Lpad attenuators

[ce24]

Are these worth building...I would be using it with my Vibrochamp and 5E3. klooks like I could build one for like 25 buks.


Thanks in advance

 

[Bob W.]

They work pretty well. Get a mono 100-watt L-pad. It's easy to find 'em in 8-ohm impedance. Mount in a box, add connectors, you're in bizniz.

It won't sound exactly the same as a loud-cranked amp, but pretty close. For one thing, the speaker's not getting driven as hard, also the amp sees a more resistive rather than reactive load. Still, it's better than a fuzz box...

 

[CrisHendrix]

I got one for my champ from parts express for like 6 bucks (just the attenuator, no box or anything) still not sure how to hook it up

Would making a box of it (I assume using guitar cable connectors for in & out) sound the same as hooking it directly between speaker & amp?

 

[StratBluesRock]

On a side note, I like to play my silverface Twin on 7, so to not level the house, I use a Weber Mass 200 attenuator, which sounds great.

 

[Frodebro]

On a side note, I like to play my silverface Twin on 7, so to not level the house, I use a Weber Mass 200 attenuator, which sounds great.

DRRI on 5 with a Hot Plate is my thing.

 

[ce24]

Im looking at the vvm now from Hallamplification.....jeeze 30 buks and a little soldering time and Im in like flint....this looks great.

 

[TheGoodTexan]

I'm not an electronics expert, but I've seen this question come up before.. about using an L-pad to attenuate an entire amp... and the answers were along the lines of "that's not what they're for... could easily damage your amp."

I think the reason being that L-pads are more or less designed to be used with higher frequencies, like tweeters, which draw little current. A full-range guitar signal will need a resistive load when it is being attenuated (like a Weber Mass), or you risk damage to the amp.

Again... I'm no electronics expert, so someone can correct me if necessary.

 

[StratBluesRock]

DRRI on 5 with a Hot Plate is my thing.

Haha. Before I got the attenuator, and when I didn't have band practice or a gig (where I'd have to play it on 3), I'd play the amp on 7 un-attenuated. Man that was something!

Got the attenuator like 3 months after I bought the amp, couldn't be happier that I'd finally be able to get those 6L6s cookin

 

[Dave_O]

I'm not an electronics expert, but I've seen this question come up before.. about using an L-pad to attenuate an entire amp... and the answers were along the lines of "that's not what they're for... could easily damage your amp."

I think the reason being that L-pads are more or less designed to be used with higher frequencies, like tweeters, which draw little current. A full-range guitar signal will need a resistive load when it is being attenuated (like a Weber Mass), or you risk damage to the amp.

Again... I'm no electronics expert, so someone can correct me if necessary.

L-pads are a resistive load. Like this old beast...

... and the Marshall Powerbrake and the Tom Scholz Power Soak. Amp runs into resistive load, creates heat-at-the-resistor instead of sound-at-the-speaker. Most L-pads aren't really designed to have 50watts pushed through them, so they'd probably get hot enough to cook an egg on. But they'd probably do fine under a 10-15watt amp. Or if built onto a heat sink of some sort.

The newer designs feature "reactive" loads. Weber uses a speaker voice coil. Not sure if it moves in a magnet or not. A mate had a Weber Mass in between a 50watt Bassman and a 2x12" which I recorded. It sounded alright. I've used a Power Soak (didn't own it) between a 50watt JMP and a quad. It, too, sounded alright. I'm not sold that the Weber (et al) are worth the extra money. IMO, YMMV, etc, etc.

But then again, I'm in the fortunate position of being able to own more than one amp. So instead of sticking attenuators of any breed between my amp and my speakers, I just bring a smaller amp

 

[tap4154]

I put one in my SF Champ a few years ago. It's only a 15 watt/8 ohm version, and I had an 8 ohm 10" speaker in the amp at the time. It worked very well, and only got slightly warm, but I've since put the original baffle and speaker back in without the L-Pad.

Here's what it looked like:

Then recently I bought a Pro Junior off eBay and decided to adapt the same L-Pad into a project box with a couple 1/4" inputs on it, and using a double-male 1/4" jack designed it so I can just plug it up into the amp chassis, and remove very easily. It works great in the PJ as well, but gets pretty hot when playing for a while, so I've stopped using it. A 15 watt L-Pad and 15 watt amp... not a good match. It should be at least double the wattage of the amp, or more. I may get a higher wattage rated L-Pad eventually, but play clean most the time so it's not a priority.

Here's what it looks like:

 

[StratBluesRock]

Just wondering, why would you want to attenuate a Champ?

 

[tap4154]

Just wondering, why would you want to attenuate a Champ?

To play in an apartment with the amp's volume on 8-10 (real nice OD) without upsetting the neighbors.

Here's one vid I made with the Champ on about 6-7, and L-Pad down to about 1. Just on the edge of breakup. It may sound loud in the video, but in person not loud enough to upset the neighbors. Just recorded with a point 'n shoot, so not the greatest audio, or playing

 

[CrisHendrix]

Yeah I find the sweet spot of my Champ at around 10.. I also have the gain stages on the pcb opened up and an 8" rola speaker in it, so it gets roaring loud at 10 (a 5 watt tube amp gets half as loud as a 50 watt tube amp, which is pretty loud for an apartment imo if you really wanna open it up)

 

[Bob W.]

I got one for my champ from parts express for like 6 bucks (just the attenuator, no box or anything) still not sure how to hook it up

Would making a box of it (I assume using guitar cable connectors for in & out) sound the same as hooking it directly between speaker & amp?

An L-Pad attenuator is designed to go between amp and speaker. It presents the correct impedance load to the amp's output, while reducing the amount of signal going to the speaker. It will dissipate a considerable amount of power as heat. For overdriven guitar amps, make sure you use an L-pad that's rated for at least double your amp's output power.

Usually, these are wired with 1/4" connectors (or whatever will mate with the amp's speaker jack). Be sure to use suitable speaker wire, not shielded instrument cable.

These will not work as stomp boxes between instrument and amp.

 

[ce24]

Is it possible to incorporate an axtra line out with an Lpad attenuator...say to go to a PA....it can't be as simple as adding an extra output jack can it?

 

[emu!]

Just change V1 to a 12au7. It will be less loud but still break up like crazy.

 

[ce24]

All i need is a dial the shifts from a 12au7 to 12at7 to a 12ax7.....nah an Lpad is easier... I want to be able to adjust vol at random....