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    Can I use 6922 Tubes in my VTA M125 driver boards?

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    Moots

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    Join date : 2017-04-23

    Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by Moots on Sun Apr 23, 2017 1:29 pm

    I was going to buy some 12AU7 tubes for my M125 driver boards, but I have (4) 6922 Electro Harmonix tubes here NIB. Just wondering if this is ok, or if it's a bad idea. Thanks in advance!
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    Bob Latino
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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by Bob Latino on Sun Apr 23, 2017 1:43 pm

    Moots wrote:I was going to buy some 12AU7 tubes for my M125 driver boards, but I have (4) 6922 Electro Harmonix tubes here NIB. Just wondering if this is ok, or if it's a bad idea. Thanks in advance!

    6922 driver tubes won't work in place of a 12AU7 ..

    Bob

    Moots

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by Moots on Sun Apr 23, 2017 1:50 pm

    Thanks Bob!
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    corndog71

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by corndog71 on Sun Apr 23, 2017 4:24 pm

    Curcio's driver circuit uses 6922 for what it's worth.

    GP49

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by GP49 on Mon Apr 24, 2017 1:02 pm

    Not worth too much...the pinouts differ. Pin 9 on the 12A*7 tubes is the centerpoint of the filament winding. Pin 9 on the 6922/6DJ8 is a shield between the two tube sections.
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    deepee99

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by deepee99 on Tue Apr 25, 2017 12:49 pm

    NOOOOOOOOOOOO!
    6922s are seriously over-priced, anyway.
    Why re-invent the wheel? Dr. Latino has come up with the best tube array for the circuits he and Roy have given us. Only mods I would consider after 5 years' fiddling with my first M-125s is upgrade the caps, do a little tube-rolling to get the sound you want out of the driver boards, slap a little wood around the chassis to make it more compatible with the XYL's taste in furniture, then leave the poor suckers alone. Bob and Roy gave a lot of thought to the basics. Mess with them at your own peril.



    Dogstar

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by Dogstar on Tue Apr 25, 2017 12:56 pm

    deepee99 wrote:NOOOOOOOOOOOO!
    6922s are seriously over-priced, anyway.
    Why re-invent the wheel? Dr. Latino has come up with the best tube array for the circuits he and Roy have given us. Only mods I would consider after 5 years' fiddling with my first M-125s is upgrade the caps, do a little tube-rolling to get the sound you want out of the driver boards, slap a little wood around the chassis to make it more compatible with the XYL's taste in furniture, then leave the poor suckers alone. Bob and Roy gave a lot of thought to the basics. Mess with them at your own peril.



    Is 'XYL' a millennial abbreviation for something?
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    deepee99

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by deepee99 on Tue Apr 25, 2017 2:01 pm

    What's a millennial, anyways? Someone born in 1900, or 2000, or on or before Jesus' birthday, er perhaps Mohammad's? Please do inform.
    "XYL" is an aulde PC upgrade to the more familial "OL.". When you're blasting Morse Code on a ham license around the planet, short-hand is critical so instead of keying "where are you from?" you just ask "QTH?.
    How's my signal? QSL and let's swap business cards and get together to confirm this conversation someday: QSO.
    OL meant "Old Lady," I term right up there with wife-beater T-shirts Then, when we discovered a woman who shared our passion for knocking about this crap, XYL became the new moniker of choice. Stands fer ex-young lady and you've snapped her up and will spend hours in the QTH and -------------------------------------------------------- when the bands are dodgy, light up up the Latino stereo.
    So, to make a long story longer, XYL means she's intelligent and beautiful and can sit for hours with you listening to Roy Orbison, And for some insane reason, she's my gal and is off the market. Ergo, the X.


    Moots

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by Moots on Tue Apr 25, 2017 4:11 pm

    depee99, I already had the 6922's just sitting around, that's why I was asking. I guess I don't understand what you meant by "do a little tube rolling to get the sound you want out of your driver Boards, but prior to that, you told me not to tube roll and accused me of questioning DR Latino's logic? I would never question DR Latino, unless I was trying to understand something better, but not to second guess him or Roy.

    But since I ha e your attention, I am on number12 on the M125 instructions, and it says "connect a 330K 1 watt resistor between lugs 1 and 2". What is meant by connect? It's like a "mechanical" connection with pliers? Do any of you have a picture of what the finished joints should look like on the SCM? (Step 12 on M125 instructions) and maybe how to clamp the parts together pre solder. And I am assuming one would tin the ends of wires to be landed? I am trying to utilize you guys and not have to bother Bob with a barrage of questions.

    Oh, one more question, the switches I have (on off and triode / pentode) are equipped with screws, is it acceptable / recommended to solder the wires to those lugs, or do you have to screw them down? I want to do whatever is the highest quality termination.
    Thanks again guys!
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    Bob Latino
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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by Bob Latino on Tue Apr 25, 2017 4:22 pm

    Moots wrote:

    But since I ha e your attention, I am on number12 on the M125 instructions, and it says "connect a 330K 1 watt resistor between lugs 1 and 2". What is meant by connect?  It's like a "mechanical" connection with pliers?  

    Make a mechanical connection with your pliers. Wrap the leads between the lugs and then crimp the leads onto the lug with a squeeze from your pliers so that the resistor will stay in place.

    Oh, one more question, the switches I have (on off and triode / pentode) are equipped with screws, is it acceptable / recommended to solder the wires to those lugs, or do you have to screw them down?  I want to do whatever is the highest quality termination.
    Thanks again guys!

    Those switches have screw connectors. You can just screw down the wire. The best way is to pre-tin the leads to hold the wire strands in place. Then wrap the lead under the screw in the CLOCKWISE direction. Then tighten the screw securely. If you want to add some solder after the fact, it is probably not necessary but won't hurt anything.

    Bob
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    deepee99

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by deepee99 on Tue Apr 25, 2017 4:37 pm

    Those switches pass a very high volts, use with care.
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    corndog71

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by corndog71 on Tue Apr 25, 2017 4:55 pm

    For most of the point-to-point connections of these amps you want a good physical connection before soldering.  For excess cap/resistor leads I use a nail clipper to trim them.

    I think millenials are those born after 1981.  

    I didn't realize 6922's were overpriced unless you consider $30-35 overpriced.

    GP49

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    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by GP49 on Tue Apr 25, 2017 11:23 pm

    Dogstar wrote:
    Is 'XYL' a millennial abbreviation for something?

    XYL is longtime ham radio slang.  A YL was a single, Young Lady but when you married her, she became your ex-YL..."XYL."

    Both my XYL and I are "ex-young" after decades of marriage.

    The less I know about Millennials, the better.
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    deepee99

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

    Re: Can I use 6922 Tubes in my VTA M125 driver boards?

    Post by deepee99 on Wed Apr 26, 2017 2:16 pm

    73 to that one.

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