Vox Ac30 CC2 users

Discussion in 'Amps and Cabs' started by Supern00b, Aug 7, 2008.

  1. Supern00b

    Supern00b Member

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    Hey,

    I was running a strat thru a vox yesterday and I was shocked to see how thin it sounded....any pointers?
     
  2. Supern00b

    Supern00b Member

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    ok, well not rly thin
    more tinny. absolutely no headroom, even with the volume down.
     
  3. Lyle Caldwell

    Lyle Caldwell Member

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    It's very easy to sound horrible with an AC30, especially if you are used to Fender/Marshall tonestacks.

    Set Treble and Bass to about 2:00 and set the Cut to about 11:00 (clock positions from the rear of the amp) and try from there.
     
  4. Mike Dickerson

    Mike Dickerson Member

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    Better yet, try one with some of Lyle's mods. Especially the treble cap mod. Big difference.
     
  5. re-animator

    re-animator Senior Member

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    put the master on full. If you want to keep the volume low, just keep the channel volume low (for cleans).


    If you need a little bit more heft, blend in some of the normal channel.
     
  6. stratocaster

    stratocaster Member

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    Agree with everything said previously especially the treble cap mod, i almost exclusively play Strats through my CC2 and the TB channel was horribly thin (and unusable IMO) before the treble cap mod, now it sounds fantastic, another little trick is to use a decent (thick-ish sounding) Chorus pedal; speed set at 1-2, depth at 3-4, mix at 3-4, fattens up the sound without givin any actual Chorus effect.
     
  7. Randy Van Sykes

    Randy Van Sykes Member

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    Hey Lyle, I was wondering if you know where the bright cap is so I can remove it from the AC15 Heritage.

    Thanks!
     
  8. sqadan

    sqadan Member

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    I love my Strat through my AC30CC2... IMO, the trick is to plug into the TB input and use the input link feature - this fattens up the sound a bit..

    Also, I'll echo previous posters on the cut control and treble control.... just roll them off till the shrillness diminishes.... I don;t think this amp really needs any mods - except for some weight reduction!
     
  9. FAC

    FAC Member

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    Agreed. The tone controls are interactive, so boosting the treble acts to cut the mids, and visa versa...very different from the typical Fender or Marshall tone stack. Don't EQ by eye, EQ by ear, and don't be afraid to really crank those tone controls around to hear how they interact.
     
  10. tzamosti

    tzamosti Silver Supporting Member

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    Am I the only one to play my AC30CC2 through the normal channel? I think with a few add-ons, it sounds fantastic.

    Definitely have the cut around 9:00 (if you are looking at the front), cutting a lot of the shrill cristaline sound, but leaving just enough chime. I have the master on full. Gain volume around 4-5 (clean but with some girth). I rarely play straight through. Always have my Vanamps Solemate reverb--just a touch, usually a bit of slap-back delay in the background, MDEQ eq'ing it and often my BJFE comp. Then, add OD to taste (TA-100, Timmy or BJFE HB). Yup, that's my sound.

    Oh...this is with a tele.
     
  11. Lyle Caldwell

    Lyle Caldwell Member

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    Across lugs 1 and 2 of the TB volume pot.
     
  12. Randy Van Sykes

    Randy Van Sykes Member

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    Thanks! I'll check it out.
     
  13. Supern00b

    Supern00b Member

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    what will takin the bright cap out help?
     
  14. Leonc

    Leonc Wild Gear Hearder Gold Supporting Member

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    I've not tried Lyle's mods but only hear great things about them. That being said, I'm able to get sounds from my AC30 CC2x with my strat that I don't consider thin at all (though it certainly can sound that way if you don't set it up well).

    First make sure there's nothing wrong with the amp or tubes by setting it up to get a decent sound with a humbucker guitar, such as a Les Paul or 335. Try playing through the normal channel and turn up the Cut; set the Treble and Bass to taste.

    Assuming you're able to get a good, non-thin sound with guitars like those, it should only take a wee bit more tweaking (if any) to get your strat (or Tele!) sounding GREAT too. If you can't get a humbucker guitar sounding good and non-thin, then you may have other issues (e.g. tubes or speakers).
     
  15. Lyle Caldwell

    Lyle Caldwell Member

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    It's a bit complicated.

    First, know that a "treble bleed cap" is placed across a volume pot because the sound of an amp's preamp naturally gets darker as you turn down the volume. This is a combination of the Fletcher-Munson effect (google) and the changing impedance in the circuit as the volume is turned down.

    So amp manufacturers commonly put a cap across the input and wiper of a volume pot to retain highs at lower volumes. As the volume pot is turned up, the cap plays less of a role.

    In theory, the goal is to use a cap that maintains a more or less consistent sound throughout the range of the volume knob.

    Historically, a Fender Twin Reverb uses a 120pf cap here, and an AC30 TB uses a 100pf cap.

    The CC uses a 120pf cap, which is noticeably brighter than a 100pf.

    Now, to add to the complications:

    1) The taper of modern pots is different than the pot used by JMI, so the 120pf cap is a lot brighter at the same volume than the 100pf used by JMI was. The difference is greater than just the straight difference between 100pf and 120pf.

    2) Modern tubes are brighter than Mullards were/are.

    3) CCs have relatively new speakers, which tend to be bright.

    Now, I have tried putting a 100pf cap across the control, per the JMI spec, but in practice, even with Mullards in the CC, the sound is still brighter than a JMI (I did my initial comparisons with a '67 Top Boost, then a '65 Top Boost). So to make the CC sound like the JMI you either have to decrease the value of the bright cap or you have to replace all the pots with old stock pots with the correct taper. As changing the pots is costly even when possible, and a new cap is inexpensive, I recommend changing the cap.

    (these factors also affect the TBX series)

    In my direct comparisons, I found that a 68pf cap in conjunction with the modern pot taper sounds the most like the 100pf cap in conjunction with the vintage JMI pot taper.

    You can of course do darker than this - some like a 47pf, some like a 33pf, and some like no cap at all.

    On the CCs I mod I make it switchable between a 68pf and no cap at all.

    As to why someone wants it darker and the next wants it brighter, it depends on what volume they play at (do they have the volume at 9:00? 11:00? 1:00? Makes a big difference in percieved brightness) and what guitars they are using (a Tele may be too bright when a Les Paul sounds its best, etc).

    Thanks for all the kind words, guys.

    I do think I should point out that while I make a lot of mods publicly available (see www.voxmods.com), if you have me revoice an amp for you, be it a CC or a TBX, I do more mods than I have "given away" on the internet. Some are proprietary, and others are complex enough that anyone who has any business tackling them him/herself already knows enough that they don't need my instructions.

    As to my "proprietary" mods, these are a collection of things I have noted in actual JMIs that happened to be particularly good sounding amps. So while some of them are deviations from the JMI schematic, they replicate what I have found in actual JMI amps. In a 40 year old amp, resistor values change - some go up, some go down. When an amp sounds particularly good, I find out why. Just as a for instance, if a good sounding amp has a 238k plate resistor when the schematic calls for a 220K, I may put in a 240k resistor. That's not an actual value I use - just a "for instance". Anyway, I'm always glad to share, but I have to keep some good stuff for myself.
     
  16. Lyle Caldwell

    Lyle Caldwell Member

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    I need to mention that this works best in conjunction with changing R6 and R7 in the CC from 100K to 220K. But it still works fine as a standalone mod.

    In the AC15CC, only change R6 to 220K, and replace R23 (220K) with a 180K resistor, or put a 1M across R23 to get the same effect. This changes the AC15CC from having a "Cut" control permanently set at the brightest sound to having one at about 11:00 (viewed from the rear on an AC30) which is a much more usable sound. Still plenty of top end, but no ice pick, and no fizziness with drive pedals.
     
  17. Supern00b

    Supern00b Member

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    damn lyle, that's too deep for me!

    haha, well, I remember buying an electronics swap kit from RS, and they had a little cap for my Volume pot to retain highs @ low volumes, but it sounded too bright overall.
     
  18. Gasp100

    Gasp100 Silver Supporting Member

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    Well, coming from someone who just got a used AC30 this week and was on the verge of selling it I will chime in and agree with all the other posts here. I played the amp last night with a humbucker guitar and it sounds freaking fantastic out of the box. I think the normal channel is a winner and might be worth the price of the amp alone. I also think they really dropped the ball with the initial tube compliment of bad Sovtek tube rec <there are some posts about this one possibly damaging the amp???> and these 12ax7's marked "china" that I just did not dig at all (microphonic, tube rattle, you name it). I am retubed with JJ's all across (bought some locally and have some from KCANOS tubes on the way) and that has made a huge difference. I currently have a Weber Blue Dog ceramic in there now and it sounds great, but I do want to retry the stock NeoDog to compare now with the new tubes. I also was able to run this through an old (~10 year) Alnico 30 watter from mojo and it simply sounds incredible. But, I can't afford a Blue or another alnico right now.
    I "think" I did the bright cap mod, I have to do some more testing (or take apart the amp again to confirm but the Top Boost side is sounding much better now.
    I reconfirmed my belief that this is a really sweet amp and has potential to be amazing last night, so I'm sending it to Lyle for him to work his magic. I would say a stock CC (newer ones might be better, older ones need work) is not to it's full potential. If you are willing to drop some more coin it's worth it. That is why I went used, new tubes, possibly new speaker, Lyle mods to come. When all is said and done I'll be at or around the price of some booteek Vox makers (used pricing in most cases) but probably closer to a real deal, JMI spec'd Vox.
    I guess the cool thing is that you can do this in stages and see improvements along the way (imho, ymmv, etc...)
     
  19. sixstring531

    sixstring531 Supporting Member

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    Hola again Lyle! -

    What is the best 220k (brand) to purchase for this R6,R7 mod and do you use a specific solder brand?


    And another thing - Am I the only one who likes greenbacks in the AC30? I love the way my amp sounds but I don't see alot of guys with the greenbacks.
     
  20. Lyle Caldwell

    Lyle Caldwell Member

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    I use Xicon 1W carbon films. They are very quiet, a bit overspec for the current going through them, and won't drift, and they sound great.

    I use Kester solder, but then I do a lot of soldering and buy in bulk. For small occasional jobs, the 60/40 solder at Radio Shack is fine. Choose the diameter that is appropriate for the pieces in front of you. For solder pads and pedals, .032 is good. For pots lugs, cases, or other things with larger surface areas, .064 is better. It's all about having the right amount of solder for a joint.

    I use a Hakko 936, but Home Depot carries a 30W Weller iron for about $17 that is fine for the average guitarist to use.
     

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