DIY Attenuator HELP PLEASE

[Mike]

OK I've checked the schematics page and the links have errors.

Does anyone know where I can get schematics and instructions for building my own Attenuator.

At this point I'll take what I can get but ideally something like the following

These would be for 100w amps, ohm adjustable if possible

Webber Mass Attenuator
Dr. Z / Tranwrieck Airbrake
THD Hotplate
Powersoak

Any helpl much appreciated.  I'll kick myself in the head if I have to pay $300 for one of these.

:lol: THanks
Mike

[Craig V]

This is from WeberVST.

[Mike]

Thanks Craig
I guess I'm too muich of a Newbie to translate that into perf-board layout.

I was hoping to find detailed  instructions on GEO or general guitarvgadgets or something.  NObdy seems to have these.

My quest conitnues.

thanks for the schem

Thanks again

Mike

[petemoore]

That one's from the Weber page, uses a large 'draw motor' like a dummy speaker coil.
 I thought of just trimming and damping the heck out of a speaker coil, and connecting that with speakers to load the amp and draw alot of power to the dummy speaker [which would be lower Ohms so it would get the lions share of the output power].
 I had [have?] an attenuator built for me from very large 'brick' resistors...the ones that converted much output power to heat were seriesed [a lot of surface area for heat dissipation] and got quite hot]...these IMO 'mush' the sound a bit.
 I like the Weber idea of a dummy draw coil...well
 I use a 50w amp for gigs lately

[Ansil]

a light bulb works great

[aron]

I guess I'm too muich of a Newbie to translate that into perf-board layout.

Mike,

That's a PERFECT schematic to start with.

Ignore the tone stack parts and you only have a speaker, resistor, pot and jacks.

You try and sketch it out and we will help you correct any mistakes you make.

You don't need perfboard for this one. Point-to-point wiring! :-)

[Alpha579]

Where do u get those mass motors?

[aron]

From WeberVST. I have 2 of them, they work.

[clutterbuck]

Hello all, back after a long long break.

I am in the same situation as mike. The weber schem seems very simple. The circuit is describes as being for a 25watt load. If I wanted to scale this up to a 100w load what extra is entailed. Do the values for the resistors remain the same?

I like the idea of having variable attenuation. The L pad idea won't offer me that without going into building a design based on several pads switched via a rotary.

[V!N]

a light bulb works great

.. excuse me ? :shock:

[javacody]

What is a mass motor? How do you control the volume from the attenuator? How loud will this be?

[clutterbuck]

Basically it is a coneless speaker. The schem shown uses var resistor to control the volume much as you would in a pedal volume control. It's just the values that concern me.

http://www.webervst.com/mass.html

[Ansil]

a light bulb works great

.. excuse me ? :shock:

i dont' have the exact schematic on me right at this moment i am out at library  but however  basically u put a light bulb standard hosue isue  or a neon is my favorite

and it will eat up extra power from power amps, it has been done in large pa cabs for years..  u can see them light up thru the port holes when they are pushed too hard

the guy i used to work for showed me that.

[Nasse]

Ansil wrote

it has been done in large pa cabs for years.. u can see them light up thru the port holes when they are pushed too hard

:shock: Yeah I remeber I have a circuit lying somewhere (think it was thorough article in some old Elektor Electronics) using lightbulbs to protect tweeters in hifi and PA. Maybe I´ll find it some day, but dont know what year and month :oops: But it was useful simple and cheap and goodsounding trick imho. Maybe some day I´ll take a copy from December issues mag index pages and archive these papers well... It maybe has something to do with my childhood, too much wooden toys and such :wink:

But just remembered this link http://www.kolumbus.fi/mikko.esala/diskanttisuo.pdf
looks like power mosfet version of tweeter protection, maybe useful if it works, dunno. It says there must be a series resistor in series with tweeter in crossover circuit to make it work, and some good heatsink is needed

[aron]

Hello all, back after a long long break.

I am in the same situation as mike. The weber schem seems very simple. The circuit is describes as being for a 25watt load. If I wanted to scale this up to a 100w load what extra is entailed. Do the values for the resistors remain the same?

I like the idea of having variable attenuation. The L pad idea won't offer me that without going into building a design based on several pads switched via a rotary.

I believe a 100WATT MASS motor and possibly adjustment of the resistors. The resistors as shown are pretty darn soft as far as output volume goes.

[Doug H]

Hello all, back after a long long break.

I am in the same situation as mike. The weber schem seems very simple. The circuit is describes as being for a 25watt load. If I wanted to scale this up to a 100w load what extra is entailed. Do the values for the resistors remain the same?

I like the idea of having variable attenuation. The L pad idea won't offer me that without going into building a design based on several pads switched via a rotary.

I believe a 100WATT MASS motor and possibly adjustment of the resistors. The resistors as shown are pretty darn soft as far as output volume goes.

You will need a higher power rating on the resistors.

Doug

[V!N]

i dont' have the exact schematic on me right at this moment i am out at library  but however  basically u put a light bulb standard hosue isue  or a neon is my favorite

and it will eat up extra power from power amps, it has been done in large pa cabs for years..  u can see them light up thru the port holes when they are pushed too hard

Oh my, how do they come up with stuff like that.

Sounds like a great and inexpensive way, but how safe will that be for the transformers of a cranked tube amp ?
I'm affraid a bulb is more fragile than Teds MASS motor.

[Peter Snowberg]

Lightbulbs can make very effective over-current protection in some cases, but as a speaker emulator?  :!: NO... forget that one quickly.

The impedance will start off too small (100W lamps have a very low resistance when cold) and then quickly get too large, never fully recovering to the too small area... but everything is 100% RMS output dependant. They work great for regulation in Wein bridge oscillators because they sit in the feedback loop (taking advantage of their negative resistance), or for a sort of over-current breaker in testing amps and appliances, but as a speaker load.... no chance. BTW: Neons will not work in the slightest for this application. Those are a totally different animal.

I would hate to see somebody blow their amp trying this.  

Take care,
-Peter

[MarkB]

I used to run sound at a club.. the place sounded GREAT... and when we pushed it too hard, it was a light show.. the 'community' speakers used in the PA had the lightbulb overload circuit in them.. it was kinda funny to see it.
"-)

[Ansil]

of course i am not suggesting them as a speaker emulator i am suggesting them to suck up power,  and well as i always state your expriences just like mileage in a car may vary, but personally when i learned this trick i found out that one of my favorite local guitarsist is using this trick built my a friend of ours to take the output of his 100watt marshall and to drop it off enough to use that into a effects rack.

as he as a powered mixer with built in fx and stuff.

anyway so far he has used this thing for 8+ years on a tube marshall 100 watt head.. and well it works.  as far as a direct lpug in for the weber mass schematic no..  but it is in the same principle and well you can try it if you wish.  i have had good luck with it myself and had no problems as i have borrowed the thing when i used to use a 5150 head, that just didnt' sound good unless it was past 6.