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Attenuator - my experience


Posted on Wednesday, December 28, 2005 - 09:26 am:   

About a year ago now I bought a slightly beat up, but electronically very 'like new' HD-410 Sixty Five, with PI tube. The friend I bought it from was a GREAT player, and the amp used to sparkle when he played it. When he needed money I was there to gobble it up!

I've had some time now to really work into the thing at gigs. I came from playing a mesa-boogie subway blues. It's a 20-watt pseduo class A amp, 22 or 11 watts. GREAT reverb, GREAT overdrive, GREAT compression. However, try play a funky 9th chord at full volume and you've got nothing, mostly because of those three things I mentioned. You want a loud clean sound? Nope that baby doesn't do that. It gets dirtier as you turn it up. A one trick pony in that sense.

In comes the music man - it's SO CLEAN. I figure cranking it will get it to break up nice. (Mind you, I've played this super compressed thing for a couple of years). No luck - I mean - it does, but it's 4x as loud as the drummer, with 65 watts and 4 tens. The distortion that comes out of the preamp is cool for some things, but not a whole lot of stuff where you would like a smooth, even harmonic overdrive. I thought about using a pedal to get overdrive but I have had mixed experiences getting a 'natural' sound from that.

Next I got a Weber MASS Attenuator. It's the 100 watt version. At first, when I could I used my amp in low power mode. However, I have an older version where that cuts the power to my preamp too. The amp really came alive though. Amp on 10, preamp on 5 or 6. Some nice breakup starts. You can turn it up to 10 - it's a good sound. The reverb improves a lot when the output tubes start to do their thing. It really sounds great.

Soon, I got comfortable doing that without things blowing up. Just incase I ALWAYS bring a small table fan - plug it in to the outlet on the back - and put it in the back of the amp pointed up at the tubes and big transformer. I think this is a MUST if you are thinking about attempting this. I know if I don't do this the top of the amp gets very warm - which means it must be very warm in the chassis.

These days I hit gigs with my music man and attenuator - and I use it on full power. I like the sound a little more. A little less "Grainy". I think the preamp stays cleaner that way - however the music man's preamp distortion not the best on it's own, when pushed through a working power section - does really come alive. Again, the fan is a must. I think without the fan something near and dear to my heart - like a transformer - may have melted by now. These days I have been playing my tele (xmas present) through it. Even the treble on the music man, which you have to be careful to control and not make to harsh - chills like a nice wine when going through the working power section.

If anyone has had weird experiences with pedals *and* understands how much stress they are going to put their beloved amp through - I would recommend this. You will porbably want to make sure you are biased right, recapped, all that stuff, before you try though. I am sure others here will have good advice on "attenuating safely". Happy picking !

PS. GF got a digital camera for xmas - pics coming soon
Steve Kennedy (admin)
Username: admin

Registered: 03-2002
Posted on Friday, December 30, 2005 - 07:06 pm:   

Thanks for the real-life experiences. I have a number of attenuators and "speaker emulators" I have experimented with and even recorded with. However, I have never used one continuously in a live setting.

Finding a 120Vac fan to plug into the accessory jack is a great idea! I did this with a modified Fender Bassman head I used to own that had 4 EL34 output tubes! It got so hot I was afraid NOT to use a fan! I simply took an AC chassis fan and fashioned a double "hook" hanger for it from a wire coat hangar and simply hung it on the outside of the amp blowing air onto the transformer, which also pushed the hot chassis air through the tubes on the way out. It kept things very cool.

I also have an HD130 head that I modified to have a fan built-inside the amp pulling air through the chassis through a cut-out in the grill board (I made the grillboard so I popped a couple of rectangular holes in it for cooling). I simply mounted the fan upright (sideways) with a few angle brackets found at the hardware store (screwed down to the cabinet in 4 places).

Here is a tip: If you can find a 240VAC fan use it instead. It will run at 1/2 speed which will make it much quieter! It still promotes plenty of airflow for most applications.


Thanks to both of you.

I just bought an 78 MM 212 HD 130 which unfortunately has some issue, currently at the repair shop waiting its turn to get cured of its ailments. I am also looking at an attenuator and your experienced opinions are great appreciated!

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