A decent tube amp? "Worldwide 300B Builders"

audioguru said:

The 30W per channel (pretty low power) tube amp has its distortion rated at only 1W. Its distortion at full output is probably horrible.
Its damping factor is not mentioned probably because it is very low and it allows speakers to resonate.
There is no guarantee on how long the tubes will last or how soon the distortion will be much worse.

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Funny how the people who come from the valve era wouldn't consider going back to valve amps

Perhaps we know something?.

I'm nearly finished with a two tube CW (amateur) transmitter. Built from scratch - design out of handbook. Why - because I wanted to do it in 1970 but didn't have the time/resources - now I do. Doing it just for fun. Probably no different that someone who might restore or build a classic automobile.

I helped a young man who just finished his EE degree with the construction of a tube guitar amp. It was his final project - he'd done plenty of high tech current technology stuff. His professor encouraged him not to ignore the learning he might get from the obsolete technologies. He and his fellow classmates loved the sound. Yes they measured distortion, harmonics, etc - none of that mattered - they loved the sound.

For relatively simple amateur transmitters the vacuum tube does seem to tolerate abuse - at least in the final amplifier stage. Yes, solid state designs today are nearly bullet proof but the design/construction isn't simple. It seems that most commercial high powered amateur amps are solid state now as the more complex designs are still relatively inexpensive to manufacture.

stevez said:

I'm nearly finished with a two tube CW (amateur) transmitter. Built from scratch - design out of handbook. Why - because I wanted to do it in 1970 but didn't have the time/resources - now I do. Doing it just for fun. Probably no different that someone who might restore or build a classic automobile.

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A radio transmitter is a different thing, quality isn't an issue - for a guitar amp it isn't, but for a HiFi amplifier it very much is.

Doing it for fun is fine at any time though, but many people aren't really doing it for fun, but for some imagined anhanced audio qualities

There is a whole subculture of audiophiles that swear by the 'sound' of using tubes in their hi-fi systems. Some pay astronomical prices (thousands and thousands) for single triode 13 watt output amplifiers, especially liking those 300A tubes pictured above and especially if that tube is a vintage old stock Western Electric brand. Many in that crowd try to describe the improvement in the sound of their system as the results of their tweaks and experiments, as if they were sampling rare vintage wine and as if electronics was based on organic compounds! Oh, and don't forget the improvement possiblities from adding designer speaker and power cables, also for hundreds and thousands of dollars.

Oh well it's their money and their hobby so they are free to believe what they wish and there will always be people willing to profit from them.

Hi,

I prefer valve in a Hi-Fi amp, there seems to be more musicality to them. The production of sound also to my mind appears smoother.

With regard to amps, valves NEVER went out of fashion. Nowadays folk are reproducing specific valve amps of old which have characterisic sounds. From my point of view there is absolutely no comparison between guitar valve and SS amps.

It is my experience that valves also have a larger dynamic range, this allows for passages of music or notes played to have greater attack and sustain. This makes the sound more "alive" in my opinion. Also, I believe that valves clip in a much less offensive manner, in Hi-Fi you would not want to drive them to clipping but certainly with guitar amps you may want to.

I suppose it also depends on what music you like. I played guitar for years, a VOX AC30 tube amp at max volume, through a distortion pedal, analogue delay, compressor and finally reverb. When recorded the music is again submitted to various effects especially compression to reduce dynamic range. Why on earth would I want to listen to this at 0.001% TDH?

If I had a good recording of the 1812 Overture ..... ah that a different thing.

At the end of the day it is what your ear appreciates, the cheaper one can achieve that the better.

Cheers
Andrew

Why not have the best of both worlds?

**broken link removed**

SparkFun Electronics

One of my favourite sites.

A tubes amplifier sounds smooth because its output transformers roll off the sizzling high frequencies and its poor damping of the resonances of speakers causes a boomy sound.

A solid state amplifier does not colour the sound so it sounds live. But some people do not like "real" sound they want it coloured and recorded.

Sorry to hijack the thread, but does anyone know of a list of tubes that people still buy? I was checking out Active Surplus (anyone from the Toronto area will know the store I mean) and they have boxes and boxes full of tubes. I skimmed quickly for some 12AX7 tubes but didnt see any.

ParkingLotLust said:

does anyone know of a list of tubes that people still buy?

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Parts ConneXion - The authority on hi-fi DIY parts and components are in Burlington. They sell high end resistors, capacitors, modules and kits. They sell many vacuum tubes.

They have a sale on until Nov30.

Andrew Leigh said:

Hi,

I prefer valve in a Hi-Fi amp, there seems to be more musicality to them. The production of sound also to my mind appears smoother.

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Interesting comment 'smoother', you mean it tailors the original sound to make it sound different - basically lowering the quality.

It is my experience that valves also have a larger dynamic range, this allows for passages of music or notes played to have greater attack and sustain. This makes the sound more "alive" in my opinion. Also, I believe that valves clip in a much less offensive manner, in Hi-Fi you would not want to drive them to clipping but certainly with guitar amps you may want to.

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Valves have less clean dynamic range, they don't go as low as they are far noisier, and don't go as high, because SS amps are far more powerful.

What you are describing is a valve amplifier driven heavily into distortion, where it's no where near as offensive as a transistor amp doing the same - and many people seem to like the heavily distorted valve sound.

You certainly NEVER want to drive a transistor amp into clipping

audioguru said:

But some people do not like "real" sound they want it coloured and recorded.

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That's why so many sound engineers would manually distort the sound to make the music or song sounds "loud". I don't why they are doing this today but it seems their bosses had told them a nice sounding track won't caught on with the youngsters today. The track must be "loud..Loud...", clipping is even better.

Gone are the days with nice smooth real sounding music.

ParkingLotLust said:

Sorry to hijack the thread, but does anyone know of a list of tubes that people still buy? I was checking out Active Surplus (anyone from the Toronto area will know the store I mean) and they have boxes and boxes full of tubes. I skimmed quickly for some 12AX7 tubes but didnt see any.

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What do ya need? I have a box full of tubes. Not sure of the condition though as they were bought as a lot. I may have a few high power devices, but I think mostly low power. If you want to get real vintage, I have a few nixie tubes for a digital readout...

I don't get this whole tube amp distortion for guitar players thing. I would think you could reproduce the same tube amp distortion with a DSP followed by a semiconductor amp.

I play guitar, I have both a digitech and a Carver DSP processor in series that allows me to make any sound I like.

Mikebits said:

I don't get this whole tube amp distortion for guitar players thing. I would think you could reproduce the same tube amp distortion with a DSP followed by a semiconductor amp.

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You pretty well can, but you need something like a 500W amplifer to reproduce a 30W valve amp.

Mikebits said:

Well I must confess I was thinking 1KW type transmitters. I really never thought about larger ones. Back in my Navy days, we had a 40KW magnetron that was water cooled. Quite a large setup.

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It depends on the frequency, an 800W micowave oven uses a magnetron to produce 2.45GHz more cheaply and efficiently that a solid state transmitter can. If you wanted to build a 10MHz SW transmitter then you'd be better of with solid state.

Mikebits said:

200 KW solid state.
https://www.electro-tech-online.com/custompdfs/2008/11/dx200.pdf

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That's only the medium wave band, 540kHz to 1600kHz which is easy with solid state components. Many SMPs switch at this frequency, you'd could probably go up to 1MW of RF power if you wanted to.

Find me a 200kW solid state 2.45GHz transmitter and I might be more impressed.

I have seen a "sound effect box" (for guitar players) that was not more than an overloaded valve preamp

It used just a 12AX7, but with a very low plate voltage (something like 12 V or 20 V)

With that low plate voltage it was more like a "clipping machine" than a preamplifier

Hero999 said:

It depends on the frequency, an 800W micowave oven uses a magnetron to produce 2.45GHz more cheaply and efficiently that a solid state transmitter can. If you wanted to build a 10MHz SW transmitter then you'd be better of with solid state.


That's only the medium wave band, 540kHz to 1600kHz which is easy with solid state components. Many SMPs switch at this frequency, you'd could probably go up to 1MW of RF power if you wanted to.

Find me a 200kW solid state 2.45GHz transmitter and I might be more impressed.

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What would be the point? At that freq we are looking at line of site anyways.

high power and high frequency and line of sight ? Perhaps space communication
but I think NASA is using higher frequencies, around 8 GHz.

Nigel Goodwin said:

They would have to be specifically designed to clip, more an overdrive circuit than clipping the amplifier - it's usually done with clipping diodes in the preamp, and not by driving the output stage past the power rails!

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You don't clip the signal for guitar amp distortion. It's done with over drive. What do you think a fuzz is? It's just a ram rod pre-amp.

Man you got some serious misconceptions about electronics. Have you ever designed anything?

Space Varmint said:

You don't clip the signal for guitar amp distortion. It's done with over drive. What do you think a fuzz is? It's just a ram rod pre-amp.

Man you got some serious misconceptions about electronics. Have you ever designed anything?

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What do you think overdrive does? /-\_/

Now be nice