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Got Tubes?

5310 Views 47 Replies 20 Participants Last post by  jk32sho, 
S
Waaay back in the day, tubes were the only game in town. As such, tube amplifiers were the only way to go if you wanted to listen to your stereo in the car. Of course, transistors were much cheaper and not nearly as fragile, but even today there are still tube enthusiasts.

Strictly speaking, there are a variety of mil-spec tubes out there that can handle the jostling of a car - take, for example, the russian GU-50, a low-distortion power pentode intended for use in MIG radar systems - they cost about $8 each, and a pair can put out over 100 watts RMS! Power supplies are'nt hard, either - a pretty standard flyback transformer configuration (as is used in quite a few solid-state car audio amps) makes it easy to provide the required voltages.

Are there any tube car amplifiers out there? And, more importantly, does anyone want them?
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First, to be quite honest, I find solid state better than tubes. It just has to be the good stuff. However, I'm curious as to wether anyone actually has done tubes in a car.

silent1 said:
I dont see how tubes can sound "better". From what I hear it adds warmth. Adding something thats not there is not better. I know tubes can be better in guitar amps, cuz of the way they sound driven hard, but distortion in guitar amps is an excellent thing. Not in my playback IMO.
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Well, yeah. It's sort of a hypothetical, but then again, this is DIY mobile audio - I'm surprised nobody's tried.


thehatedguy said:
I have a HSS Fidelity HT230 all tube class A SET amp...it's for the car. It's the only class A tube amp made for the car- the Tru and Milbert are a/b push-pull. The Tube Drivers. US Amps, DLS, Planet Audio, and US Amps only use tubes in the preamp...well, the Tube Drivers don't really have any signal going through their tubes.

The HSS uses 2 paralleled KT88s wired in triode mode to put out about 30 watts a channel. The KT88s can be swapped to 6L6s, KT77s, KT90s, or KT100s if you want.

My amp was/is very expensive...heavy, and large. But boy does she make some sweet music on my horns.
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Cripes! That thing must pull, what, four hundred watts?
That said....why not build your own instead? Aside from the power supply, DIY tube amps are availible in a million bajillion permutations.

thehatedguy said:
I haven't seen too many people going for the KT90s, but from what I've read QC has improved on the tubes. I have seen a few folks going for the KT77s though. But from what I've read the 88 is a better tube...and the 6L6 is the US version of the KT88 and is less prone to microphonics...so I guess the 6L6 is even better in some respects to the KT88s.
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No. No, they're not. The 6L6 is a very different tube from the KT88 - as a rule of thumb, the KT88 is both more linear than the 6L6 and capable of much higher voltages. There's a reason that 6L6s are rarely found outside of guitar amps nowadays.

truejoker said:
but in home, you could get desent amp in the region of 1000-2000 . in car you get integrated that isn't all tube and it cost arm and legg.
so if i could get a realy tube amp in the region of 1000 , i think i will bay it. but that seems **** a dream
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For $1,000, I, personally, would build you a tube amp for your car. Probbably a heavily modified Dynaco ST-70 with a custom flyback transformer setup and enough shockmounting not to kill the tubes.
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Finding a power supply to get the plate voltages I need is tough. I have found a couple DIY tube car power supplies, but dunno how good they are. But yeah, I have a few SET KT88 home schematics book marked that I would love to build for the car and house.

The HSS has an idle current of 23 amps :). She's only putting 230 volts to the plates.

BTW, there is already a Dynaco car amp on the market...the Tru Technology C7AT is a Dynaco ST-35 with a 12 volt power supply.
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chad
I'm wondering how "easy" it would be to get 400+ VDC with a decent amount of current out of 12VDC.

Me thinks this is why these tube amps for the car are so expensive.

Other than the fact that most people who know tubes know that the transistor was created to eliminate the tube in mobile applications be it land, sea, or air and also the elimination of tubes in trans continental telecom lines.
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the other hated guy
from what I ahve read from numerous well respected people in the home hifi bus...is that the Art Audio home amps are some of the best sounding that money can buy...and their philosophy is not to overdrive the tube with an insane amount ov voltage..infact they preach against it...saying it had a harshness or strain to the output...
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chad
the other hated guy said:
from what I ahve read from numerous well respected people in the home hifi bus...is that the Art Audio home amps are some of the best sounding that money can buy...and their philosophy is not to overdrive the tube with an insane amount ov voltage..infact they preach against it...saying it had a harshness or strain to the output...
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That's no joke, too many these days run tubes VERY hard to get "that tube sound" but in all actuality "that tube sound" came from running low enough voltages and sane bias levels to actually PROLONG tube life. The voltages in the Sonic Frontier gear is absurd, trust me I had one knock me across a room!

There's nothing wrong with running a simple 400V plate voltage on big bottles and less on the little bottles.

What irks me is the "tube gear" out there that runs at such a low voltage that it barely works... hmmm.... I can think of a TON of Chinese mic pre's doing this. Some even put LED's behind them to make the "tube glow" knowing full well that a 12AX7 does not glow :D
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Butler did that with the Tube Driver Blue...and I have seen LEDs behind/near tubes in other places too.

But yeah, I don't think it is easy to get 400-450 volts out of 12.
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O
How do you think these will fare?


GENESIS P15 – VALVE TECHNOLOGY FOR THE CAR - TAYLOR MADE IN GREAT BRITAIN

British based car audio manufacturer Genesis ice Ltd is using CES 2007 to launch a special edition Class A amplifier with valve front-end for automotive applications.

This Gordon Taylor designed amplifier pulls together the finest technologies available to reproduce near flawless music. Utilising a Russian built 6H30Pi tube, any question of inherent fragility is answered. This incredibly linear triode was developed for use in missile guidance systems and can withstand up to 500G-force while working quite happily at loads of 100G.

The power amplifier features OnSemi ‘Thermaltrak’ series transistors configured to run in Class A up to 30 Watts per channel RMS and then run to 200 Watts per channel RMS in class AB. This is achieved using the same Class A+G circuitry used in last years highly successful special edition DM-A.

The amplifying devices are specifically designed for audio and have specific on-board sensing built into each transistor to ensure perfect bias tracking.

Separate power supplies are provided for both preamp and power stages with a third supply dedicated to preheating the tubes on activation of the vehicles central locking. This ensures that by the time the driver is ready to drive off, the amplifier is ready to deliver awesome performance all the way to his/her destination.

The amplifier casing is made from 10mm thick aluminium plate with pillars turned from solid billets. These provide anchor points for the cooling fins, which are individually machined from solid 4mm alloy plate.

A plexi-glass top cover adds visual highlights by exposing the warm glow of the tubes within.

The overall dimensions of the amplifier are: 25 X 13 X 4” and it weighs in at approximately 50Lbs.
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T
Should be a great amp as are all Genesis amps are, but not all tube...solid state with a tube preamp. This one is different b/c it's a Class A solid state with a tube front end, which should be pretty darned cool.

I'm still wanting a Genny DM-A and 2 Dual Mono Extremes....:cool:
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N
My first inclination was to use the Butler tube amps when I started my project. I think I was scared off due to members (or someone) stating noise issues were a common problem with those amps. I had listened to this butler amp back in the early nineties and loved it. I saw many tube amps at the 07 CES show and was intrigued by their design but the cost and rarity turned me back to the solid state design.

It's cool to see the tube amp camp chiming in here. I would love to here some car tube amps. Anyone got a tube amp connected to a DRZ or Mac? How would you cool these things in a car? Is a stealth install out of the question? I know that for home audio, the heat these things generate is a major problem for many, especially when they have kids.
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chad said:
I'm wondering how "easy" it would be to get 400+ VDC with a decent amount of current out of 12VDC.

Me thinks this is why these tube amps for the car are so expensive.
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Yep. You're going to need a flyback transformer or some other sort of switched mode power supply. Most of these can reach efficiencies of over 90% efficiency, and the heaters can usually be run directly from the car battery (just wire two identical 6v-heater tubes in series.) However, while the parts are not necessarily expensive, most transformers used in power supplies are custom-made - the easiest way to get some is to find a burned-out server-class (400 watts or more on the 12v rail alone) computer power supply, which often share a similar sort of transformer.

NoFlyZone said:
It's cool to see the tube amp camp chiming in here. I would love to here some car tube amps. Anyone got a tube amp connected to a DRZ or Mac? How would you cool these things in a car? Is a stealth install out of the question? I know that for home audio, the heat these things generate is a major problem for many, especially when they have kids.
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I have no idea what a DRZ or Mac is. However, in a car, heat certianly will be a problem.
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T
If you were in North Carolina, you could listen to the HSS Fidelity in my car once it it finished. I loaned my Milbert to a buddy in Texas, but I'm sure if you were close, he would let you take a listen to it.

I haven't had noise issues with the HSS or Milbert, and they were running 112 dB efficient horns...so if I couldn't hear the noise on those puppies, it would be hard to hear on other speakers.

If you came out here, what deck would you want to hear the amp on? I will be using a Pioneer P9 deck with the P70x processor, but I have a few more toys- Nak CD700II, can get hands on Denon Z1 or DCT-1, have Eclipse ECD-416 and 510. And if you wanted processing in the car with those decks, I have a Rane RPM88. If you wanted to listen to the amp in the house, we could use one of those decks as a transport or use my Sony DVP-7000 which feeds either a modded Bel Canto DAC2 or a modded Benchmark Media DAC1 (need to get it back).
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|Tch0rT|
thehatedguy said:
The Tube Drivers. US Amps, DLS, Planet Audio, and US Amps only use tubes in the preamp...well, the Tube Drivers don't really have any signal going through their tubes.
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The Tube Drivers don't have the signal going through the tube in the preamp?

thehatedguy said:
Butler did that with the Tube Driver Blue...and I have seen LEDs behind/near tubes in other places too.
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Did Butler just put a blue LED behind the tubes in the TDB's?

So what is Butler just a "hack" in the hybrid tube class? Just curious as I don't know. I think I've heard that with the Butlers if you remove the Tube sound still go through the amp.

Spasticteapot said:
I have no idea what a DRZ or Mac is. However, in a car, heat certianly will be a problem.
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I'm pretty sure he's asking if someone is running a Clarion DRZ9255 or one of the McIntosh head units with some tube amps.

Ryan
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T
Some of the first Tube Drivers would play with the tubes removed. Now, they have a circuit that disables the amp if you pull a tube out...not that there is any signal going through the tubes. They use the tubes in some sort of "resonance" circuit.

I never understood why they were using power tubes in a preamp.

Yeah, there are LEDs making the blue glow. You aren't going to get a blue glow like that from a tube unless there is something seriously wrong with the tube...or you are sending 1000+ volts to a mercury vapor power tube. But he isn't the only one doing this...

I wouldn't call him a hack. BK Butler is a smart dude. They were just capitalizing on the "tube" sounding amp...and having tubes physically in the amp helped sell that illusion.
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chad
Spasticteapot said:
Yep. You're going to need a flyback transformer or some other sort of switched mode power supply. .
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So it's not a design... it's a far reach. A "flyback" needs a quick HF trigger and is generaly not designed to provide plate voltage, just a damn hard, very high voltage charge to a CRT tube, the current requirements are low. That ain't plate voltage.


Spasticteapot said:
Most of these can reach efficiencies of over 90% efficiency.
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12VDC to +/- 48VDC ain't nothin' 120VAC to 480VDC ain't Nothin' 12VDC to 480VDC is another story......

Spasticteapot said:
and the heaters can usually be run directly from the car battery (just wire two identical 6v-heater tubes in series.)
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Preamp tubes will need regulated supplies, power tubes MAY not..... But, would be good idea due to sag when the wipers are on, the lights are on, your sub amp is going, rear defog, sitting in traffic, pissed in the middle of winter, trying to buy time..... it hapens......

BTW bias will have to be regulated too, there's another PS for ya..... Hate to lose bias in slow traffic.....

Spasticteapot said:
However, while the parts are not necessarily expensive, most transformers used in power supplies are custom-made - the easiest way to get some is to find a burned-out server-class (400 watts or more on the 12v rail alone) computer power supply, which often share a similar sort of transformer.
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mmmmKAY ;)
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chad
thehatedguy said:
Yeah, there are LEDs making the blue glow. You aren't going to get a blue glow like that from a tube unless there is something seriously wrong with the tube...or you are sending 1000+ volts to a mercury vapor power tube. But he isn't the only one doing this...

I wouldn't call him a hack. BK Butler is a smart dude. They were just capitalizing on the "tube" sounding amp...and having tubes physically in the amp helped sell that illusion.
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OH, ho ho ho ho... I love ya! :D :D :D

You mean the blue is not the "tube glow?" :p

Blue tube?...... Gassy?...... Get rid of it!
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G
Now now ...

First gen of Tube Driver amps used simple, low-plate voltage cathode followers in a feedback circuit, shunted by a zener diode that would "clamp" the grid/cathode voltage until the tubes warmed up, or if the tubes were removed. So the amp would still function with the tubes removed, or cold ... just at a probably higher distortion level.

The Tube Driver Blue amps are altogether different. Low-power tubes are used in a cathode-follower configuration to directly driver the base nodes of the output stage, high-power bipolar transistors. In this way, the current through the tubes is an attenuated version (by the output bipolar beta) of the actual current delivered to the loudspeaker ... something no other hybrid tube amp (with tubes in a preamp stage only) could claim. The designer based this design on the AES paper that discussed tubes vs. transistors.

Note that in each incarnation of Tube Driver amps, the cathode followers provide no voltage gain at all, although they are definitely in the signal path. That's why Butler can get away with silly-low plate voltages, and still claim a certain "tube characteristic".

I'm not endorsing ... just clarifying.
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Thanks Jeff...been a while since I was versed in the Tube Driver stuff, and with school this week- 1 test, 3 Finals and 4 labs due by thursday, I probably shouldn't be talking technical anything...lol.
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chad
werewolf said:
Now now ...

First gen of Tube Driver amps used simple, low-plate voltage cathode followers in a feedback circuit, shunted by a zener diode that would "clamp" the grid/cathode voltage until the tubes warmed up, or if the tubes were removed. So the amp would still function with the tubes removed, or cold ... just at a probably higher distortion level.

The Tube Driver Blue amps are altogether different. Low-power tubes are used in a cathode-follower configuration to directly driver the base nodes of the output stage, high-power bipolar transistors. In this way, the current through the tubes is an attenuated version (by the output bipolar beta) of the actual current delivered to the loudspeaker ... something no other hybrid tube amp (with tubes in a preamp stage only) could claim. The designer based this design on the AES paper that discussed tubes vs. transistors.

Note that in each incarnation of Tube Driver amps, the cathode followers provide no voltage gain at all, although they are definitely in the signal path. That's why Butler can get away with silly-low plate voltages, and still claim a certain "tube characteristic".

I'm not endorsing ... just clarifying.
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But... That... Ain't... Tube...

:D :D :D :D :D :D :p
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Jeff, think we gave Larry something to think about on the other forum?:D

Class A 50x2...with 3A idle current my ass...and 3 more channels in the same chassis.

Anyways, tubes RULE!
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D
silent1 said:
I dont see how tubes can sound "better". From what I hear it adds warmth. Adding something thats not there is not better. I know tubes can be better in guitar amps, cuz of the way they sound driven hard, but distortion in guitar amps is an excellent thing. Not in my playback IMO.
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There are a lot of reasons that a tube amp will sound better than transistors but it isn't always clear why. There has been a lot of theories, both psychoacoustic and electronic and probably no one reason is correct. There are a few interesting articles that you can read and decide for yourself. One of them, http://usuarios.uninet.com.br/~edelima/REASONS.htm, says
Moving coil speakers drivers are essentially a very simple electro-mechanical system and they normally have a very high total harmonic distortion specification compared to any other device in this digital based chain. But if we examine the distortion spectrum of any reasonable speaker we will see that all the distortion is low order. In most cases it is mainly second harmonic with some third harmonic also appearing with lower levels. The higher order terms will only become noticeable near the limit of power
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What will happen when we put a high distortion tube single ended amplifier in the same system in place of the low distortion amplifier ? Single ended tube amplifiers are very simple electronic devices. They normally have a high harmonic distortion specification. But if we examine the distortion spectrum of most single ended amplifiers we will see that all the distortion is low order. In most cases it is mainly second harmonic with some third harmonic also appearing with lower levels. The higher order terms will only become noticeable near the limit of power

If two devices have only second harmonic distortion in the same quantity (lets say 1%) what happens if we connect them one after the other ?

The result will depend on the phase of this second harmonic in relation to the fundamental in each of the devices. (this phase can be anything from zero to 360° or if you prefer from -180° to +180° , always spanning a 360° range). At this point I should say that the multiplication will generate 3rd and 4th harmonics but at much lower levels. Lets look at the 2nd harmonic:

-If the two devices are just equal, with the same phase relation between the distortion and the fundamental, the result will be a total of 2.0% of 2nd harmonic distortion.

- A 30° difference in the relation of the 2nd harmonic and the fundamental between the two devices will produce a total of 1.93% of 2nd harmonic distortion.

- A 60° difference will produce a total of 1.73% of 2nd harmonic distortion.

- A 90° difference will produce a total of 1.41% of 2nd harmonic distortion.

- A 120° difference will produce a total of 1.0% (exactly the same distortion as any of the devices alone)

- A 150° difference will produce a total around 0.52% (about half of the distortion of any of the devices alone)

- If there is 180° difference in the relation of the 2nd harmonic and the fundamental between the two devices the sum will be zero 2nd harmonic (yes that is right, in this ideal situation there would be NO 2nd HARMONIC DISTORTION).
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There's more, including
that second harmonic distortion is a mathematical construction that happens to describe an aspect of nature and has a precise definition that does not take in account if it was generated electrically or mechanically or by whatever means
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IOW, a solid state amp may sound more distorted to the human ear than a tube amp, at least when taking into account total system distortion and that the solid state amps will produce odd order harmonics as opposed to the more natural sound even order harmonics from tubes. That explanation has been considered too simplistic, but goes to show that your statement about "adding things that isn't there" is also an oversimplification and partially untrue.

http://www.vac-amps.com/no_se_amps.html
There are tons of links in the following website:
http://www.milbert.com/articles/?mais=d25e4222203cae7c0fc517142103e573
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