New Fender Rumble Stage 800 Impedance Switch

[G-Dog]

Anyone seen the new Fender Rumble Stage 800 combo bass amp introduced at NAMM recently? There's not much info available to the public yet, and some of what is brings questions, like this. The switch, shown below, on this new model is new to the Fender Rumble line and is perplexing to me.

I'm familiar with internal auto-switching from 8 to 4 ohm operation without any manual, or external, switch. In combos the amp operates the internal 8 ohm speaker load alone at some fraction of the nameplate wattage (140 for the Rumble 200 and 350 for the Rumble 500) and automatically goes to full nameplate wattage when another 8 ohm load is connected, giving a 4 ohm total load. And I assume that is what happens with this new switch in the 8 ohm setting.

But this new switch in the 4 ohm setting seems to allow connection of a 4 ohm external speaker load along with the internal (assumed) 8 ohm speaker load?! I assume the internal load stays connected because this setting only requires a 500W rated external cab. So, this would have the amp running a 2.67 ohm total load!? Does that seem correct?

The labeling seems to leave the internal load out of the equation and set only the requirements for external connection, perhaps to simplify things for the user since it is a combo.

Has anyone seen something like this before?  I've tried to search up other impedance switched combo amps, unsuccessfully.  Anyone know of any?

 

Edited February 4, 2018 by G-Dog

[G-Dog]

Wow!  50-something views and no comments!?  Is this that unusual?

I got a pretty definitive answer from Fender, via a respected industry journalist, on another forum:

 

Quote

"The power rating is 400W/8ohms (internal speakers) or 800W with an extension cabinet. The impedance switch allows for some flexibility to pair different cabinets with the combo other than a single 8ohm cabinet. Now a single 4ohm cabinet is another option, or 2-8ohm cabinets daisy chained since there is only 1 extension jack present.

Adding an 8ohm extension cabinet creates a 4ohm total load, with 800W delivered evenly to each cabinet (400W ea).

Adding a 4ohm (total) extension cabinet creates a 2.67ohm total load to the amplifier, and the power would divide unevenly between the cabinets - roughly 300W to the internal speakers, and 500W to the external 4ohm cabinet(s). To keep things simple for the customer, we avoided referring to the 2.67ohms total load on the product and only focused on the rating/impedance of the external cabinet connected.

There are no power resistors or anything complicated involved. The switch simply reduces the output to match the lower impedance for ‘constant’ power. The amp won’t be damaged if the switch is set in the wrong position, but there is risk of activating thermal protection circuits particularly if a 4ohm cabinet is used with the switch set to 8ohm. The amp produces less power in the reverse situation (ext cabinet = 8ohm, switch = 4ohm). The minimum load impedance for this product is 2.67ohm, so connection of external cabinets below 4ohms (total) is not recommended."

 

Sounds quite reasonable.  And very flexible, what with daisy-chaining cabs to make a 4 ohm load!  

 

Edited February 6, 2018 by G-Dog

[Ghost_Bass]

It's just a diferent way to do the same thing other builders are doing. As an example, the Mesa D800, or the Genzeler Magellan 800:

 

The amp is designed to have two separte operation modes, here you can chose betwen using it at 8/4Ohms or adding more cabs to make it go down to 2Ohms (2.6Ohms on the Magellan).

 

The Rumble is the exact same thing - the amp itself can be driven either at 8/4Ohms or at 2.6Ohms - but being a combo and having an internal 8Ohm driver the developers decided to change the writting on the ext. speaker connector so it wouldn't confuse the user as to wich cabs can be added (IMO they made it more confusing instead). In the end it's exactly the same thing.

Edited February 6, 2018 by Ghost_Bass
spelling

[G-Dog]

7 hours ago, Ghost_Bass said:

It's just a diferent way to do the same thing other builders are doing. As an example, the Mesa D800, or the Genzeler Magellan 800:

The amp is designed to have two separte operation modes, here you can chose betwen using it at 8/4Ohms or adding more cabs to make it go down to 2Ohms (2.6Ohms on the Magellan).

The Rumble is the exact same thing - the amp itself can be driven either at 8/4Ohms or at 2.6Ohms - but being a combo and having an internal 8Ohm driver the developers decided to change the writting on the ext. speaker connector so it wouldn't confuse the user as to wich cabs can be added (IMO they made it more confusing instead). In the end it's exactly the same thing.

Exactly, @Ghost_Bass, on amp heads you are responsible for counting up the total amp load and setting the switch for that, since the amp itself brings zero load.

Perhaps I should clarify my remaining question:  Are there other combo amps with an impedance switch?  And, if so, how are they marked?  

Since the internal 8 ohm load is always part of the total on this combo amp, why not remove it from consideration and label only what the user may connect externally for each side of the switch?  (Non-technical musicians often have enough trouble counting ohms and cab ratings without having the "gotcha" of the internal load to remember.)  

But, if there are other combos that show only "8/4 or 2.67" on the switch (and hopefully also show the internal load, too) maybe Fender is breaking new ground in user-friendliness?!

Edited February 7, 2018 by G-Dog

[Ghost_Bass]

Probably but i think that these days builders are going more for the "detachable amp head" thing so the only have to build one type of amp. In those, the impedances can't take in to account the combo version because the amps cam be used separatly with other cabs. I remember my old Trace Elliot combo having something written on it saying 8Ohms min for the ext. cab but the head wasn't detachable.

I'm not familiar with these new Rumble lineup but i would bet that the combo version doesn't have a detachable head an that the head unit will have a diferent writting on the switch.

Edited February 9, 2018 by Ghost_Bass
spelling and grammar

[G-Dog]

On 2/9/2018 at 09:36, Ghost_Bass said:

Probably but i think that these days builders are going more for the "detachable amp head" thing so the only have to build one type of amp. In those, the impedances can't take in to account the combo version because the amps cam be used separatly with other cabs. I remember my old Trace Elliot combo having something written on it saying 8Ohms min for the ext. cab but the head wasn't detachable.

I'm not familiar with these new Rumble lineup but i would bet that the combo version doesn't have a detachable head an that the head unit will have a diferent writting on the switch.

I'm totally unfamiliar with combos having detachable amp heads.  You're correct that the Rumble Stage 800 does not have a detachable head.  But, yes, that would be a very different thing.

This is the first of Fender's class D Rumble line to have any impedance switch at all.  Up until now all it's heads, or combos that could take extension cabinets, were of the 4/8 ohm auto-switching type.  That's why this new combo, which does not yet have a corresponding head version, is so curious.

 

[G-Dog]

So, has no one seen a combo amp with an impedance switch before?

 

 

[Bigwan]

6 hours ago, G-Dog said:

So, has no one seen a combo amp with an impedance switch before?

No, but then how many 800w combos have you seen?

Edited February 17, 2018 by Bigwan

[MoonBassAlpha]

Did the Orange terror bass have one?

[Ghost_Bass]

On 17/02/2018 at 02:55, G-Dog said:

So, has no one seen a combo amp with an impedance switch before?

 

 

The impedance switch for 2Ohms operation is a relatively new thing (in class-D amps, not valve ones), from what i've seen Fender is the first one to make a combo with this feature, using probably the same 800W poweramp module as the rest of other manufacturers out there. The examples i've given before (Mesa and Genzler) only sell the head as a unit. If Fender is going to release a Stage 800 head in the future i bet they'll be changing the description on the switch.

[G-Dog]

On 2/19/2018 at 07:37, Ghost_Bass said:

The impedance switch for 2Ohms operation is a relatively new thing (in class-D amps, not valve ones), from what i've seen Fender is the first one to make a combo with this feature, using probably the same 800W poweramp module as the rest of other manufacturers out there. The examples i've given before (Mesa and Genzler) only sell the head as a unit. If Fender is going to release a Stage 800 head in the future i bet they'll be changing the description on the switch.

 

Agree.

 

[rushscored4]

I've got one of these on order, due to arrive in March. Looking forward to gigging it in pubs and clubs around the north west. Still not much information available online however.

[dannybuoy]

On 18/02/2018 at 00:59, MoonBassAlpha said:

Did the Orange terror bass have one?

Not sure about the combo but the head does, but it's different to the ones mentioned here so far. It's designed to let you get the full amp power at 8 ohms, rather than to allow the amp to work at 2 ohms.

[Ghost_Bass]

Regarding the Orange, i believe that it's a valve amp (havent checked), and like other valve amps will allow the choice of impedance so it may safely work on the correct impedance for the cabs hooked up to it. Lots of valve amps have had this option for a long time, so it has nothing to do with this new design of class-D power amp module that puts out 800W in 4 or 2 ohms.

[G-Dog]

4 hours ago, rushscored4 said:

I've got one of these on order, due to arrive in March. Looking forward to gigging it in pubs and clubs around the north west. Still not much information available online however.

I look forward to your review, then, @rushscored4!  Will you get the Fender amp cover for it, too?

 

 

[dannybuoy]

It's not a valve amp, it's a valve pre mated to a Class D power amp. The impedance switch on the OTB will let you get the full power into am 8 ohm load instead of just over half that you would normally expect to get.

Sounds like a similar concept to these newer amps except since these are mostly 2 ohm capable, the switch lets you get the full power out of a more common 4 ohm load rather then having to have 2 ohms connected.

[Ghost_Bass]

Oh, i see. I stand corrected on that one then.

[rushscored4]

So I phoned Rich Tone today to check on my pre-ordered Rumble Stage 800 as their website was showing them in stock and it's on it's way to me - hopefully arriving tomorrow! 🤘🏻

[rushscored4]

The Rumble Stage 800 didn't arrive yesterday unfortunately so I politely emailed Jack in customer services at Rich Tone to express my disappointment, complaining that I'd stayed in all day (I was working from home with the weather anyway...) and how I'd now seen them cheaper at GAK and Absolute Music at £738 compared to their £769. Got a nice response apologising, saying the amp's on its way ("problem with the supplier") and as a goodwill gesture they will only charge me £728 which is fair enough but I've got to wait until Monday for delivery now! 

[Delberthot]

really? You were working at home because of the weather but complained because the delivery driver couldn't get to you because of the weather?

[rushscored4]

3 hours ago, Delberthot said:

really? You were working at home because of the weather but complained because the delivery driver couldn't get to you because of the weather?

No. I was complaining because they'd promised me next day delivery 24 hours earlier. The problem wasn't with the couriers who were delivering as normal in my area (there's hardly any snow here) it was because the suppliers hadn't sent the amp but nobody from Rich Tone checked until I called them.

[Delberthot]

now that makes sense

[Muppet]

On 3/1/2018 at 22:16, rushscored4 said:

So I phoned Rich Tone today to check on my pre-ordered Rumble Stage 800 as their website was showing them in stock and it's on it's way to me - hopefully arriving tomorrow! 🤘🏻

How did this work out for you? I'm trying to find a list of amp models and effects for this but I'm struggling!

[G-Dog]

11 hours ago, Muppet said:

How did this work out for you? I'm trying to find a list of amp models and effects for this but I'm struggling!

Did you try the Fender UK website for the owner's manual?  Lots of good info in there.

[rushscored4]

12 hours ago, Muppet said:

How did this work out for you? I'm trying to find a list of amp models and effects for this but I'm struggling!

Arrived yesterday, not had much time to play with it and the latest version of the Fender Tone app with the Rumble tones added was only released today. There were 100 already preset on the amp and a further 9 already added from other users after I installed the app. I'll see if there's anyway of downloading the list but if not I'll add some screenshots here.