Photo Gallery

[kodabmx]

The two OPTs are interleved. Together, the would make a PT that's 480V primary to 36V secondary, but in this case, they make a 1k:6R OPT that does full power at 30Hz.

 

[markcomp77]

Can you draw a conclusion from this?
Instead of a typical speaker transformer, use two normal 230/18, connected in primary and secondary in series?

 

[kodabmx]

Kind of. Like this:

 

[markcomp77]

in series (on secondary) but with interleaving ...
And it works well?
is it well matched? (at least computationally)

 

[soundbrigade]

My new project pure tube SE EL11 Telefunken /pseudo PP - maybe/, no saturation, small OTs, with amazing sound. Rec.- 5Y3, chock Hammond, preamp EBF11, Catod caps Black Gate, interstage caps Russian K73.

Where are you right now? Maybe I send you my 7 boxes with unfinished tube projects and humbly ask you to finish them ...

Actually I am in Chicago and will be back in Sweden by the end of next week. I did, before leaving, two weeks ago, dig up my Luxman clone and fond NINE 50CA10 tubes to go with it. The chassis is ready drilled and milled, I bring PSU caps back from USA and hopefully all components I purchased are still left.

 

[azazello]

Where are you right now? Maybe I send you my 7 boxes with unfinished tube projects and humbly ask you to finish them ...

Actually I am in Chicago and will be back in Sweden by the end of next week. I did, before leaving, two weeks ago, dig up my Luxman clone and fond NINE 50CA10 tubes to go with it. The chassis is ready drilled and milled, I bring PSU caps back from USA and hopefully all components I purchased are still left.

Im in Baltimore MD for permanent.....I hope I will be in Chicago in Christmas...../You can send me Your stuff for finishing/

 

[emk2]

814 PP, only one channel built so music in mono with one 15" FR.

These tubes, 814-"A" were made for a french military contract, probably Philips France factory.

 

[kodabmx]

in series (on secondary) but with interleaving ...
And it works well?
is it well matched? (at least computationally)

Works better than a real OPT IMHO. Especially if you're looking for low Ra-a (My monoblocs are about 1k Ra-a:6R with peak current of almost 1A on the primary).

 

[Carlp]

814 PP, only one channel built so music in mono with one 15" FR.

These tubes, 814-"A" were made for a french military contract, probably Philips France factory.

Interesting lighting on the tube heaters/filaments. Is that a camera artifact or do they glow that white? In any case, nice amp!

Edit: And nice cat!

 

[lexx21]

@carlp


Thoriated tungsten heaters glow that way. My 811a tubes glow like that.

 

[dady]

https://frank.pocnet.net/sheets/049/8/814.pdf
Is American RCA

 

[emk2]

Thanks, as lexx21 said, tungsten filaments glow very bright.

Nice but personally I think I prefer the more discrete orange glow of usual tubes

Will be soon dismantled, it was just an experimentation, about 150W of heater power for a stereo PP is too much.

 

[gideon1990]

Your experiments look better than some people's finished amps. Cool project though

 

[dady]

Ask jan first has for sell YL1350, is an amazing modern valve with 80watt of dissipation with low voltage.

 

[zman01]

emk2,

To echo carlp's comment - that is a nice lighting effect, and cute feline friend.

P.s. The amplifier looks well built too.

 

[Carlp]

@carlp

Thoriated tungsten heaters glow that way. My 811a tubes glow like that.

Ah, that makes sense, thanks. And it's a DHP? (Directly heated pentode?) Not sure I've ever encountered such a beast. Anyway, that's one heck of a tube, though as you say, also a heck of a lot of power consumption! How did it sound?

 

[emk2]

Yes, a DHP but used in triode with only 400V B+ (fixed bias).

Impressive because big bottles and tungsten filaments but probably not better than a PP of KT66 triode connected in these conditions

Triode curves here:

814 SE A2 Amplifier – Bartola(R) Valves

 

[kodabmx]

Oops.

They had a good 5 year run at 70c though... I bought these at the local electronic surplus/junk store when I was just starting to DIY tube stuff.

When it blew, it took out an 8R 5W resistor, a diode, and a 5A fuse Apparently, the force of the blast sent it into the chassis and dumped the power supply to ground.

 

[TonyTecson]

what dc voltages were you running them at? and what working dc voltage were they rated for?

 

[Carlp]

Yes, a DHP but used in triode with only 400V B+ (fixed bias).

Impressive because big bottles and tungsten filaments but probably not better than a PP of KT66 triode connected in these conditions

Triode curves here:

814 SE A2 Amplifier – Bartola(R) Valves

Thx. I see Ale was using a 46 to drive it. What did you use? Or maybe at this point I should ask if you posted a thread about it so I don't take this too far afield.