Tone King Gremlin Improvement

Discussion in 'Amplifiers' started by GuitarAddict, Feb 23, 2021.

  1. GuitarAddict

    GuitarAddict New Member

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    Thought I'd share my experience of my Gremlin amp. I touched on this briefly in another post where I mentioned the ABY switch sapping the tone, which has now been discarded, but the other main problem I found with it was when running it on maximum attenuation which I do from time to time when my tinnitus is playing up or it's the early hours and I can't sleep and end up in the music bunker, was that the tone really suffered and the sound went all fizzy and harsh. The normal TK attenuator has an adjustable presence switch to compensate for this but the one built in to the Gremlin doesn't. It was almost like the attenuator was struggling to cope with the amount of power.
    I bought some new valves from China, (I've found a good seller on eBay and the quality of the valves is as good or better than I can get from a retailer in the UK, not harsh, just a great tone), and I swapped out the power valve for a 6V6 rather than the KT66, and substituted the first preamp valve for an AT7 rather than AX.
    Problem solved, great tones at all attenuation levels and slightly more headroom, still plenty of overdrive.
    Hope someone with a Gremlin amp reading this finds it useful. The SilverSky into this amp now sounds amazing and I don't think I'll ever need another amp, finally got the sound I've always wanted.
     
    DreamTheaterRules and LSchefman like this.
  2. AP515

    AP515 Mostly Normal

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    How about just turning the amp down and not using any attenuator. For me, I do hear that the amp can't "breath" so to speak, but the sound isn't muffled like an attenuator does. The sound isn't magical but it isn't bad either.
     
  3. GuitarAddict

    GuitarAddict New Member

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    Well the Gremlin has no master volume, just Volume (gain increases with Volume) and Tone. So I can't turn down and still have the level of overdrive I want and I don't use pedals. ToneKing chose not to add a master volume, so you can't run it with just preamp distortion, which really is a poor substitute for power amp and preamp distortion together, but until now the attenuator has killed the tone.
     
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  4. LSchefman

    LSchefman Hears Tones

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    Master volumes can be great things, but adding one to a circuit truly affects the tone of the amp. One of my amps is a Mesa Lone Star with a global master volume that can be switched out of the circuit. Switching it out opens the amp. So that's how I run the amp. I understand why an amp maker will build amps without them, especially if they have attenuation built in.

    Tubes do make a big difference in tone. At some point you might want to check out some NOS (new old stock) tubes. The first thing I do with a new amp is install NOS. They sound better, they last longer, and unfortunately, they're more expensive. But worth it.
     
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  5. GuitarAddict

    GuitarAddict New Member

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    I have had a fair share of valve trouble. I had just bought a new guitar and it sound really really bright and harsh, turns out it was a power valve going south and I didn't realise until I'd sold the guitar that it was the valve at fault. It was a really good brand of valve too, and I swapped it out for a nondescript Chinese one that surprisingly sounded amazing, so I tracked down the brand on eBay and I always use them now. I've heard good and bad about NOS. It mentions them in the Gremlin manual, and says that they can be hit and miss, and to stick with new ones from Russia or China I think, from memory, but I will give them a try on your recommendation next time I swap them out. Any particular brand you think are good to try??
     
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  6. LSchefman

    LSchefman Hears Tones

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    You know, I've had far less hit and miss with NOS than with new tubes. Going back to the late '60s when I started using amps, I never had a tube blow - until the last couple of decades. I spoke with one of Mesa's techs about it in a conversation about tube rattle in one of my amps before installing NOS, and he said there's no question that newer tubes are being made worse and worse each year, and that they've seen far more issues with new tubes.

    They've got a pretty large customer base, so I'm guessing their info is based on a large enough sample to be worthwhile.

    If you look closely at a quality US, UK, or German NOS tube and compare it to even a decent new Chinese or Russian tube, you can easily see that on the new tubes, corners are being cut in the subassemblies and wiring gauges. The assembly quality is also worse, with things like tilted and bent parts in the tubes. These contribute to problems like increased microphonics, shorter life, and how the tube sounds. For example, many Chinese preamp tubes sound extremely 'ringy' to me due to microphonics.

    Remember, too, that new tubes are made with very old equipment that was originally purchased by Eastern countries from Western factories when the West stopped producing tubes by around 1980. Whether the equipment is properly maintained or worn out now is anyone's guess. Perhaps that's a factor.

    On American style amps, I use NOS GE and RCA preamp tubes, and with 6L6 power tubes, I like GE, RCA, Sylvania, and a few others. I like the NOS JAN (Military Spec) Philips 5881s. I've also had good luck with other US-made NOS JAN preamp tubes. If you can get them, the RCAs sound great in V1, but the GEs are no slouches and they're considerably less expensive. The NOS GEs I like have been the JAN military versions, but I'm told that they're identical to the civilian version, they were off the same line, and simply tested to meet military spec back in the day. I've been using JAN GE and NOS RCA 12AX7s for years, and never had one go bad. Doesn't mean it can't happen, of course, but my experience has been very positive. And of course, the sound is nicer.

    On British-style amps, I use NOS Mullard or Brimar in v1, sometimes NOS Siemens in other spots, sometimes Mullard or Brimar, and lately always NOS Siemens EL34s, because the NOS Mullard EL34s have gotten so expensive. I've had pretty good luck with NOS '80s manufacture Russian EL84Ms for my DG30 amp (the EL84M is a different tube than a standard EL84). The Brimars are not as consistent as the Mullards for some reason, which is surprising, since many of them were branded Brimar and made by Mullard. However, I have never had an issue with a Mullard 12AX7.

    You might wonder about the tone of these things, so here goes:

    About 18 years ago, I became a Two-Rock player. At first, the amps came with NOS tubes, but after a while, it became an option. However, when I got a new Two-Rock, I would install NOS tubes. The amps' tone improved, but more importantly, there was greater satisfaction with each amp long-term.

    I equipped my HXDA with NOS, and even though it was a keeper with the stock tubes, the NOS tubes made it even more satisfying as a long-term #1. My DG30 was one of the first 20 made, and came with NOS from the factory. I love it.

    I also have two Mesa amps. I bought a Lone Star because my son was touring with one, and there were times he wanted to cut tracks at my studio when he visited from LA. At first, I really didn't love the tone. So I installed NOS GE, and the amp changed in subtle but audible ways. To my surprise, however, the amp became a keeper, and a studio staple I really like now. The harshness is gone, the tube ringing is gone, the brittle high end is gone, replaced by a lovely treble. It went from an amp of convenience to a keeper. I've had it for about 5 years, and since installing NOS, the amp hasn't needed a tube change. I record a lot of tracks with it when I want a more pure clean tone.

    I found that putting NOS in my Mesa Fillmore improved it in a similar way - it sounds like a more expensive amp now.
     
    #6 LSchefman, Feb 24, 2021
    Last edited: Feb 24, 2021
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  7. GuitarAddict

    GuitarAddict New Member

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    I am surprised at how quickly the valves I’ve used in the last year have gone ‘off’. I tend to leave the amp on all day from around mid morning to mid evening and it doesn’t have a standby switch.
    I think I’ve got through 2 power amp valves and had 2 preamp valves that were horrible and went in the bin.
     
  8. GuitarAddict

    GuitarAddict New Member

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    Thanks for your advice on the NOS brands. I’ll have a chat to the valve supplier i use in London and see what he has.
     
  9. DreamTheaterRules

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    Leaving them on all day is not a recipe for long life.
     
  10. LSchefman

    LSchefman Hears Tones

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    I wouldn't leave my amp on all day. I can't see how that would help.
     
  11. GuitarAddict

    GuitarAddict New Member

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    Sorry, I should have been more specific, on the days that I’m in the bunker most of the time playing, I leave it on, rather than turning it off for a 30 minute break etc. If I’m going for a break of an hour or more it gets turned off.
     
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  12. andy474x

    andy474x Knows the Drill

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    You did the same thing I’ve done to a few amps lately, swapping a high gain preamp tube for a lower gain tube. In some amps, for my taste, the 12ax7 is just too hot, and almost feels like it’s overloading the signal with gain right off the bat. Swapping in a lower gain tube allows the gain and distortion to cascade and increase more gradually through the preamp, rather than just blowing up right away, and the resulting sound is much smoother and less raspy.

    I put a 12ay7 into the V1 of my PRS Sweet 16, which really opened the sound up - before, it was breaking up even at the lowest preamp volume settings, and max gain was far more than I needed. Now it will stay clean until about halfway up the preamp volume, and maxes out at just the right spot.

    I’ve even been changing out different brands of 12ax7’s in other amps, just to drop that V1 gain a little bit. It’s something that gets swept under the rug, but I think it makes a big difference! Especially in an amp like your Gremlin, which your only way to balance the preamp and power amp is by tube swaps.
     
  13. The Guitar Hunter

    The Guitar Hunter in progress

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    I had a Gremlin and thought it was great. I liked the their attenuation so much, I bought their standalone attenuator for my other amps. Good to hear that the tube swap was beneficial.
     

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