Amp project - Need some suggestions!

[sparchead]

Hi folks!

I would like to build an amplifier from parts I got from a tube radio.

Here it is, coming from an old Philips B4X61A:



The power transformer:



On the secondary (no load) I get 270-0-270 (A-B-C) for the hi voltage and 6.3 for the filaments (D-E)

I think B is center tap.. but it was originaly solded with D (in the radio)

The tubes are EZ80 rectifier, EL84 and EL86 (no output transformer)

Here is the power transformer section from the schematic:



What can I do with this transformer? Suggestions for schematics?

I found this one:

http://www.projetg5.com/Projets/MI18/MI18.pdf

the rectifier is EZ81 instead of EZ80 ... can I use my transformer for this one? can I use EZ80 in this schematic?

thank you!

[olddawg]

Don't see why you can't make an 18 watt variant. You could even could even do a Vox EF87 preamp channel. The EZ81 uses a 5v separate filament.

[sgelectric]

EZ81 (6CA4) actually uses a 6.3 volt filament and draws 1 amp of current.

http://tdsl.duncanamps.com/pdf/ez81.pdf

http://www.nj7p.info/Common/Tube/SQL....php?Type=6CA4

[olddawg]

Yep, that's what it says. I could swear the in my amp runs off a separate 5v tap though.

[sparchead]

EZ81 (6CA4) actually uses a 6.3 volt filament and draws 1 amp of current.

http://tdsl.duncanamps.com/pdf/ez81.pdf

http://www.nj7p.info/Common/Tube/SQL....php?Type=6CA4

Thanks for the reply!

I know...

I'm trying to get some information about swapping an EZ80 in a design that calls for an EZ81 :

http://www.projetg5.com/Projets/MI18/MI18.pdf

is it possible?

are there any differences that would make using the EZ80?

based on the datasheet, I see that the EZ81 has higher current output capability, woult it make any differences using the EZ80 in the above schematic? wondering if the EZ80 has enough current to power all the tubes...

If its possible, should I modify any other part? resistor, capacitor?

thanks for helping me!!

[strata]

Dont reuse the chasis, it's a good idea to start with something clean. Transformers and tubes are probably ok. As for ez80/ez81 see http://music-electronics-forum.com/t21041/

[sparchead]

Dont reuse the chasis, it's a good idea to start with something clean. Transformers and tubes are probably ok. As for ez80/ez81 see http://music-electronics-forum.com/t21041/

I think that, considering 1.2ma X2 per 12AX7 tubes, so 5ma, adding the 2 EL84 at about 34 or 40ma X2, the EZ80 is on the border line with the 90ma available I think I gonna try with the EZ81, or maybe replace it with a bridge rectifier.

Why not using the old chassis? I don't care about all the holes :P

I am still open for suggestions =)

[strata]

Why not using the old chassis?

You'll regret the way it looks later