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Home MiniMASS 50w Attenuator
Item Code: MiniMASS
MiniMASS 50w Attenuator Item Code: MiniMASS

MiniMASS 50w Attenuator

  • Designed for use with 35w amplifiers and lower.

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This attenuator has a main volume knob and 3-position treble compensation switch which affect the signal to the speaker. The line out signal is dependent on your amplifier settings.

Impedance selector for 4, 8, 16 ohms, 3-position treble compensation switch, MASS bypass switch, unbalanced line out. The MiniMASS employs an actual speaker motor for realistic interaction between the attenuator and the output circuit of the amplifier. The attenuation is continuously adjustable from about -3dB to over -50dB.

By turning the speaker control to minimum (maximum attenuation), the unit may be used as a dummy load for testing or for DI use.

5.5” x 5.5” footprint (add 1” in front for knob). 3.75” tall. 3.35 lbs basic.

Line Out jack has no volume control and is dependent on your amp volume setting, but we do offer a Line Level Volue Control here:

This item is hand-built to order, to ensure the best attention to detail is paid to its construction.  We build them one at a time, on a table - not hundreds at a time on an assembly line.  This allows us to reduce the margin for error and produce an overall higher-quality product.  Please allow at least 7-10 business days for your order to be built and then shipped.

Technical Details


More often than not, your amp's output is more than your ears can handle.  To maintain the tone of a cranked amp with saturated tubes and output transformers, a device called an attenuator is placed between the output of your amp and the speaker.  Weber offers a variety of attenuators for different applications.

A note about the power level: You should select an attenuator that can handle at least as much power as your amp puts out.* (see FAQ)

Amplifiers are generally designed to operate clean, and most manufacturers specify the output power as clean power. When you run the amp full blast, the output devices actually become more efficient because distortion is not considered. Under those conditions, the amp may be capable of putting out as much as 50% more power than its rated clean power. Be aware of that when choosing an attenuator, because the idea of using an attenuator is to run the amp full blast into power tube distortion and then controlling the level going to the speaker. If you are going to dime a 50 watt amp, you should choose a 100 watt attenuator.


Please read and consider the following prior to ordering an attenuator:
(The following text is reprinted with permission from Eurotubes

Here are some facts to consider when using an attenuator. Attenuators do work. They are not the cause of transformer failures. An attenuator can only simulate two out of the four components that are involved when you crank up an amp. The four components are #1 preamp tube distortion, #2 power tube distortion, #3 speaker distortion and #4 the physical movement of air that your speakers produce at high volumes. So the two components missing are speaker distortion and the physical movement of air and these are huge components! So if you’re playing at moderate volumes and just want to tame the amp down to get a bit of power tube breakup then an attenuator is a great tool, but do not expect to be able to dime your amp and then use any attenuator on the market to get the exact same sound from your amp at whisper quiet volumes. You can't get there from here. You would be better off with a one watt amp.

So, now some answers. Catastrophic power tube failure will cause transformer and screen grid resistor failures. The reason you will read and hear horror stories from un-knowledgeable attenuator users is because they do not understand how attenuators work and the stress they put on your tubes.  If in fact, a player chooses to run his amp cranked all the way on and attenuate the volume down to a whisper, then in most cases power tubes will only go a few months. Power tubes will die in one of two ways. The first and most pleasant is by simply fading and dying. The second and more popular way is to go out in a blaze of glory which is what I referred to above as a catastrophic failure which can and most often will, take out screen grid resistors.

Tubes sound great when they are really working hard but the harder you work them the faster they wear out. If you understand this and either use the attenuator sparingly or change your tubes regularly then your amp will not suffer damage.

If you are going to dime your amp out and attenuate it down to very quiet volumes then we recommend using an attenuator that is rated for twice the power of your amp's rated output.

If you are simply going to dial an amp up to where it starts to breakup in the clean channel and then knock it down a few dB so the club owner and the sound man are happy, then using a 50 watt attenuator for a 50 watt amp will be ok.


Understanding Attenuators
An article by Michael Farnsworth
This is a wonderful article written by one of our customers, which explains attenuators in even more depth.

Customer Reviews of MiniMASS 50w Attenuator

Better than expected


August 27,2019
Better than expected

As an attenuator, it does a fine job of letting me dial in the amp and get a reasonable facsimile of that at bedroom volumes. A+

Even more impressive to me is the recording line out quality, it is far superior to the onboard line out of my previous amp! A++

Weber MiniMass Attenuator


July 10,2019
Weber MiniMass Attenuator

I bought this attenuator to use with my Jcm800 Studio 20 watt head. It works perfectly for me, now I’m able to crank this amp without fear that the sheet rock will melt off the studs!

I’m now able to get all the great tones and responsiveness of a tube amp cranked! This little attenuator is an amazing little product. It does the job perfectly and for a very reasonable price.

Some attenuators cost hundreds of $,...and some thousands. The Weber MiniMass does all that I need it to, and it does it very well.

There’s even a +3 snd +6 db setting to add some treble if needed. Also you have a choice of 4, 8, or 16 ohm settings for the cab being used.

I am exceptionally happy with my purchase, this attenuator does everything I want it to do, and it does a great job doing it,.....and at a great price,....what more could a person want?



January 01,2019

After owning my vintage Princeton Reverb for many years and rarely getting to crank it to hear it's magic, I finally purchased the Weber MiniMASS. Now I can sit in my tiny NYC apartment with the amp volume at 5.5 and not destroy my hearing or have the neighbors call the cops.

Does it sound the same as a very loud Princeton, no. Does it sound very good, yes. No need for pedals, just the amp's natural break up, reverb, and tremolo. It definitely sounds better than putting an overdrive pedal in front of the amp. And no battery or power supplies to deal with (MiniMass does not require power).

I'm also using the Line Out to record directly into my laptop via a Zoom U-24 interface. This required installation of impulse responses on my laptop (like any line out would) and the results are fantastic.

I confirmed with Weber that you can disconnect the amp's speaker if you have the MiniMASS fully attenuated (even fully attenuated, you still get sound from your amp unless you disconnect the speaker, it's quiet but there is sound).

Weber even hand constructed a custom cable to connect my amp to the unit that matches my existing amp/speaker cable.

There was a slight mix up with the cable delivery but I added the cable after the order was placed so no big concern. Weber was super responsive through the order/delivery process and helped me understand how to confidently use the MiniMASS with my beloved amp.

Great purchase from a great company.

Wish I bought this earlier!!!


March 02,2018
Wish I bought this earlier!!!

I’m not one to leave reviews but this has made my playing life 10x better. My wife and I have 2 young kids which dropped my playing substantially mostly due to volume. This has tamed my Bad Cat 30r’s volume but not its growl. I couldn’t be happier. I just wish I bought it 10 years earlier when neighbors were an issue.

... and within a few minutes I found my sweet spot!


February 19,2018
... and within a few minutes I found my sweet spot!

It was a long way til I found my sound, but thanks to the Minimass 50 I finally found it. I play a Vox AC30 and as everyone knows: it's a damn loud amp. Playing with the band it's quite funny when you're louder than the drummer AND the Bassist together. But just funny for a minute or two ... in fact it's just annoying. Two years ago, I tried to attenuate my amp with an EHX Signal Pad - cheap and effective. But it destroyed the chimey sound of the AC30 and made it dull. After hours of browsing the Internet I spotted the Minimass. And hey, the guys of Weber really make a fine Job! With the harness (PV30MH) it's so easy to install. The sound is amazing, it still sounds like an AC30, and I can't hear any loss of brillance or heights or whatever in the tone! Within a few minutes I found my personal sweet spot at a reasonable loudness. It just felt like having a new amp. The little box is build like a tank, and the treble boost switch is a great little helper! The Minimass is an absolute must-have for any loud tube-amp. PS: The support from CJ is awesome! [You are welcome, Michael!]

Minimass 50


November 22,2017
Minimass 50

My mesa boogie is too powerful for home use unless you run it very quietly.
Problem there is that the tubes are then not running properly. Sticking the minimass in to the amp means I can now get the tubes breathing, and crank them up but still maintain sensible decibel volume. With the treble boost switch you can also remove the problem of treble loss at higher gain. So how does the rig now sound ? Face meltingly lovely and also at low volumes. In fact the minimass is getting me sounds which I never dreamed of. I must conclude therefore that this is a very good device and that if you want an attenuator then Ted makes them good.

Perfect Solution for my needs


May 10,2016
Perfect Solution for my needs

Just got this yesterday and almost missed dinner because I was playing with it so much. I love the headphone out feature as I am a bedroom player. I have my Orange Dark Terror 15 watt tube head running into this right now and can really get the tubes nice and warm while using headphones.

I use a lot of pedals with my setup so this is great to have a platform that allows me to run everything into my amp, including my modulation pedals through the effects loop and have a headphone out at the end of my chain.

Also, with the attenuator volume I can dial in some nice bedroom volumes without the headphones while keeping the tubes running optimally. Great product at a much better price than the factory built competitors. Thanks Ted Weber for saving me from eviction!

Weber MiniMASS 50w


November 23,2015
Weber MiniMASS 50w

Hey Ted, I just received my MiniMASS 50w this week and absolutely love it! I'm using it with a 15W Mack Skyraider SR-15 tube head. I've always loved the sound of the Skyraider, but to get it to really sing it had to be cranked. The Skyraider is a non-master volume amp, so it was impossible to get these great tones at studio volumes, but now I can thanks to your product. The treble boost is a great addition especially useful for when you attenuate down to bedroom levels, it helps keep your sound crisp and clear. Thanks again for building a fine product.

Excellent in an unconventional way


September 14,2015
Excellent in an unconventional way

I have to admit that when I first received my MiniMass I was a bit disappointed. I tried it with a number of amps Fender Concert 1X12, Orange OR-15, Blues Deluxe, Egantor Tweaker and several others and I couldn't find a sound I liked at all. I was hope to get some good, overdriven power tube crunch and I couldn't find it anywhere.

Then I let it sit on my desk for a year.

Then I had an idea and got it out again.

I've been on a quest for low volume tone for a long time and had almost given up.

It occurred to me that I might be able to use this device as a load box, utilizing its line out to feed other things.

OMG. I finally found what I was looking for. I run amps directly into this unit into various DAWs and use a speaker sim plug in and the results are phenomenal. Currently I'm using RedWires cab and mic sims but there are lots of good options out there these days. I've also had excellent results using several year old Line 6 Pod Farm cab models.

So, in the end, I'm using about 10% of the features of this box, but it's doing exactly what I need it to.

Now I just need Weber to make a 'no frills' version. Just and impedance switch and a bypass switch. Attenuation either at 0% or 100%. I'd buy loads of them.