2x el84 Rocket Trannies

[milkyBK370]

Hi,

I'm toying with the idea of a 2xel84 Rocket using the layout posted by MFowler. I'm reluctant to build the 4xel84 hole Rocket because of concerns about the volume. I built an AC30 type build based on Ceriatone's layout and it is mega loud. I'm gigging it these days but have to use it on half power all the time. Even then it's massively loud.

I have a couple of transfomers I had initially intended for a couple of 18 watt TMBs. The only problwem is there's no 5v winding on the PT. I would need to deviate from Mark's layout in terms of the rectification. I could also get the supplier to make me a PT with a 5v winding if the rectification issue becomes unworkable (for my abilities).

Could someone please comment on the suitability of these transformers? Ignoring the 5v winding issue for now.

The OT
http://www.ampmaker.com/store/18W-push- ... ormer.html
The PT
http://www.ampmaker.com/store/0-190-275 ... ormer.html

These trannies are priced really well and perform great. I have used a couple of alternatives in previous 18 watt builds and found these trannies to sound best in A/B tests.

Cheers,
Gary

[ampgeek]

Maybe consider using an EZ-81 rectifier (common in Marshall 18W builds) and a separate 5V tranny for the heater?

Check out this thread for a bit more "grist for the mill":

http://www.thegearpage.net/board/archiv ... 52018.html


Good luck!
Dave O.

[Richie]

Maybe consider using an EZ-81 rectifier (common in Marshall 18W builds) and a separate 5V tranny for the heater?

Check out this thread for a bit more "grist for the mill":

http://www.thegearpage.net/board/archiv ... 52018.html


Good luck!
Dave O.

The EZ81/6CA4 is a 6v heater tube. Unless you mean adding a 5v heater transformer for an option to use 5v rectifiers. Or just lower the rating on the transformer and use SS recto.

[overtone]

+1 on the EZ81, but I would look for a PT with a separate additional 6.3V winding for the EZ81.

I have used both those transformers on various builds. They are good value and Barry is always a pleasure to deal with.
That PT with two HT outputs can be fun to get you a lower voltage option. I have only used it with SS rectification.

Take look at the transformers from IG Präzisions-Wickeltechnik too, which are rather good. Bear in mind it is a one man operation so the supply can dry up quickly. I tend to buy them well in advance. Recently tubetown.de has started stocking them, but they are usually sold out straight away.

Good luck,
tony

[milkyBK370]

Cheers lads and Tony, I will check those transformers out.

[gary]

if you're preferring UK based, Steve at Valvepower has some decent transformers for 18 watt el84 builds

[M Fowler]

If your going to use solid state rectification then just use the lower HT and use EL84 or other types that can handle the increased plate and screen voltage.

Mark

[ampgeek]

My bad! Forgive me for not being clear/proof reading before posting.

I meant EZ-81 (6.3 volt heater) after checking the rating on the existing secondary...OR....adding a 5V transformer to provide other tube recto options.

Cheers,
Dave O.