Power to the tubes! Always?

[DizRotus]

Mobile Homless and others have recommended that CD players be left on at all times.

Could there be advantages to leaving tube equipment powered up at all times? Which causes more wear on the tubes, idling with no input signal or the thermal cycles going from cold to hot to cold, etc.?

An obvious drawback to constant power is the cost of the electricity. Is that expense outweighed by sonic benefits or extended tube life? Perhaps the variables among the many different pieces of equipment are too great to generalize.

Has anyone left tube gear powered up indefintely? If so, what were the consequences?

If NOS440 or mdeneen view this post, please re-visit my earlier post about Squealing 7199s. I have questions about testing pin voltages.

Neil

[Jobman]

Diz:

This is a question very similar to the "Which type of cables or wire is best". I have seen numerous heated (pun intended) threads on it in the AA. Seems to be fairly evenly split on which is best - on or off.

I asked the maker of my amps and preamp, George Wright of Wright Sound, that question when I bought my equipment. His reply was that accoring to the way he has the amps and preamp set up and biased, unless I wanted to spend a lot of money replacing tubes, I should turn them off. Of course, I can lower the bias via a 3 position switch, so for my part, if I am not going to be listening for more than 24 hours, I turn them off. Same with my CD player. Keeps it simple.

I hope others will give their views and how they handle the question.

Jobman

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Chorus II's

Wright Sound 3.5 - 2A3 Monoblocks

Wright WPL-20 PreAmp

Jolida 602A Tube CD

Thorens TD-165

Silverline Speaker Cables

Various Monster, Rat Shack Interconnects.

Forte II's for Surrounds

[NOSValves]

Well I'm a vintage nut and I just find leaving a amp on a scary thought. With 40 year old parts in them you just never know when something could go wrong although I've yet to have a total break down . Also constant on just can't be good for tubes. All tubes have a hourly rating so every hour there on is another hour off there life.

Here's what I do ...

If I'm going to be home all day they stay on all day. If I know when I get home from work that I'm going to listen to music later the first thing I do is turn my amp on. When I'm ready to listen she is warmed up and ready to please (wish I was talking about my wife )

I also think a good amp should have slow start built into the curcuit it keep the initial shock of start up off the tubes and extends tube life.

Craig

Jobman,

Good to see haven't noticed you posting much. The heresy's are still singing like a dream.

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HH Scott 299 Amp

HH Scott LT-110B Tuner

HH Scott P-87 Turn Table

JVC JL-F50 Turn Table

Sony CDP-CA7ES CD Drive

1985 Walnut Heresey I W/Layne Audio Woofers

KSW-15 Subs>c>

This message has been edited by NOS440 on 08-14-2002 at 10:29 PM

[lynnm]

All components will age/deteriorate with use,(yes,yes I know that some components will benefit from use but those same components will also begin to wear out over time - especially if subjected to excessive use).

FWIW I leave my EL 34 based amp off when not in use for any significant amount of time but allow it to warm up before playing it - unless of course I am really anxious to hear some tunes.

My take is that there is a finite - (but probably very long term amount of usage built into any quality Power Amp tube) but unlike transistors which are on/off devices which are active when in use and essentially comatose when not in use - Tubes in a class A amp will operate at something approximating full power whenever they are powered up and that the stresses involved in being powered up are likely of less significance than those of being left running.

In other words I believe that requiring tubes to operate at full bore when nothing is happening is probably detrimental to their life expectancy and wasteful of energy.(Luddite ancestors here intervene and demand that I admit that a 35/w.ch. class A amp draws less power than a modern refrigerator).

There are many variables to be considered in the question of tube life. My amp is classed as a class A but the circuit goes into A/B depending on the BIAS voltage setting and the input signal to the O/P tubes,(look the various classes up if you need to know - I cannot type that much - at the moment).

To make a long story short - the higher the BIAS setting the closer the ampflifier comes to pure Class A operation - Which is a good thing sonically BUT..... The trade off is that the higher the BIAS voltage the higher the physical stress on the tube because the tube is working full time in Class A. This of course leads to the question - How often are you prepared to replace tubes? FWIW I was able to contact the designer of my amp who recommended a BIAS setting of 450 mv. subject to the caveats above.

For further information on this subject search on amplifier classes and plate conductance.

Me: TUBERS UBER ALLES !!

She: Potatoes Rule??

Me: THHHHHHHHHHHRRRRRRRRRRRAPPPPPPTH - The Reasoned Intellectual Response Always Wins In The End!!

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It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900)

This message has been edited by lynnm on 08-14-2002 at 11:17 PM

[ShapeShifter]

I closely follow the guidelines posted on Cary Audio's web site. I begin weekends by powering everything one Friday morniing before leaving for work. The preamp is actually on standby. Everything stays on or in standby mode through Sunday night. For weekly sessions I generally turn on the CD and have leave the preamp in standby mode if planning a listening session.

Wes

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KLIPSCH IS MUSICf>

My Systems f>s>c>

[Randy Bey]

I used to leave mine on all the time but then a 5ar4 started glowing a bit too brightly for my continued mental well-being. Probably just that silvery powder getting too thin on the top (as are we all) but the thought of that puppy sparking up and setting fire to the untreated MDF rack, and subsequently the entire basement, .....

I try to turn them on at least 15 minutes before I start listening. If not, well, so it goes. I leave them on all day if there's a chance I'll listen again, but overnight, no way.

[Guy Landau]

I have once left my precious Marantz 8B power amp on,and had left for an hour.When I came back it was toasted and burned the output transformer and few other parts.

I recommend not to leave vintage tube amps unattended.Mine became worthless and I could never enjoy it again.

Tubes have heaters and reach their optimal operation in less than an hour.Transistors don't have heaters and reach their optimal operation in 3 days.

[Clipped and Shorn]

Mdeneen stated:

"tubes are nothing like light bulbs in spite of the appearance. "

right, if they were. we would all be searching eBay for those extinct NOS/NIB Mazda light bulbs at $100 a pop.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2130878376

http://cgi.ebay.com/ebaymotors/ws/ebayISAPI.dll?ViewItem&item=1851063108&r=0&t=0

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2131429967

By the way, does anyone know which NOS light bulb yields the most mellow and yellowy warm light, the Stanleys or the Mazdas. How much break in time is recommended and how important is the power cord used, braided or solid core?

-C&S

we'll leave the light on for you......

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Cornwalls

currently upgrading

to all tube components

This message has been edited by Clipped and Shorn on 08-15-2002 at 09:11 AM

[NOSValves]

Clipped and Shorn

To funny

[lynnm]

mdeneen

What BIAS setting are you using on your EL34's ?

I have set my BIAS to 450 mv. on the recommendation of Joseph Lau who designed mine, (Antique Sound Lab AQ1003). They had been running at 300 mv. and I noticed a considerable improvement when I set them to 450 mv. I am wondering if the BIAS could be safely increased further.

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It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900)

[sunnysal]

As a private pilot I have been brainwashed by the "hour meter syndrome", I cannot stand the thought of going to the beach for the day while the hours are racking up on my precious NOS tubes. I know their life is measured in hours, so why leave them burning away their lifetime while I am not listening. No doubt they sound better after they are fully warmed up...so...my happy medium has been to leave them on for at least a half hour before serious listening sessions. MTC, tony

[lynnm]

mdeneen

Thanks for your response. I am at work and don't have access to a readable schematic. There is one here:

http://www.divertech.com/aslcd1003.htm but I can't read the plate voltages.

The BIAS can be set for each of the EL34's. The Bias voltage as I recall from my correspondence with Joseph Lau is measured across a 10 ohm cathode resistor connected between the cathode and ground. I will see if the schematic I have at home shows the plate voltages.

Greatly appreciate your input.

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It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900)

[Jobman]

mdeneen:

I expect to get 5,000 hours from the tubes. At 2 hours per day, that's about 6.5 years and the tubes cost me about $160. At 24 hours per day the life will be around 6 months. Big difference to me.Textc>

That is the most telling part of this question for me. The overall cost in terms of tube life. It is getting harder and more expensive day by day to find and replace those 1943 RCA Black PLate 2A3's. What will they cost in 2005?

My tube system has been off for 6 days, as I knew I would not have the time to sit an listen. I use my Sony HT receiver just to listen to background music in the morning before work and when I get home for awhile. No serious listening. But I am looking forward to turning it back on Friday evening!

Jobman

[NOSValves]

Jobman

I hope your listening to the Sony is not serious I have a Sony AV receiver and can hardly stand to listen to it . In fact it is what made me yern for the sound I remeber from years ago and started my quest for tubes !!

Craig

[prodj101]

there are alot of tube amps with a stand by that leaves power to the heaters on all the time.

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-Trevor

[Jobman]

NOS:

Yea, the Sony is a DB940, and we really only use it for HT duty. I know there are beter HT units out there, but for now it is fine. Since I don't expect Tube or High Quality sound from it, I am not disappointed.

Someday, when my 2 channel system is just perfect, and there are no more upgrades or changes I can or want to make, I will look at changing the Sony.

Of course, I'm sure that the sun will have exploded or some other place will have frozen over by that day! LOL

Jobman

[jnorv]

What is the deal on the Music Fidelity Nu Vista tube setut? They claim great things about tube sound and 10K hours of life. I put it dow-0n to the level of another politican talking.

J Norvell

[NOSValves]

Jobman,

Actually I find that my Sony DB*)&_( 975 not really sure of the rest of the letters. Its a 500.00 Best buy job. I have no desire what so ever to upgrade it. I think it does a bang up job at Movies. I've had freinds over that have much more expensive home theaters (not Klipsch) and they always leave scratching there heads when I tell them what I have invested in my setup.

I really think High dollar recievers for HT are a big waste of cash. Just not needed !! But hey I'm a cheap SOB !!

Craig

[DizRotus]

Craig,

I agree regarding HT. I use a Sony STR D515 AV Receiver to power LS3/5A clones (KEF drivers) and passive but equalized subs that each contain a KEF B-139 driver in a large transmission-line enclosure. The surrounds and center channel are Audio Source (they were free). I have never felt the need to improve upon that for listening to TV and movies. Afterall, it's not like it's real music.

Neil

[lynnm]

jnorv

The Nuvistac> amplifier uses Nuvistorc> tubes.

The Nuvistor tube was an attempt by tube makers to counteract the inroads being made by the SS crowd at the time it was introduced and it succeeded technically but not commercially. It is a classic example of too little - too late - at too high a price.

Why?? Because the Nuvistor tubes were very - can you spell OUTRAGEOUSLY) - pricey as opposed to transistors and were not percieved by the buying public as the latest in technological innovation - as were transistors - and furthermore could not claim that they were as durable as the SS stuff.

The transistor makers could truthfully claim that a transistor would -if it survived the first few seconds of use and if not subjected to conditions outside of its design parameters - last indefinitely. That same claim cannot be made for tubes. Religiously obey the tube and/or amp makers recommendations and the tubes will still die at some point in the future - (The good news is that a well designed tube amp will rarely require more than 2 sets of O/P tubes in a user's lifetime).

It is also fair to say,(even by a committed tubophile),that a well designed SS amplifier can approach the sound of a tube amp overall and furthermore that while a high quality tube amp driving high efficiency speakers can produce exceptional bass response a really good SS amp even when driving low efficiency speakers can run circles around most tube amps in that frequency range and if fairly priced can do so at a much lower overall cost to the consumer.

Returning to the original question - The Nuvistor tubed amp you describe is from everything I have read a real gem and further my understanding is that you will have a guarantee from the manufacturer that a full set of Nuvistors will be set aside for each buyer.

Nonetheless tubed amps of equal or possibly superior performance can be had for much less money and use tube types that are much less expensive and far less difficult to obtain. I do not doubt that should I need a quad of EL34's 20 years from now they will still be obtainable,(although at a premium price), as they are widely used and are still in production by several makers. Further bear in mind that demand for vacuum tube amps based on the EL34,(amongst others),is on the rise lately.

The same cannot,unfortunately, be said of the Nuvistas which are based upon the Nuvistor tube. My understanding is that the amp is no longer being produced because the NOS Nuvistors are simply not to be found - even by the amp's maker.In the unholy event that an original Nuvistor tube and its guaranteed replacement go south - Where the hello will You find a replacement when the amp's manufacturer has had to suspend shipment of a highly regarded and highly profitable product due to lack of available tubes ?

True you could have the amp rewired to utilise a replacement tube but wouldn't that defeat the purpose of having something that almost every other tube freak wants - especially given that you can buy equally good sounding tube amps that sell for much less money ?

On the other hand it may well be that the collector community may fix on the Nuvista amp as being the epitome of otherwise unobtainable excellence and the value of those amps might then rise beyond their current,(outrageous - In My Not Especially Humble Opinion),price level.

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It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900)

This message has been edited by lynnm on 08-16-2002 at 11:15 PM