Weber MASS Attenuators

Tube or solid-state, this section goes to eleven!

Re: Weber MASS Attenuators

Postby mora_di2 » 07 Nov 2008, 03:03

I probably will.
But on the page where they are selling the motors they say something like "we prefer to only sell these to builders who really know what to do with them."
Indicating that they prefer not to answer a lot of questions from people like me who don't know much about electronics.
mora_di2
 
Posts: 4
Joined: 05 Nov 2008, 23:46
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby soulsonic » 08 Nov 2008, 09:50

I've tried using a MASS motor as a dummy load before, but I honestly preferred the sound of a non-inductive power resistor. The MASS motor behaves in kind of a strange way to my ears, and even though it is an actual speaker voice coil and pole piece, a line out tapped from it still requires extensive filtering via a cab simulator like a Red Box to get anything close to a real speaker sound. Though the MASS motor has a similar resistive/inductive load as a speaker, it's missing other elements and it had a strange feel to me when I tried it. Using a resistor just felt more safe to me and it's easier to get high power ratings and dissipate the heat. A MASS motor's coil can get VERY hot when it's the only thing used as the load, and since it's not moving air like it would in an actual speaker, I'm not sure about trying to put the full rated wattage into it. I'm not trying to go out of my way to be negative about it, but it concerned me very much when I tried it, and I was much happier with the results I got when using a simple resistor.
User avatar
soulsonic
Old Solderhand
 
Posts: 3531
Joined: 27 Jun 2007, 04:38
Location: Buffalo, NY
Has thanked: 56 times
Have thanks: 281 times

Re: Weber MASS Attenuators

Postby mora_di2 » 08 Nov 2008, 12:36

Thank you, that's interesting.
I would be re-amping via a Crate Powerblock power amp into guitarcabs so I wouldn't need speaker simulating filters.
I guess it would've been interesting if someone did a measurement of the speakermotor to check how many ohms it presents at the different frequencies compared to a normal guitar speaker. I don't know if it is constructed the same way as a normal guitar speaker?
mora_di2
 
Posts: 4
Joined: 05 Nov 2008, 23:46
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby fish_35 » 01 Apr 2009, 02:27

Soul, im using your schem to make a mass 100. When i buy the rheostat, is it just a 100watt one? Does the ohmage matter? anyone have a link of where to buy proper one? Thanks guys
User avatar
fish_35
 
Posts: 4
Joined: 01 Apr 2009, 02:17
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby Fuzzer » 01 Apr 2009, 02:56

It's resistance value is 50 Ohms.
The Freestompboxes Forum search function is soo great, use the search function..., the S E A R C H function.
User avatar
Fuzzer
Transistor Tuner
 
Posts: 1037
Joined: 16 Sep 2007, 16:17
Has thanked: 0 time
Have thanks: 20 times

Re: Weber MASS Attenuators

Postby soulsonic » 01 Apr 2009, 07:37

Yes, 50 ohms, but if you can't find that, then 25 ohms will also work (that's a value that had been used previously). If you're going to use it with a 100 watt amp, then you absolutely have to use a 100 watt rheostat minimum... it would probably be better to bump it up to 150 watt if you plan on running the amp all the way up into it.
Here's a link to a 100 watt one:
http://www.mouser.com/Search/ProductDet ... ckbzKZU%3d
Yes... good high power rheostats are expensive. If that's too salty for you, I guess you could look on ebay or surplus places.
User avatar
soulsonic
Old Solderhand
 
Posts: 3531
Joined: 27 Jun 2007, 04:38
Location: Buffalo, NY
Has thanked: 56 times
Have thanks: 281 times

Re: Weber MASS Attenuators

Postby fish_35 » 01 Apr 2009, 16:10

.
soulsonic wrote:Yes, 50 ohms, but if you can't find that, then 25 ohms will also work (that's a value that had been used previously). If you're going to use it with a 100 watt amp, then you absolutely have to use a 100 watt rheostat minimum... it would probably be better to bump it up to 150 watt if you plan on running the amp all the way up into it.
Here's a link to a 100 watt one:
http://www.mouser.com/Search/ProductDet ... ckbzKZU%3d
Yes... good high power rheostats are expensive. If that's too salty for you, I guess you could look on ebay or surplus places.

My amp is 50watts. I want to play it safe Can you tell me how to make a speaker motor? i have lots of old PA and guitar speakers that i am willing to take apart. Also i wish i knew where to get a cheap rheostat like weber (from china) instead of paying $35+ for one...Thanks guys for your help! :D
User avatar
fish_35
 
Posts: 4
Joined: 01 Apr 2009, 02:17
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby Rorer714 » 01 Apr 2009, 18:48

My 2 cents... I have a Weber MASS 50, it is one of the older ones in a black and grey box around the size of a shoebox. The one thing that I don't like about it is that it is oriented so the smaller ends of the "shoebox" are at the front and back, so it never seems to fit anywhere where space is at a premium, which means my whole studio! But other than that I have no complaints.

Mine is 8 ohms only. It has an on/off treble boost toggle on the rear, the input, and one out each for speaker and line. On the front is the single knob for the attenuation and a four knob tone stack. On mine, the tone stock does not work with the attenuation; only the treble boost on the rear does. This is good, because I prefer to control my tone with the amp or other methods. I want my attenuator to attenuate, that's all. The treble boost function is there to replace any of the highs lost to attenuation; it's not a treble boost per se. As far as the tone stack goes I cannot comment because I have never used my MASS as a DI box, although I plan to give it a try. I have several methods of DI but the MASS is the only one with a true dummy speaker in it. I am going to give it a try feeding into a software speaker sim like Audio Ease Speakerphone. Perhaps the actual dummy speaker will help with the overall feel of using the sim.

The list of what my older unit doesn't have (compared to a new one) is longer than the list of what is does have. Mine has no bypass for the attenuation or tone stack; no switchable impedence; no three way treble boost; no high/low range switch. However these things are not an issue for me, although I'd like to be able to bypass the attenuator so I can do A/B comparisons; one of these days I'll see if I can figure out how to install one. The impedance selector would be nice too, I'm not sure what I would have to do to install that though. But at the end of the day none of these things really matters to me, the MASS is an attenuator, that's what I got it for and that's what it does for me. For the $50 that I paid for it in like-new condition I cannot complain.

As far as the sound of the attenuation, well it pretty much retains the amp's tone until it's most extreme setting of full attenuation. A lot of the bottom drops out when the rheostat is cranked full counterclockwise. This is normal behavior for any attenuator though (I have not tried any of the fancy new ones though, like the Bad Cat Leash, maybe they are better in this respect?). As long as you can find a useable volume that does not require the attenuator to be at 100% then you can retain almost all of your tone. And even at 100% it does not sound bad; just different. It's still useable for some things, and you can massage it with compression and/or eq to get the low end back.

My Weber MASS 50 is built very well, I removed the cover and found top notch workmanship inside. I've used it with amps up to 50 watts, although it is recommended that your attenuator be capable of handling twice the rated power output of the amp. So I don't dime any amps that put out over 25 watts when using it, and of course no amps over 50 watts. I mainly use it with a Blues Junior and it's fine for that, I can get nice sounds at relatively low volumes although for true 2am bedroom levels I have to max the attenuation and give up some tone. But I just ordered a Blackheart Killer Ant head, it's a fractional tube amp head putting out around 0.25w with 2 12AX7's. Even so, it may be loud for the 2am stuff but the attenuator here should be extremely helpful and knock out any extra volume without getting near the end of it's range. I'm hoping that it can do the same thing for the Blackstar HT-5H that I have on back order (those things are hard to get your hands on - better order yours before they double the price)!
Rorer714
Breadboard Brother
 
Posts: 91
Joined: 29 Sep 2008, 22:29
Has thanked: 0 time
Have thanks: 3 times

Re: Weber MASS Attenuators

Postby soulsonic » 02 Apr 2009, 01:31

fish_35 wrote:.
soulsonic wrote:Yes, 50 ohms, but if you can't find that, then 25 ohms will also work (that's a value that had been used previously). If you're going to use it with a 100 watt amp, then you absolutely have to use a 100 watt rheostat minimum... it would probably be better to bump it up to 150 watt if you plan on running the amp all the way up into it.
Here's a link to a 100 watt one:
http://www.mouser.com/Search/ProductDet ... ckbzKZU%3d
Yes... good high power rheostats are expensive. If that's too salty for you, I guess you could look on ebay or surplus places.

My amp is 50watts. I want to play it safe Can you tell me how to make a speaker motor? i have lots of old PA and guitar speakers that i am willing to take apart. Also i wish i knew where to get a cheap rheostat like weber (from china) instead of paying $35+ for one...Thanks guys for your help! :D


You don't want to use one of those cheap rheostats from China. They're much more trouble than they're worth! It's not something you want to cheap out on.
You could just take one of those old speakers and carefully cut the cone off and figure a way to mount it. I guess you could cut off the bulk of the basket as well, and just have the magnet with the remaining motor assembly sitting there. In on of the Kendrick books, Gerald Weber (NOT the same guy! not even related!) talks about doing that and also mentions gluing the voice coil in place so it won't move... I think freezing the coil is a bad idea because without moving, it's not able dissipate the heat that normally generates in it, and you don't get the same response to the signal as you'd get if it were moving, so just cut the cone off and leave the motor free to vibrate. If it makes too much noise, you could try damping it with something, but you'd have to be sure it's something that wouldn't be harmed by heat (ie; catch fire) because the voice coil can get VERY hot.
User avatar
soulsonic
Old Solderhand
 
Posts: 3531
Joined: 27 Jun 2007, 04:38
Location: Buffalo, NY
Has thanked: 56 times
Have thanks: 281 times

Re: Weber MASS Attenuators

Postby fish_35 » 02 Apr 2009, 13:59

Anyone have pics of the inside of their Mini Mass?
User avatar
fish_35
 
Posts: 4
Joined: 01 Apr 2009, 02:17
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby fish_35 » 02 Apr 2009, 14:57

Thanks Soul for the tips! Much Appreciated :D
User avatar
fish_35
 
Posts: 4
Joined: 01 Apr 2009, 02:17
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby gray2210 » 11 Jul 2009, 14:48

I recently built a 50W clone of a minimass/mass100 and it handles the full punishment of my 50WRMS mosfet transistor amp when connected and configured with 4, 8 or 16 ohm speaker loads. I used two (slightly butchered) 5", 8 ohm, 30WRMS full range drivers wired in serial antiphase for a speaker motor unit and they cope very well, even when used with 16 ohm loads at full attentuation and full amp output for prolonged periods of up to 2 hours. I recently connected up to a Peavey Delta blues 30W combo and the results were spectacular.

Last night, I decided to run tests with the treble boost set at +6dB as I had not tried this on my maxed out mosfet amp before.
Capacitor C1 did not like the punishment and exploded, coating the inside of the enclosure with oil and paper, representing a good tarring and feathering for my ego :D
I was surprised, as I had recently included a 2R2 series resistor (as used in the mass100) to limit current, because I noticed the caps were getting warm without it. I can only imagine the caps I used (standard 10uF, 50V, NP) were not correctly rated for the job. The diagram posted on this forum specifies "high current type" caps. I have searched, but found no specific info on, nor local suppliers of this type of cap.
Does anyone have any suggestions?
gray2210
 
Posts: 1
Joined: 11 Jul 2009, 13:16
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby SPeter » 11 Jul 2009, 15:26

Soulsonic,
Thanks a lot man!!!
:applause:
:D
SPeter
Cap Cooler
 
Posts: 573
Joined: 08 Jan 2008, 22:10
Has thanked: 7 times
Have thanks: 76 times

Re: Weber MASS Attenuators

Postby greatmagnet » 02 Sep 2009, 17:59

Hey this thread is awesome...I am in the thick of trying to simplify my Weber MicroMASS and as a newb circuit builder this thread is right-on-the-money!

My original idea was to simply strip out the bypass switch and the second rheostat/capacitor combo that is allegedly for "tone" (ha-ha) and make the whole thing a little more svelte and basic in function.

But now that I've seen Soulsonic's suggestion about using the L-Pad from Parts Express instead, I think I'll go that route instead rather than using the rheostat that's already in the MicroMASS, since I'm just taming my sub-1-watt blackheart Killer Ant.

Incidentally, in case you all didn't notice, there's a hookup diagram for the L-Pad on the Parts Express website...
Image

So hey anyhow: I am VERY new to designing/modifying circuits...a TOTAL newbie...and I was wondering id someone here could explain to me how exactly the load dump (i.e. the Weber speaker motor from my existing MicroMASS) would be wired into that L-Pad drawing I posted above? Maybe somebody could just draw on top of that drawing or something?

I don't really understand how the unused voltage from the guitar amp makes it's way to the speaker motor exactly I guess...the relationship between the L-Pad and the dump, etc...
greatmagnet
 
Posts: 1
Joined: 02 Sep 2009, 17:32
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby DougH » 22 Oct 2009, 20:22

soulsonic wrote:I've tried using a MASS motor as a dummy load before, but I honestly preferred the sound of a non-inductive power resistor. The MASS motor behaves in kind of a strange way to my ears, and even though it is an actual speaker voice coil and pole piece, a line out tapped from it still requires extensive filtering via a cab simulator like a Red Box to get anything close to a real speaker sound. Though the MASS motor has a similar resistive/inductive load as a speaker, it's missing other elements and it had a strange feel to me when I tried it. Using a resistor just felt more safe to me and it's easier to get high power ratings and dissipate the heat. A MASS motor's coil can get VERY hot when it's the only thing used as the load, and since it's not moving air like it would in an actual speaker, I'm not sure about trying to put the full rated wattage into it. I'm not trying to go out of my way to be negative about it, but it concerned me very much when I tried it, and I was much happier with the results I got when using a simple resistor.


Responding to an old post here-

I agree. I got a MASS motor years ago when Weber first started building them. I tried it in a couple attenuator circuits and although the second one sounded pretty good, I could never get completely happy with it. A few months ago I built an Airbrake attenuator and much prefer it. It is a simple resistive attenuator with power resistors, rheostat and a rotary switch. You can get the plans and bill of materials from ampgarage.com if anyone is interested. I got all the parts surplus except the rotary switch (and I had the jacks) and it only cost me $35. If you buy the parts from Mouser, as spec'ed in the BOM it will cost a little less than $100. Took about an hour to put it together. It's pretty simple.

I've been using it pretty regularly with my modded 100W PV Windsor with no problems. It sounds great. The only change to the normal amp sound is a very subtle treble rolloff. This can be easily compensated with the amp tone control if it's an issue. And if you turn it down to the lowest extreme, yes it will get fizzy and lose bass response but this happens with all passive attenuators. Part of this is due to the Fletcher-Munson effect of how our hearing works. But within reasonable and usable volume levels with a 100W amp, it sounds really fantastic.

Another thing to keep in mind is that some speakers are better candidates for attenuation than others. Think of it this way- if you depend on some dynamic effect of your speaker (compression, rolloff, etc) that only occurs when it is driven hard to get a good sound- that's not going to happen if you attenuate the signal to it. A speaker that maintains a consistent tone/response no matter how hard it is driven will have a tendency to work better, IMO. For this reason I think higher wattage speakers probably work better since you never really drive them that hard to begin with.

I do like the idea behind the MassLite though. I think giving separate volume control to individual frequency bands is very smart. This way you can compensate for perceived bass loss at low volume levels. My motor is only 25W so I may get a 100W motor or try this with just a resistive load.
"You have just tubescreamered or fuzzfaced yourself " -polarbearfx
DougH
Transistor Tuner
 
Posts: 1104
Joined: 18 Aug 2007, 05:53
Has thanked: 4 times
Have thanks: 23 times

Re: Weber MASS Attenuators

Postby bbishop110 » 06 Nov 2009, 20:47

I'm new here, and just came across this site looking for Weber schematics... and I found them, big thanks!

I was wondering if on the MassLite scematic if it would be possible to use L-pads instead of rheostats (i know this part is ok) but also replace the Motor Assembly with a power resistor of the same size, 8 Ohm, 100 watts in this case, or 8 Ohm, 50 watts as the case may be.
bbishop110
 
Posts: 1
Joined: 06 Nov 2009, 20:43
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby airfox » 24 Sep 2010, 00:34

I've had great success with Weber attenuators and would like a 2-channel version--something they don't make. Specifically, I'm looking to build an attenuator with two different volume levels that are foot-switchable. Anyone have any idea what this requires? Thanks.
airfox
 
Posts: 1
Joined: 24 Sep 2010, 00:29
Has thanked: 0 time
Have thanks: 0 time

Re: Weber MASS Attenuators

Postby IvIark » 24 Sep 2010, 01:06

I've got a stompbox type attenuator that switches between two levels which was made by Torres Amps here in the UK. I've also got a Mini Mass 50 but if I'm honest I much prefer the Torres even if it isn't as versatile, because it has less of an impact on the overall sound of the amp. It's great to have the option of the MIni Mass for the variable level or silent recording, but it does change the fundamental tone more.

The Torres just uses big power resistors, and it is fairly cheap considering the alternatives. It has an attenuated input from the amp and a normal input which bypasses the circuit completely. This is good but it would be much better if it had an attenuated or normal toggle switch instead so you could then quickly switch between the two levels and complete bypass more easily without pulling out leads. If you're interested I could dig it out and do a layout.

As an extra bonus it looks like Sonic the Hedgehog :mrgreen:

Image
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP
User avatar
IvIark
Tube Twister
 
Posts: 2297
Joined: 02 Jan 2008, 00:59
Location: Manchester UK
Has thanked: 668 times
Have thanks: 684 times

Re: Weber MASS Attenuators

Postby celadine » 26 Sep 2010, 04:49

Looks fun...but very unsafe design. That heatsink should be enlclosed, or kept up off the floor. :?
User avatar
celadine
Solder Soldier
 
Posts: 208
Joined: 22 Aug 2007, 07:12
Has thanked: 16 times
Have thanks: 16 times

Re: Weber MASS Attenuators

Postby phatt » 26 Sep 2010, 12:16

Firstly a thankyou *Soulsonic* for posting it at least confirms the mass driver is only used as an inductive device,, (not driven as a speaker)

Here is my 2 cents worth;
(only 20 years of researching and real world testing of similar concepts)
Attenuators (Any type) are a very limiting way to get the job done.
(reasons are many fold and no need to rehash them all)

Some get good raps and do the job ok but seriously if you are prepaired to think outside the box there are very simple ways to circumvent most of the complexity and loss of such devices.

To cut to the chase;
A simple Voltage division from a tube amp output which is loaded with the *RIGHT Resistive load* will deliver a very real and well balanced *Line Output*.

The Missing link for Attenuation is the second Amp!
**Reamplified** (Via a second Amplifier) will give quite stunning results at any level. Output power is Limited entirely by the power of second amp. Low power = use small amp, Hi power = use a big Amp.
The first Amp need only be a few Watts,, $keeps cost much lower$.

Arrh but one more thing is still missing?
ReAmplifiying also means **Tone Reshaping** has to also happen!

Heck you wish to play guitar don't you? Like do you really want to spend 10 years in a mathatical inductance minefield trying to extract another 2% of tone mojo? Trust me just go get yourself a simple EQ setup.

I have no doubt that all that hypothetical complex stuff that supergeeks bore us with is real
But I DO seriously question how much of it is actually audible.
IME Very little.

By implimentation of a *Secondary tone circuit* (In my case an $8 secondhand HiFi graphic tone control) before sending the signal to the second Amplifier or Recording device if that's your intention will deliver more Mojo than you could ever ask for from Attenuation alone.
IME,,,Attenuation of *one Amps output* even with all the bells an whistles tone compensations don't do a covincing job.
TONal loss is inevitable so Adjustment/Compensation of TONE is manditory no matter what.

Caveat:
If you want Very Very Low levels of output or you have a 200 watt Marshall Major with two quad box's and you wish to play flat out at 2 am in the morning and expect a perfect authentic reproduction of sound at only milliwatts of power then clearly nothing can help you, cept maybe a dedicated Hphone setup.

On the other hand if you wish to;
1/ Rip off or Add some wattage (SPL) in a live situation?
2/ Take a line level for recording with or without a speaker box?
3/ Take a line level (post Powerstage to add time EFX) and ReAmp it for live use?

Then it's very easy to achieve good results as long as Some form of Secondary Tone Control is used.
I've had stunning results with a simple Load R and a voltage divider converting to *Line Level*.

Take note,,**Important bit**
The LOAD R needs to be about 3 to 4 times the speaker Impeadance otherwise it's going to be very lifeless. 8 Ohm Loads on 8 Ohm tap will just turn your favorite tube amp into a limiter (a valve version of a TS9)
i.e. An 8 Ohm speaker out needs more like 30 Ohm Resistive Load. A Huge improvement will be immeadiately apparent.
The *Line Level* is done via a simple Voltage divder, around 10 to 1 divider will get you close.
I use 470k (Series) into a 25k pot across signal to ground.
This gives you a *Post powerAmp level control*
(See Schematic)

The rest can be whatever you want it to be. Better if the second Amp is a plain old power Amp,, don't make the mistake of using a monster gain Guitar Amp for the second Amp as you need a flat response for that part. You have already captured the Tone mojo thang now you just need to amplifiy it all without added artifacts,, for that a clean power amp is ideal.

Oh one more thing, Wise to add a ground lift for the lineout box,,
negates the dreaded earth loop hum issues.

For those that think Resistive loading robs tone just Google *Guytron GT100*
You would be hard pressed to find much better.

Guytron is effectively all of the above but in one monster All Valve *Heavy Head*
If I had endless money I would purchase that Amp head, sadly I will never be that rich so it's make my own stuff from scraps of junk.
Phil.
You do not have the required permissions to view the files attached to this post.
phatt
Transistor Tuner
 
Posts: 1097
Joined: 04 Aug 2010, 06:17
Location: Morayfield SE Qld AU
Has thanked: 0 time
Have thanks: 283 times

PreviousNext

Return to Amplifiers

Who is online

Users browsing this forum: YellowBoy and 5 guests