The Mongrel

[Harry Dalek]

Love the little valves Steve never had my hands on one ,must be rare or rare down here .

I use a Canadian company for most of my tube supplies, or another one in the UK, both reliable and not rip-off merchants. PM me if you want to know who. Both have websites...though if you want the 'premium' tubes (e.g.12AX7/ECC83) you'll still pay the going rate for them, there are plenty of alternatives if not 'better'.. though I use that word cautiously due to the Audiophools that may/will want to shoot me down...I like good sound, but most of these guys are living an hallucination...peace man...

Thankfully one of my brothers-in-law is a 'metal basher', so I can get metalwork done quick, locally and cheap..(family discount and priority, but he still has to make a living...)..

Steve A.

I will Keep that on my mind see how this project go's could turn my into a valve guy ;0 ) tell you what i would like the sight of a circuit board with these little globes powered up .
What were they used for ? must of only been a short time only due to the transistor
I have just been looking at my valve list on the first page and marked what i found most are looks like i am right for the time base i have both valves and valve rectifiers any case i will work on the high positive supply .

[Steve Anderson]

What were the 6111's used for? No idea, except somewhere they were mentioned in connection with aircraft. I bought them simply for their novelty factor. One day I may find a use for them. Likewise the 9002s, but I have found a use for them in a mic pre-amp as I mentioned. Built July 2008, still in almost daily use for Skype chats. occasionally other things too...a whim...why not? Still the original tubes...

With tubes it's worthwhile seeking out the lesser-known versions, quite often they're known by a different type number, a CVxxx instead of an ECCxx. Or they have a different heater voltage/current but otherwise the same. Instead of a dual triode, a single or even a triple, useful when you need an odd number of devices. As we're designing/building from scratch we don't need an exact replacement.

Steve A.

Mic Preamps Initial 1.gif (13.92 KiB) Viewed 9931 times

[Harry Dalek]

What were the 6111's used for? No idea, except somewhere they were mentioned in connection with aircraft. I bought them simply for their novelty factor. One day I may find a use for them. Likewise the 9002s, but I have found a use for them in a mic pre-amp as I mentioned.

Steve A.

Mic Preamps Initial 1.gif

That makes sense using them in planes cut down size of gear if any thing ,should use them for sure they look like you'd have a bit of with them ...tiny Valve monitor sounds good ! if i had them and a tiny CRT tube might be able to get it all on a PCB to size of project ...are the voltages low for the plate ? i know they had low voltage valves used them in those Tandy kits in the 70s .

I just worked on my current project i will post next update

[Harry Dalek]

I mounted the CRT and its easy at the moment to remove and replace ,i ended up using the ex fan fan holder metal in this caser for the CRT it made more sense as i would of had to cut away a lot of metal to get it to fit so went lazy
i will have the panel controls either side of the CRT still have to cut some aluminium plates to size either side of the CRT .

So far i have the AC supply working moving onto the DC side now this meant working out the tube sockets for the 6X4 rectifier valves i have a ruff idea i would need about 3 if i do need the 12v supply for Steve's Deflection circuit and i know i need a HV positive and Negative which i will work on first ,have 290 0 290 AC to play with just to work out need around 400 for the circuits for a start .

Once i have the DC supply i can build the circuits one at a time and do some testing .

I was thinking about how to mount the tube sockets go PCB or your way Steve mount above the board or traditional mounting and go air wiring which i hate all ways possible with this case .

I recalled i could cut nice neat holes in PCB with a wood bit making larger holes and i happen to have at least one so far the right size for 7 pin sockets if lucky i have the next size up for the larger sockets .

the sockets fit to the mm

[Steve Anderson]

...are the voltages low for the plate ? i know they had low voltage valves used them in those Tandy kits in the 70s.

Somewhat, they are quite low-impedance by valve/tube standards. For real low-voltage tubes try the space-charge versions used in some valve car radios. They worked quite happily with just 12V on the anode...though no real 'power' devices..

Steve A.

[Harry Dalek]

...are the voltages low for the plate ? i know they had low voltage valves used them in those Tandy kits in the 70s.

Somewhat, they are quite low-impedance by valve/tube standards. For real low-voltage tubes try the space-charge versions used in some valve car radios. They worked quite happily with just 12V on the anode...though no real 'power' devices..

Steve A.

There were valve car radios ! Amazing i always thought this had to Wait for Transistors .

[Steve Anderson]

...There were valve car radios ! Amazing i always thought this had to Wait for Transistors .

Sure were...we had one in our 1960s Austin A40, so gutless were the electrics in the car that the lights dimmed when you turned the radio on! I had a 1969 Ford Escort, it only had a 22 Amp generator, not an alternator...so in that Austin it was probably less than 22 Amps! Thinking about it, my 1980 Suzuki 550cc motorcycle has almost the same electrical power, 20A. Yes, I still have it, I bought it new in 1980.

Most valve/tube car radios used a vibrator power supply, this generated the HT for the more conventional valves/tubes...

The car in the photo is exactly the same as our one, even the colour...Hmm, showing my age here...

For some reason this link is 'acting up', but follow where it leads to..

https://en.wikipedia.org/wiki/Vibrator_(electronic)

If you get nowhere with that link, try this one...they only mention 6V types, but there were 12V and 24V versions for trucks/buses/boats too..

http://www.radioremembered.org/vpwrsup.htm

Steve A.

Austin_A40_(Farina)_Mk_I_reg_ca_1960.jpg (166.6 KiB) Viewed 9926 times

[Harry Dalek]

...There were valve car radios ! Amazing i always thought this had to Wait for Transistors .

Sure were...we had one in our 1960s Austin A40, so gutless were the electrics in the car that the lights dimmed when you turned the radio on! I had a 1969 Ford Escort, it only had a 22 Amp generator, not an alternator...so in that Austin it was probably less than 22 Amps! Thinking about it, my 1980 Suzuki 550cc motorcycle has almost the same electrical power, 20A. Yes, I still have it, I bought it new in 1980.

Most valve/tube car radios used a vibrator power supply, this generated the HT for the more conventional valves/tubes...

The car in the photo is exactly the same as our one, even the colour...Hmm, showing my age here...

For some reason this link is 'acting up', but follow where it leads to..

https://en.wikipedia.org/wiki/Vibrator_(electronic)

If you get nowhere with that link, try this one...they only mention 6V types, but there were 12V and 24V versions for trucks/buses/boats too..

http://www.radioremembered.org/vpwrsup.htm

Steve A.

The attachment Austin_A40_(Farina)_Mk_I_reg_ca_1960.jpg is no longer available

I came a cross a vibrator power supply radio in the 1980s i ended up leaving a lot of stuff behind when i moved ,i knew it was for a battery use but never had any valves to test it ,i can't recall its exact size of the radio but it was no bigger than a normal valve radio from memory , may it was like you explaining for a boat looked a bit big.

I wish i still had it to show but long gone now .

Today i did a start on the 6X4 Valve DC side and Testing i gave this idea a go .Just showing the dual supply ...the 3rd valve is a copy of the positive side but with just 1 450v capacitor not in use at the moment .
Also 2 bleeder resistors not shown to drain the caps voltage after switch off 1.8meg across the positive supply caps and a 4meg across the negative side cap just what i had handy 2 watt.
Sorry its a bit messy i just drew it up for my self to construct .

Well on the positive supply i was thinking i would get double result since using both sides of the transformer windings ,i am very rusty working with these things ,looking at other circuits similar seems right ,i will have to change things for the CRT anode side i do have another on board 6N4 to work with .

The Negative result side about the same as the positive side

Checking the voltage across the dual supply its showing double the voltage i was expecting for the positive side and ground .

The positive supply looks fine for the circuits but not for the CRT anode 4 a touch low just below the 400 v minimum and a little to high on the negative side for use but that can be adjusted .

OH well first go and no mistakes causing Heating smoke and exploding capacitors so that's a good thing i say that's a good start so far

i will have to do some more reading

[Steve Anderson]

Harry! STOP! The top 6X4 needs a separate winding or transformer for it's heater. You're placing too much stress on the heater-cathode insulation and for 50% of the time it's the wrong polarity...

In fact it applies to the other tube as well...see first page of attached pdf...

Steve A.

Replacing 2x1N4007s with a 6X4 requires a bit of thought...

The European designation for a 6X4 is an EZ90, not often seen though...

6X4_A.pdf

(538.58 KiB) Downloaded 196 times

[Harry Dalek]

Harry! STOP! The top 6X4 needs a separate winding or transformer for it's heater. You're placing too much stress on the heater-cathode insulation and for 50% of the time it's the wrong polarity...

In fact it applies to the other tube as well...see first page of attached pdf...

Steve A.

Replacing 2x1N4007s with a 6X4 requires a bit of thought...

The attachment 6X4_A.pdf is no longer available

OH ok i just did a test this afternoon which i showed ,no more testing today ,i was reading Heater positive with respect to the cathode 200v negative 450 ?

I wired all the 3 6X4 rectifiers same direction as i placed all the sockets the same direction ..i am not tube expert so i am listening .

I was reading up on this page mainly to see if i could get a negative voltage out of them but unlike here i have not used it as a doubler as not using either side as ground ,i was expecting the positive side to be higher than it is .
Used the positive side as a full wave rectifier which seems very common.

https://www.bonavolta.ch/hobby/en/audio/supply.htm

vdbl.gif (2.46 KiB) Viewed 9862 times

[Steve Anderson]

...I was expecting the positive side to be higher than it is.

That's possibly down to errant currents when the heater(s) go positive r.e. their cathode. Whatever, the tubes aren't designed for this arrangement and may have a short life...very short...

In general tube heaters shouldn't go positive relative to the cathode, some (like the 6X4) can go a small amount positive, but less than the more normal arrangement. As always there are exceptions, the 6X4 isn't one of them though...

Is the secondary winding really just one winding as drawn?

Steve A.

[Harry Dalek]

...I was expecting the positive side to be higher than it is.

That's possibly down to errant currents when the heater(s) go positive r.e. their cathode. Whatever, the tubes aren't designed for this arrangement and may have a short life...very short...

Is the secondary winding really just one winding as drawn?

Steve A.

Yes Steve Oh i see ! Secondary as this 290v 0 290v Ov to ground pretty much 6.3v all same direction wired ....um and i just left out the bleeding resistors to drain the caps .
i all left out the 3rd 6X4 its wired up but no AC in up heater working at the moment

[Harry Dalek]

...I was expecting the positive side to be higher than it is.

That's possibly down to errant currents when the heater(s) go positive r.e. their cathode. Whatever, the tubes aren't designed for this arrangement and may have a short life...very short...

Is the secondary winding really just one winding as drawn?

Steve A.

Yes Steve Oh i see !
Secondary 3 wire .. 290v 0 290v Ov to ground ,Heaters pretty much 6.3v all same direction wired ....um and i just left out the bleeding resistors to drain the caps .
all i left out the 3rd 6X4 its wired up but no AC in ,just the heater working at the moment

Never of the 2 the heater connections are to ground just wired to the 6.3v Transformer windings

[Steve Anderson]

In general tube heaters shouldn't go positive relative to the cathode, some (like the 6X4) can go a small amount positive, but less than the more normal arrangement. As always there are exceptions, the 6X4 isn't one of them though...

Time for a large re-think...

Steve A.

[Steve Anderson]

If that transformer secondary is as drawn I can't think what it might have been used for - most unusual...where/what did it come from?

Don't forget the possibility of an internal short either...

Steve A.