Crate Vintage Club...

Discussion in 'Amps and Cabs' started by jmac006, Oct 14, 2008.

  1. jmac006

    jmac006 Member

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    I know I posted this in a couple other forums, so sorry if you're reading this again...

    OK, so for those of you who didn't read my previous threads, I picked up a used Crate VC50H a couple weeks ago and the thing sounds absolutely great with new tubes through my new avatar cab. My only problem now is that whenever I play it for about 45 mins to an hour, the volume will start to cut in and out sporadically. I've read on the Internet that these amps seem to have this problem quite frequently and that it's an overheating issue within the head. (I've even tested that it is in fact an overheating issue by standing up a floor fan right next to it and the volume issues ceased almost immediately.)

    So my question is, firstly, has anyone here had this same problem with this amp? If so, how have you gone about fixing it? I absolutely love the tone of this amp and I want to do everything in my power to keep it alive. I got a sweet deal for it, so I figure I could put a little more $$$$ into keeping it going.

    Secondly, I've toyed around with the idea of mounting a fan within the amp head to prevent this from occurring. Would this be a very difficult task? Has anyone installed an internal fan into their amp head before? I have actually got an extra 12v computer fan lying around the house that I figured I could use for this if it isn't too technically difficult. I would love if it would just switch on with the amp when it powers up to ensure proper air circulation from the get go.

    Any help on this one would be greatly appreciated. Thanks everyone!

    J
     
  2. jmac006

    jmac006 Member

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  3. rockon1

    rockon1 Member

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    Ive got two VC50 heads. Ones actually my sons but as far as mantainance goes its mine! lol! Niether have experienced an issue like you described.
    Mine has no fan and no problems.I installed a 120 volt fan with a switch on my sons. Half the time he forgets to turn it on but no problems.

    A 120v or even 220v(so it will run slower) fan is easier to wire in.

    It seems your amp has a problem that show's itself when it gets good and warm. Perhaps a bad solder joint or something. Does this happen on both channels? Bob
     
  4. CBTWOYOU

    CBTWOYOU Member

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    I just bought a VC50H off of e-bay a couple of weeks ago, it had the exact same problem. I took a look inside and found some capacitors (cheap plastic top) that had bubbled up, probably from the heat. I replaced all five and put in new tubes and have had no problems since. Only problem is, I don't know if it was the tubes or the caps, I would try replacing the tubes first if I were you, the cap job was time consuming and I had to modify the inside of the cabinet for the quality metal top replacement caps to fit. A great sounding amp though!
     
  5. rockon1

    rockon1 Member

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    Good point. First thing I do with a used amp is replace the tubes. (power at least)
     
  6. Wesman61

    Wesman61 Supporting Member

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    I had the same problem with My VC5212. Someone told Me it was due to dirt and grime in the F/X loop jack. I cleaned it with electronic cleaner and haven't had a problem since.
     
  7. rockon1

    rockon1 Member

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    A bit of a recap...

    The amp gets warms loses connection perhaps as things expand.Hopefully at the tube sockets,FX loop jack,etc- not a solder joint or something else. Simple stuff first. Get some new tubes. (Even iif its has nothing to do with the problem you'll need them.) Clean poor connections. As guittguy1 pointed out FX loop contacts can be a culprit. A bit of electrical contact cleaner may help this. On regular FX loops a simple patch cord in the loop will "troubleshoot" this but unfortunately the VC has an insert (tip,ring,sleeve) style FX loop. Its also a good idea to spray a bit on the tube pins and work them in and out a few times to clean the sockets. HTH-Bob
     
  8. Jay Mitchell

    Jay Mitchell Member

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    Ditto. I've got two VC3112s, and they both had the issue. Cleaning the contacts in the footswitch jack fixes it. If you're on the gig and the problem occurs, you can fix it immediately by plugging in the channel footswitch.
     
  9. jmac006

    jmac006 Member

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    Yes it does happen on both channels.

    Thanks! I'll tear it open tonight and check the caps and see if they all look like they're intact. I have already tried replacing the tubes with new ones and I am still having the volume problem.

    The first time I stumbled upon this volume issue, I had a footswitch plugged in... I don't know if this rules the 'cleaning the footswitch contacts' method out or not... I'm sorta thinking I might as well clean the footswitch contacts while I'm in there though. Any contact cleaner in particular that you all might recommend to me? I heard that Deoxit stuff works well, anyone else have experience with this stuff?
     
  10. rockon1

    rockon1 Member

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    Even radio Shack Contact cleaner works well enough. Dont forget to clean the FX loop jack contacts as well as the tube sockets with it. After all this if it still occurs you may have a bad solder joint or something else(obviously).
     
  11. jmac006

    jmac006 Member

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    Sounds good, I think I've got some contact cleaner lying around the house somewhere... I actually just got a schematic for my vc50h from the Crate people, so I'm going to poke around and see if there are any loose connections/bad solder joints.

    Any other suggestions anyone?
     
  12. CBTWOYOU

    CBTWOYOU Member

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    Just some additional info about what I found when I removed the chasis, five green plastic topped caps, four are 450mV and one (the big one) is 10000mV, I'm not positive, but I think the big cap is for the channel switching and it was the one that was bubbled up on the top (normal top should be flat), also, a reminder, if you are not comfortable and knowledgeable about working on cicuit boards you should just take it to a tech, a discharging capicitor can contain enough voltage to hurt or even kill someone. Good luck!
     
  13. waylay00

    waylay00 Member

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    The VC50H is the first tube amp I ever owned. It's such a great amp for the money! Very AC30-ish cleans and a nice overdrive channel.

    I've noticed that mine gets very hot, but I haven't yet encountered any problems. What should I do to prevent any from occurring?
     
  14. mvd18969

    mvd18969 Member

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    I used to have a Crate G40CXL solid state combo and it did the EXACT same thing. I'm not sure how far back the VC series goes, but I do recall a tech telling me that a lot of Crate amps had this phantom volume cutting problem. It wasn't limited to just their tube gear.
     
  15. nomadh

    nomadh Member

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    Yes my tube amp is also fine but crate my s/s G80 also has the cut out problem. So far it also seems connected to the line in/out jacks. Thats how crates stay so inexpensive. It seems adding decent jacks nearly doubles the price for crate. Funny I can get a nice switchcraft on ebay for a few dollars.
     
  16. Wesman61

    Wesman61 Supporting Member

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    As far as controlling heat I have a question. Since the amp is cathode biased it would obviously be tricky to implement adjustable bias. Also since tubes vary would tubes that draw less current in a given circuit cause the tubes and therefore the amp to run cooler? I had read in Gerald Weber's first book where He talked about trying different tubes in a tweed Champ to get the idle current He wanted. Just a thought.
     
  17. jmac006

    jmac006 Member

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    so here are a couple of gut shots of the amp in question...

    [​IMG]

    [​IMG]

    To me, it looked like everything was in good shape. I tried cleaning out the input and footswitch jacks with contact cleaner, so i'm going to try and test it out tonight (wanted to give it enough time to dry and everything... don't know if this is necessary or not.) Well anyways, while i was in there, i also noticed that the reverb tank was shot, so i ordered a new accutronics tank for it.

    Anything look out of the ordinary on these pics to anyone?

    Thanks!
     
  18. Wesman61

    Wesman61 Supporting Member

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    Looks like there's been some over heating around those diodes below the 3rd filter cap from the left (big dark blue cylinders) in the second pic. That looks to be related to the filament supply if I'm reading the numbers right. If the volume drops are abrupt then it's probably nothing to do with the filament.
     
    Last edited: Oct 16, 2008
  19. jmac006

    jmac006 Member

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    What would these overheating diodes effect? Is this something that can be easily fixed?
     
  20. rockon1

    rockon1 Member

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    The VC50 is fixed bias without an adjustment pot from what I remember. It could be running too hot though if the bias hasnt been checked. A fan never hurts though too. Bob
     

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