Dummy Loads

Bainzy · Post by **Bainzy** » Wed Jan 11, 2006 6:27 pm

I've got a 100w solid state Marshall head (MG100HDFX) as my backup head, and noticed EVH used something similar with a dummy load to function as an attenuator. Is finding a dummy load cheaper than an attenuator, and if so where do I get one? Does it work well?

I'm not bothered one bit whether it sounds like EVH, I'm just too poor to afford an attenuator right now so I'm brainstorming cheaper methods to preserve my hearing while getting great tone

908ssp · Post by **908ssp** » Wed Jan 11, 2006 11:45 pm

I did a bunch of experimenting with dummy loads. Trying to get my amps quieter and not pay for any more attenuators that weren't doing what I wanted. The problem is in the basic physics. You can't make a slick purse from a sows ear. There is an article on Aiken's site in the advanced tech papers it shows a picture of a frequency curve plot when using a load parallel to a speaker the load changes the curve. In another article same site he describes a reactive load for testing amps that simulates a speaker and retains a closer frequency response curve. The only way is complicated and the only company that has addressed the problem head on is Motherload with their Richter attenuator.

Yea you can buy 50 watt 15 ohm resistors on eBay arrange them just as thou they were speakers. You can run one for 3db drop or as many as you want maintaining a 15 ohm load for more attenuation but not if you want the same tone you had without it.

I use a single resistor on occasion to match a 16 ohm speaker to a 8 ohm output and the 3 db volume drop isn't enough to seriously alter the tone it might even be improved as you turn up the treble and bass to compensate. But start adding more and more resistors and the tone gets worse. Only the Ultimate came close to the Richter the others I have tried aren't close those include Weber Mass, Weber Load Dump, THD, Alessandro.

Richters are made in your country by the way not here in the states.

908ssp · Post by **908ssp** » Thu Jan 12, 2006 12:10 am

I thought about your question and I think you want to do a bi-amp set up with your spare amp? In that case 100% of the load is run into a dump. Any large ceramic resistor 100 watts or better and 16 ohm or so will do the trick. I bought a 300 watt 8 ohm ceramic resistor from eBay for $10 it is used on CNC machines, looks like a stick of dynamite. Hook the resistor to your speaker jack. You then use your line out on the amp and if you don't have a line out those are pretty easy to make and add to any amp. Since they typically go on the speaker outs you can add it to the speaker in of your dump and add a line out jack to your home made dump. Will this work better? The Ultimate works this way but they run a 32 ohm load which is probably closer to the load your speaker is putting on your amp at high frequencies but will that hurt the amp at low frequencies? I don't know and with my vintage amps I don't want to take that chance.

Crunchboy · Post by **Crunchboy** » Thu Jan 12, 2006 7:29 pm

Alex, good info. I really want to get a UA. I'm running a PPIMV now on my SLP and I really want to hear the "whole" amp (without going deaf). I had a Hotplate and thought it sounded like poo. Tell me why I should or shouldn't buy the UA. THX

908ssp · Post by **908ssp** » Thu Jan 12, 2006 11:03 pm

I have an Ultimate and prefer the Richter they are the same price. The Richter is a 8 ohm input and output, the Ultimate is 32 ohm load input whatever output. The Ultimate has a power cord for the fan and transistor amp. The Richter has neither. The Ultimate is a nice size put the feet are too low and it painted an awful hammer tone green (at least mine was till I repainted it gold). The Richter is black it is a bit bigger and the feet are a bit taller. The Ultimate goes from 100% loud to 0 quiet, the Richter goes from 50% loud to 0 quiet (the difference truly isn't even noticeable).

Even if they sounded exactly the same it boils down to the fact that I will most likely sell my Ultimate and buy another Richter. Both of these are head and shoulders better sounding then the rest.

BashCoder · Post by **BashCoder** » Fri Jan 13, 2006 9:05 am

If you buy an attenuator for a solid state amp, make sure that the manufacturer intends it for that purpose. I know the THD Hot Plate is exclusively for tube amps (though I admit that I don't understand why -- one would think power is power but I'm sure I'm missing something...). I wonder if they are counting on the output tubes to be more forgiving of varying impedances.

Marshall's Power Brake doeesn't say anything about tube vs SS amps, and it doesn't have a line level output. But it sounds pretty dang good for a load box. Buy them used for $300 on eBay instead of new for $600.

The Richter looks cool, but from my perspective I'm really not looking for tone controls and presets in a load box. Just personal preference on that one. It is quite expensive -- it's tough to spend as much for a load box as you can spend for the amp head.

In the 80's, the gold standard was Harry Kolbe Soundsmith's two products, the "Silent Speaker" and the "Attenuator". They are unavailable today, but session players I've worked with still use them in their racks.

I've never played through a Marshall SS amp, so I don't know if you can get a decent overdriven tone at low volumes with one. Even if the amp sounds good low, it's often the speakers that need to move some serious air for it to sound the way it should.

Volume controls can sound terrible when they are almost zero, so maybe that's a reason to buy an attenuator for a SS amp. Similarly, load boxes sound worse the more you attenuate, in my experience. When you're gain staging, usually two volume controls at the halfway point sound MUCH better than the first one turned down to '1' and the other turned up to '10'.

I have three attenuators -- two Hot Plates and a Power Brake. Just know that you will lose some of the character of your sound. The point, obviously, is to gain more than you are losing. When you can, attenuators can be great -- especially for tube amps, where the tradeoff is acceptible to get that overdriven tone.

BashCoder · Post by **BashCoder** » Fri Jan 13, 2006 9:17 am

One more thing -- if you do decide to homebrew an attenuator, be careful -- it's pretty easy to fry your finals if you don't give them what they expect as a load. Especially with an SS amp, that will cost you more to fix than the $300 for the load box.

Besides, simple resistive loads have been pretty well rejected by the guitar community in favor of reactive loads, which can respond to the inductive reactance of alternating current and act and sound more like a speaker motor. If you are looking for tone, resistors won't cut it.

As an aside, I'm reminded of my days as a young ham radio operator in the 70's, where the popular dummy load for a transmitter was Heath Kit's "Cantenna", which was basically a paint can with a connector on the lid, full of oil. That would dissipate up to 100 watts of power at 52 ohms.

Billy Batz · Post by **Billy Batz** » Fri Jan 13, 2006 10:15 pm

908ssp wrote:I have an Ultimate and prefer the Richter they are the same price. The Richter is a 8 ohm input and output, the Ultimate is 32 ohm load input whatever output. The Ultimate has a power cord for the fan and transistor amp. The Richter has neither. The Ultimate is a nice size put the feet are too low and it painted an awful hammer tone green (at least mine was till I repainted it gold). The Richter is black it is a bit bigger and the feet are a bit taller. The Ultimate goes from 100% loud to 0 quiet, the Richter goes from 50% loud to 0 quiet (the difference truly isn't even noticeable).

Even if they sounded exactly the same it boils down to the fact that I will most likely sell my Ultimate and buy another Richter. Both of these are head and shoulders better sounding then the rest.

You got the Richter. I see it is really good. You think it really does compete with the UA at very low volumes?

bmf5150 · Post by **bmf5150** » Fri Jan 13, 2006 11:11 pm

where do i find info on the Richter attenuator.

BashCoder · Post by **BashCoder** » Fri Jan 13, 2006 11:17 pm

In the US, right here:

Load box/DI:

http://www.motherloadusa.com/motherload ... x-home.asp

Attenuator:

http://www.motherloadusa.com/motherload ... ichter.asp

bmf5150 · Post by **bmf5150** » Fri Jan 13, 2006 11:22 pm

so is it really that good?what do you guys think!

Billy Batz · Post by **Billy Batz** » Fri Jan 13, 2006 11:53 pm

908 is the only person I know of whose even seen one. From what I can see the Richter is just like the Hotplate only its a reactive load. What thart equates to tonally I dont know but according to 908 it sounds pretty good.

908ssp · Post by **908ssp** » Fri Jan 13, 2006 11:55 pm

There are only handful in the states so you aren't going to find many people with them yet. There are no tone controls or preselects on the Richter just one volume knob.

I had a friend and professional guitarist recording engineer over tonight we tested the Richter on a number of amps and against the Ultimate and the Alessandro to be blunt there is no contest. The Richter is hands down better. It is simply so transparent it is uncanny. There is no change in eq curve until the volume is below talking level. There is no grainy fizzy rough no change in distortion just as smooth quite as it is loud. I need to sell my Ultimate, Alessandro and Weber so I can buy another one so forget you read this.

Billy Batz · Post by **Billy Batz** » Sat Jan 14, 2006 12:03 am

I have to say that review is gasing me a bit. I like the weber as far as attenuators go but it sure as hell aint perfect, especially at low volumes.

Zeppo · Post by **Zeppo** » Sat Jan 14, 2006 10:51 am

Hi guys
What do you think of the THD? I'm building a 68 Metro and are thinking of getting one.