Fender Rumble Club

[dORSY]

But, I respectfully submit that the Pre/Post switch is not so much a preamp feature as more of an amplifier module, if not power supply, function.

The signal goes to the power section afterwards. FX return is the last bit before the power section, where the signal goes 2(3) ways > poweramp and cabsimmed(sometimes switchabale) lineout(DI)/headphones. And yes, the poweramp needs to sense if heaphones are plugged to mute. That is why it makes sense to be close to eachother. (pun intended )

Kind of in between pre/poweramp, but isn't really. Parallel to the poweramp.

But the different power levels and speaker configurations certainly add a whole great lot of versatility for those us familiar with them.

Yes!

the 200/500 heads share the same preamp with the 800 HD.

Almost, but not exactly, they are the same as the "old" 100 and the current 200/500 combos: no pre/post switch

Perhaps the 200/500 heads just didn't sell as well

Agreed. I think the 800 was just a bit more in price, but much more power/versatility (2Ohm capable). Also the lower powered heads were not viable 'cause with the 200/500 combos You got a lot more for the money.
The current 800 combo costs around 150 eur more than the head itself. That is a really good price for a matching well made 2x10! The Rumble 2x10 is 400 EUR+ alone!
Basically Fender was (is) it's own competition there IMO.

"due to ongoing supply issues"

That supports my point.

Thank you, dORSY, I do so enjoy our discussions.

So as me!

Got no insights at Fender's management, I just tried to rationalize/get a sense from an engineer/product designer standpoint.

 

[SharpCat]

Wow, you all WERE ready to rumble !

 

[Miles_ONeal]

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And why in the world is bass still the only instrument that "is supposed" to strip all the player's hard-won EQ & voicing so somebody else (FOH, who may have no idea what songs or sounds you're going for) can apply their idea of what you should sound like? Don't get me started.​

...​

THIS. This is what I was trying to get at elsewhere.

 

[Miles_ONeal]

I specifically meant V3 preamp designs. I still think making 1 universal option for all 100W+ combo/amps is a cost saving move. In terms of inventory management, supply chain for components, etc. Same preamp circuit with lots of poweramps/combos/cabs as options. (they are effectively modular, even sitting on separate PCBs inside)
Also helps with "if you've used a rumble, you used/know'em all"

PS: remember 200W/500W heads? They were almost the same as the 800HD inside. Also costs almost the same to make and therefore to sell. So they were phased out. (and had no pre/post switch either!)

If I could guesstimate I'd say the r100 was/is the most popular of the 100W+ combos, so it was just the fitst to be upgraded to pre/post preamp (AKA: HD800) design. At least I'd have done so if I worked as a Fender product engineer.

Based on the informal TB poll, the 100 is, indeed, the most popular Rumble in terms of current ownership.

 

[JakobT]

Agreed. I sorry, yes, I missed that distinction from his first post on this subject.​

Indeed, Jake! Yet, just a few years ago in my poll, you thought the Stage & Studio were just different flavors of V3! What changed?​

​

Aha, there it is. Getting a Studio 40 after my poll and comparing it to your regular R40 made you think they are different animals altogether! I think you got a better understanding of the reason for my poll.​

Yes indeed. Living with the Studio 40 for a couple of years convinced me that it was a different animal in everything but name.

 

[G-Dog]

... ... ... Got no insights at Fender's management, I just tried to rationalize/get a sense from an engineer/product designer standpoint.

Are you an electronics engineer or product designer, dOR? Just curious. I'm certainly neither one, so pardon me if I overstep my boundaries.​

​

... ... ... But, I respectfully submit that the Pre/Post switch is not so much a preamp feature as more of an amplifier module, if not power supply, function.

The signal goes to the power section afterwards. FX return is the last bit before the power section, where the signal goes 2(3) ways > poweramp and cabsimmed(sometimes switchabale) lineout(DI)/headphones. And yes, the poweramp needs to sense if heaphones are plugged to mute. That is why it makes sense to be close to eachother. (pun intended ) ... ... ...

I guess it depends on where you "draw the line" for the preamp, intermediary components, and amplifier/power section. Not being an electronics engineer, but just looking at the block diagrams, I think of the preamp as ending, in the Rumble's case, with the Active Equalization, Bass, Mid(s) and Treble. The Power Amp is very plainly labeled just before the speaker(s) connection(s). Everything in between those I consider to be intermediary, or optional; such as the entire FX Loop, Line Out, Pre/Post Switch, Aux In and/or Headphone module, filters, limiters, even the Master volume control in the case of those Rumbles with Pre/Post Switch! I could be wrong of course, if some of the intermediary functions are included on the Rumble preamp PCB, since I'm not that intimate with the actual electronics. ​

​

And puns aside, electronically speaking at least, I don't believe the Headphone Detect sensor has to necessarily be physically close to the poweramp to shut it off. ​

... ... ... Kind of in between pre/poweramp, but isn't really. Parallel to the poweramp. ... ... ...

Electronically speaking, "parallel" means, to me at least, that the signal can take either, or possibly both, paths. What I'm calling intermediary functions are definitely not parallel at all. The signal must traverse through them in some manner before it can reach the poweramp.​

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... ... ... Yes, I too believe that the 200/500 heads share the same preamp with the 800 HD. ... ... ...

... ... ... Almost, but not exactly, they are the same as the "old" 100 and the current 200/500 combos: no pre/post switch ... ... ...

You are quite electronically correct there, sir. One preamp (by my lines drawn above) includes the Master volume control and one does not. I was referring to the sharing of all the other preamp functions (again, by my previously drawn lines).​

... ... ... Agreed. I think the 800 was just a bit more in price, but much more power/versatility (2Ohm capable). Also the lower powered heads were not viable 'cause with the 200/500 combos You got a lot more for the money. ... ... ...

If you call approximately double "just a bit more in price"!?! Yes, you certainly should get a lot more for that price difference.​

... ... ... The current 800 combo costs around 150 eur more than the head itself. That is a really good price for a matching well made 2x10! The Rumble 2x10 is 400 EUR+ alone!
Basically Fender was (is) it's own competition there IMO.

Yes, indeed! But, It's not being their own competition. That's the higher quality, more expensive components required for the 2 ohm capable 800 HD over the same less expensive components for the 2.67 ohm capable 800 combo. Yes, from what I've read elsewhere here on TB, 2 ohm does require that much better components than even 2.67 ohm capable units.​

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... ... ... However, as previously mentioned, the R100 "upgrade" of some, not all, units is officially "due to ongoing supply issues", which implies an isolated temporary situation, not a full-blown upgrade program for the whole existing model line. ... ... ...

That supports my point.

I'm sorry, but I don't see how. ​

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Thanks, again.​

 

[Miles_ONeal]

...​

I guess it depends on where you "draw the line" for the preamp, intermediary components, and amplifier/power section. Not being an electronics engineer, but just looking at the block diagrams, I think of the preamp as ending, in the Rumble's case, with the Active Equalization, Bass, Mid(s) and Treble. The Power Amp is very plainly labeled just before the speaker(s) connection(s). Everything in between those I consider to be intermediary, or optional; such as the entire FX Loop, Line Out, Pre/Post Switch, Aux In and/or Headphone module, filters, limiters, even the Master volume control in the case of those Rumbles with Pre/Post Switch! I could be wrong of course, if some of the intermediary functions are included on the Rumble preamp PCB, since I'm not that intimate with the actual electronics. ​

...​

The line out/DI is typically associated with the preamp, regardless of switchery.[1] Common examples include preamp pedals that have DIs. When present, it's associated with the last stage of a preamp, whether the preamp is separate from the amp or integrated as in the Rumbles.

While you can associate it however works for you, trying to divorce it from the preamp and marry it to the power amp and/or power supply is at best a minority view and at worst may be considered bigamy and illegal in the US.[2]

[1] "She's a switch! Kill the switch!" "Kill switch engaged."
[2] This was a meager attempt at humor and not intended to start a discussion on bigamy and/or polyamory, much less any case for or against such.

 

[G-Dog]

The line out/DI is typically associated with the preamp, regardless of switchery.[1] Common examples include preamp pedals that have DIs. When present, it's associated with the last stage of a preamp, whether the preamp is separate from the amp or integrated as in the Rumbles.

While you can associate it however works for you, trying to divorce it from the preamp and marry it to the power amp and/or power supply is at best a minority view and at worst may be considered bigamy and illegal in the US.[2] ... ... ...

​

Oh? Well, I'd certainly expect a preamp pedal to have its own line out and not make the user have to rely on that of whatever unknown-to-the-pedal-designer system it may become connected to. I don't see that necessarily holding true for combo amps where the systems are fully known to those designers. At least, that works well with the associations I'm making.¹ ​

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And then, too, why would "an alternate power supply and amplifier module" necessitate adding a Pre/Post to the R100? I use the term "necessitate" because, assuming some small extra cost for the alternate components (including alternate speaker), it would certainly seem to be simpler, cleaner, and possibly minimally cheaper, to not add an unnecessary switch. Again, that works well with the associations I'm making.² ​

[1] "She's a switch! Kill the switch!" "Kill switch engaged."
[2] This was a meager attempt at humor and not intended to start a discussion on bigamy and/or polyamory, much less any case for or against such.

1. Does that make me a BuzzKill? OK, OK, I unnerstan', "Kill the BuzzKill!" ​

2. Well, I'm not "married" to my preferred component associations, so I admit I could be wrong and am willing to divorce my views for cause. But I'm not yet seeing anything to convince me of that (short of agedhorse calling me a doofus about all this, switch could happen!). ​

 

[Miles_ONeal]

​

Oh? Well, I'd certainly expect a preamp pedal to have its own line out and not make the user have to rely on that of whatever unknown-to-the-pedal-designer system it may become connected to. I don't see that necessarily holding true for combo amps where the systems are fully known to those designers. At least, that works well with the associations I'm making.¹ ​

​

And then, too, why would "an alternate power supply and amplifier module" necessitate adding a Pre/Post to the R100? I use the term "necessitate" because, assuming some small extra cost for the alternate components (including alternate speaker), it would certainly seem to be simpler, cleaner, and possibly minimally cheaper, to not add an unnecessary switch. Again, that works well with the associations I'm making.² ​

1. Does that make me a BuzzKill? OK, OK, I unnerstan', "Kill the BuzzKill!" ​

2. Well, I'm not "married" to my preferred component associations, so I admit I could be wrong and am willing to divorce my views for cause. But I'm not yet seeing anything to convince me of that (short of agedhorse calling me a doofus about all this, switch could happen!). ​

They'd have to change production to not include the switch on some of the boards, and add a jumper or two in its place. Instead they chose to change the number they print onto a chassis. I'm guessing the latter was more cost-effective.

 

[dORSY]

They'd have to change production to not include the switch on some of the boards, and add a jumper or two in its place. Instead they chose to change the number they print onto a chassis. I'm guessing the latter was more cost-effective.

I'd say they just grabbed what was on the shelf readily available. AKA: support chain issues

 

[dORSY]

Are you an electronics engineer or product designer

System Architect. I design computer systems for customers including baremetal and software defined solutions.

I guess it depends on where you "draw the line"

Theoretical. For example my new poweramp pedal has EQ controls. But no preamp! So it does not boost the signal before the power section, but could shape the pre-amped tone. It would not become a preamp by this fact despite most of us think EQ as part of the preamp.

(we could say a boost/cut EQ can be a preamp too, just not for every frequency every time... i'm rumbling here XD)

Electronically an amp is an amp, the only thing it (should do) does is gain.
Pre-amp does lower voltage level gains (for the poweramp or headphones or line outs, sometimes with distorsion too), power-amp does the higher voltage for the speakers.

the Headphone Detect sensor has to necessarily be physically close

It's "electronically" or "logically" close. Has to have the "killswitch" logic wired together.

The signal must traverse through them

Not at all! Think about the headphones. If You plug'em in, the signal does not even go to the power amp!

One preamp (by my lines drawn above) includes the Master volume control and one does not.

Theoretical again. Technically (electronically) Class D poweramps are "wide open", driven by high frequency (usually couple hundred kilohertzes) PWM which switches on/off very rapidly inside the chip depending on the input volume, hence the output volume changes: the more it is on/sec (higher input signal) the more Watts come out. This switchery makes them so power efficient. They do literally nothing if no need to. Same goes for the power supply.

I'm sorry, but I don't see how.

This is my own imaginary theory. Fits. I guess

 

[SharpCat]

It’s quite common to create printed circuit boards with sections that are left unpopulated in different models. With large manufacturing runs, the left-off component savings adds up.

How or if that applies to Fender or Rumble amps, no idea. My guess is that they saw a need for different features when designing the R800c, and rather than creating a dead end board for just this model, they designed something more adaptable. That came to their rescue when the 8 ohm speakers for the R100 became scarce—it was quickly pressed into service for the new 4 ohm R100 version.

It would be interesting to compare the R40/100/200/500 boards. I bet they’re the same with possibly a different power module, and a jumper telling the board how much power to allow.

 

[dORSY]

It’s quite common to create printed circuit boards with sections that are left unpopulated in different models. With large manufacturing runs, the left-off component savings adds up.

How or if that applies to Fender or Rumble amps, no idea. My guess is that they saw a need for different features when designing the R800c, and rather than creating a dead end board for just this model, they designed something more adaptable. That came to their rescue when the 8 ohm speakers for the R100 became scarce—it was quickly pressed into service for the new 4 ohm R100 version.

It would be interesting to compare the R40/100/200/500 boards. I bet they’re the same with possibly a different power module, and a jumper telling the board how much power to allow.

The PCBs are modular in theese models. Some components are omitted for lower powered models (like jacks for EFX send/return on r40s), sometimes they just use different ones depending on the power rating.

Class D poweramps can be limited by their input voltage, my r100's power chip (TDA8950 2 × 150 W) could output 300 Watts bridged with the proper power supplied to it, but limited to 100@8Ohm by the ~23Volts:

Of course they could have changed almost anything inside in the last 10+ years

 

[G-Dog]

System Architect. I design computer systems for customers including baremetal and software defined solutions.

Ah! Well, your technical expertise beats mine. And I have too much trouble trying to follow the logic of your descriptions, so I'll debate no further. But I do appreciate your input. ​

 

[dORSY]

Ah! Well, your technical expertise beats mine. And I have too much trouble trying to follow the logic of your descriptions, so I'll debate no further. But I do appreciate your input. ​

The thing that matters in the long run is to keep the magic smoke inside! But get good tones out!

 

[G-Dog]

The thing that matters in the long run is to keep the magic smoke inside! But get good tones out!

On that we most definitely agree! Rumble, ... but don't stumble.

 

[dORSY]

On that we most definitely agree! Rumble, ... but don't stumble.

Guess all we need to know is

 

[Miles_ONeal]

I'd say they just grabbed what was on the shelf readily available. AKA: support chain issues

That’s what I’m saying, but with detail for G.

 

[Miles_ONeal]

It’s quite common to create printed circuit boards with sections that are left unpopulated in different models. With large manufacturing runs, the left-off component savings adds up.

How or if that applies to Fender or Rumble amps, no idea. My guess is that they saw a need for different features when designing the R800c, and rather than creating a dead end board for just this model, they designed something more adaptable. That came to their rescue when the 8 ohm speakers for the R100 became scarce—it was quickly pressed into service for the new 4 ohm R100 version.

It would be interesting to compare the R40/100/200/500 boards. I bet they’re the same with possibly a different power module, and a jumper telling the board how much power to allow.

They can’t just leave the switch off. They need jumpers in its place. Even then the other switch would be off-center. Since they now have to use a different chassis because of the latter, it’s easier and cheaper to just use existing components as-is.

 

[dORSY]

That’s what I’m saying, but with detail for G.

Even if they designed a less complex preamp with some pennies saved in components, it still must be RND'd, tested, made, stored, whatever. Using readily available parts could be cheaper also easier specially considering what happened with the pandemic.
Also, in rumbles the I/O board containes all the plugs/ports (excuding powercord and input jack), so makes sense to make them the same baseboard for all combos.