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  • December 31, 2016 at 12:35 am in reply to: Wailer Wah adding white noise #122452
    Iron Mang
    Member
    Quote:
    Hi I had a question about the wailer wah. I just recently purchased it and I love the sound but it adds white noise/hiss to the pedal chain when bypassed and also turned on. The weird thing is that it only does this when placed before overdrive/dirt boxes but when placed after dirt boxes no added noise when bypassed or turned on. I was just wondering if this is normal for this pedal or not. Im not daisy chaining any effects, they are all on an isolated power supply. I also tried before and after dirt with just one dirt pedal and the wah with individual plug in power supplies, one for each straight into the amp. No noise with wah after dirt but with it before dirt a lot of noise bypassed and the effect engaged. And finally I tried it with just the 9 Volt battery supplied and still got the same results. I prefer the wah before dirt sound but it just adds a lot of extra noise and just wanted to know if this is normal. Thanks in advance.

    You have to remember that any time you put Wha pedal in front of a booster and/or distortion device, it’s going to amplify any noise including hiss or even become micro-phonic.

    December 30, 2016 at 10:54 pm in reply to: MEL9 direct into PA problem #122450
    Iron Mang
    Member
    Quote:
    This is crazy!
    It is like turning on the wall light switch and having the water start pouring out of the kitchen faucet!

    LOL exactly! I was trying to figure out if the reverb Channel or the effects loop with feeding signal back into Channel 4, but that doesn’t seem to be the case.

    December 30, 2016 at 8:25 pm in reply to: MEL9 direct into PA problem #122447
    Iron Mang
    Member

    Take a picture of the front end of the PA head?

    December 30, 2016 at 7:54 pm in reply to: MEL9 direct into PA problem #122445
    Iron Mang
    Member
    Quote:
    there is reverb! each channel has its own level control as well as a master reverb control. i turned all channel reverb to zero as well as the master and no change.

    and there is not an effects loop, there is just an effect send 1/4″ jack, no return.

    Since there is no Jack set up as return, is there one that says “power amp in”? If that’s the case plug in a guitar chord into the effects send and just leave it loose on the other end, not plugged into anything all. And if you have the same problem still, I give up.

    December 30, 2016 at 7:21 pm in reply to: MEL9 direct into PA problem #122443
    Iron Mang
    Member

    Last question, “is there reverb or an effects loop in this PA head?” If so turn off the reverb and shunt the effects loop if it has one. And I mean turn off the reverb/effects control in each channel and on the Masters. And then try it and see if you have the same issue

    December 30, 2016 at 7:03 pm in reply to: MEL9 direct into PA problem #122441
    Iron Mang
    Member

    Are the quarter-inch input jacks on the PA TRS or just TS?

    December 30, 2016 at 6:53 pm in reply to: MEL9 direct into PA problem #122439
    Iron Mang
    Member

    I have a question you referred to “bass amp” is that what you’re playing through? And is your instrument a bass or a guitar?

    December 30, 2016 at 4:29 am in reply to: 6CA7 EH Short? #122431
    Iron Mang
    Member
    Quote:
    One more note on the original post I made.
    That answer was from was from our resident tube genius Alan Otto.
    This man KNOWS hie stuff and is a radio buff like me.
    He had an additional comment you will find interesting.

    “The vintage Ampeg V-4 and V-4B amplifiers actually had damper diodes installed from the plate connection to ground at the power tubes to suppress any flyback spike that occurred to reduce the chance of the tubes arcing. We also incorporated the same type of damper diode circuit in the Sovtek Mig-60, Mig-100, and Mig-100H for the same reason. As far as I know, Marshall never used the damper diode flyback spike suppression in any of their amplifiers.

    Otto”

    The best part about working at EHX is you get to hang with all these people are brilliant in their field.
    ALWAYS work with people smarter than you. They pull you up:-)

    Those are good suggestion, what you are calling damper diodes I would call transient suppression and it does work well. Although in this case I actually took the tube and broke the envelope and disassembled it, “there was a loose piece of metalwork inside the the plate housing.” So in this particular circumstance I don’t think it would’ve saved anything.

    Another thing you can do and this only pertains to EL34 power tubes (true power Pentode) only, “you can connect the suppressor grid (G3) pin 1 to a negative supply i.e. the main output of the bias supply. This keeps an EL34 on a shorter leash and really extends the life of the Tube. With the quality of today’s current production tubes this is not a bad idea. But you have to remember that you cannot use this on a 6CA7 as it is actually a beam type Tube and you could have some major fireworks. If you do attach the suppressor grid to a negative supply you will need to re-bias the amplifier and a small heads up is that the amp will sound a little different, what I would consider “tighter”.

    December 30, 2016 at 2:21 am in reply to: 6CA7 EH Short? #122429
    Iron Mang
    Member
    Quote:
    Were not old were cool!
    HAHA
    Happy New Year!!

    Bill

    Ha ha! Well I think I’m a little old because I can still explain an ultra-linear output section to the young guys and they kind of get it.

    Happy new year and best wishes!

    John

    December 30, 2016 at 1:57 am in reply to: 6CA7 EH Short? #122427
    Iron Mang
    Member
    Quote:
    OMG what a story! Glad you made it through.
    I am an old ham radio operator and we also get shocked (burned) by radio frequency (RF).
    I touched a set screw in an antenna tuner while transmitting a 2000 watt RF signal.
    RF rather than run along the top of the skin, it burns a hole through the the skin and runs along the bone up your arm!!!

    HAHA this is funny we both have old high voltage war stories.

    That amp looks killer, aluminum chassis?

    Yeah I’ve never messed with any high-powered radio (RF) stuff. The highest powered AF tube driven equipment I worked on was a single channel 1500 W power amplifier. One of my uncles in the 60s was a sonar technician in the Navy and I got to go on board a ship that had three 50,000 W tube driven sonar amplifiers, “it was scary just being around those things!

    Yes I hand bent the aluminum chassis from scratch, my grandfather left me an old bench brake/bender. Sounds like we’re a couple of the older guys here! lol

    December 30, 2016 at 1:36 am in reply to: MEL9 Problem with isolated power supplies #122425
    Iron Mang
    Member

    I found it most commercially made so-called “isolated” power sources aren’t actually isolated. In order to be a truly isolated power source, each individual output must have its own AC supply, step down transformer, rectification, filtering, regulation, safety circuit and the really well-built ones may have an actual isolation transformer. A truly isolated DC power source are quite bulky, not to mention expensive.

    December 30, 2016 at 1:10 am in reply to: 6CA7 EH Short? #122424
    Iron Mang
    Member

    Pic 2

    December 30, 2016 at 12:08 am in reply to: 6CA7 EH Short? #122423
    Iron Mang
    Member
    Quote:
    Well great ! its working and hope no more trouble.
    Just be careful with the high voltage.
    As mom would say…always keep one hand in your pocket when you working on the inside of a tube amp chassis :-)
    I personally have been thrown off my chair with 500 volts.

    Well thank you very much for the input, I really appreciate it. Also thank you for the safety warning, but I will tell you that I’ve been building and repairing amplifiers for the last 25 years. I have a good zap story too, “when I was in college I was working on a Marshall major 200 watt, which had been unplugged for at least a week. Anyway there was loose B+ wire that bit me, the caps had so much charge in them that it cut a half inch long gash in my arm and cauterize the wound at the same time; I’m lucky that the same arm that got zapped was grounded to the chassis and it didn’t go through my chest.”

    This particular amplifier was a custom build that’s basically a 59′ Bassman front and with an EL34/6CA7 power section, and last year we installed the 6CA7 EH’s (which my customer loves) and I was wondering if there was any concerns or occurrences of heater to plate shorts in these tubes.

    Again thanks for everything’
    Iron Mang

    December 29, 2016 at 10:26 pm in reply to: 6CA7 EH Short? #122417
    Iron Mang
    Member

    (Update) I replace the power tubes with some EL34’s re-biased the amplifier and fortunately all is well. I’m going to continue to run it under load and make sure everything is fine.

    December 29, 2016 at 10:17 pm in reply to: 6CA7 EH Short? #122416
    Iron Mang
    Member

    Thanks for your response. I checked the tube sockets and there is no arc tracing on the top or bottom of the socket, “this has decent tube sockets in it (Belton).” and the correct load was connected at the time of the incident, all jacks and speaker cables are in good condition. I also opened up the back of the speaker cabinet to make sure there wasn’t anything wrong back there and again no issues. I took the output transformer apart to see if there is any obvious flyback burning or traces, and everything was okay there too. It’s just a really strange occurrence because the amplifier never moves and is always connected properly.

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Viewing 15 posts - 1 through 15 (of 15 total)