18 Watt Lite 2 build is off the bench

[Renegade]

I finished up the electronics for my 18watt Lite II build last night.

Here are a couple of shots. I shoehorned the thing into a 13.5x5x2 hammond chassis. I used a recycled PT and the Heyboer 18watt OT.

This little thing rocks... B+ is a little higher than I'd hoped @ 398v but it seems to want to rock hard and sounds great. I'm going to double check the cathode current. The low end on this thing is enormous sounding through my 2x12, it's quite a bit louder than the full build that I did in the Traynor carcass as well.

[Gabi]

Hey Renegate...

I see you are taking the attachments feature seriously!

Your "Renegate" is quite cozy indeed! I see a real monster hiding in that little innocent looking chassis there...

Do you have any mp3s recorded?

thanks for posting,
Gabi.

[loverocker]

Wow - nice looking build. Is that a BNP lasers faceplate?

398V seems a bit juicy - do the EL84 dissipation figures work out about right?

[Plexi]

You might be able to rob an idea from bruce Collins 5E3 site..
and use a big zener to drop the voltage if you need to.
The EL84s would work fine if you dropped about 50 volts..
and adjust the cathode when you settle on the voltage your after..
Heres a couple links..scroll to the bottom to see the zener..

http://mywebpages.comcast.net/tweeddeluxe/build.htm
And here is a link to the layout showing how to wire it..
http://mywebpages.comcast.net/tweeddelu ... ayout1.gif

Just one solution to help lower the voltage a bit..

Richie

[zaphod_phil]

For power dissipation as well as safety reasons it's better to use several zeners in series. For example a string of four 12V zeners would give you a 48V drop, the power dissipation would be shared between them, which is better for long-term reliability, and if any single one blew, you only have a sudden increase of 12V on your tubes.

[Renegade]

Loverocker - No, it's not a BNP plate. I have a local shop that I use to have plates laser engraved.

I got out the DMM and figured up my power dissapation. I was dissapating 13.5 watts. ( A little high don't you think... ) I installed a 210 ohm cathode resistor and I'm dissapating 10.25 watts now. So I'm looking good, If I go with any larger cathode resistor I'll bust the 400v mark and don't want to do that. 85% dissapation is good for a hot/not overly hot bias.

Nah, I'm not going to fool with dropping the voltage. The Heath branded Mullards that were in the donor amp were running for many years at that voltage and still sound bad ass... I'll deal with it.