Chugga-Chugga said:
Hey, thanks for all the replies, guys. Nice to come home from work and see some interest in my topic. Here are my comments and questions about what I've read so far...
Getting a low wattage cab makes sense, and I kind of figured that. Here's what I don't understand though... I looked up the Marshall 1960ac/ax cabs and see they have four 25 watt greenbacks in them (100 watts for the cab), so why are the Mesa cabs with the vintage 30's listed as 240 watts instead of 120? Is the 240 peak and 120 is RMS?
'Vintage 30' is a misleading name because these speakers actually have a 60watt handling capacity. (it used to be 70watts like in my mesa cab, which is a 100 watt head) I think they are called Vintage 30s because Celestion tried to make a new speaker for high gain heads that had the same warmth as the old 30 watt speakers. (I'm guessing G12H - 30s) The result of this was the v30. These speakers are also surprisingly tight which means they need a lot of gas to respond in a musical fashion, especially when running a quartet of them. The good news is that the low levels of speaker distortion and aggressive high end make them fantastic for high gain application such as a punishing metal tone. The bad news is that they sound constipated at any reasonable sound level.
Converting a Rectifier head down to 15-20 watts sounds like a decent option, and I understand the explanation about needing a low wattage cab if the head is configured for low wattage output b/c 15 watts isn't enough to push the speakers in a 4x12... but I have a question about this. Say you have 2 Rectifier heads, one converted to 15 watts and the other is stock at 100. The numbers you're about to read are just arbitrary, but say you set the volume of the 15 watt head to "6" and the volume of the 100 watt head to "1" and they sound equally loud.... are they sending the same current into the speaker load?
Well, people have commented a lot about the headroom of higher power amps and I think this really addresses this query. I personally have not looked into the numbers but as a guitarist, a 50watt amp has a very different 'feel' from a 100 watt or 150watt head. At a similar volume, the more powerful heads simply have more jam than the less powerful ones. The attacks are more bold, percussive, and aggressive. Like I said, the one way to replicate this with a less powerful amp is to run it through less powerful speakers because when loudspeakers are performing optimally, it adds a lot to the tone. It gives the illusion of punch because it seems there is less speaker to move. A good analogy is horsepower vs torque. A 300hp four cylinder engine can make a little honda civic go fast but to tow a heavy load or drive a larger pickup truck, you need an 5.0 litre 8 cylinder engine instead. Both engines are capable of a lot of work, the larger engine at a low RPM and the small one at a high RPM but ultimately, the larger engine with more torque can pull a bigger load. This basically applies to speakers because a speaker with a higher wattage rating need more signal to move them in the same way you need torque to move more weight. Note this is not talking about speaker resistance but wattage rating. Correct me if I'm wrong but the ohm rating relates to current and wattage is related to the magnitude of fluctuation between positive and negative charges in the current.
Guitar amps are a lot like any other amp aside from the fact that guitar amps shape tone and linear output amps simply reproduce it. Linear output amps Signal -> amp -> LOUDER Signal. Guitar amp: 'siGNal' -> amp -> LOUDER "S1gn4L", 'Got that?'. In most high gain heads, the tone is shaped in the preamp and then the power amp makes it louder. Contrary to old amp designs, the preamp adds much of the distortion and the power amp makes it louder. Because of this, there is a lot of percussive oomph available to a guitar playing a rig like this. This happens because the attack of the guitar sound is much louder than the decay so there is a peak in volume each time you strum.
As far as I understand headroom, it basically means that an amp with lots of wattage can peak at a much higher power than is required during regular operation so the percussive elements of playing are much more pronounced. Clipping is the point at which an amp can no longer make a linear representation of the input signal because the signal is bigger than what the output on the amp can handle. Basically, an amp running at 15watts turned up to 6 is most likely clipping out the power section of the amp. By contrast, a 100watt High Gain amp at one is nowhere near clipping out the power section of the amp on a gain channel. This means a louder signal is not cut off at its apex in a bigger amp, which translates as a much more powerful feeling while playing.
As for the 'low wattage mod', it isn't so much a mod as it is a plugin. It takes all of 30 seconds or less to 'reverse' it and you can swap back an forth as necessary. The yellow jackets are a little sleeve that sit in the tube slots and you plug low wattage into these. The yellow jackets have a circuit that basically convert the plate current to something EL-84s can handle. http://www.thdelectronics.com/pdf/yj.pdf
One thing I left out in my first post was what sound I was looking for. I want a heavy rhythm sound, like B & C tuned Dream Theater stuff. I'm not even thinking about lead tones. Anyway, it was suggested that I look at some other Mesa amps. I only know about the Rectifier line, the others are a mystery to me. Do people use the other Mesa amps for really heavy rhythm stuff?
Rectifiers have a great rhythm tone and they really are pros at handling the low tunings but you can also look at the mark series amps such as the Mark IV or Mark V as well.
TheMagicEight said:
The Rectifier series aren't designed to utilize power tube distortion; they get their distorted tone from the preamp. Sure, a nearly cranked Recto is a beautiful thing, but you can still get a good sound at lower volumes - IMHO.
Awesome point. It just depends how low of a volume you need. You have to at least saturate the preamp section of the Dual to get a decent sound in my experience and in some situations, even that is too loud.
What you'll really need to think about is the type of cab you're going to use. In my experience, 1x12 cabs are always too thin and small for a significantly distorted sound. For a lower volume, I'd go with a Dual Recto dropped to 50w, plugged into a 2x12. 50w is still really loud when turned up, but what you'll gain is low end clarity and the tone of the real thing.
Good point. I dislike 1 x 12s too except for the thiele design. A 2 x 12 with low wattage speakers such as a couple of greenbacks is a great solution. Just keep in mind that the speaker distortion can mudify things for a super high gain sound.
I haven't had much success with EL84s because I think they take away more than they give. Bottom line, if it were me, and I needed to play quietly but still have the Recto tone I love, I'd do a Dual at 50w into a 2x12. I might even take it a step further and use a power attenuator. The one thing I would really try to do though, is use low powered speakers. They'll give you the most kick at low volumes, as opposed to s really stiff speaker that only wakes up when you hit it with 150w!
I completely agree with your comment about EL84s to a point; they absolutely do not work with a high wattage 4 x 12 because they simply can't put out enough oomph without involving the power section of the amp in a big way. I find they sounded simply terrible with my Standard Rectocab but when I put my head with the yellow jackets through a 100watt marshall cab, it sounds amazing and at surprisingly low volumes. The 50watt Dual setup is also amazing but believe it or not, I have been in situations where sound guys complain that is TOO LOUD! You only get about a 3db decrease in volume when you half the power of an amp. This difference can be replicated when switching from a 100db/watt/metre speaker to a 97db/watt/metre speaker. (V30 or G12H to a G12T 75 or a G12M for instance)
For practice and volume sensitive situations this can be a deficient solution and instead, sometimes a 1 x 12 with an amp running at 15watts is what is necessary to get a decent tone and maintain the peace. It is really what you need that is important. (Think apartment vs home here) Also, the el84s do affect tone. If you want super tight and aggressive metal, they can take away from that. (mostly because of the tonal characteristics of the low wattage speakers available) The clean on a Yellow Jacketed Dual itself improves immensely, taking on the characteristic of a Vox. The gain sounds more vintage and 'Marshally', even if it is still huge and punishing with the right settings on the amp. Perhaps it could be compared to a Tiny Terror but the tone circuit is distinctly 'Mesa-ish'.
It should be mentioned that the perceived volume of a 10watt amp is half as loud as a 100watt amp, given that the speakers and guitar are the same.
