School Me On Attenuators

Discussion in 'Glowing Bottle Tube Amp Forum' started by colchar, Oct 18, 2017.

  1. colchar

    colchar Friend of Leo's

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    I know nothing about attenuators so need some advice.

    I have a Marshall Vintage Modern 2266C (a 50 watt 2x12 combo) and would like to get the KT66 power tubes working, while still preserving my hearing (I have noise induced hearing loss).

    Using an attenuator will allow me to turn up the amp while keeping the volume at a reasonable level but I don't know which ones are good, which aren't, whether to get reactive or passive, etc. so I would welcome any and all advice anyone can give on attenuators.
     
  2. uriah1

    uriah1 Telefied Gold Supporter

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    This is a large issue and the tone will be in your ears. I remember I had plexi back in the day and would pull 1 and 4th
    tube to reduce. or 3 and 4. Back then they didn't even have power soaks.

    The market has sprouted with these recently and a lot of good posts here. All depends how much you want to spend also.

    You might add variacs also. Van Halen used those and new companies (Amprx brownbox) to name a couple. I have a Dr Z brake lite I have not used.

    Wish you luck. A lot of users here.
     
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  3. Chicago Matt

    Chicago Matt Friend of Leo's

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    I am a big proponent, and much prefer the sound of the power tubes working to that of any drive pedal I've tried.

    I have had the best results with an attenuator/reamp system. This is a unit that has an amplifier in it. Like an attenuator, it sits between the amp's output transfomer and the speaker(s). It attenuates the energy from the OT and re-amplifies it with the unit's power amp which is connect to the spearker(s). You get the tone of the cranked amp and can adjust the reamp volume to be the volume you need, either quieter or louder than the amp on its own. My first such unit was an Ultimate Attenuator that worked well, especially for attenuating. I used it for 6 years or so until it crapped out. Unfortunately, not under warranty and pretty much impossible to work on. I replaced it with a Bad Cat Unleash a few years back and have been very happy with it. I love that it has an effects loop as well. Expensive at $450, but worth every penny to me. It makes all of my amps much more versatile. I never play without it these days. I hear the Fryette Power Station is great too, although more expensive. I haven't tried one. Good luck in your quest!
     
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  4. gtrjones

    gtrjones Tele-Holic

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    Here's my $0.02...

    I have a tweed deluxe - it's running at maybe 20 watts, probably a little less. I have a Weber Mass (or mini-mass) attenuator for it, as I like to run it at the spot where it just starts to break-up a little. For several clubs/bands I've played in/with, that works out to about 6dB of attenuation, with the amp turned up not quite halfway. But the amp is still loud enough to be heard onstage with drums, bass amp, and another guitar amp. It's not quiet.

    I don't believe there's any attenuator that will give you a 'reasonable level' on a 50 watt amp, that preserves the tone of that amp.

    Of course, I'm defining 'reasonable' as bedroom level, not stage. If you're playing live, and just need to tame it down a bit, that's what attenuators are great for.
     
  5. colchar

    colchar Friend of Leo's

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    I do not play live, I only play at home.
     
  6. Wally

    Wally Telefied Ad Free Member

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    Off the subject...but I have to point out that with that Marshall, one should never remove both tubes on one side of the OT primary. That is, in that Marshall, it would have been correct to pull the 1 and the 4 as those two tubes operate on separate sides of that OT’s primary. However, to remove tubes 3 and 4 would be removing both tubes on one side of that primary....that is not advisable in a push/pull amp. I have to think that Uriah meant to type perhaps a 2 instead of a 3 there. One could pull these combinations—-1/3, 1/4, 2/3, or 2/4—and be safe....as long as the OT tap in that Marshall was placed one impedance higher than the cab showed the OT....16 for an 8 ohm cab or 8 ohms for a 4 ohm cab. If one had a 16 ohm cab and pulled two tubes, there would be an impedance mismatch. That is something that it not advisable with one of those Marshalls. They wanted see a match, and running the amps at higher settings would put the OT at risk.
    There are some amps that arrange the power tubes differently. There is at least one big modern Peavey that has the tubes arranged alternately......tubes 1 and 2 sit side by side but are opposite ends of the primary winding as are 3 and 4..... so one would want Tull either 1/2 or 3/4...and again...adjust the impedance for a match.
     
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  7. Old Tele man

    Old Tele man Friend of Leo's

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    Two types to choose from:

    1) Simple = RESISTIVE usually consisting of a 4, 8, or 16 Ω, high-wattage ceramic (heat dissipating) resistor; what factory uses to measure output power.

    2) Complex = REACTANCE consisting of combined RLC circuit emulating the dynamic impedance (Z) of a real speaker; more costly, not easily designed by amateurs.
     
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  8. xafinity

    xafinity Friend of Leo's

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  9. Wally

    Wally Telefied Ad Free Member

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    From Randall Aiken's TEch INfo Q&A....

    "
    Q: Why are resistive attenuators harder on an amp than an inductive attenuator or speaker load?
    A: A resistive load is not any worse than a speaker load or reactive attenuator load. In fact, the opposite is true - a purely resistive load dissipates all the amp's power in the load, while a reactive load varies the dissipation between the load and the output tubes, depending on the phase angle of the reactive component of the load. The worst case load for an amplifier is a purely inductive load, with a phase shift of 90 degrees between the supplied voltage and current. In this case, when the voltage across the load is zero, the current is maximum, which means that the output device now has maximum voltage across it at maximum current, which results in maximum dissipation. In effect, the load gets no power while the output devices are cooking!

    In addition, a reactive load has a very high impedance at the low frequency resonant point (typically up to 4 or 5 times the nominal 400Hz impedance) and a rising impedance at higher frequencies that can go up to many times the nominal impedance. These high, reactive impedances can cause very high, frequency-dependent voltages on the reflected primary impedance of the output transformer, which can cause arcing. The problem is much worse if the impedance is mismatched. The main factor in amps blowing up from attenuator use is not the fact that most attenuators are resistive, it is the fact that the amp is run full-out all the time, something that would not normally happen because the amp would be too damned loud to use that way.

    Another factor in amplifier damage from attenuator use is when the amp is run into an attenuator that is not properly impedance matched to the amplifier. Contrary to some attenuator manufacturer's claims, there is no way to make an "automatic" impedance matching attenuator, or a "one-size-fit's all" product. Their products are single-impedance attenuators marketed as "safe" for all load impedances. Lower than normal impedances cause higher than normal currents in output tubes, and higher than normal impedances increase the risk of arcing in tubes, sockets, and output transformers. I believe the "resistive load is bad" argument has the same origins as some of the other common misconceptions in the amp world. Look on any amp designers or tech's workbench, and you will find a purely resistive dummy load for amp design and testing. All Aiken amplifiers are designed and tested flat out at full power into a purely resistive load for long periods of time, in addition to being tested using reactive loads and actual speakers."

    http://www.aikenamps.com/index.php/technical-q-a
     
  10. colchar

    colchar Friend of Leo's

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    Thanks.

    Sometimes I think it would just be easier to get something like an Eleven Rack, Helox, or whatever as that would enable me to get cranked amp tones at low volumes, and would also allow me to get different amp sounds with the flick of a switch.
     
  11. Frank'n'censed

    Frank'n'censed Doctor of Teleocity

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    Wish I could, unfortunately, I have attenuator deficit
     
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  12. jackdc100

    jackdc100 Tele-Meister

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    I use a Dr. Z Airbrake with my 50 watt Marshall Plexi Reissue. That is my most toneful setup. It works great as long as you're still loud enough to keep up with a medium volume-level drummer. At apartment levels it can sound a little fizzy though. I also used a Marshall Power Break with my head and a Bogner 4/12 cab once. It also sounded really nice....maybe even better. I'm not sure if that has to do with the fact that my 2/12 cab doesn't sound as good as the Bogner cab or if it was the attenuators. Regardless, I think those two attenuators work great. You still have to play kinda loud though with a 50 watt amp though. If you are playing at home I'd just get something digital. Tube amps don't sound their best unless they're turned up kinda loud. When I play at home I'm usually just using my 11 Rack.
     
    Last edited: Oct 19, 2017
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  13. colchar

    colchar Friend of Leo's

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    As mentioned above, something like an Eleven Rack is an option. Can I ask what you think of the amp models in the Eleven Rack? As a Marshall owner, you would be well positioned to comment on how the models sound in comparison to the real thing.
     
  14. TimothyC

    TimothyC Tele-Afflicted

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  15. Mike_LA

    Mike_LA Tele-Afflicted

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    Well, I own a few Marshalls but haven't tried to make my 11R sound like them. My only interest is finding a sound that I like, and I have not been dissapointed. My best patch is a Satriani patch that I found on youtube. I guess what I'm saying is, use the unit to get a tone you love and don't worry what base amp you use. I LOVE my Marshal 6101 and can find sounds in the 11R that are great but to my suprise my fav is based on an Orange...
    Though I thought the vintage modern had a master volume. I can turn my 6101 down to a whisper with massive OD in the preamp.
    Best of luck....
     
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  16. LiteAsh

    LiteAsh Tele-Meister

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    What about this
    Eminence Maverick

    or

    Eminence Reignmaker - 12" FDM 8 Ohm

    (guitar speaker with g FDM technology puts tonal control at your fingertips. Simply adjust the knob on the back of the speaker to attenuate volume while creating an overdriven, saturated tube tone.)
     
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  17. Budda45ftw

    Budda45ftw Tele-Meister

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    I play a budda sd45 and a Rivera rockcrusher let's me get a lot more useful sounds at noon ear bleed levels
     
  18. moosie

    moosie Doctor of Teleocity Ad Free Member

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    I don't know if they're still well-received, but I used to have a Weber Mini Mass. Or was it Mass Lite? Anyway, I hated it. It sucked tone horribly. I've never considered attenuation since. I use other ways to get the sound I want.
     
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  19. jimmytheshoe

    jimmytheshoe Tele-Meister

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    Years ago I used to use a THD Hot Plate for my 50 watt Carvin Belair. Condo living forced me to try it. Maybe the THD, Weber, other brands work good on stage, I don't know. For bedroom/home use I found it to be a tone suck.
    I've learned to play at lower volume after certain hours. Mid afternoon when most of the rest of the building is at work the amp gets a little bit of breathing time. Working later in the day has some benefits :D
     
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  20. VintageSG

    VintageSG Friend of Leo's Ad Free Member

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    I have the Harley Benton direct clone of the Jet City Jettenuator. It's a simple thing, with an L-Pad and some series/parallel resistors to impedance match and heat dump.
    It allows me to crank my amps to get the power stage working in their region of sweetness without disturbing others. It isn't too bad a tone suck either. There is some alteration compared to actually moving air, blame Fletcher-Munson for that, but overall, it's ( and by extension the Jet City ) a useful piece of equipment.
    It features a line out and a micsim. Both of which sound pretty awful and are best ignored.

     
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