If you had to choose a range of valves....?

[G6Tanuki]

Thought-experiment: if you had to choose a 'standard' set of valves for all your projects, what would they be?

Mine would be:

6AK5 - nice little RF amp for up to 100MHz or so. Triode-connect a pair and use Cascode-style for the higher frequencies.

ECH81 - general-purpose frequency-changer for up to 30MHz.

7360 - RCA Beam Deflection tube usable as a HF mixer and as a balanced modulator/demodulator for SSB applications.

EF183/184 - Gainy straight- and variable-mu flavours of a good valve for RF/IF stages.

EB91 - because everybody needs a small-signal double-diode!

12AT7 - general-purpose AF/HF/VHF double-triode, usable everywhere from low-level audio-amps/phase-splitters to oscillators (both RF, and LF multivibrator...) and mixers.

6BW6 - small AF power-output, and small modulator/RF PA (Codar AT-5 !).

6146 - Beefy audio- and HF power-amp.

4X150A - VHF power-amp.

GZ34 - HT rectifier.

0D3 - 150V cold-cathode voltage regulator. Because I hate drifty oscillators!


Admittedly this list is very much focussed around radio applications.

What would be on your 'must have' valve-list??

[GrimJosef]

Since almost all of my projects are audio ones I can whittle your list down a bit and I'll make a few additions too.

EF184 - an EF86 might hum less, but these days DC heater supplies are dirt cheap

12AT7 - more versatile than a 12AX7 and the lower gain is usually a price worth paying

6BW6 - you'd better be able to fan cool it though if you want to get the most out of it

GZ34 - a no-brainer, simply the best rectifier in its class

0D3 - I might have said 0A2 but the regulation on the 0D3 is better

I'd add

EY84 - because occasionally you need very high voltages

E88CC - could be a cascode in one bottle, but in a stereo amp it makes more sense to split each bottle between the channels to ease the Vh-k problem

6H30 - a bit like an E182CC, very high perveance, as a cathode follower it will drive anything

KT90 - a really beefy audio amp, a modified colour TV line output valve so will handle watts and volts

304TL - some people have a soft spot for 'trawler triode' audio amps - as a bonus this one is also pleasingly bonkers-looking

EL86 - optional, but paired with the 0D3 will make a very stiff HT rail indeed for low-noise pre amps

Cheers,

GJ

[turretslug]

I reckon the 6V6GT should qualify in most lists for most things! Admittedly, the 6BW6 is basically the B9a condensation, but the IO base and GT size envelope give confidence for reliabilty and (relatively) cool running. I suspect the 6BW6 packaging probably has the edge towards VHF but the 6V6 is my choice for so-reliable-you-forget-it's-there AF output.

The modest little EF92 for low-mu, low heater-power, low HT consumption IF strips.

The EC90, 6C4 for general-purpose oscillator duty, again appealingly low power usage.

Everyone liked and used the ECH81, even in pro- applications where the triode wasn't needed- the under-utilised 6H1 surely deserves a look-in, keeping in the compact, low-power theme.

For specific ranges, I reckon both pre-war Loctal and post-war Rimlock deserve more appreciation, they offered some excellently-performing valves let down by packaging that didn't hit the spot at the time.

Yep, GZ34 for pretty much unparallelled heater power/HT current capabilty.

[Radio Wrangler]

A biscuit tin, some nesting material and a breeding pair of EF80s and you'll never be short of small pentodes...

I'd go for the 6V6 rather than the 6BW6. Longer lived and keeps its cool

How could we forget the 807?

David

[G6Tanuki]

Some interesting suggestions: must admit I've never had any heat-related problems with 6BW6, even when running a pair of them in push-pull to get 30 Watts of output in a modulator. They seem to survive abuse somewhat better than the EL/UL84. 6V6 just seems big and bulky by comparison. The 6AQ5/EL90 - which is essentially a 6BW6 crammed into a B7G envelope - is *not* one of my favourites though: they get hot-and-bothered too easily (have even seen one where the envelope has sucked-in).

I see the 6146 as the next stage in the evolutionary-hierarchy from the 807 - just as good for push-pull audio, and vastly better as an amp at HF/low-VHF. The 807 struggles once you get above 15MHz.

I forgot about the EF92; I've used them in the past, along with their related partners-in-small-crime the EF91 and EL91.

Thinking about it, I'd like to also add something like a PL519 or 6LF6 TV "sweep tube" to my list, for those occasions when you need something that can instantaneously handle an amp of anode-current.

[kalee20]

The list is pretty complete! There's not much that you can't do with that set.

I'd add: DK92, DF97, DAF96, DL92 for battery purposes.

And EM34's (plural, crateloads of them in fact, for when they go dim).

[G6Tanuki]

If we need to include battery-valves I'd go with that list but substitute the 3A4 or 1299A/3D6 as the 'output' bottle of choice, because these can deliver rather more 'oomph' and as well as producing half-a-Watt or more of audio they have history as final-stage amplifiers in a range of HF/low-VHF transmitters.

[The DCC90/3A5 - http://www.r-type.org/exhib/aaa1001.htm - is also worthy of a mention for the same reason: I remember this was the valve-of-choice for 27MHz model-aircraft control transmitters in the 1960s]

And for battery-valve service can I also remind you about the 1D8GT: http://www.r-type.org/exhib/abo0185.htm - a diode-triode-pentode in one IOctal bottle, so fitting the entire detector/AGC, driver and audio-output chain into a single chassis-hole footprint!

[Biggles]

Re post #4 RW. I'm pretty sure a breeding pair of EF80's will produce a brace of EB91's too. Where do all those little beggars come from? Some of my favourite valves? The nice red painted DF33 along with the DK32, and it's brothers in the octal battery range. B7G battery and mains valves next. Not generally attracted to the B9A series, but I have the odd favourites such as the ECL80.
Alan.

[GrimJosef]

Originally Posted by G6Tanuki

... Thinking about it, I'd like to also add something like a PL519 ...

I thought about it too. With enough of them you can make a quite good (that's how good the very best ones are) output transformer-less audio amp.

Cheers,

GJ

[G6Tanuki]

Agreed: and four of them can work well as a 400-watt "Frinear" HF amp - https://pa0fri.home.xs4all.nl/Lineai...0/fripg400.htm

[intersting use of diode/capacitor dropper options for the series-connected filaments...]

[turretslug]

Oh, yes, the 807- tough and plentiful, caned by umpteen radio amateurs and proven in the torment of series regulator and even line output service.

[Cobaltblue]

A range of valves to do what?

Radio the 96 series DK96, DF96, DF97, DAF96, DL96.

Yes I know there is a 7 in there rather than a 6 I hope you will indulge me on that.

Cracking bottles that probably represented the pinacle of low power valve design.

The Ever Ready Sky Monarch showed what this series could do.

If looking earlier tricky.

Depends how early

Lets assume early 30's FC4, VP4, 354V, 904V, PEN4VA, IW3

Was a pretty decent lineup for an early 30's superhet.

I have a mixed relationship with EL84's and EL34's

6V6 is a cracking bottle as are 807's.

To be fair most of the octal valves are hard to beat.

2P 2XP 4XP PX4 and equivelents the stuff of nightmares.

Cheers

Mike T

[Bazz4CQJ]

So, the EF91 is in, isn't it?

B

[joebog1]

I mostly do audio so most of the octal and noval valves already mentioned are fine.

After somebody suggested to me to try 5718 and 5719 miniature wire ended triodes, I have been playing around with them and so far I'm blown away with results. Even with AC heaters they are quiet. All the ones I have bought could be identical twins!! ALL measure almost identically. The thing I like best about them is I pay $3.75 each for them (about a quid and a half). They can run hot though if you push them, but I am going to use some in my next project.

I must say one thing I have problems with is the different numbering systems in use. When I read a post from England its always DAF this and DK that. Australia followed the Americans in this and I instantly know what valve is being discussed. When England talks about valves I get very tired because of the constant perusal of my equivalents book, Thats not really a criticism, but perhaps an explanation of why I use BOTH systems when I post here eg:-

EL34/6CA7
EL84/6BQ5

Joe

[Radio Wrangler]

I bought a tea-chest full of EF91s from Jim Fish, when I was a young teenager. For a while everything I built was >90% EF91

David

[Argus25]

One unsung hero in the beam power tube department is the 6BG6. I first found these used as line output valves in early American TV sets and was astonished at the massive cathode construction with a huge surface area. I have noticed of late the audio fraternity is starting to use them in audio amp output stages.

I agree with all the other valve suggestions. One thing though, if it came to choosing a converter valve for a radio I would go for an ECH35 over a 6k8 because the ECH35 has a higher conversion transconductance. The Eddystone 640 radio for example specified either could be used, but the ECH35 is just that little bit better.

Very good RF valves for TV are the 6J6 and 6AG5. The 6SN7 & 6SL7 are good for oscillator work and it is pretty hard to beat a 6V6 for the audio out in a small radio. But these valves have become expensive now.

[Peter.N.]

I used to build my amplifiers entirely from 6V6s and 6SN7s, then 6L6s when I acquired some, and probably a GZ32 rectifier.

Peter

[G6Tanuki]

One I forgot to include in my initial list: the 6CW4 Nuvistor - a lovely little 'peanut' which makes a great low-noise VHF/UHF RF amp.

Be warned though - I did try one once as an oscillator running around 215MHz (double it to get to 70cm). Drifty as hell! A 12AT7 with both halves paralleled was better by a factor of ten!

[julie_m]

Wot no EL84? As long as you don't try to treat the maximum ratings as a target to aim for, they can soldier on forever. There's also anecdotal evidence, here on this forum, of them being usable as emergency rectifiers!

[G6Tanuki]

I see the 6BW6 as my reason not to include the EL84: the 6BW6 does everything an 84 does, but does it with a lot lower heater-consumption!