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MTS_07

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I think some would agree the power section of an Rm100 sounds good when cranked right? and the preamps at about 11 O'clock, but thats really, really loud 8)

I started thinking today while talking about power soakers. Wouldnt a DI like the behringer with the two -20db cut buttons be okay if placed in the serial FX loop with one or both -20db buttons on to lower the signal and then looped back into the amps return, to lower the volume of the preamps which would then allow me to run them at 11 O'clock with the power section cranked?

This would allow the sweetspot of the preamps to be run at lower volumes into the cranked 6L6's, for when I'm playing at home

Am I missing something? could this really work?
 
I know it takes high levels of volume to reach the "sweet spot" but im confused as to what the audio pot/master volume does and why is it uncommon?
 
That's essentially what a Marshall Power Brake does...
Works great with SOME amps...haven't tried it with the RM100, but it worked great for the Mesa Mark IV, not so much with the Mark III.

I do have one of those Behringer DI boxes, so I could test it...
 
It does work but only for the preamp tubes, it allows the them to be run with a nice strong signal at low volumes however the signal is then weak going into the power section unless the audio pot can boost the signal back up? does the master/audio pot drive the power tubes even with a low signal?...... Need some help on this one.
 
I read somewhere that somebody just wired up a volume pot and put it in the effects loop...sounded like it might do the same thing...
 
jimosity said:
I read somewhere that somebody just wired up a volume pot and put it in the effects loop...sounded like it might do the same thing...

So adding a 3rd volume control between the preamps and the poweramp, I'm guessing the way it works on the RM4 is like the RM100 the channels sound best around 11 O'clock and by doing that it makes it extremely loud so the master RM4 volume knob brings all the levels back down while retaining the preamps tone and that seems to be what the I was trying to do but the master volume seems to be both the master channel volume and the power section gain/level control.............

Sorry just trying to sort it out :(
 
I used a THD Hot Plate with my RM50 with very good results.
 
Okay so it turns out attenuating the preamp does work and works very well at low volumes using the DI 8) Tone at low volume just got a whole lot better for me 8) 8)
 
You could do the same thing by taking a Boss GE-7 and cutting the level all the way down. Unfortunately it's not the same thing as using an attenuator. All you are doing is lowering the volume feeding the power amp which means you have to turn the master volume up louder. What you are hearing is the same sound as if the module volume is turned down. To effectively get that "cranked to 11" tone you really have to hit the power amp and crank it. If you want to have this sound at a lower volume a power attenuator is needed which sits between the speaker out and cab.
 
RD/Rich said:
You could do the same thing by taking a Boss GE-7 and cutting the level all the way down. Unfortunately it's not the same thing as using an attenuator. All you are doing is lowering the volume feeding the power amp which means you have to turn the master volume up louder. What you are hearing is the same sound as if the module volume is turned down. To effectively get that "cranked to 11" tone you really have to hit the power amp and crank it. If you want to have this sound at a lower volume a power attenuator is needed which sits between the speaker out and cab.

Yeah, it cuts the preamp level but since they're set to 11 they sound really good, Just cutting it enough so that the preamps can be set to 11 without my house shaking apart :wink:
 
Are you talking about running the module at 11 (1 louder than 10) or 11 O' Clock? I would think that you should be able to run the modules at 11 O' Clock at elast even w/ the amps master set low. Even in an apartment I can set the modules between 11 and 1 O' Clock w/ the Master at 1.5-2 (around 8 O' Clock).
 
RD/Rich said:
Are you talking about running the module at 11 (1 louder than 10) or 11 O' Clock? I would think that you should be able to run the modules at 11 O' Clock at elast even w/ the amps master set low. Even in an apartment I can set the modules between 11 and 1 O' Clock w/ the Master at 1.5-2 (around 8 O' Clock).

11 O'clock for the modules, the amp seems more clear with the master around 1 O'clock which is why I thought lowering the level output from the preamp would work..... I'll try running it the other way around with the preamp high and power amp low.

Thanks.
 
When you turn the amp up to the volume level you are talking about what you are hearing is power amp tube saturation. You can only get power amp tube saturation by feeding it signal, hot signal, a lot of it. Then it is loud. If you cut the signal down in any way before it hits the power tubes it isn't the same sound. Putting volume pots or signal reducing elements before the power section just isn't the same. The only way to hear power tube saturation at lower volume is to use a attentuator like Ned mentioned. And if I'm not mistaken a Marshall Power brake is an attentuator that goes between the head and the speaker cab isn't it?
 
I run my RM50HB Master at around 1 to 2 o'clock into a THD Hotplate set for 8dB. This allows me to run channel masters anywhere from 9 o'clock (reasonable volume depending on module) and 11 o'clock (really rocking! :D )

I think the whole box sounds better with the Head Master set higher.
 
The idea was to get the best tone out of the preamp section only, not for power tube breakup.....
 
MTS_07 said:
I think some would agree the power section of an Rm100 sounds good when cranked right?

This made me think otherwise. I'm still confused though. You have the gain on the module, the master volume on the module and then the master volume on the amp. I don't think what you are proposing would accomplish anything except intruding another place (somewhere in effects loop) to have another knob that just re adjusts one of the levels you already set somewhere else. Unless I'm missing something?
 
Adding another resistor on the effects loop to lower volume is exactly the same as turning the amp master volume down.

To get the best tone, you need to saturate both the preamp tubes and power amp tubes. Of course, that gets really loud. I suggest installig 6v6s or using yellow jackets to install EL84s for the power tubes and get lower wattage. A 100 watt amp is only twice as loud as a 10 watt amp, so you will probably not get all of the reduction in volume you want from this step alone. Alternatively or additionally, I suggest installing lower sensitivity speakers. Replacing 100dB speakers with 94 dB speakers will drop the loudness by another 45%-60%.

A lot of the pleasing breakup that people perceive is actually speaker breakup, and you will need to get your preamp tubes, your power tubes, and your speaker breakup all in their respective sweetspots at the same time. So if you are having to crank it to get the speaker breakup, then you will need lower wattage speakers. High quality speakers list the power rating at half the max wattage. So you can safely pair a single 50-70 watt speaker with a 50 watt amp and get good results in most cases. If you are using a 4x12 with a 50 watt amp, then you can use four 15-20 watt speakers. If you are using a 4x12 of Vintage 30s, those are actually 70 Watt speakers, which is way too much headroom for any amp in my opinion. And there sensitivity is way too high. The 100 watt head was designed to be used with an 8x12 of 20 watt speakers, and a 4x12 of 30 watt speakers sounds even better with a 100 watt head.

After doing all of these things, if your rig is still too loud, then try an attenuator, but only attenuate 4dB or so. If you attenuate 8dB, that cuts your loudness almost in half, and you will need to use much lower wattage speakers (e.g., a single 10-15 watt speaker with a 100 watt amp). If you cut it by 4dB, then it cuts loudness by 20-30% or so, and you can use, say, a single 30-35 watt speaker with a 50 watt amp. But you will always have to use the attenuator or you will blow the lower wattage speaker.

The failure of an attenuated amp to push the speakers into breakup is, quite possibly, a major reason why people perceive a decrease in tone quality resulting from use of an attenuator. So you could try the attenuator first with some appropriately low wattage speakers. If you try that, I'd like to know how it turns out.
 
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