Output power - rule of thumb?

[mikhailwatt]

Without actually taking measurements - any idea how much power a DR103 (early '70s) is pumping into a cab at a given setting?
Obviously it varies with the guitar and other factors, but let's say:

PAF humbucker, medium output
No pedals
Channels jumped & dimed
Tone stack straight up (all controls @ 12:00)
Master volume @ 12:00
Impedance set @ 16 ohms, into 16 ohm cab

I'm assuming maximum clean power is at least 100 watts, but this setting is quite a bit beyond clean. How far can you go before a 200 watt cab sends up the white flag?

[gtomax]

General rule of thumb is have a cab rated at twice the RMS of your amp. RMS is the power output at full clean before clipping. This varies by amp, tubes, etc. but generally around 3-4 on a plexi Marshall NMV to give you an idea. Obviously the amp is capable of much higher power output than that when dimed. For a 100w RMS amplifier, you'd be safe with a 200w cabinet.

[mikhailwatt]

Right, I've heard of healthy old plexis putting out close to 200 watts in some cases. I'd figure a HIWATT is in that category as well.

So, at the setting I described, maybe no more than 100 - 150 watts?

[Dr.HI-TONE]

if memory serves me correctly a healthy DR103 can put out upwards of 180 watts maximum. Plexis are wussies!

[mikhailwatt]

if memory serves me correctly a healthy DR103 can put out upwards of 180 watts maximum. Plexis are wussies!

POWER TO THE PEOPLE, indeed!

[Dr.HI-TONE]

Power To The People was the HIWATT slogan until the British Gov't decided it was politically incorrect and put an end to it.

[mhuss]

I agree with max, rated cab power = 2x rated amp power is generally a good ratio, both tonally and safety-wise.

--mark

[OldSchoolDave]

...rated cab power = 2x rated amp power is generally a good ratio...

Unless you like that "electric train" smell (and spending money on recones).

Dave

[mikhailwatt]

Unless you like that "electric train" smell.

It's normal, though, for them to get a little warm (but not hot) to the touch during extended high volume use?

I noticed a faint smell last night when I took the back off the cab, but I think it was the glue I used the day before to reattach a magnet cover. At least I hope it was the glue, and not a voice coil. Channels dimed, master on 4 into two 50 watt Fanes... they should handle that without any problem.

"It sounded great, right until it blew up."

[mikhailwatt]

RMS is the power output at full clean before clipping. This varies by amp, tubes, etc. but generally around 3-4 on a plexi Marshall NMV to give you an idea.

Is that roughly equivalent to a DR103 with the channels dimed, master on 4? Never played a super lead plexi, so I don't have anything to reference.

[mhuss]

More or less, yes.

--mark

[OldSchoolDave]

It's normal, though, for them to get a little warm (but not hot) to the touch during extended high volume use?

Warm is normal. There's a lot of motion under those conditions, creating friction, producing heat. You'll know *the* smell when you smell it...

Channels dimed, master on 4 into two 50 watt Fanes... they should handle that without any problem.

Only problem is that is that we don't know how linear the power output is, relative to master volume position. I think Hiwatt cabs were conservatively rated. So, in theory, a pair of those Fanes should be o.k. with a throttled-back DR103.

Dave

[mikhailwatt]

Only problem is that is that we don't know how linear the power output is, relative to master volume position. I think Hiwatt cabs were conservatively rated. So, in theory, a pair of those Fanes should be o.k. with a throttled-back DR103.

They survived the onslaught just fine, though I won't test my luck again with just the pair.

[countdecibel]

Count Decibel PROUDLY Sported His "Mars-Hall Killer" in San Fran...a "3/4 Stack"...with a 4123 (paid $75, unloaded) on the bottom...a 2x12 Mars-Hall on top ($100)...all 6 holes filled with EVM12Ls (Guys, you GOTTA try them; they KILL when allowed to "Speak HIWATT"; OldSchoolDave NAILED IT when he said similarly). Well...'twas the '80's...EVERYONE "Addicted to Mars-Halls". Harrumph. Being "Basically Broke" I had to "settle" (not really; they're GREAT Heads, my 2nd Favorite) for a used Traynor YBA3A I scored for $50. Then I found a 250 watt Traynor MOSFET P.A. Slave...a Tech who wired a "Slave Out" DIRECTLY off the YBA3A's Output Tranny, using one of its spkr outs, padded w/a Pot so as "not to overdrive". Well. @ 8 ohms, the Traynor punched out some 90 watts...but at 4 ohms...90 became 141.5. Ergo: 141.5 drove the 2 top EVMs...and 250 (into 8 ohms) drove the 4 EVMs in the 4123. My, "3/4 Stack" Sally Proctor (Heiress to Proctor & Gamble) was backing ALL KINDS of Bands...buying Mars-Hall stacks left & right...and if she REALLY Liked You...she'd buy you 2 (stacks) !!! Shoulda seen the JAWS DROP...when I'd DROWN OUT the "Double Stackers" (pre=Wendy's).... Heh. 391.5 watts into 6 EVMs ??? Try it sometime... I attribute the success of "Count Decibel Machine" (#1) largely to the 4123 on bottom, my "Main Component", what with it's "HIWATT Vent" (I call it), that unloads the cabinet PERFECTLY...taking ALL "Flabbyness" OUT OF THE PIC-A-TURE...and THUMPS...every heart in the room.... I went to such length on this comment to cover a number of concerns expressed by my fellow HIWATTers, here...as I just spent 6 HOURS reading MOST of the 10 pages of entries/questions. The Count's been around...QUITE...a while...used/played thru most everything...and to where did He Gravitate ??? With ALL OF YOU...My Fellow "DR's of Rock" (pun intnd; R.I.P. David Reeves).... Peace and Love...(The Count's an Olde Hippie)...and HIWATTs Too....