‘bout time I listened to 46

What people are working on at the moment
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#1 ‘bout time I listened to 46

Post by Paul Barker »

Image
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#2 Re: ‘bout time I listened to 46

Post by Paul Barker »

Shouldnt encounter grid current at 46 grid so I can stack small PV waifer,s built in a light proof environment so I can control the level.

Very simple construction. I need to set a simple goal and actually achieve that goal. Obviously hard to make -33v exact, Ill fall short and complete the bias with very small un-bypassed cathode resistance, which may occur through the hum pot.

I dont know any better that Stephie how to do things so as Im in a mental state where I’d never get out of the cycling wild ideas stage, hence going with Stephie’s triode connected D3a.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#3 Re: ‘bout time I listened to 46

Post by Paul Barker »

I’m assuming Steve will let me bring it to listen on his super efficient speakers, in Steve’s listening room 1 watt is loud.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
andrew Ivimey
Oooo, Roberts Radio's sound nice
Posts: 7677
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#4 Re: ‘bout time I listened to 46

Post by andrew Ivimey »

Wow, minimal. I like it!
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#5 Re: ‘bout time I listened to 46

Post by Paul Barker »

andrew Ivimey wrote: Sun Aug 29, 2021 10:08 am Wow, minimal. I like it!
Thanks for youre support Andrew. I would love to pick up on Mark’s experiences with D3a pentode mode, but the triode mode just screams “interstage couple me”, no Im not hearing voices!
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
Nick
Site Admin
Posts: 14370
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#6 Re: ‘bout time I listened to 46

Post by Nick »

Not sure what the PV provided bias gives in terms of problems solved?
Little known fact, coherent thought can destructively interfere with itself leaving no thought at all, that’s why I prefer incoherent thought.
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#7 Re: ‘bout time I listened to 46

Post by Paul Barker »

I know, was talking to Neal at a gathering about using it for b+. I said “we don’t know what it sounds like”!

Remembering that day in you’re listening den when you suggested my lead acid battery bias and compare it to resistor bias. I learned that day the batteries sounded bad and have never gone back to them.

I’m doing this because I want to find out what it sounds like.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
IslandPink
Loony Bin!
Posts: 9274
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#8 Re: ‘bout time I listened to 46

Post by IslandPink »

Paul Barker wrote: Sun Aug 29, 2021 1:01 pm Thanks for youre support Andrew. I would love to pick up on Mark’s experiences with D3a pentode mode, but the triode mode just screams “interstage couple me”, no Im not hearing voices!
I think for a power amp you'd be battling too much gain with a D3a in pentode mode, same as the 12GN7 which I found a bit troublesome. The transconductance, limited dissipation and likely B+ would force an anode resistor that would give too much gain. That's why C3m is quite a good choice , less Gm. I eventually went to DHP with the 4P1L which to be honest is a bit low in gain for many systems, but my speakers are fairly efficient. The extra current and direct heating seems to give the best transparency and midrange tone that I've had.
Anyway, will be good to see how this one works out. What is the interstage ?
"Peridots and periwinkle, blue medallions Gilded galleons spilled across the ocean floor" ( Mitchell )
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#9 Re: ‘bout time I listened to 46

Post by Paul Barker »

I can’t off hand say model butt Hammond bifilar 1:1

I have a pair AE bifilar but if I mount those they take too much chassis room up and their current capability well in comfort zone.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
steve s
Shed dweller
Posts: 2610
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#10 Re: ‘bout time I listened to 46

Post by steve s »

Paul Barker wrote: Sun Aug 29, 2021 8:51 am I’m assuming Steve will let me bring it to listen on his super efficient speakers, in Steve’s listening room 1 watt is loud.
Of course Paul, your always welcome
I have a pair of ST 46's somewhere too..
Be good to hear them
Get it built up quick on a bread board !
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#11 Re: ‘bout time I listened to 46

Post by Paul Barker »

Cool
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
RhythMick
Old Hand
Posts: 718
Joined: Fri Jun 23, 2017 12:24 pm

#12 Re: ‘bout time I listened to 46

Post by RhythMick »

I'll have a look through my boxes. I have a nagging thought that I may have a pair of Cunningham globe 46.
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#13 Re: ‘bout time I listened to 46

Post by Paul Barker »

"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#14 Re: ‘bout time I listened to 46

Post by Paul Barker »

Ooh
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8247
Joined: Mon May 21, 2007 9:42 pm

#15 Re: ‘bout time I listened to 46

Post by Paul Barker »

Image
picture to url
Image
picture to url

I oriented the D3a base same as EL84 but that put both D3a’s different to each other and different to EL84. Anyway, whose to say the EL84 won’t in future occupy those bases and the BRitish 5 pin valve might not provide the gain. I have the base ready for that, or for ending up modifying amp to px4.

You never know, but first iteration, let’s find out about the 46.

I’m going to have to either make a variable bias supply or if my surplus b+ before I tame it, have selectable bypassed cathode resistors. After I’ve hooked up power supply I’ll know better.
Last edited by Paul Barker on Mon Aug 30, 2021 2:24 pm, edited 1 time in total.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Post Reply