Solid-State TUBES !!

[engrguy42]

james_s, before you get offended, I think you're missing my point.

I certainly get that people think the old equipment is well engineered and high quality. In many cases I tend to agree. But folks here seem to be unable to comprehend how others might value things differently and have different priorities.

For example, I'm not a car guy. Yeah, I see how some cars are high quality and well engineered, but for the most part I don't give a rip about a Bentley or Mercedes. And while the old Tektronix analog scopes I used years ago are high quality, I don't care. I'm unwilling to invest money in them for a number of reasons. That doesn't mean I don't respect quality, it just means I'm not interested in investing in stuff solely because it is perceived as "high quality" or "well engineered". To me there are far more important criteria for judging stuff that I'm going to use and rely on. 

I'm an engineer, and if I need to use something on a practical and regular basis like a car and a scope I tend to value cost vs. benefit, not that it's old stuff that was well engineered. I value stuff that will last and be up to date and has the functionality I need.

Nor do I value fine wines. I don't like wine. So sue me. Instead I used to spend crap-tons of money going around the world doing scuba diving. Different people have different values. Would I ever recommend that everyone needs to spend all their money going around the world scuba diving, and search for a bunch of irrelevant reasons to justify my recommendations? Hell no. It's a dumb idea, and a waste of money. I freely admit it. And if you told me, "dude, you freakin' wasted tens of thousands of $$ with nothing to show for it", I'd be the first to agree.   

Now if others do value the old analog electronics stuff because it was well engineered then that's fine. I just wish people would be honest and say "yeah, basically I like it cause I like old stuff. And honestly, I don't think it's appropriate to recommend it to newbies (or anyone else) because, even though I like it and value it, it's probably not the best choice for someone starting out, for a number of reasons. Nor is it appropriate to look down upon those who have different values and priorities".

Now if someone actually believes that it's a good idea to recommend those old analog devices, then that's fine. As long as we're being honest and considering others' needs, not just our own biases.

Instead, as in most tech discussions all over the universe, it comes down to "I like it, therefore everyone should value the same thing and like the same thing", and people get upset when others disagree.

 

 

[sam[PS]]

vs 

valve circuits generate lots of even harmonic distortion

Please provide an actual frequency analyser plot to back up that, i'm very curious about is as all those i seen don't actually show that.

even harmonic distortion which sounds less harsh than the mostly odd harmonic

Please provide evidence, of course that's very subjective but still some protocole exist to get data on subjective things.

mostly odd harmonic distortion from badly designed transistor stuff.

Ha ok now i see so well designed tube circuits tend to sound better than bad designed transistor circuits. Well let's take the words "transistor" and "tube" out of there and that still stand true. Invert them and that still stand true. So yeah that's a good news for competent EE designer, there is still work for us.

And yeah that odd harmonic vs even harmonic thing is an argument that's been repeated a lot over the years. You ear/read that all the time whenever the subject of tube is put on the table. But actual measure are not consistent to it so...

Odd vs even harmonic is mostly a matter of topology i.e. single ended vs push pull, that's just basic mathematics (taylor series anyone ? ).
If you build a simple single stage triode common cathode voltage amplifier and a similar Jfet common source or a bjt common collector voltage amplifier, the three with the same voltage gain (under load please) and you just plot the harmonic content at the output using a frequency analyser  (the fft function of any decent digital scope will do just fine). You will see difference in the harmonics generated by those three circuit but those are most of the time nowhere near the statement you make. From the measure i seen and some i made triode tends to generate more harmonics both odd and even than the solid state counterparts but their harmonic spread is very focused on low order harmonic while solid state tends to generate more high order harmonic. Now with a penthode i got about the same spread as the Jfet, just more of it. I'd have to redo this experiment and document it one day, probably won't stop the myth to spread, actually it have been done several time in electronic magazines and the myth is still alive. Now it's an EE forum here not an audio forum, so please behave as an engineer and before spreading things get some measure done. 

Don't get me wrong i love tube. I play electric guitar and playing thru my all tube head give me thrill. And one of my curent electronic project is recreating original Beatles's era abbey road REDD .47 all tube mic preamps. But that's about mojo not EE !!!! I do believe mojo is something of importance in music, musician do play slightly better when they feel the look of the instrument they have in hand is cool. But that has nothing to do with the quality of the instrument. Same goes for tube vs solide state. 

Now the OP's subject is interesting could we please come back to it, and please talk a little more about EE and a little less propagating myths.

[John B]

I see nothing wrong with preferring tubes in an application where particular shaping or distortion of the waveform is the goal, ie a bass/guitar amplifier.

[Circlotron]

The best thing about valves is how they made you feel when you were a little kid, peering in the back of a running radio or tv, wondering just how it worked, smelling the warm transformers and dust. Now we're adults and that magic feeling has slipped through our fingers and we just want to relive it again. It's not technology, it's psychology.

[peter-h]

I think the last two posts above are spot on

[engrguy42]

The best thing about valves is how they made you feel when you were a little kid, peering in the back of a running radio or tv, wondering just how it worked, smelling the warm transformers and dust. Now we're adults and that magic feeling has slipped through our fingers and we just want to relive it again. It's not technology, it's psychology.

Perfectly legitimate. No question.

As long as everyone realizes and accepts that "how they made you feel" refers to how they made YOU feel, not the rest of the world.

[GlennSprigg]

(O.P. here).  Wow... Everything people are saying has merit/truth.
It gets down to 'young-un's' VS 'Oldies' here I think.  I didn't want to get into the 'finness' of the 'Sound'. As some people have touched on, some of us 'oldies' just love the LOOK & feel of old valve/tube equipment. NOT just for Amps, (with audio considerations) but even the likes of old Signal Generators, or Frequency Counters etc etc.  I don't care how long it takes to 'Warm Up', I just like the historical oldness of the construction, and the warm glow of the filaments, and the virtual 'artistic' beauty of the construction of some tubes! It excites us!!  And I know some tubes have limitations.

For instance... some people may not have known/grasp why we have/had 'Tetrodes' instead of just 'Triodes', especially for higher frequencies?  A 'Transistor', being so internally small/compact with it's P/N/P etc construction, doesn't have the SAME (keeping it simple here!) Reactances between the relatively 'large' mechanical design/size/spacing plates & components within a 'Tube'.  At higher frequencies, (in a typical 'Tube'), there is a now CONSIDERABLE amount of CAPACITANCE between the Grid & the Anode, to VASTLY effect the circuitry!!  The EXTRA Grid, (Screen Grid), is designed to cancel out, or at least greatly minimize this inherent internal capacitance...  (Typically held at about 70% of Anode voltage). MY POINT here, is to highlight that a lot of this 'WIZARDRY' is due to the PHYSICAL problems associated with some Vacuum Tubes. HOWEVER, we love to see the GLOW, as it brings us many memories of what once was!!   

[bobdring]

It is interesting that here we are seeing the valve transistor debate continue.
Being of the older generation I too remember valves. Then again I am firmly into solid state now.
Let me explain my current quandary:-

I recently acquired an elderly Leader LSG11 RF signal generator. It’s valve based.
I only got it because I wanted one in my youth and couldn’t afford it.
There is an article available about converting this SG to solid state and it then runs on a ht of 9V. The conversion needs other component changes.

I have three choices

1. Find 2 new valves and leave it original.
2. Convert it to solidstate as per the article and so make it not collectable
3. Come up with a plug in solidstate conversion that works at the original ht of around 100v.

I’m leaning towards #3 if I can dream up a circuit. I could then put valves in a bag inside the case  to allow for the future return to valve operation.

Any ideas?

Bob

[wraper]

3. Come up with a plug in solidstate conversion that works at the original ht of around 100v.

I wonder why would you bother with that nonsense which would be a piss poor hack and not original. I googled a bit and replacement tubes are easily available. And even when they are not, usually you can use a socket converter and use a different tube.

[vk6zgo]

It is interesting that here we are seeing the valve transistor debate continue.
Being of the older generation I too remember valves. Then again I am firmly into solid state now.
Let me explain my current quandary:-

I recently acquired an elderly Leader LSG11 RF signal generator. It’s valve based.
I only got it because I wanted one in my youth and couldn’t afford it.
There is an article available about converting this SG to solid state and it then runs on a ht of 9V. The conversion needs other component changes.

I have three choices

1. Find 2 new valves and leave it original.
2. Convert it to solidstate as per the article and so make it not collectable
3. Come up with a plug in solidstate conversion that works at the original ht of around 100v.

I’m leaning towards #3 if I can dream up a circuit. I could then put valves in a bag inside the case  to allow for the future return to valve operation.

Any ideas?

Bob

I also have a Leader LSG11,which I bought at a Hamfest for no other reason than that it was dirt cheap.

I've had a lot of use of it, but it is now awaiting recapping & ditching the selenium rectifier.
The Mains wiring is a bit "iffy", so I am thinking about fairly radically revamping that so that there is a power switch on the back, along with a IEC socket with built in fuse.

I think I might use the existing switch pot to turn the HT on & off, but that is probably too much of a "nicety" for an old "roughie".
Or I could just ditch it & buy a higher spec but still old sig gen.

The tube complement of the Leader is another thing----I've probably got a 12BH7 in my odd valves, but a I doubt there is a 6AR5 there.

I did "solid state" a dipmeter, but that was to eliminate the power cord limitation on where I could use it.

[floobydust]

Leader LSG-11 converted to solid state back in 1970. The wheel must be reinvented lol. It does run off a 9V battery now instead of mains.
If you left it with tubes but go from selenium to silicon rectifier, I end up adding a zener like 150V or 200V 5W to keep B+ from going too high. Or resize the 3kΩ resistor.

[b_force]

I don't understand the whole negative and snarky vibe in this topic?

After a week of working with all kinds of micro's, DSP and multi-layer boards, I sometimes like to dive into some tube circuits, old tube radios and builds as well.
Why?

Because it's simple, straightforward and you can basically draw out an entire circuit on the back of an envelope.
You can also assemble and work on it on the fly basically, without having to stare at a monitor screen for hours.
The mechanical structures just looks a lot better than an unknown blob of something on some kind of multi layer PCB.

Is it "better", more efficient etc? No of course not!
It's just pure interest and fascination of technology and history in general.
For the same reason I have also converted solid state circuits to tube sockets, just simply to match the look-and-feel of the whole device.

Not everyone who works with tubes/valves is a total audiophool lunatic.
And still, what if someone is?

The very vast majority of engineers have a oscilloscope and DMM/benchmeter that they purely bought for kicks, specs and looks.
Most people don't even use 1/100th of the capabilities or barely know of all its functions.
In fact, I know and have seen many people who don't even use them at all!

Other people buy a fancy car, sofa or motor bike for no particular reason.

Same thing, just different.

[wraper]

I don't understand the whole negative and snarky vibe in this topic?

It's about making a stupid drop in solid state replacement for tubes rather than tubes as such.

[floobydust]

It was already tried with Fetrons, look at the claims of millions of $ to be made in telecom swapouts.
Teledyne Fetron (late 1960's) but they flopped due to price, crazy expensive. I thought ~12x the price of a tube. It's too bad, the ENIAC surely could have used some There were some HP400 and Tektronix 500 CA series upgrade kits too.
It may have been the high labour costs in making them, or the price point was too greedy I'm not sure.
Example inside they used 2N4881 HV JFET's 300V TO-5 I_DSS 0.4-2mA along with a small 2N3823 for the input. JFETs from Teledyne (Amelco databook).
Today, you can find HV depletion-mode MOSFET's by IXYS to 1,700V. If that's your thing.
In winter time I get 100% efficiency with tube gear heating my house 

[EPAIII]

The idea has been around for quite some time. It probably started with rectifiers.

The big problem is they don't heat the room in the winter like real tubes do. Or in the summer for that matter.