Author Topic: A mere 50 years of misunderstanding  (Read 819 times)

Rob

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Re: A mere 50 years of misunderstanding
« Reply #15 on: July 04, 2017, 04:19:37 PM »
Yes. Standby is more controversial among guitarists who tend to elevate every part of the signal chain except practice to near-religious icon status. Most bass amps made in the past 60 years already have one and need it and it should be used as described in the above quote. I've seen it recommended to never put the amp in standby once it has been in use already (ie- a set break) but I disagree.
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amptech

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Re: A mere 50 years of misunderstanding
« Reply #16 on: July 04, 2017, 10:20:05 PM »
Thank Aspen Pittman's marketing of Groove Tubes in its early days for the ideas the kids have about tube life.  Between his and Mesa Boogie's asinine suggestion that tubes barely last six months (convenient when you sell them, no?) the modern myth about tube life exists. In the early days of Chinese and Russian imported audio tubes when dealers were selling REJECT tubes from said countries, caution was more in order, but making tubes is not rocket science and nowadays modern tubes equal the sound and robustness of nearly anything from the past. The most dangerous thing for tubes outside of vibration and physical shock is very rapid cooling of the envelopes, which will shatter them, but you really have to try to do that.

..I'm with you PBG, but let's add mains voltage to the list. I don't know how it is in the US, but here in Norway (and many other european countries) mains voltage have increased with about 20VAC since the late 70's. Some tube equipment rated for 220V just don't work well if you feed it 240V. Add tolerance and you can have an amp that actually 'wants' 210V but 'gets' 250V!

If you have no mins selector that lets you switch it to 230V or 240V you'll wear tubes fast. I've had musicman amps with 825-850VDC on the plates because of this, with the owner going 'it must be these crappy modern tubes I installed when the originals wore out'. Well, no tube could take such strain over time. And high anode voltage is only half the story, you also get too much heater voltage - and that shortens the tube life drastically.

And, on top of this.. Many eastern countries (those who supply most amp factories with transformers) still have 220V mains voltage in their countries. Very few of them make 'special' export transformers. They just label them 230/240V. Whenever an amp with eastern transformers come to my shop, first thing I do is measure heater voltage. In most cases (I've documented this for over 10 years now) I get 6,3V when the variac is set between 210V and 220V. I've seen as low as 6,3@200V.

So yes, as PBG said - modern tubes can equal old in quality. But modern people don't care about giving the tubes correct operating conditions.

Psycho Bass Guy

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Re: A mere 50 years of misunderstanding
« Reply #17 on: July 05, 2017, 11:50:10 AM »
I've not encountered near as many problems with mains voltage being higher, probably because even though US mains voltage has risen proportionally to your observations over the years from the rated 110 to an average of 117-125v, power lines here sag more under the higher current flow and help mitigate the effect somewhat. I can definitely see with a mains voltage based on the 220v rating how it would be harder on amps.
« Last Edit: July 05, 2017, 12:17:53 PM by Psycho Bass Guy »

Pilgrim

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Re: A mere 50 years of misunderstanding
« Reply #18 on: July 06, 2017, 08:04:13 AM »
My 1967 Bassman still has some good original tubes. Of course, it probably hasn't been played more than 50 hours since 1967.

And I check them, since I'm the proud owner of two tube testers!  8)
Good sloppy playing is an art in itself. (Uwe)