-125's on the left ..


    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: M-125 Review

    Post by Bob Latino on Fri Dec 23, 2011 6:18 am

    Hi Troy,

    Is there any chance we could get a photo or two of your music system ? From your description it sounds very different from the average home audiophile's music system. This forum can't host a photo but if you can host the photos on some other web site, you can hit the little photo button on the top of the reply box and just put in the photo's web address. Alternately, if you can send them to me via Email, I can see to it that they are posted with your comments.

    Note - 12/26/11 - OK - photo has been posted above

    Bob




    Last edited by Bob Latino on Mon Dec 26, 2011 6:56 pm; edited 1 time in total

    TMadden

    Posts : 99
    Join date : 2011-12-22

    Re: M-125 Review

    Post by TMadden on Fri Dec 23, 2011 9:22 am

    Sure thing Bob, they are on the way, please pardon the bachelor house-keeping skills and the poor photography.

    Bob Latino
    Admin

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    Join date : 2008-11-26
    Location : Massachusetts

    Re: M-125 Review

    Post by Bob Latino on Fri Dec 23, 2011 10:14 am

    Troy,

    Thanks for the photo ... wow! what a system you have there ...

    Bob

    RockyAM

    Posts : 26
    Join date : 2008-12-14

    Re: M-125 Review

    Post by RockyAM on Fri Dec 23, 2011 12:05 pm

    I cannot agree more with TMadden. I got my two M-125 kits in June of this year. They went togther with no problems at all thanks to the excellent build manual from Bob. The only minor glitch I had was not related to the amp itself. One of the 12BH7's on one of the amps was noisy. I sent it back to the tube seller and he sent me a new one which cured the problem. One thing that really struck me in comparison to the 200 watt per channel solid state amp that I had been using was the far better soundstaging of the M-125's. The whole sound field was noticeably wider and deeper. The Adcom solid state amp seemed flat by comparison. The other thing is that although the M-125's are rated at 125 watts each they seemed to play as loud as (or louder) the 200 watt per channel Adcom? Can't figure that one ? In the 6 months I have had these there have been no problems at all with either amp. I turn them on each day after work and they just play ... RockyAM

    RockyAM

    Posts : 26
    Join date : 2008-12-14

    Re: M-125 Review

    Post by RockyAM on Fri Dec 23, 2011 5:38 pm

    Hey Bob, Right now I am running two matched quads of KT88 output tubes in my M-125's and they sound great. I have seen photos of your amps using the TungSol KT120 output tubes. I was thinking of trying them and comparing them to the Gold Lion KT88's that are in there now. Just today I saw a post on the Tubes Asylum mentioning that these KT120's draw .3 amps per tube more current than a KT88 and that might overheat the power transformer on some amps. Link is here http://www.audioasylum.com/audio/tubes/messages/24/242449.html

    Have the M-125's been tested with the KT120 tubes? RockyAM

    Bob Latino
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    Re: M-125 Review

    Post by Bob Latino on Fri Dec 23, 2011 7:51 pm

    RockyAM wrote:Hey Bob, Right now I am running two matched quads of KT88 output tubes in my M-125's and they sound great. I have seen photos of your amps using the TungSol KT120 output tubes. I was thinking of trying them and comparing them to the Gold Lion KT88's that are in there now. Just today I saw a post on the Tubes Asylum mentioning that these KT120's draw .3 amps per tube more current than a KT88 and that might overheat the power transformer on some amps. Link is here http://www.audioasylum.com/audio/tubes/messages/24/242449.html
    Have the M-125's been tested with the KT120 tubes? RockyAM
    Hi,

     The M-125's have been thoroughly tested with the Tung-Sol KT120 output tubes. In fact right now the KT120's are what I have in my own M-125's. The power transformer on the M-125's has plenty of headroom for the extra current draw. When I tested the KT120's in my M-125's I gave the two amps a real workout. I ran the bias up to 75 milliamps per tube (1.50 VDC per bias pot rather than the 1.20 VDC recommended bias setting - NOTE - 8/30/16 > The recommended bias setting on these amps has been lowered to 1.00 VDC from the 1.20 VDC. The amps sound exactly the same and tube life will be longer).  I remember running both amps about 5 hours like this and listening to music at fairly loud (but not maximum) sound levels. I made no definitive temperature test but I think that the power transformer was probably a little warmer than normal. In short > the power transformer on the M-125 is rated at 450 milliamps and has no trouble driving four KT120 output tubes.

    The sound of the Tung-Sol KT120's to my ears sounds just a little "tubier" than the Gold Lion KT88's with perhaps a bit more output in the mid-bass and vocal range than the GL KT88's. IMHO the Gold Lion KT88's may have just a tiny bit more output at the extreme top of the audio range. That is not to say the the KT120's are rolled off in any way. It's just the way both tubes sound to me. Either tube is a good choice in the M-125's. Both output tubes give a spacious soundstage with an accurate placement of instruments within the soundstage.

    Bob


    Last edited by Bob Latino on Tue Aug 30, 2016 5:23 pm; edited 1 time in total

    baddog1946

    Posts : 304
    Join date : 2010-02-03
    Location : Costa Rica

    Re: M-125 Review

    Post by baddog1946 on Sun Dec 25, 2011 12:51 pm

    Merry Xmas to all:
    Good observations about the differences in the KT120 vs. KT88 tubes Bob. I can detect only very minor differences between the two as well.
    I am staying with the 120's though and will buy no more KT88's as I now have a very nice collection of Gold Lion KT88 corpses that died or flared out running at 60-75MV bias. They just don't live as long as the KT120's I haven't had one KT120 failure so far. The KT120's are also very affordabe especially when compared to some of the more exotic KT88 varieties.
    I have one set of four with at approx. 2000 hours on them and they hold bias perfectly and seem to be as good as the day they were put in there. IMHO the KT120 is a superb tube.

    costerdock

    Posts : 33
    Join date : 2011-07-27

    Re: M-125 Review

    Post by costerdock on Wed Dec 28, 2011 4:38 pm

    Nice review - welcome to the club!

    TMadden

    Posts : 99
    Join date : 2011-12-22

    Re: M-125 Review

    Post by TMadden on Thu Dec 29, 2011 1:18 pm

    costerdock wrote:Nice review - welcome to the club!
    Thanks! I have dabbled in hi-fi for years (decades really) Shocked , but Bob's and Roy's products have really put the fun back in it for me. I really enjoy building kits, and their kits really deliver value and performance as far as I'm concerned.

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