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    Favorite driver combo?

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    Maintarget

    Posts : 209
    Join date : 2013-02-10

    Favorite driver combo?

    Post by Maintarget on Mon Dec 23, 2013 12:10 am

    Listening to Jimmy Vaughan on a  ST-120 with 140 hours with 3 matched Sylvania  12BH7 this thing just keeps sounding better every time I listen to it incredible!
    Whats your favorite driver tube combo?

    Bob Latino
    Admin

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    Join date : 2008-11-26
    Location : Massachusetts

    Re: Favorite driver combo?

    Post by Bob Latino on Mon Dec 23, 2013 9:26 am

    This is a really hard question to answer .. First of all I don't recommend doing much "tube jockeying" until the amp has fully broken in. If you do try different driver tubes while the amp is breaking in, you are "chasing a moving target". After 200 hours or so of play time the sound of the amp will stabilize AND you will be very familiar with how the amp sounds.

    Certain driver tubes that sound good (to you) in your system may not sound good to someone else in their system. Sometimes you may need a brighter tube to compensate for speakers that don't have much top end. Sometimes the reverse is true? The tweeters on your speakers are too hot and you need a softer sounding tube to compensate.

    The CENTER (voltage amplifier for both channels) driver tube has the most influence of the three, I would suggest at first just trying different center driver tubes on the VTA ST-70 or ST-120 before you start changing out the two side driver tubes. On the M-125's the FRONT driver tube is the one to try different tubes in.

    In these amps you can use any 12AU7, 12BH7, 5963, 5814, 6189, CV4003 driver tube in any of the three driver positions. Which one might be best for your system cannot be determined in advance. You will have to try them on your own and then be objective when listening. I would suggest you play the same few (3 to maybe 5) tracks you are familiar with after each tube change. Maybe have others listen also. They may not hear a change in the amp the same way you do ?

    Bob

    sKiZo

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

    Re: Favorite driver combo?

    Post by sKiZo on Mon Dec 23, 2013 3:40 pm

    I'm afraid I'm one of those "chasing a moving target" ... although I'm getting real close to the 200 hours now. My "favorite" combination of the day is an Amperex Holland 12AU7 in the middle with matched Sylvania 5814a's triple micas in the sides. Great soundstage and warmth, with boatloads of realism and good pop on the vocals.

    My room does tend toward shrill, so one of the targets is taming that ... these do that nicely. Sometime soon I've gotta do some work on the reflection points, but this also works nicely.

    Is there a break in required for drivers?

    Maintarget

    Posts : 209
    Join date : 2013-02-10

    Re: Favorite driver combo?

    Post by Maintarget on Mon Dec 23, 2013 4:44 pm

    I'm not surprised that break in is closer to 200 hours based on my own experience, for me I noticed a difference in sound at about 75-80 hours and then at around 105-110 hours with kit supplied tubes and no other changes.
    My system sounded a little bright and shy on bass using the supplied 5814s, I'm using mid 70s horn loaded Klipsch Heresy's speakers with re capped cross overs that have a reputation for what I'm describing and why I decided to change driver tubes.
    IMHO this made a positive change in correcting what I feel were short comings of my system, My wife who enjoys the music (but that's were it ends) validated for me the change when she noticed an improvement in the sound shortly after rolling in the 12BH7s (She had no idea I did this)   
    I listen to MP3 & FLAC files on a MAC with a Dragonfly DAC and have noticed the quality of the original recording makes a big difference in the sound quality.
    I asked about favorite driver tubes & combinations others are using more because of curiosity and to learn about others systems.
    I really enjoy this forum, thanks for your help!
    sKiZo I have a Amperex Holland 12 AU7 waiting to be rolled in at some point can't wait.
    Merry Christmas & Prosperous new year to you All!

    sKiZo

    Posts : 1312
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Favorite driver combo?

    Post by sKiZo on Mon Dec 23, 2013 5:52 pm

    I'm afraid Bob & Co have created something of a monster here ...



    Something like 230 possible combinations keeping matched tubes in the sides, if my math is correct ... I should probably think on picking up on some socket savers ...

    Maintarget

    Posts : 209
    Join date : 2013-02-10

    Re: Favorite driver combo?

    Post by Maintarget on Mon Dec 23, 2013 7:16 pm

    Great tube storage idea!

    TMadden

    Posts : 99
    Join date : 2011-12-22

    Re: Favorite driver combo?

    Post by TMadden on Mon Dec 23, 2013 8:20 pm

    sKiZo,

    Just got to say, I like your style!

    sKiZo

    Posts : 1312
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Favorite driver combo?

    Post by sKiZo on Mon Dec 23, 2013 8:40 pm

    Just an old Mouser box with foam pipe sleeve cut to size ... cheap and available at any hardware store. Works nice!

    Not sure how the labels will hold up to the stuff, but it'd be easy enough to cut the tube so it fits over the pins and stops short of any delicate printing ...

    Bob Latino
    Admin

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    Join date : 2008-11-26
    Location : Massachusetts

    Re: Favorite driver combo?

    Post by Bob Latino on Mon Dec 23, 2013 9:18 pm

    The 9 pin PCB ceramic tube sockets on all the VTA amps are made for "tube jockeys". The composite photo below shows the type of 9 pin ceramic tube sockets used on all VTA amps at the TOP of the photo. The reason these are used is that you can bend in the two pin holders from the side with a small flat jewelers screwdriver should they become a little loose from repeated tube changes. The lower part of the photo shows the other type of ceramic 9 pin PCB tube socket. These have a smaller hole which does not allow you to get a small screwdriver in there to retension the pin holders in the socket.

    To retension the pins on the socket I usually use TWO small flat bladed screwdrivers and push the two pins towards each other a little on all 9 positions. This will give you better tension on the pins ..

    Bob




    kaner

    Posts : 88
    Join date : 2011-09-20

    Re: Favorite driver combo?

    Post by kaner on Mon Dec 23, 2013 11:30 pm

    I'm probably at about 200 hours on one of my high gain ST70's. About a month ago I lost one of the driver tubes and subbed in a NOS RCA 12at7 black plate. I can't do a side by side but I swear the mids are much cleaner. I also have a NOS Raytheon that I will give a try.

    Merry Christmas!

    sKiZo

    Posts : 1312
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Favorite driver combo?

    Post by sKiZo on Tue Dec 24, 2013 12:49 am

    Hey, if someone were to start a Driver of the Month Club, I'd be a charter subscriber.  

    I do have a very nice Telefunken that's a bit bright for the room, but has incredible width as a center driver. Gives me incentive to go ahead and do some tweaking to the hardscape in the listening room.

    Of course, I'll probably end up with a dozen or so different diffusers that have different sonic properties that I can roll as needed ... hmmmm ... have to come up with some clever way to store them ...  geek 

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 60

    Re: Favorite driver combo?

    Post by dougmon on Tue Dec 24, 2013 1:12 am

    I'm also one of those guys who tried to hit a moving target. I replaced the driver tubes on a newish VTA-70 because of my unfounded fear that one of the driver tubes was bad. But I think I'm going to give it 3 or 4 more months before I try anything else. It's not worth experimenting yet.

    If anybody wants to start a thread about stockpiling NOS rectifiers, though, I'm in.


    Last edited by dougmon on Tue Dec 24, 2013 1:13 am; edited 1 time in total (Reason for editing : clarification)

    nerpissad

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    Join date : 2012-09-16
    Age : 43
    Location : amsterdam

    Re: Favorite driver combo?

    Post by nerpissad on Tue Dec 24, 2013 7:31 am

    after my ST70 amp had just broken in (+/- 300 hours) I decided to change the driver tubes. I had been reading about how the driver tubes have the largest influence on the sound so thought I'd go luxurious. I have a telefunken as the center driver and two mullard cv4003 as side drivers.
    doing side by side comparisons is hard when you only have one amp, but the night and day differences I was, naively, expecting never surfaced.
    although I can see the fun and charm in collecting and looking for nice tubes, the benefits are marginal to me.

    Maintarget

    Posts : 209
    Join date : 2013-02-10

    Re: Favorite driver combo?

    Post by Maintarget on Tue Dec 24, 2013 1:10 pm

    Maybe instead of asking about driver tube recommendations we should compare hearing tests I have 25 years worth from work Laughing 
    sKIZo I kind of like your idea of driver of the Month club............

    arledgsc

    Posts : 340
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Favorite driver combo?

    Post by arledgsc on Tue Dec 24, 2013 8:36 pm

    In the ST-120 I am currently off the NOS bus and running a Shuguang Black Treasure CV-181 (6SN7 type with tube socket adapter) in the center slot and Psvane 12AU7s as phase splitters.  Really like the sound!

    frank

    Posts : 95
    Join date : 2011-02-14
    Location : Pacific Northwest

    Re: Favorite driver combo?

    Post by frank on Tue Dec 24, 2013 11:40 pm

    My amp is different from most (all?) of you guys. It uses EF-86/6267 tubes for drivers. My favorite combo uses 1 Cifte(Mazda?) 12AU7 for the center tube, and Mullards for the drivers.

    The Mullards are now in "Tube Heaven", so I am using Amperex "Bugle Boy" tubes in their place. Like them too.

    I would recommend a try of the Cifte tubes. I think they're great.

    sKiZo

    Posts : 1312
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Favorite driver combo?

    Post by sKiZo on Wed Dec 25, 2013 12:18 am

    arledgsc wrote:In the ST-120 I am currently off the NOS bus and running a Shuguang Black Treasure CV-181 (6SN7 type with tube socket adapter) in the center slot and Psvane 12AU7s as phase splitters.  Really like the sound!

    For that kind of money, I'd expect them to lick my ears and call me daddy ...  tongue 

    Interesting combo though ... what adapter did you use? I see they offer them in 6.3v and 12v ... might be a fun experiment with a cheaper alternative to the SBT ... yikes!

    Then again, some say the center driver IS the most important tube ...


    arledgsc

    Posts : 340
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Favorite driver combo?

    Post by arledgsc on Wed Dec 25, 2013 4:09 pm

    "what adapter did you use? I see they offer them in 6.3v and 12v ... "
    The Psvane 12AU7s are expensive but knocked the CBS Hytron 5814s out of the phase inverter position.  So they are no slouch.  

    I got the BT CV-181 used off Ebay.  Low hours and turned out good for 1/2 price.  I want to try some NOS 6SN7s Sylvanias one day and see what all the hubbub is for that tube.  The Treasure sounds mighty good though so no rush.

    The 6SN7 to 12AU7 adapter was again off Ebay from seller "happydiy98".  It was a gamble but works great.  You definitely want the 6SN7 version (6.3V heater) and not the 12V heater 12SN7 wiring.   The seller sent me an Ebay message confirming my choice after purchase and I did ohm it out before use.  You won't be able to use three CV-181s as there is not enough room in the ST-120 but may can squeeze in three regular 6SN7s.  An adapter is highly recommended for further exploration of tubes in these amps!  And Roy has a low gain board with 8-pin sockets if you fall in love.


    tubes4hifi
    Admin

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    Join date : 2008-11-30

    Re: Favorite driver combo?

    Post by tubes4hifi on Thu Dec 26, 2013 9:36 pm

    for the price of 3 of those adaptors it would cost about the same just to buy the complete VTA70 octal driver board and parts kit !!

    Donkeyshins

    Posts : 19
    Join date : 2011-07-18

    Re: Favorite driver combo?

    Post by Donkeyshins on Mon Dec 30, 2013 3:36 pm

    Granted, I'm using a DIYTube board (12AX7 driver + (2) 12AU7 phase splitters), but the combination I've found that works the best in my system is an RCA triple-mica 5751 for the driver and a pair of RCA black-plate 12AU7 tubes for the phase splitters. All tubes were salvaged out of some Tektronix preamplifier modules I picked up at a salvage so (a) they were treated gently and (b) they are highly matched.

    -D

    sKiZo

    Posts : 1312
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Favorite driver combo?

    Post by sKiZo on Mon Dec 30, 2013 4:56 pm

    Thread should be renamed "Favorite driver Combo of the Day"  tongue 

    *** ST120 ***

    I just stumbled across another one that's by far my favorite ... so far. Still have the Sylvania triple mica JHS5814a's in the sides, but went with a GE McIntosh 12BH7 in the middle. Very tight bottom, great mids, and a bit dark at the top - still plenty of treble, but no ringing or screaming.

    That's with the TungSol KT120s and a Mullard GZ37 rectifier.

    What surprised me is the improvement in the sound stage using a 12BH7 in the splitter position ... it was my understanding that was a bit of a weak point with that tube type. So much for rumors. Not as noticeable with the "rock anthems", but instrument placing on orchestral works is very defined and piano is simply outstanding ...

    He shoots ... he scores!!  cheers

    deepee99

    Posts : 1337
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Favorite driver combo?

    Post by deepee99 on Thu Jan 09, 2014 3:05 am

    Haven't even tried rolling driver-board tubes in the 125s yet; thanks for the observations. 'Stead of Tube of the Month Club maybe we should establish a tube-lending library ...

    sKiZo

    Posts : 1312
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Favorite driver combo?

    Post by sKiZo on Thu Jan 09, 2014 8:14 pm

    Yah ... I'm sure we'd all jump at the chance to throw our favorite tubes into the mailbox and keep our fingers crossed ...  clown 

    I just got a new favorite set of drivers ... picked up on a well matched pair of 1940's RCA black plate 12AU7's with foil getters. I'm running those with an Amperex BB in the middle. Very smooth and exceptional sound stage.  

     pig  I swear ... those are the last set I'll buy!   pig

    deepee99

    Posts : 1337
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    Location : Wallace, Idaho

    Re: Favorite driver combo?

    Post by deepee99 on Thu Jan 09, 2014 8:30 pm

    sKiZo wrote:Yah ... I'm sure we'd all jump at the chance to throw our favorite tubes into the mailbox and keep our fingers crossed ...  clown 

    I just got a new favorite set of drivers ... picked up on a well matched pair of 1940's RCA black plate 12AU7's with foil getters. I'm running those with an Amperex BB in the middle. Very smooth and exceptional sound stage.  

     pig  I swear ... those are the last set I'll buy!   pig

    Yeah, and the check is in the mail!

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