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    Driver tubes M-125 or?

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    ac2

    Posts : 28
    Join date : 2014-03-01

    Driver tubes M-125 or?

    Post by ac2 on Wed Mar 12, 2014 12:12 am

    Hey guys,

    Question, what tubes tickle your fancy?

    Lots of questions but I will list the few below. Please give comments, I would like to see if there is a general consensus on tube type/mfg/NOS vs NEW


    1- 12AU7 or 12BH7?
    2- NOS or current production?
    3- Brand?
    4- Source? (supplier if possible).

    Thanks guys!!!!!

    Bob Latino
    Admin

    Posts : 2374
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Driver tubes M-125 or?

    Post by Bob Latino on Wed Mar 12, 2014 9:47 am

    These are tough question to answer because everyone has an opinion. What tube sounds good in one person's amp may not (because of their hearing, different speakers etc.) sound as good in someone else's amp.

    1. 12AU7 (includes also 5963, 5814, 6189 and the Mullard CV4003) vs. 12BH7. Many like the 12BH7's because they are a physically taller tube than a 12AU7 but I don't hear any particular "sound quality advantage" to 12BH7's especially in the front (voltage amplifier) position of the M-125. In my own VTA M-125's I do use a GE 12BH7 in the rear phase splitter position. I use a Mullard CV4003 in the front position.

    2. In general NOS tubes will usually last longer than current production tubes. Some newer production tubes sound pretty good. With respect to 12BH7's, the ElectroHarmonix 12BH7 is the only current production 12BH7 tube. You have more brand choices in modern production 12AU7 driver tubes.

    3. You can still find NOS RCA, Sylvania or GE 5963, 5814 and 6189 tubes out there at reasonable prices. A lot of tube dudes do not know that these three tubes are 12AU7 "clones". Sometimes you have to weed out a noisy or microphonic tube but these three all work well in the VTA M-125's. Of the modern production driver tubes, I like the Russian made ElectroHarmonix tubes.

    4. For well tested tubes get in touch with one of our forum members "jimmcshane". Jim is a private tube seller with an excellent reputation for providing quality tubes to customers.

    Bob

    corndog71

    Posts : 444
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Driver tubes M-125 or?

    Post by corndog71 on Wed Mar 12, 2014 11:16 am

    Lately I've become a big fan of RAM Labs tubes. Roger Modjeski has been selling computer matched and selected tubes for decades and really knows his stuff. Just changing the driver tubes in my ST120 from NOS RCA Clear tops and new issue Genalex to RAM tubes made a huge improvement in clarity. My ST35 went through a similar transformation when going from new Genalex tubes to RAM tubes.

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Driver tubes M-125 or?

    Post by sKiZo on Wed Mar 12, 2014 6:20 pm

    My only issue with Ram Labs is they never actually get around to telling you what the base tube is before the do the testing and slap their logo on the glass. I've found that different OEMs have completely different characteristics, and it'd be nice to have a baseline to compare them with and give you some idea what to expect.

    In the meantime, my favorite set (of the week) is a 1960's RCA clear top in the center with a matched set of 1940's RCA foil getter 12AU7's on the sides.


    ac2

    Posts : 28
    Join date : 2014-03-01

    Re: Driver tubes M-125 or?

    Post by ac2 on Thu Mar 13, 2014 9:56 am

    Seems like I've been hearing a lot about the 60's clear top RCA 12AU7's.

    About 15 years ago I bought a bunch of Westinghouse 12BH7's I think from antique radio supply in az when they used to have large stock or inventory reduction sales.... I still have them somewhere put away.... amazing how the prices have changed.

    Thanks guys!

    corndog71

    Posts : 444
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Driver tubes M-125 or?

    Post by corndog71 on Thu Mar 13, 2014 10:28 am

    sKiZo wrote:My only issue with Ram Labs is they never actually get around to telling you what the base tube is before the do the testing and slap their logo on the glass. I've found that different OEMs have completely different characteristics, and it'd be nice to have a baseline to compare them with and give you some idea what to expect.

    I know what you mean but I think Roger is less concerned with tube brand than he is with tube performance. If it measures well enough for him then it should be relatively transparent. He's not opposed to tube rolling. But I get the impression that tube rolling is like rolling the dice and getting random results. It's fine if that's what you want to do but if you just want high performance tubes and aren't concerned with what's popular, then the RAM tubes are an excellent choice.

    ac2

    Posts : 28
    Join date : 2014-03-01

    Re: Driver tubes M-125 or?

    Post by ac2 on Thu Mar 13, 2014 11:54 am

    I had a Music Reference RM-9 years ago driving my Acoustat 2+2's and that's why I wanted the M-125. I am so glad I found these amps! Nothing less than 100wpc would do.

    I can't wait to get them up and running Smile

    Now if I can find a pair of accoustats....oh yeah Wink

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