Members Fire and Glass Posted February 3, 2011 Members Share Posted February 3, 2011 I have acquired some great amps lately, but they are all 130watts+ and sound best of course, at loud volumes. I got a Bugera 1960 (140 watts) and a Musciman HD-130 (130 Watts). Having a new born baby girl...cranking the amp isnt always an option so i bought a groove tubes speaker emulator. The speaker emulator says it can only had 100 watts max. 1. Could I break the speaker emulator if i try to run these amps through it? Even at low volumes?2. If so, is there a way i can lower the wattage/volume?3. Can you install a master volume without changing the tone?4. I heard about pulling tubes, would this achieve what i want? Thank you in advance for any help. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted February 3, 2011 Members Share Posted February 3, 2011 I know what you mean. I picked up a 65W Music Man recently and its a very loud 65W. I run it in the studio with 4X10" speakers so my pant legs arent flapping in the breeze from the thing. It does have a master volume so I can lower the output to around 40W and it still sounds good. There arent a whole lot of options for you but heres a few. First you could use speakers with a low SPL. This will lower the volume from the cab but still allow you to crank the amp volume a bit. Second, Depending on the tube types you can get some of those yellow jackets and bring the wattage way down. Third, if the amp doesnt have a master volume, you could install one of those. You would be able to get preamp saturation but you'd loose the power amp saturation. With the master volume turned down you could then use a hot plate safely. (If the amp has a serial effects loop you could use an attenuator there too.) Lastly you may be able to safely remove a pair of power tubes and cut the wattage in half. This can be done safely with some amps and other can apply to much voltage to the remaining tubes. Lastly, you may be able to install a bias reduction switch to drop the voltage down and cut wattage. Both of these last two should be done by a qualified technician who knows what he's doing. In reality though, unless you're playing arenas, those amps just have to much power to use anywhere. Even Musicians who play those big shows use smaller amps for rehursals and smaller gigs. Thats why they usually rent the big stuff for the big shows. You may just want to down size to something that will do club work fine yet be very tolerable at home. Link to comment Share on other sites More sharing options...
Members k tone Posted February 3, 2011 Members Share Posted February 3, 2011 I have the Bugera 1990 (great amp). I run it at half power and can turn it down to a usable level when the kids are in bed. Link to comment Share on other sites More sharing options...
Members Lurko Posted February 4, 2011 Members Share Posted February 4, 2011 1. Could I break the speaker emulator if i try to run these amps through it? Even at low volumes? Yes. Don't ignore manufacturer's instructions. 2. If so, is there a way i can lower the wattage/volume? Yes, with an outboard attenuator.3. Can you install a master volume without changing the tone? No. The tone will change and it's difficult to do. You are better off selling the amp and getting something that will work for your situation.4. I heard about pulling tubes, would this achieve what i want? Depends on the design, but if it's a 100W amp, even if you pull two tubes it will still be more or less 50W, which is very, very loud. Buy a new, 5W amp with a built in MV. You'll be much happier in the long run. Thank you in advance for any help. Good luck, see my answers above in bold. Link to comment Share on other sites More sharing options...
Members musicdog400 Posted February 4, 2011 Members Share Posted February 4, 2011 I have built a few attenuators, and recently a cab with an attenuator. I can tell you that you will have to take the power WAY down before you notice a difference. Reducing the power by half, you will barely even notice. If I made a switched attenuator I think the steps would be 100%, 25%, 5%, 1%. I like attenuators but the ones I made changed the sound a bit, losing treble. It's not so bad if I leave the inductor out, but then the load may not be enough for the high frequencies. If you're willing to risk it, leaving out the inductor sounds better. All in all I think the attenuators are a good trade off. Link to comment Share on other sites More sharing options...
Members SHinybulldozer Posted February 6, 2011 Members Share Posted February 6, 2011 I dont know if you have any soldering experience... But adding a pentode/triode switch will do good for cutting the power to roughly half it will change the feel and sound of the amp a little but it will also allow you to use the emulator. i would not recommend removing tubes. your output transformer has a primary impedance that matches (or very closely matches) the tubes giving the most power transfer between output tubes and speaker... removing half of these tubes doubles the impedance of the output stage and the only thing the transformer can do is change the secondary impedance (what connects to your speaker) now your speaker is not matched and your whole output stage isn't happy. Pulling tubes in summary mismatches your whole output stage and can cause damage (putting a the wrong load ie 16ohm into the wrong impedance jack ie 4 ohm also mismatches the output and is very bad) Now for something useful! Since your planing on running the amp through the speaker emulator id highly recommend a purely resistive attentiator. this is simply a voltage divider attenuator. This is a simple voltage divider that passes the ratio of signal you want to the emulator and dumps the rest into a power resistor. kinda wasteful and gets very hot but super super cheap and very simple to build. May require a fan(cpu case fan). Ive looked online for you and you can get huge 100watt power resistors for about 12-16 bucks and you only need two. and aluminum case and the jacks. probably run about 40 bucks. This is by far the easiest diy project for guitars. The only trick is computing the values of the resistors so that they cut down your required decibels but still match the input to the output. luckly ive made a tool for that if your intrested! Link to comment Share on other sites More sharing options...
Moderators isaac42 Posted February 7, 2011 Moderators Share Posted February 7, 2011 I have built a few attenuators, and recently a cab with an attenuator. I can tell you that you will have to take the power WAY down before you notice a difference. Reducing the power by half, you will barely even notice. If I made a switched attenuator I think the steps would be 100%, 25%, 5%, 1%.I like attenuators but the ones I made changed the sound a bit, losing treble. It's not so bad if I leave the inductor out, but then the load may not be enough for the high frequencies. If you're willing to risk it, leaving out the inductor sounds better. All in all I think the attenuators are a good trade off. True, but, if he reduces the power to below 100 watts, he can use the speaker emulator safely. Link to comment Share on other sites More sharing options...
Members iancandler Posted February 16, 2011 Members Share Posted February 16, 2011 Get a THD hotplate, just choose the correct model for your speakers impedance, plug in and go, they handle up to 150w as opposed to most of the powerbrake's etc that only handle 100w continuous. Link to comment Share on other sites More sharing options...
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