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    Completed the Wonderful M-125's

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    jpd555

    Posts : 2
    Join date : 2013-02-18
    Location : Folly Beach SC USA

    Completed the Wonderful M-125's

    Post by jpd555 on Thu Mar 14, 2013 7:24 pm

    Recently completed my 2 kits after much soul searching about what to buy after one channel of my McIntosh 240 (purchased from a friend in 1988 who bought it new in 1965) lost its left channel.  After seeing how much it might cost to have it repaired, I decided to look for something new.  I had been looking on and off for a couple of years as there was some humming in the McIntosh that I was putting up with.  

    I usually don't do reviews, but am so impressed with the M-125's, plus the information I gleaned from this board that helped me make my decision, that I feel compelled to say how pleased I am.  I love how the amplifiers look, I love the sound, and I am more than impressed with Bob Latino who helped me when I made stupid mistakes.  Bob has the patience of Job, and never once asked me why I did something crazy.  It must be that 40 years of teaching experience that gave him such tolerance.  I can't say enough good things about Bob and his assistance.  Once when I had no sound after completing the second amp, I sent a picture of the underside to Bob and within a few minutes he sent a message back saying I had left off a jumper wire.  

    I have to mention the packaging of the kits.  My wife prides herself in packing, and she was more than impressed with how small a package and well put together it all was.  The UPS guy carried the 80 pound package upstairs and inside for me.  I tipped him well.  The instructions on how to assemble the kits were great.  The first kit went fine, it was the second that caused me problems.  I didn't seem to read the instructions as well, as I already knew what to do, ha, ha.

    The amps are driving 1965 Bozak B-313 speakers (used with the McIntosh).  They sound better than they ever did.  Did I tell you I am impressed?  I am hearing sounds I haven't heard before.  Amps have 4-KT120's in each plus Weber WZ68 copper caps, Golden Dragon 12AU7A in front of driver board with Golden Dragon 12BH7A in rear (both from the McIntosh 240).  I had to change out one of the front tubes with another because of noise - thanks to Bob & the board leading me in the right direction.

    After the amps were completed, I was getting a pretty consistent hum from both speakers, louder than from the McIntosh.  It didn't matter whether the volume was high or low.  All this time I had been blaming the aging McIntosh, but turned out that when I disconnected the Comcast cable to the cable box (which was connected to the pre-amp) the humming disappeared.  It took me too long to figure this out.  I tried a new ground from the Comcast cable to the existing ground for all in the house, but to no avail.  I believe it was only grounded at somewhere outside of my yard.  A Jensen TV Ground Isolator (VRD-1FF @$50) has been ordered and hopefully that will solve the problem.  I read many good reviews of the Jensen.  Meanwhile, the Comcast cable is not connected when listening to music and these amps are DEAD silent.

    But there is more.  The monoblocks that weigh ~38 lb. each are much easier to move around than the 53 lb. McIntosh.  The nearly 50 year old McIntosh chassis is rusting in spots.  I love stainless steel.  Just completed a deck using only stainless steel hardware.  Soldering and putting the kits together turned out to be very relaxing.  I'm giving the Dynaco M-125's a 5 out of 5 for Looks (much thanks to that stainless steel chassis); 5 for Packaging; 5 for Quality of Parts; 5 for Assembly Instructions; 5 for the UPS Delivery; 5 for Sound; 5 for Enjoyment of Assembly; 5 for Bob's Kind Soul; and 5 for most importantly, my enjoyment of the entire package.

    Thanks to all,
    john

    Bob Latino
    Admin

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

    Re: Completed the Wonderful M-125's

    Post by Bob Latino on Fri Mar 15, 2013 8:03 am

    Hi John,

    Thanks for the kind words about the VTA M-125 amp kits ..

    The kits are shipped in one heavy box to save the customer on shipping costs. It costs less to ship one 70 pound box than two 35 pound boxes. The M-125 kit is packed tightly because those four transformers have a lot of inertia and you don't want them moving around during shipment.

    It is recommended that you do one amp at a time (as you did) - test it to make sure that it works - and then go on to the second amp. The reasons being that (1) You can get confused going back and forth between two amps and (2) you need a much larger work space having two amps laying out on a table or work bench. Parts get crowded together .. This can also lead to confusion/mistakes ..

    I also had, when I lived at another home, an issue with an improperly grounded cable which caused some type of ground loop and a little extra hum. I was able to use a different circuit in my home for the audio system which solved that problem. The M-125's, if built properly and used with low noise driver tubes, have a very low residual hum level. On my own two M-125's, I can't hear any noise/hum with my ear on the grille cloth of my 89 dB efficient speakers.

    Bob

    costerdock

    Posts : 33
    Join date : 2011-07-27

    Re: Completed the Wonderful M-125's

    Post by costerdock on Sat Mar 16, 2013 7:41 pm

    Great read - my M125s are still running strong. I had some hum issues as well - and used the HumX device on each amp - they are now dead silent. You should post some pictures.

    jpd555

    Posts : 2
    Join date : 2013-02-18
    Location : Folly Beach SC USA

    Re: Completed the Wonderful M-125's

    Post by jpd555 on Sun Mar 24, 2013 12:47 pm

    OK, this is my umpteenth try at posting photos.  It seems the forum site takes "http" but not "https" like my Google picture account when trying to put a URL in the image block.  Servimg.com created an account for me (I'll bet Bob notified them of my problems) from which I'm now successfully uploading these pics.









    Guess you can see that the amps are in a cabinet.  Doors to front are kept open & I have cut some holes in the back - some were there from the McIntosh, but the M-125's put off a bit more heat, so I added the holes at top.  I measured temperature at the top right of the cabinet, just below the right hole and above the right amp.  House temp. was 75 and in the cabinet was 101 deg - that's after the amps had been running for about 8 hours.  Hope that is not too hot.  Seems like Bob said he had someone using the M-125's in South America somewhere that was pretty warm & they were working fine.  But I welcome advice.  I could always cut more holes or add a small fan to get rid of the heat.

    Thanks,
    john


    Last edited by Bob Latino on Thu May 22, 2014 6:36 pm; edited 5 times in total (Reason for editing : Bad URL's)

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