‘bout time I listened to 46

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Paul Barker
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#16 Re: ‘bout time I listened to 46

Post by Paul Barker »

Plenty of options in the bases. At present I’ll just make a 2.5v power supply and mirror the relevant pins including heater supply from 46 use to 45 use. Same b+ and heater.

The ht transformer is 170mA so the increased current of the 45 from 22mA (46) to 50mA (45).

The “Neptune” potted transformer just right, but some voltage to spare. The plan is 5u4 or potato masher full valve rectified, choke input straight to one Black Gate, because I’ll use my best choke Ferranti 130H 400mA double C core frame mounted but tropicalised which should be as good for purpose as a potted military surplus choke. Purchased for £100 thiugh he wanted £200 I offered £100 which he eventually accepted. Image So as I’m a utilitarian and subjective about these matters, the best choke I have is my choice. The weight will bring solidity against microphonics in the rectifier and Black Gate. Seperate HT board obvs. Choke looks inocent reality is : boatanchor.

I dont like compromised power supplies, its a key element in SET.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Paul Barker
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#17 Re: ‘bout time I listened to 46

Post by Paul Barker »

So first I’ll hook it up as an EL84 triode connected.

Image
3mm doesn’t sound hard to punch but I had to use my 24” Stilsen to turn the 40mm punch!
Image
Image
The purpose of hooking up a Triode connected EL84, is it gets me back into building, and there’s a similarity with the 46. So the EL84 should give the 46 a run for it’s money, which is important excercise. More power from EL84 but not a lot more. Sadly with the EL84 I cant use the final grid to prove the concept Bartola came up with that the 46 second grid is the reason for the aparently much loved 46 sound, by emulating a mesh plate. The el84 is internally combine with cathode. Back of my head I think Mullard EL34’s are nod tied, and they are due to Mullard holding the patent a rare true pentode. But that is a bridge too far for my anxiety, as the changes required too much away from 46. After all the ultimate priority is the 46.

Im trying to get Shinko Tants for the 46; so far Im at the ! I’ve enquired, Nick Lucas hasnt answered, stage.

The el84 will be a cooking every day amp, and I shant pay £20+ per resistor.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Paul Barker
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#18 Re: ‘bout time I listened to 46

Post by Paul Barker »

Neal’s chassis’ are proving a sound investment for this type of scenario, Ive got more options than enough. Ill not discuss possible further developments as Im just finding my way through a similar worked up mental state as Steve C described, and Im fixing it myself by puting blinkers on until Ive built something at least.

You realise if I do get round to trying EL34 therel be two IO bases on it aswell as all the excess already. Its not a bad demonstration of the state of my mind. Did you notice the British Bases?

The EL84 topology is the same but autobias resistor different and b+ affected by differences in autobias voltage. But the two valves can share a chassis with minor selection requirements. Might have a two way switch for the b+ labelled EL84 and 46 To bring the correct cathode resister to bear, simply plug in the valve, whilst necessarily unplugging the other one.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
RhythMick
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#19 Re: ‘bout time I listened to 46

Post by RhythMick »

Paul Barker wrote: Mon Aug 30, 2021 2:13 pm Plenty of options in the bases. At present I’ll just make a 2.5v power supply and mirror the relevant pins including heater supply from 46 use to 45 use. Same b+ and heater.

The ht transformer is 170mA so the increased current of the 45 from 22mA (46) to 50mA (45).

The “Neptune” potted transformer just right, but some voltage to spare. The plan is 5u4 or potato masher full valve rectified, choke input straight to one Black Gate, because I’ll use my best choke Ferranti 130H 400mA double C core frame mounted but tropicalised which should be as good for purpose as a potted military surplus choke. Purchased for £100 thiugh he wanted £200 I offered £100 which he eventually accepted. Image So as I’m a utilitarian and subjective about these matters, the best choke I have is my choice. The weight will bring solidity against microphonics in the rectifier and Black Gate. Seperate HT board obvs. Choke looks inocent reality is : boatanchor.

I dont like compromised power supplies, its a key element in SET.
That's quite a choke - 130H @ 400mA !
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Paul Barker
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#20 Re: ‘bout time I listened to 46

Post by Paul Barker »

Yep, I already had a 500mA choke ffs.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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