Amp question

[Daniel Nestlerode]

Hey folks,
Should a tube amp start warming up after it has been plugged in and before it gets turned on?

It's a little montgomery-wards or sears thing from the 60's I'd guess.
The on-off switch is in the volume knob which is the only control on the amp. Seems to me the on-off switch is operating only as a standby switch at this point. Not sure that was the intent when the amp was built.

Thanks!
Daniel

[Daniel Nestlerode]

I called the guy who repaired it for me.
He said that those little things are wired strangely sometimes and that having the switch serve as basically an standby is not unheard of.
I'm going to give this thing its own surge protector and use that switch too. Not sure I like the idea of that amp sitting there, warm, sucking down kilowatts when I'm not playing it.

Daniel

[F-2 Dave]

I'd sure like to be able to turn it off while it's still plugged in. I can't imagine that it was intended to be used otherwise. Although I suppose it might be nice to have your tubes all warmed up and ready to go at a moments notice. Do you have another amp guy?

[Daniel Nestlerode]

Dave,
Nope. I don't have another amp guy.
I do like the pre-warmed tube though. Like I said, I'll give this amp it's own surge protector and use that surge protector's power switch.

Daniel

[mandroid]

yea off, it reads from the information offered, is go to the wall and unplug the extension cord,
then let the tubes cool down before moving the amp.
My home amp, a studio monitor, switch failed in the On position, so I got a Power Strip.

the whole computer kit and audio gear is plugged into a power conditioner ..

there are portable sized power conditioners .. takes care of over /under voltage as well as surge spikes, gear savers at gigs when the building wiring is questionable.

[Ken Olmstead]

Having the heaters running all the time would be expensive in terms of electricity and reduced life span of the tubes. Also, the fire hazard with a glowing, unattended 60's era amp is a little unsettling!

Your power strip plan is the way to go, or wire in a real power switch prior to the transformer.

Does it sound good?

[Daniel Nestlerode]

It sounds great.
It overdrives real fast on the dial, near about 3. The breakup is sweet and crunchy and the single notes stay clean. I like playing straight into it without pedals, but that won't be practical at gigs. I have too many sounds to create, and a one-trick pony --no matter how cool the trick is-- won't fill the bill.

I ran it yesterday as a slave off of the Line Out from the Marshall G15. That way it uses the Marshall amp and preamp settings, and I can add a bit more tube warmth to the overall sound while I move more air. This is the configuration I'll use at gigs.

Overall the two amp set up is loud enough and bright enough to cut through everything the band does. I may have to add the Ampeg 1x12 when we get a drummer, but until then I'm a very happy camper!

Daniel

[bonny]

Having the heaters running all the time would be expensive in terms of electricity and reduced life span of the tubes. Also, the fire hazard with a glowing, unattended 60's era amp is a little unsettling!

I don't really know that much about the fine technical details myself but a couple of audiophiles I know leave their McIntosh tube amps running all the time. I don't think the energy consumption would be very large.....I doubt it would draw very much until you hit it with signal.
My understanding of their thinking on the tube life issue is that the warming process is hard on a tube and they'll last longer left running and always warm.

[Ken Olmstead]

I don't really know that much about the fine technical details myself but a couple of audiophiles I know leave their McIntosh tube amps running all the time. I don't think the energy consumption would be very large.....I doubt it would draw very much until you hit it with signal.
My understanding of their thinking on the tube life issue is that the warming process is hard on a tube and they'll last longer left running and always warm.

You may be right but if it makes heat, it is costing $.

[desh]

I don't think the energy consumption would be very large.....I doubt it would draw very much until you hit it with signal.

No. Most of the current drawn by a tube is used for the heater. It's a like having a lamp always turned on, for each tube.

Also, preamp tubes and class A power tubes draw about the same current, wheter or not there's a signal.

[Daniel Nestlerode]

nevertheless, I'm not digging the fact that if I leave the amp plugged in without a kill switch on a surge protector I end up getting a very warm amp all the time. Because...
1) It's warm enough here already (hit the mid 90s today), and the idea of an amp fighting the AC just bugs me.
2) That tube (it's just one 50L6GT) gets at least as hot as a 100w bulb in a desk lamp. and I worry about possible fire danger. Maybe I'm just a worry-wart.

Daniel

[rohan]

If your using your amp several times a day then leaving it pluged in saves the life of the tube(s). Many tube designs reduce the heater voltage when the unit is "off". The heater is still on but at a reduced voltatge. If you have to move the amp after using it, unplug it and wait several minutes. When using tubes, its a good ideal to turn the amp on several minutes before using it. This warm-up will present the proper characteristics to the tube for the best performance. Just turning the amp on and running full power is likely to shorten the life of the tube(s).

[bonny]

If your using your amp several times a day then leaving it pluged in saves the life of the tube(s). Many tube designs reduce the heater voltage when the unit is "off". The heater is still on but at a reduced voltatge.

So it' like an "auto-standby"? If the amp didn't have that feature I wonder if a manual stand-by switch could be installed for a reasonable price? I have a 40's RCA instrument amp I've been meaning to have fixed up and I'd be interested in this.....

[aries753]

It sounds like the old "instant on" vacuum tube color TV I had last century. In the "off" position the tubes still had power to the heaters. They got a lot brighter when the TV was turned on. Or, there was a "vacation" switch that would turn the TV off completely. It took forever to warm up then.

[rohan]

Yea, Yee old instant on TV. First saw them in the mid 60's. I wouldn't want to try to retro fit any tube device that wasn't setup initially for "instant on". I can only guess the "new" design had another tap off the power transformer for the low heater voltage. Turn it "on: and cut-in another tap and be at operating voltage. When we went of vacation (seldom) we just unplugged everything which is a good time to check the power meter going into the house. U'd be surprised how many house power meters show a draw with everything unplugged