Switchable 25/50/100W output switch same as attenuator?

[chaos731]

Self explanatory...
Wondering if the 25/50/100W output switch on my new X100B is, in effect, the same thing as a hot plate (or other attenuator). I know it's essentially an attenuating circuit, but will the end result more or less be the same (i.e. more reasonable "house" volumes while maintaining the overall tone/feel at lower volumes, at the sacrifice of some overall headroom)?

[Lefty Robb]

No, not really, a Attenuator allows the amp to run full tilt at low volumes, and the 25/50/100 switch just runs less tubes for less output usually, remember 100 watts is only like twice as loud as 10 watts, or something like that. To get the most tone out of your amp with the lowest volume, run it on 100 watts with a attenuator.

[chaos731]

Originally Posted by Lefty Robb

No, not really, a Attenuator allows the amp to run full tilt at low volumes, and the 25/50/100 switch just runs less tubes for less output usually, remember 100 watts is only like twice as loud as 10 watts, or something like that. To get the most tone out of your amp with the lowest volume, run it on 100 watts with a attenuator.

Well, to throw a layer of complexity at the matter, the manual (and Carvin confirms this) states that the amp will be running on all tubes, whether it's set on 25, 50, or 100.

I get what you're saying, but all available literature seems to indicate that the amp will supposedly be running at full tilt boogie even at lower settings. Built-in attenuator in addition to the switch?

[Lefty Robb]

Well I'll be..

18. RMS POWER SWITCH
The 3-position RMS POWER switch reduces the 100watt
output of the amp down to 50 or 25 watts, while still using
all four output tubes. Lower settings will allow the great
sound and feel of the tube power amp being overdriven,
but at lower volume levels. For maximum output
power and headroom set the switch to 100watts. For
early power amp saturation move this switch to
50watts. Setting this switch to 25watts can change the
sound dramatically if desired, by turning up the MASTER
or using the FS BOOST (#7) to produce even more
power amp overdrive!

I guess it is a type of attenuator!! Thats really cool. Most amps just cut power to some tubes. Another reason why Carvin is the R0x0r!!11!!

[chaos731]

Originally Posted by Lefty Robb

Well I'll be..

18. RMS POWER SWITCH
The 3-position RMS POWER switch reduces the 100watt
output of the amp down to 50 or 25 watts, while still using
all four output tubes. Lower settings will allow the great
sound and feel of the tube power amp being overdriven,
but at lower volume levels. For maximum output
power and headroom set the switch to 100watts. For
early power amp saturation move this switch to
50watts. Setting this switch to 25watts can change the
sound dramatically if desired, by turning up the MASTER
or using the FS BOOST (#7) to produce even more
power amp overdrive!

I guess it is a type of attenuator!! Thats really cool. Most amps just cut power to some tubes. Another reason why Carvin is the R0x0r!!11!!

They are indeed teh 1337 A[\/]P [\/]a|<3r5!!!1

Thanks, lefty...I wanted to make sure I wasn't crazy when I was interpreting the manual that way.

I went home at lunch to unpack the X100B. It's a thing of beauty (especially in red tolex!). When I get home from work in about two hours, I'm going to crank that sumbiatch up and shatter some farking windows.

EDIT: I have a feeling I'm going to be getting a lot of use out of the 25W setting...that's going to be perfect for recording without making my cat's ears bleed. Or my wife's, for that matter.

[Lefty Robb]

I guess I would call it a Built-in Non-Variable Power tube attenuator The 25 watt setting is only going to be like a 6db cut in volume I believe, might be 9 I forget, well, something like that anyways, its gonna still be damn loud. Which might make you want to get a external attenuator after all, but unlike a regular amp running at 100 watts on an attenuator, your not going to wear out the tubes fast, like you would running it at max.

[chaos731]

Originally Posted by Lefty Robb

I guess I would call it a Built-in Non-Variable Power tube attenuator The 25 watt setting is only going to be like a 6db cut in volume I believe, might be 9 I forget, well, something like that anyways, its gonna still be damn loud. Which might make you want to get a external attenuator after all, but unlike a regular amp running at 100 watts on an attenuator, your not going to wear out the tubes fast, like you would running it at max.

...and that was my main concern about going (back) to a tube head after all this time. It's a good thing that there's a well-respected "tube guy" nearby...he carries lots of NOS stuff, and vintage tubes as well. He's one of THOSE guys.
I might just have to get a few spares/swaps to experiment with...

[Lefty Robb]

Oh hell yeah experiment with different tubes, its what makes owning tube amps fun KT66 ftw, because in Russia, Amp plays you!!

Just don't go blowing $1000 pimping this thing out on Mullards

[chaos731]

Originally Posted by Lefty Robb

Oh hell yeah experiment with different tubes, its what makes owning tube amps fun KT66 ftw, because in Russia, Amp plays you!!

Just don't go blowing $1000 pimping this thing out on Mullards

No no no...nothing like that...no mullards today, thank you.
I'll take some vintage RCA tubes or something (maybe $65 bucks a pop...not cheap, but not super expensive either), but no...I plan on experimenting, but not quite to that extent. Besides, I'm going to give the stock tubes (completely decent GT 12's and 6L6's) their fair chance to blow me away. Then, I'll migrate into swapping the EL34's for 6L6's or something along those lines...

But now...absolutely no permanent modifications and no single tubes costing over $100 each.


I want a good schematic of this thing, though...can't seem to locate one for the IV series...

[Lefty Robb]

Will this guy let you try the vintage tubes out before buying them? I'm only saying this because they can be a real hit or miss.

[chaos731]

Originally Posted by Lefty Robb

Will this guy let you try the vintage tubes out before buying them? I'm only saying this because they can be a real hit or miss.

That I'm not sure about...I'll have to check.
I would imagine if I schlepped my amp head all the way over there and said, "if you let me try some tubes, I'll buy at least a few from you", he probably wouldn't care.

[chaos731]

Just for posterity, here's some pics of the new head (took these literally five minutes ago):







...and, because it's relevant to this thread, here's a detail of the rear controls, including the RMS/Attenuation/wattage-selection switch in question. I tried out that feature, and it works...nice round, thick, beautiful gain with lots of creamy goodness, and some seriously nice "edge" that can be dialed in pretty easily.



Anyway...gorgeous, ain't she?

[jim777]

When I run my '87 on 25 Watts through the 4x12, it is loud as hell on 3. Just sayin'

Congrats on that redhead!

[Lefty Robb]

[chaos731]

Originally Posted by Lefty Robb

Your sister...is she the #4 Prostitute In All Kazakhstan?