Altec 436C Build Project (PCBs, schemes)

[iprovlek]

Im waiting for my Edcor output trannie.....

 

[andre tchmil]

so apart from  the wrong potmeter connection, what else is wrong on this pcb or schematic ?
resistor values ?

 

[weiss]

i'd be interested as well!

any news?

btw i found another schematic, maybe this one is better? anyway p2p probably seems to be the best option here..

thanks

 

[Bernardo]

hi, what result did the constructions of this clone have?
It seems that the thread died without any results?
Is it worth the research time and material cost to undertake this project?
thank you

 

[Bernardo]

does anyone know how I can plug an audio transformer into the output of this thing?

 

[scott2000]

does anyone know how I can plug an audio transformer into the output of this thing?

Omit the section at the output that differs from the original 436 drawing and replace with the components/transformer as in the original 436 drawing...

 

[Bernardo]

and the power transformer?
How many amps must the 200v winding have?
and the 6.3v?

 

[andre tchmil]

anyone successfully build this with the pcb ?

 

[HerbertR]

Hi, does anyone finished this build? It looks very promising.

 

[TimG]

I’m taking a swing at this too. I managed to get a pcb from Ares Audio but not any kind of support.
I’m figuring this out as I go and now collecting the errata you can collected up above.

I’m wondering what the value of the cap is on the 6.3 v line. Is that the .1uf in discussion? Where the screwdriver points.

I have a UTM Altec output transformer I hope to try after I try it this way. I had considered a much bigger input transformer but I found ONE vendor who was willing to sell me the OEP it was built for. Carnell referred me to RS UK, but it isn’t available from RS USA. That’s Audio in Oxford had one for me. After the floods went down.

Also! Anyone have a good “generic” Altec 436c front panel fpd with just the basics?
Thanks

 

[dmp]

I’m wondering what the value of the cap is on the 6.3 v line. Is that the .1uf in discussion? Where the screwdriver points.

Don't install that cap. A 0.1uF across the AC heaters makes no sense.

 

[TimG]

A couple more questions maybe. The designer had an adorable little torroid I could get made, but I have this Antek AS-05T200. Is it too big? I’m bad at the maths. He was assuming a 10w?

 

[scott2000]

Also! Anyone have a good “generic” Altec 436c front panel fpd with just the basics?
Thanks

From Weiss....there's an Altec in there...Not sure if it's useful with some changes....

 

[TimG]

Thanks!! This pcb might be RS-124 enough.
I set out to P2P a basic 436c when the board came up!

 

[dmp]

A couple more questions maybe. The designer had an adorable little torroid I could get made, but I have this Antek AS-05T200. Is it too big? I’m bad at the maths. He was assuming a 10w?

That Antek is 50VA which means ~50 Watts, and looking at the specs can supply 130mA @ 200v (~26 Watts). So plenty for the B+ (can see from the schematic the total B+ mA is small, the plate dissipation of the 6BC8 is 2 W and the6CG7 is 5.7 W).

But should check the heater current. The Antek has two 6.3v windings both rated at 2A.
Have to check the tube datasheets to get the heater current at 6.3V:
6AL5 300mA
6CG7 600mA
6BC8 400mA
and the two 47 ohm resistors: 6.3/47*2 = 268mA

Total heater load is 1.568 A
That is sufficiently less than the 4A the transformer rating to be OK

 

[TimG]

Thanks dmp! I promise to work on my maths before adding power.
But this helps with the big planning.

I’ll posts more as I go so hopefully we see a working unit