Big attenuators

[Mr. Foxen]

Originally Posted by dmusic148

Or, it means that you love the SVT sound and nothing else will do, but it's too loud by the time it starts to 'work' a bit. That's what this is about. There really is no suitable smaller amp, if you must have SVT sound.

Too loud is part of the sound, being that loud is what it is made for. That is why is is 'Super' they made small amps too.

[will33]

So now we're getting all techy

Sure somebody could make one...but why?

Guitar players I've known who were regularly using these things were constantly cooking their amps. Lots of repairs, tube replacements, etc. A real tech may be able to refute that because of poor design of the particular attenuator or something, but, experience has told me to not put one of those things on my amp.

A lot of amps you can pull power tubes and rebias for lower power. The impedance taps change along with this, but I don't think you can do that to an SVT. It's power tubes works as a pair of 3 each.


To your other question, a 4 ohm Black Widow will play fine with an SVT, but, you could blow the speaker turning the amp up as much as you'd like to. Speaker wattage ratings are the thermal handling of the voice coil. My 8ohm BW's model to about 150-160 watts clean bass. You can push them farther, but, thermal compression is going to start setting in then. Keep that up long enough and you can toast the coil with less than it's rated power.

[Cartoonist]

Originally Posted by Mr. Foxen

Too loud is part of the sound.

So recordings of an SVT don't sound good unless played at concert volumes? An SVT attenuated to a lower volume won't sound good in a smaller venue?

[JimmyM]

For the record, I LOVE the sound of an SVT at low volumes. Nice and clean, rich, and thick. People talk about the "My bass only louder" sound. That's it for me.

Jes' sayin'.

I don't know...I still think the best solution for you is to get a B-15 or a B-25B or some other lower wattage tube amp.

[Cartoonist]

Originally Posted by will33

Guitar players I've known who were regularly using these things were constantly cooking their amps. Lots of repairs, tube replacements, etc. A real tech may be able to refute that because of poor design of the particular attenuator or something, but, experience has told me to not put one of those things on my amp.

This would be partly due to design and partly due to operation. As far as operation goes, if you run the tubes flat out then they will die faster. Attenuators let you run the tubes flat out at any volume. Therefore increasing risk of tube failure.

I have a Weber mini mass on my AC30, have had no problem whatsoever and I use it a lot. I'd recommend that brand to anyone whose guitar amp fits their range (up to 200W)

Originally Posted by will33

A lot of amps you can pull power tubes and rebias for lower power. The impedance taps change along with this, but I don't think you can do that to an SVT. It's power tubes works as a pair of 3 each.

There's a thread on another forum where some guy was trying this. It worked, but the sound wasn't that great.

Originally Posted by will33

To your other question, a 4 ohm Black Widow will play fine with an SVT, but, you could blow the speaker turning the amp up as much as you'd like to. Speaker wattage ratings are the thermal handling of the voice coil. My 8ohm BW's model to about 150-160 watts clean bass. You can push them farther, but, thermal compression is going to start setting in then. Keep that up long enough and you can toast the coil with less than it's rated power.

Thanks for the warning! Then, what is the minimum power that I would need in a suitable low efficiency speaker for my amp?

[Mr. Foxen]

Originally Posted by Cartoonist

So recordings of an SVT don't sound good unless played at concert volumes? An SVT attenuated to a lower volume won't sound good in a smaller venue?

They sound fine like that, which is why an attenuator isn't on the market. Kind of the point. Sometimes a bassist doesn't sound good without compression and distortion though, and sometimes they aren't phallically blessed enough to be able to just use the right gear to achieve that in an appropriate sized rig.

[aborgman]

Originally Posted by will33

So now we're getting all techy

Sure somebody could make one...but why?

Guitar players I've known who were regularly using these things were constantly cooking their amps. Lots of repairs, tube replacements, etc.

Running your output tubes full out - whether you're driving an attenuator or a cabinet - will shorten the life span.

...but that is nothing to do with an attenuator, and everything to do with running full out.

[Cartoonist]

Originally Posted by Mr. Foxen

...sometimes they aren't phallically blessed enough ...

Takes one to know one. As I say, why buy another amp rather than use the same one for all scenarios big and small and with a consistent sound? Besides, this is a technical discussion, or call it a hypothetical if that helps you grasp the concept. It's a forum, not a high school locker room.

Anyway as it turns out the rig isn't as loud as I thought it would be, so I'll be passing on the attenuator / small speaker argument from here on in. The VR through a Golight 410 is perfectly suitable for pubs and the like.

But for the sake of continuing a technical and hypothetical discussion, for the interest of others who may wish to do what can be done, no matter their endowment: Weber got back to me today with an idea to use a 200s power resistor from one tap from the amp which would cut the power in half - and from the other tap to run a 200W Mass attenuator (which is their variable attenuator using a speaker motor as the load).

[will33]

A word about the speaker models re: the Black Widow. Those models are based on a constant sine wave input, which a bass signal isn't. You can usually get away with hitting the speaker a little harder than the model predicts, but still. Running the SVT on the single speaker, you'll still be pushing it past it's clean excursion limits, at least at the attack of your lower notes, and making the coil dissipate a lot of heat too. Basically riding the edge of getting the tone you want and destruction.

@ the real techs here. You think it would knock his volume down enough to use an 8ohm dummy load in parallel with an 8ohm driver? The amp should still see 4ohms right? With the dummy load absorbing roughly half the power sent to the cabinet. Or would that start wandering, ie: more power going through the voice coil at low spots in it's impedance curve and (choosing) to go through the resistors instead at spots in the speakers impedance with higher impedance than the resistors?

I'm thinking you could knock a 97db speaker down to 94 that way if it works, and maybe save the single voice coil from the big amp.

[will33]

Not sure if I got my thinking/terminology straight there but you get the idea. Have a dummy load take the place of 1 voice coil. Of course, that may not be any different than using an attenuator. It basically is one, no?

[Mr. Foxen]

Originally Posted by Cartoonist

As I say, why buy another amp rather than use the same one for all scenarios big and small and with a consistent sound?

The sound not being consistent at all volume levels is all of the point of the attenuator, it is a necessity created by having an amp not suited to producing the required sound at the required output level. Once you get the cab involved, which is a whole chunk of the SVT rig sound, its another game again because the cab breakup is part of it. It is right tool for the job vs bodging the wrong one. Concrete your walnut so you have something left to eat when you use a sledgehammer to crack it.

[will33]

Good point about the speaker breakup being part of "that sound". May want something that can handle being sent into non-linearity a bit and survive.

I don't know what xlim is on Black Widows. Xmax varies by model. The old 1502's advertised as bass speakers had a short 2.8mm. Can get grindy pretty quick but might not handle enough power to get amp breakup. The 1505's used in PA have almost twice the excursion. I've used those in bass rigs and like them, bit don't know that their breakup is anything pleasing to the ear.

Those Faital 15PR400's people are using are said to have a smooth transition into non-linearity. They come in 4ohms too. Would take a couple hundred watts to distort them. They might be able to handle it based on your description of having a little cleaner fat sound when laying back and getting some hair when digging in and not running all out distortion all the time.

Eminences Pro series have xlims way out there. Could run them into a lot of distortion without killing them, but I don't know that their breakup is anything musical either.

[JimmyM]

Originally Posted by Mr. Foxen

The sound not being consistent at all volume levels is all of the point of the attenuator, it is a necessity created by having an amp not suited to producing the required sound at the required output level. Once you get the cab involved, which is a whole chunk of the SVT rig sound, its another game again because the cab breakup is part of it. It is right tool for the job vs bodging the wrong one. Concrete your walnut so you have something left to eat when you use a sledgehammer to crack it.

LOL!

[dmusic148]

Originally Posted by JimmyM

LOL!

Indeed! Sig-worthy IMO!!! LOL!!!

[will33]

Genz 12" NeoX cabs are another that have a smooth transition into breakup. Your SVT would lay waste to a 112 in short order. Judgement call as to whether the 212 would hit the sweet spot or still be too loud. They basically hang with a heavy hitting drummer/fill a typical bar/smaller club on their own.

They ain't cheap, but they sit well in a band mix. Got some mid punch, got lows you need but not an overly deep/hyped up lowend. Available in 4 ohms.

[will33]

Originally Posted by dmusic148

Indeed! Sig-worthy IMO!!! LOL!!!

That is pretty funny, man.

[will33]

@ the OP. The Genz cab I mentioned would have about similair output to your 410, just a different flavor of lows vs. breakup/grind. Don't know if there's enough difference there to justify the expense.

[Cartoonist]

Good discussion re. the speaker breakup. If after speaker breakup it'd have to be the right speaker or it can sound ugly, I know that from experimenting with guitar rigs.

I haven't experimented or researched enough to know exactly what I'm hearing with tube vs speaker breakup. But in the efforts of consistency at all volumes and keeping the walnut intact maybe its better to choose a speaker with max headroom and rely only on tube distortion.

I have some other 6550s to chuck in there which will break up differently too. Also wondering if a higher gain 12AX7 driver tube would push the power section into an earlier breakup. I'm trying to maintain creamy saturated distortion without too much grumbly dirt.

[will33]

Having higher gain in the pre will make it get dirty at lower setting on the volume dial, but it won't be any quieter when it gets there, just less inbetween "wiggle room" in the knobs.

One of the techs might be able to explain the "biasing cold" thing, but I don't know that that would sound all that great, and likely stress the amp from running outside of where it's designed to, and may not knock down your output all that much.

[JimmyM]

Well all I can say is good luck with it. Maybe the Weber thing will work out for you. No talking someone out of an idea when they've got their mind set on it as you do, so have fun