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Big attenuators

C

Cartoonist

Guest
Feb 21, 2012
42
1
Australia
#1
Hi all,

I've just bought an Ampeg SVT VR (woo hoo) and I'm trying to find a suitable attenuator (dummy load type).

The amp (which as a 300W RMS tube monster is as loud as it is sweet) will be used from everything up to large outdoor events down to med-small venues, studios and rehearsals. Actually, anywhere I can lug this 40kg (85lb) beast. I prefer to have the best and most consistent sound available to me in all scenarios so I want an attenuator so I can run the tubes where I need to to get the right answer.

And I know, running the attenuator means running the tubes hotter which means shorter tube life. But it sounds good, and isn't that what this is all about?

I have a Weber Mass for my guitar amp but even the biggest Mass is only 200W... and they recommend getting an attenuator that is sized 2x the size of the amp (i.e. 600W for the Ampeg!) to ensure there is enough capacity for high attenuation for extended periods).

Short of linking two units in parallel, I can't find anything anywhere near that powerful.

Ultimate Attenuator (UA) tell me their 300W unit, which is fan cooled, will do the job and I'm considering that.

Before I take the plunge (it's not a cheap device), I'd really appreciate any advice from anyone who has experience with big-wattage attenuators or who can provide any theoretical info that might help, particularly as to whether the UA could handle running at high load for a long time (and whether it'd do the job).

Thanks
Cartoonist
 
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#2
There isn't a Powerbrake/Hotplate, or other type attenuator made that can handle anything more than a 100 watt guitar amp. What you need is a 100-150 watt tube bass amp, and maybe a cabinet with a couple less speakers in it to hit that sweet spot and not send bar patrons towards the door.

Look for an old Ampeg V4 and something like a 410/212, or 215 that isn't super high spl.
 
#3
Thanks Will33,

I'm only rocking a 410. And I already have a backup head that I can (and do) use for smaller venues. Rather than getting a third amp I have decided to investigate attenuators.

I figure that there isn't any physical reason that these things can't be built bigger, it's just a matter of whether they are in the marketplace (and I have found one, UltimateAttenuator, who tell me they can do the job), and if they are whether they are suitable (hence my first post).

Cheers,
C
 
#5
As I said, I already have a smaller amp suitable to smaller venues. Buying yet another amp and speakers is much more expensive than just attenuating the SVT.

I just want to get the most out of the SVT without limiting it to larger venues. That's why an attenuator makes sense me.
 
#7
Thanks for your input will33. You are giving good advice. I just have a plan to get the most out of this amp and I think I can see it through (whether it's practical for everyone out there is to be pondered).

The attenuator I am looking at is around $500. I am looking for a cheaper one and talking to some manufacturers to see if they can knock one up for me. I think the reason you can't find one in the marketplace is at least partly due to the attenuator market being far bigger for guitarists wanting to control tone than for bassists wanting to play quieter! And 300W is a pretty ridiculous size for a guitar amp.

Where I am, it's not practical to go shopping for bass heads - but I can buy attenuators over the net with a predictable result in sound. Again, I'm not necessarily trying to be practical, just trying to achieve a goal without blowing up an amp.
 
#8
Dude, good luck with your SVT using an attenuator. Will is right...if they made an attenuator that would work for it, we'd all have them. You will burn up your SVT with ANY attenuator on the market. You can either trust us on that or you can burn your SVT up. But don't say we didn't warn you.
 
#9
Hi JimmyM

Thanks for the warning.

Do you still think the SVT would burn up with the 300W UltimateAttenuator? Does anyone actually have any experience with this unit to support or refute your claim?

These are the exact words the manufacturer emailed me:
"We continually fan cool the UA so 300 is good for 300. If the load begins to fail you would know it long before it happened. Never has though."

I would need a watertight guarantee if I went with these guys, but at least they are confident enough to put the above in writing.

I'm also investigating using using Yellow Jackets but dunno if they've released a design for larger amps yet. Failing that i could maybe sub in some KT66s but this wouldn't be as flexible a solution as I'd probably need to rebias every time I switch.

And yes, I know this is a big amp for big venues, I'm just trying to introduce some flexibility. It's a project, and it's not impossible.
 
#10
300w is when it is still clean, if you are using the attenuator to get dirt, then 300w is the minimum output for dirtyness, the dirt comes when you exceed it, since output is clean rating. And to get noticeable sound loss, you are going to have to be sinking more than half of that power.

VT bass for dirt without stupid power.
 
#12
Mr. Foxen said:
VT bass for dirt without stupid power.
Click to expand...

Yes, you should at least try a Sansamp VT or VT deluxe pedal before buying an attenuator. I use one with my tube powered SVT's, but not just for dirt. They can do a dam fine job of copping that natural compression feel you get with a cranked SVT, but at any volume level. If you haven't tried this pedal before, you really should.
 
#14
Mr Foxen - thanks for the info on the higher wattage output by the tubes when pushed. I didn't know that was the case.

I'll check out the VT but I'm not a big fan of pedals. Also, yes I'm considering building my own attenuator but if 600W is really necessary then even I think it's ridiculous. However I'm not so much after high levels of dirt so maybe a smaller unit can do it.

My simplest option might be the Yellow Jackets, if they come big enough.

Thanks for all the useful advice.
 
#16
Peavey - to clarify, I'm just not after HIGH levels of dirt. The sweet spot for me is when digging in gets some dirt, but standard playing is more mellow. This can be achieved turning up to a reasonable volume just not fully cranked like some might want it. While just turning the volume down still gets a beautiful tone it doesn't give enable the full capabilities of the amp to be accessed.

I'm starting out with the volume down and no fancy attenuators or anything. Like I say, it's just a project to add some versatility to the amp in less than enormous room settings.
 
#18
CL400Peavey said:
Im confused. If you are not wanting to push the amp past being clean, why not just turn it down? I dont really understand your usage of "getting the most" from the amp. The SVT has a pretty spectacular clean tone. What are you trying to accomplish tonally with your attenuator idea?
Click to expand...

My question too.

Guitarists use attenuators to get tube overdrive at lower volumes not, IME, to acheive clean tones at a lower volume.
 
#19
You can accomplish your goals with a different cab. Your Golite is a very sensitive cab. 105 dB/w/m from what I have found with a quick search. That is like having two 102 db/w/m 410 cabs stacked! I would be looking for a cab in the 99-100 db/w/m range. You will be able to push your head much harder and keep the volume reasonable.

To put it in perspective if you starting out with 99 dB/w/m 115 you would have to stack a total of 4 of those cabs to get the same sensitivity.
 
#20
Good idea on the cabs. I'll see if I can pick up a 115, even if it would look funny with an enormous SVT plugged into it (by looking funny I guess that means pointing out that this is a slightly ridiculous goal I'm pursuing).

Also I forgot to mention that the VR, like the originals, doesn't have a master volume control so I could look into a reversible mod here (though I will be trading 6550 richness for higher preamp drive).

Again it's about achieving some dirt, not pure clean tones, hence why I am seeking an attenuator.

(and no Mr Foxen, it's not the wrong amp for my purpose, it just is not currently suitable for all of my intended purposes - if you read what I've said several times above I'm trying to add versatility not replace its main function).
 

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