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    Tube Newbie

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    Tube Nube

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    Re: Tube Newbie

    Post by Tube Nube on Tue Aug 16, 2016 8:26 pm

    Your ready to main-line it now, LeGrace! Welcome to your new addiction.

    Bob Latino
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    Re: Tube Newbie

    Post by Bob Latino on Tue Aug 16, 2016 8:39 pm

    LeGrace wrote:Woohoo, it works perfect!

    So I connected the amp up, the other channel I left on the SS amp. At first I thought I must have an issue. I was hearing nothing coming out of my tower speaker, it was absolutely silent. No trace of hiss, nor hum. I thought oh-oh, this likely means no sound either. Then I turned on my source. Wow! OK came this wonderful warm, rich sound! Listening back and forth what a difference!  

    Legrace,

    If the M-125 amps are built properly they have about a 95 dB signal to noise ratio provided the front driver tube does not have some noise/hum issue.

    Bob

    LeGrace

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    Join date : 2016-08-07

    Re: Tube Newbie

    Post by LeGrace on Tue Aug 16, 2016 9:17 pm

    Not hearing anything is an odd feeling, I'm used to a little bit of hiss. With the M-125 the music just emerges. Wonder what two will sound like!!!

    Kentley

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    Age : 64
    Location : Worcester, MA

    Re: Tube Newbie

    Post by Kentley on Tue Aug 16, 2016 10:43 pm

    LeGrace wrote:Not hearing anything is an odd feeling, I'm used to a little bit of hiss. With the M-125 the music just emerges. Wonder what two will sound like!!!
    Twice as much quieter. drunken

    cci1492

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    Location : Bergen County NJ

    Re: Tube Newbie

    Post by cci1492 on Tue Aug 16, 2016 11:26 pm

    silence! I keel you!

    They are dead silent aren't they. Plus, they get noticeably better as they break in. So you'll be loving them even more later. I was a little surprised about that aspect.

    deepee99

    Posts : 1333
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Tube Newbie

    Post by deepee99 on Wed Aug 17, 2016 10:18 am

    LeGrace,
    You'll get more racket out of your pre-amp if it's not tubed and capped right than you ever will out of an M-125, the exception being, as Bob L noted, you've got a crummy tube or socket in the front driver slot. I too continue to be amazed at how quiet these puppies are. There's just nothing but music comes out of them.
    My routine is to fire up the pre-amp first, let it settle down for a minute or two, then light the M-125s. Shutdown sequence in reverse: power down the amps first to let the caps lose their charge, then turn the pre-amp off. At least in my set-up, it saves a lot of thumps, crackles and clunks.
    Sounds like you built 'er right. Congratulations.
    -d-

    Tube Nube

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    Re: Tube Newbie

    Post by Tube Nube on Wed Aug 17, 2016 8:22 pm

    It must be a satisfaction of near-spiritual proportions for Bob and Roy to witness the moment they "light" the filament in the heart of a new toobaholic.

    ;-)

    LeGrace

    Posts : 92
    Join date : 2016-08-07

    Re: Tube Newbie

    Post by LeGrace on Thu Aug 18, 2016 9:04 pm

    Working on the second M-125, much easier second time around. What's not easier is reverting to my old setup in the mean time, after that brief taste of tube sweetness! I see posts now about K120 tubes and copper rectifiers, I can see I'm just getting started!!

    deepee99

    Posts : 1333
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    Re: Tube Newbie

    Post by deepee99 on Fri Aug 19, 2016 11:02 am

    LeGrace wrote:Working on the second M-125, much easier second time around. What's not easier is reverting to my old setup in the mean time, after that brief taste of tube sweetness! I see posts now about K120 tubes and copper rectifiers, I can see I'm just getting started!!

    LeGrace, don't rule out the Gold Lion KT-88s for output tubes. They're a bit spendier than the Tung-Sol KT-120s (both are Russian re-issues) but in my completely subjective opinion they just sound a little sweeter. Jim McShane at http://mcshanedesign.net/ is my go-to guy for Russian tubes and he stocks both. Jim was recommended to me by Bob L. a few years back and is a pleasure to deal with.

    Another word to the wise, from one who's been there, don't go overboard squandering a lot of money rolling output tubes. It's tough on the sockets and the law of diminishing returns applies. There's always "something better" out there than what you've got, but you'll go bug-nutty and broke trying to find it. Been there, done that, got the T-shirt. Plus, I've found that the front driver tube has far more influence on sound quality than the output tubes. I would seek Bob L.'s advice on that for starters, then get 10,000 opinions on the forum.

    Again, congratulations on your first successful M-125 build. They really are a joy.







    LeGrace

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    Re: Tube Newbie

    Post by LeGrace on Fri Aug 19, 2016 11:51 am

    Thank you for the sage advice dp99! To illustrate what a total newbie I am when the time comes do I need to order a set of matched quads?

    deepee99

    Posts : 1333
    Join date : 2012-05-23
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    Re: Tube Newbie

    Post by deepee99 on Fri Aug 19, 2016 12:18 pm

    LeGrace,
    Matched quads are best, but McShane does that automatically. It's a matter of all the horses working equally in a push-pull circuit. "Matched" means simply that the tubes have roughly the same gain or amplification, so you don't have one weak tube holding back the healthier ones.
    The um gain matching compatibility need not apply to both M-125s. Just one matching quad for each one works fine. So if you get a quad of matched 80s, use them in one amp, and a quad of 90s, roughly matched, use them in the other amp.
    I'm a newbie and an amateur as well, so please verify what I'm telling you with Bob L. or McShane. But this has been my experience.
    Cheerio,
    Dave

    cci1492

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    Re: Tube Newbie

    Post by cci1492 on Fri Aug 19, 2016 12:42 pm

    LeGrace wrote:Thank you for the sage advice dp99! To illustrate what a total newbie I am when the time comes do I need to order a set of matched quads?

    Sorry for the somewhat of a hijack, as a newbie myself, here's a related question to your question LeGrace (thought it would be better to keep it here rather than start a new thread). Jim sent me 2 quad matched sets. Set 1: 95, 95, 95.5 and 96. Set 2: 94, 94.5, 93, and 93. On my M-125 amp 1/set 1, I have placed the 2 95s on the left side of amp 1(1 95 on the front left and the other 95 on the back left). The other 2 of this matched set 1 went on the right side of amp 1 (95.5 and 96 on right). Followed the same logic on amp 2 (94 and 94.5 on left, the 2 93's on the right side). Did I do this correctly or did I screw this up? I'm thinking maybe, the pairs (on each amp) go left and right instead of from and back?

    deepee99

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    Re: Tube Newbie

    Post by deepee99 on Fri Aug 19, 2016 1:17 pm

    Yes, the push-pull circuits operate as pairs, one pair on the front set of holes, the other on the pair of rear holes. So for closest matching, match the ones in front and then the ones in the rear holes. So if you have, say a pair of 97s, couple them up in the front holes, and a pair of 87s, put them in the rear holes, or vice-versa.
    Also, Bob L. recently advised that a lower bias setting than listed in the original literature, is to be preferred. If you're using two bias pots for front and back, that means around 1.1 as opposed to the earlier 1.2v setting, which means .55 per tube rather than .6. I let mine loaf at .5 each (1.0) total for each pair and it sounds just fine to me.
    If you're going to NOS Tung-Sol or GE 6550s, .45 per tube is best for their longevity, unless you're whanging on a guitar amp in an amphitheatre. Tubes get louder as you crank the bias up, but you're walking them to the graveyard.

    cci1492

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    Join date : 2016-05-09
    Age : 56
    Location : Bergen County NJ

    Re: Tube Newbie

    Post by cci1492 on Fri Aug 19, 2016 1:46 pm

    Ok thanks, I'll put them back the way I had originally had installed them.

    skriefal

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    Location : Utah, USA

    Re: Tube Newbie

    Post by skriefal on Fri Aug 19, 2016 10:39 pm

    Those tubes are so close that it probably wouldn't matter which tube you put in which socket. But it also won't hurt to strive for perfection!

    deepee99

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    Join date : 2012-05-23
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    Re: Tube Newbie

    Post by deepee99 on Sat Aug 20, 2016 3:21 pm

    skriefal wrote:Those tubes are so close that it probably wouldn't matter which tube you put in which socket.  But it also won't hurt to strive for perfection!
    Yes, Scott is right, um is not a big worry if the tubes are bought from a reputable dealer like McShane.. The first objective is to keep the bias in line. You can cook your tubes pretty quickly is it's too high. Once everything is set up right, set the bias to Bob's specs. Now, the bias readings will rise over the ensuing next hour or two as the amps heat up, so re-check and dial it down accordingly. Then you should be good to go.

    LeGrace

    Posts : 92
    Join date : 2016-08-07

    Re: Tube Newbie

    Post by LeGrace on Mon Aug 22, 2016 6:42 am

    Curse my newbieness. Right now sitting with a dead unit #1. Bob Latino is amazing though. I sent him a plea for help email, on a Sunday evening mind you, and he responded right away! Talk about commitment. I did get about an hour of listening time in before the fuse decided to let go. Just a little taste, but enough to make me appreciate what I have to look forward to once I track down whatever the issue is.

    LeGrace

    Posts : 92
    Join date : 2016-08-07

    Re: Tube Newbie

    Post by LeGrace on Mon Aug 22, 2016 4:51 pm

    Bob's your uncle! Back up and running now. The M-125's sound amazing! Will post pictures of my setup shortly...

    LeGrace

    Posts : 92
    Join date : 2016-08-07

    Re: Tube Newbie

    Post by LeGrace on Mon Aug 22, 2016 6:59 pm

    Another newbie success story. Had one minor hiccup along the way, but Bob immediately replied and got me through that one issue (thanks Bob!)  If I can do this anyone can! The M-125s sound amazing, talk about dynamic range ! Here are some images. I'm hoping these pictures show up OK (preview mode not showing anything):

    LeGrace

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    Join date : 2016-08-07

    Re: Tube Newbie

    Post by LeGrace on Mon Aug 22, 2016 7:41 pm

    Lets try that again....








    pedrocols

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    Re: Tube Newbie

    Post by pedrocols on Mon Aug 22, 2016 9:53 pm

    Congratulations! You have a very nice set up!!!! However, I would place the amps on the to shelf.

    Kentley

    Posts : 335
    Join date : 2015-03-06
    Age : 64
    Location : Worcester, MA

    Re: Tube Newbie

    Post by Kentley on Mon Aug 22, 2016 10:15 pm

    pedrocols wrote:Congratulations! You have a very nice set up!!!! However, I would place the amps on the to shelf.
    I'm sure Senor Pedrocols meant "top" shelf -- for heat dissipation. But it looks so darned nice the way it is.
    There's another solution - two small fans like these placed discreetly behind the M-125s. Many choices on Amaze-On.
    https://www.amazon.com/Coolerguys-Powered-Receiver-Component-Cooling/dp/B00DCCJQ0S/ref=sr_1_21?s=electronics&ie=UTF8&qid=1471918367&sr=1-21&keywords=computer+fan

    LeGrace

    Posts : 92
    Join date : 2016-08-07

    Re: Tube Newbie

    Post by LeGrace on Tue Aug 23, 2016 9:10 am

    Decided I had better adopt pedrocols suggestion, thanks. Gave the amps a several hours workout yesterday and they got super hot; and we all know what excessive heat eventually does. Yet another learning, boxing in high power tube amps like these is not an optimal arrangement! Anyway here's the new layout. I can actually touch the power transformers now! Plus I'm proud of my new amps, may as well let them share center stage! Even my wife approves!

    Now I can sit back and relax, and simply enjoy   cheers  cheers  cheers



    System components:
    Phono: Rega RP6 w/AudioMods Five tonearm, Dynavector Karat MC cartridge
    CD: Cambridge Azur 640C
    Integrated: Marantz PM11S1 (preamp section only)
    Speakers: Polk LSiM705, SVS subwoofer
    Pending: GFI with manual reset!

    Bob Latino
    Admin

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    Re: Tube Newbie

    Post by Bob Latino on Tue Aug 23, 2016 9:29 am

    Legrace,

    The change to having your amps up on the top shelf is a better idea .. The top of the amps should "look at the ceiling" for better heat dissipation. Having the amps up there also keeps them out of reach of inquisitive pets and toddlers ...

    Bob

    deepee99

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    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Tube Newbie

    Post by deepee99 on Tue Aug 23, 2016 9:47 am

    In hot weather (which we get about a week of in the Bitterroot Mountains here in northern Idaho, I'll often just pull the rear pair of tubes out and just run on the front bank. Gives the transformers and rectifiers a little breathing room and unless you're really wanting to crank things up into some inefficient speakers, you won't miss anything. Just be sure to re-bias the front tubes.

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