The Dynaco Tube Audio Forum

Would you like to react to this message? Create an account in a few clicks or log in to continue.
The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


5 posters

    Slight background crackle--can the source be a rectifier tube?

    jsl1234
    jsl1234


    Posts : 76
    Join date : 2017-08-28

    Slight background crackle--can the source be a rectifier tube? Empty Slight background crackle--can the source be a rectifier tube?

    Post by jsl1234 Mon Jun 07, 2021 4:00 pm

    So my VTA120 has worked flawlessly for three years until yesterday. While listening I detected a background 'crackle' in both channels.

    My first inclination was to pull the driver tubes and shuffle them around to see if the noise moved or even disappeared. For some insane reason I also pulled the rectifier tube at the same time. I then realized that this would complicate matters so plugged it back in.

    However in the process of plugging it back in, I somehow did not align it correctly (even though there is a tab on the tube base) and with the pins in the wrong holes turned the unit on.

    Rectifier tube did not light, even though the driver board tubes did along with the power tubes. I shut the until off, realized my mistake and re-inserted the GZ34 properly.

    Turned on the unit, but the GZ34 didn't light.

    Shut the unit down, inserted a fresh GZ34 and fired the unit up.

    Everything sounds fine now. Not sure if pulling/re-inserting the driver tubes cleared the crackle of if the original rectifier tube was going bad in the first place.

    Thoughts?
    peterh
    peterh


    Posts : 1599
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Slight background crackle--can the source be a rectifier tube? Empty Re: Slight background crackle--can the source be a rectifier tube?

    Post by peterh Tue Jun 08, 2021 1:00 am

    As the sound comes from both channels it should have a common cause. Powersupply is a possibility.
    Also bad contact in the mains supply ( fuse not ok, bad solders, bad power switch could cause this).
    Another common source is the bin electrolytic cap, and as you mentioned the rectifier tube, although
    a failing rectifier tends to self-destruct fast.

    jsl1234 likes this post

    Bob Latino
    Bob Latino
    Admin


    Posts : 3101
    Join date : 2008-11-26
    Location : Massachusetts

    Slight background crackle--can the source be a rectifier tube? Empty Re: Slight background crackle--can the source be a rectifier tube?

    Post by Bob Latino Tue Jun 08, 2021 8:46 am

    jsl1234 wrote:

    Everything sounds fine now. Not sure if pulling/re-inserting the driver tubes cleared the crackle.

    Thoughts?

    This is a distinct possibility .. The center driver tube affects BOTH channels and the fact that these driver tube pins have less surface area than the output tube pins makes them more susceptible to contact issues with the socket pins. Static and crackling noises can many times be eliminated if you remove the driver tube(s), clean the pins and reinsert the tube.

    Bob

    jsl1234 likes this post

    jsl1234
    jsl1234


    Posts : 76
    Join date : 2017-08-28

    Slight background crackle--can the source be a rectifier tube? Empty Re: Slight background crackle--can the source be a rectifier tube?

    Post by jsl1234 Tue Jun 08, 2021 9:10 am

    Thanks. Really wish I hadn't mucked with the GZ34 but that is water under the bridge. I don't have many hours on the unit taken as a whole, so was surprised when the noise started. Running it all day today to see if things are truly cleared up.
    MechEngVic
    MechEngVic


    Posts : 92
    Join date : 2019-01-16

    Slight background crackle--can the source be a rectifier tube? Empty Re: Slight background crackle--can the source be a rectifier tube?

    Post by MechEngVic Sat Jun 19, 2021 10:46 pm

    jsl1234 wrote:Thanks. Really wish I hadn't mucked with the GZ34 but that is water under the bridge. I don't have many hours on the unit taken as a whole, so was surprised when the noise started. Running it all day today to see if things are truly cleared up.

    So how's the amp?
    jsl1234
    jsl1234


    Posts : 76
    Join date : 2017-08-28

    Slight background crackle--can the source be a rectifier tube? Empty Re: Slight background crackle--can the source be a rectifier tube?

    Post by jsl1234 Sun Jun 27, 2021 8:43 pm

    Sorry for the late reply, on a road trip. Yes, it seems removing and reinserting the driver tubes cleared things up. As I mentioned I also replaced the rectifier tube so I’ll never be 100% certain which one was the root cause, but my money is on the driver tubes.

    MechEngVic likes this post

    avatar
    Rbertalotto


    Posts : 73
    Join date : 2021-02-25

    Slight background crackle--can the source be a rectifier tube? Empty Re: Slight background crackle--can the source be a rectifier tube?

    Post by Rbertalotto Mon Jun 28, 2021 7:28 am

    Is it advisable to use some type of dielectric grease on the tube pins to stop any type of corrosion?

    Sponsored content


    Slight background crackle--can the source be a rectifier tube? Empty Re: Slight background crackle--can the source be a rectifier tube?

    Post by Sponsored content


      Current date/time is Mon Dec 06, 2021 3:48 pm