100 watt amp into an 80watt speaker?

JD50

Can I run a 100watt amp into a Celestion G12p 80 8ohm speaker?

Modulus_Amps

yes, if you are playing in your bedroom
No if you are playing on an open air stage with the amp cooking

anything else in between a risk

JD50

What if I remove a couple valves to bring the amp down to half power at 50watts?

ecc83

JD50 said:

What if I remove a couple valves to bring the amp down to half power at 50watts?

Yes but you should change the amp impedance setting to 16 Ohms if you can. If not it will probably be ok at 8R.

N.B Not all 4 OPV amps allow you to run with 2, almost none of the Blackstars do and you void the warranty if you try it with the one 100 watter that will (not that it would really care!)  Note too that some '50W' amps will kick out considerably more than that. The Stage 60 easily hits 80W and I dare say a lot more if you ran one into serious distortion...See, 50 watt amps DON'T have 100 watt amp power supplies!  If mains V hops up to an allowed 250, Whaa-HEY!

Dave.

JD50

The Amp is a Tremoverb if that makes any difference?

JD50

The Amp is a Tremoverb if that makes any difference?

Cirrus

Seem to recall running the Tremoverb in Valve rectifier mode knocked a few watts off, maybe down to 80 or so? And spongy mode on top of that reduced it to 60 or so...

olafgarten

You have to remember that the rated output of the amp is usually the clean rating, distortion can double the output.

If you use the Tremoverb and pull 2 output Tubes it would output around 100W at full power, but due to Celestion ratings being rather conservative, you might be safe.

ICBM

ecc83 said:

JD50 said:

What if I remove a couple valves to bring the amp down to half power at 50watts?

Yes but you should change the amp impedance setting to 16 Ohms if you can. If not it will probably be ok at 8R.

No, 4 ohms . The Trem-o-verb can definitely be run with only two power valves, but for the proper 'sound' you should also remove one rectifier valve if you're using the valve setting.

Cirrus said:

Seem to recall running the Tremoverb in Valve rectifier mode knocked a few watts off, maybe down to 80 or so? And spongy mode on top of that reduced it to 60 or so…

Yes.

Bold/diode is 100W
Bold/tube is about 80W
Spongy/diode is about 70W
Spongy/tube is about 60W

(Not exact but close enough for your purposes.)

Anything other than bold/diode should be safe, if you aren't cranking the amp - if you can still get a clean sound on the orange channel at the volume you're playing, and don't go any louder than that on the red channel, you're safe.

JD50

Cheers guys. Wont be cranking the amp nor using the heavy channels so should be good, thanks for your wisdom.

JD50

Just need to locate a footswitch for it now..... Rocking horse shit!

ICBM

JD50 said:

Just need to locate a footswitch for it now..... Rocking horse shit!

Any plain single-button latching footswitch will work if you just want to change the channels. If you want an LED it's in series with the switch, cathode to ground (I think!) - but not necessary for the switching to work.

If you want to switch the other functions you just need more of the same - if you use an LED in the tremolo switch it pulses in time with the effect!

ecc83

"No, 4 ohms ." I stand corrected IC. I was mixing up SPEAKER load and turns ration with the doubled VALVE load (but I am getting on you know!)

The B's WOULD be safe, just that the heaters are in series!

Dave.

DJH83004

What always tickles me about the Tremoverb, is the fact that the trem oscillator is built around a 555 timer, which I suspect most people will have built as a school project (astable multivibrator) in physics lessons